[{"Id":400806,"Creation Time":1632145414,"Link":"https://cmt.sym.place/knowledge/view/400806/pacific-final-events-pacific-symposium-and-kallak-workshop","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"PACIFIC Final Events: PACIFIC Symposium and Kallak Workshop","Field Brief description":"
The PACIFIC symposium and Kallak Workshop will take place on 27-28 October 2021 at the Killian Amphitheater of the Earth Science Institute (ISTerre). ISTerre is located on the campus of the University of Grenoble-Alpes (UGA) in Saint-Martin d’Hères/Gières, France.
\r\nIt is expected that participants will attend on site but please note that the PACIFIC final events can also be attended online. All participants are invited to register using the link to the dedicated registration platform (below, see URL section). The program and the logistic pack are also available from the registration platform.
\r\nDeadline to register: Monday 11th October 2021 at the latest
\r\n","Text Brief description":"The PACIFIC symposium and Kallak Workshop will take place on 27-28 October 2021 at the Killian Amphitheater of the Earth Science Institute (ISTerre). ISTerre is located on the campus of the University of Grenoble-Alpes (UGA) in Saint-Martin d\u2019H\u00e8res/Gi\u00e8res, France. It is expected that participants will attend on site but please note that the PACIFIC final events can also be attended online. All participants are invited to register using the link to the dedicated registration platform (below, see URL section). The program and the logistic pack are also available from the registration platform. Deadline to register: Monday 11th October 2021 at the latest","Field WP":["WP7 Clustering with other projects","WP8 Dissemination training innovation management and exploitation"],"Field Type of information":"Event","Field File":false,"Field URL":null,"Field Date":"2021-10-27","Field Precise the type":null},{"Id":390354,"Creation Time":1625485816,"Link":"https://cmt.sym.place/knowledge/view/390354/pacific-final-events-at-universite-grenoble-alpes-save-the-date","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"PACIFIC FINAL EVENTS AT UNIVERSITE GRENOBLE ALPES: SAVE THE DATE !","Field Brief description":"Funded by the European Commission and coordinated by the Universite Grenoble Alpes, PACIFIC is a research project in the field of mineral exploration. The project aims at developing new exploration techniques that respect the environment and incur relatively low costs. Join us in Grenoble on 27-28 October to find out how the PACIFIC consortium has been conducting fundamental and applied research to develop two radically new and complementary mineral exploration techniques, both based on passive seismic imagery.
\r\nThe detailed programme and registration platform will soon be available. Stay tuned !
\r\n","Text Brief description":"Funded by the European Commission and coordinated by the Universite Grenoble Alpes, PACIFIC is a research project in the field of mineral exploration. The project aims at developing new exploration techniques that respect the environment and incur relatively low costs. Join us in Grenoble on 27-28 October to find out how the PACIFIC consortium has been conducting fundamental and applied research to develop two radically new and complementary mineral exploration techniques, both based on passive seismic imagery. The detailed programme and registration platform will soon be available. Stay tuned !","Field WP":["WP1 Compiling background information","WP2 Development of codes","WP3 Pilot test of the passive reflection seismic technique at the GEN Marathon deposit","WP4 Pilot test of the multi-array and reflection techniques at the Kallak Fe deposit","WP5 Environmental and safety risk assessment","WP6 Social acceptance & perception of risk for mining activities","WP7 Clustering with other projects","WP8 Dissemination training innovation management and exploitation"],"Field Type of information":"Event","Field File":false,"Field URL":null,"Field Date":"2021-10-27","Field Precise the type":null},{"Id":385527,"Creation Time":1623154503,"Link":"https://cmt.sym.place/knowledge/view/385527/teodor-d-beard-c-pinzon-rincon-l-a-mordret-a-lavoue-f-beaupretre-s-boue-p-and-brenguier-f-high-frequency-ambient-noise-surface-wave-tomography-at-the-marathon-pge-cu-deposit-ontario-canada-egu-general-assembly-2021-online-19%E2%80%9330-apr-2021-egu21-13152-httpsdoiorg105194egusphere-egu21-13152","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"Teodor, D., Beard, C., Pinzon-Rincon, L. A., Mordret, A., Lavou\u00e9, F., Beaupretre, S., Bou\u00e9, P., and Brenguier, F.: High-frequency ambient noise surface wave tomography at the Marathon PGE-Cu deposit (Ontario, Canada), EGU General Assembly 2021, online, 19\u201330 Apr 2021, EGU21-13152, https://doi.org/10.5194/egusphere-egu21-13152","Field Brief description":"Ambient noise surface wave tomography (ANSWT) is an environmentally friendly and cost-effective technique for subsurface imaging. In this study, we used natural (low-frequency) and anthropogenic (high-frequency) noise sources to map the velocity structure of the Marathon Cu-PGE deposit (Ontario, Canada) to a depth of 1 km. The Marathon deposit is a circular (ø = 25 km) alkaline intrusion comprising gabbros at the rim and an overlying series of syenites in the centre. Cu-PGE mineralisation is hosted by gabbros close to the inward-dipping footwall of the intrusion. The country rocks are Archaean volcanic breccias that are seismically slower than the gabbros, and similar in velocity to the syenites. We used ANSWT to image the footwall contact that controls the location of the mineralisation.
\r\nAn array of 1024 vertical-component receivers were deployed for 30 days to record ambient noise required for surface wave analysis. Two overlapping grids were used: a 200 m x 6040 m dense array with node spacing of 50 m, and a 2500 m x 4000 m sparse array with node spacing of 150 m. The signal was down-sampled to 50 Hz, divided into segments of 30 minutes, cross-correlated and stacked. Surface wave analysis was conducted over the dense array and the sparse array data. We considered the fundamental mode of Rayleigh wave propagation for our frequency-wavenumber (F-K) analysis and focused on the phase velocity variation in the high-frequency ambient noise signal (up to 22 Hz). We reconstructed the shallow structure with progressively increased resolution using surface wave dispersion curves extracted from receiver arrays divided into segments of variable lengths. Several average dispersion curves were computed from individual dispersion curves belonging to different seismic lines. Each average dispersion curve was inverted to obtain S-wave velocity models using an McMC transdimensional Bayesian approach.
\r\nThe tomographic images reveal a shallow high-velocity anomaly, which we interpret as being related to the gabbro intrusion that hosts the mineralization. The large-wavelength structures in the S-wave velocity models are relatively consistent with the geological structures inferred from surface mapping and drill core data. These results show that the ANSWT, focused on the high-frequency signal provided by anthropogenic noise sources, is an efficient technique for imaging “shallow\" (1 km depth) geological structures in a mineral exploration context.
","Text Brief description":"Ambient noise surface wave tomography (ANSWT) is an environmentally friendly and cost-effective technique for subsurface imaging. In this study, we used natural (low-frequency) and anthropogenic (high-frequency) noise sources to map the velocity structure of the Marathon Cu-PGE deposit (Ontario, Canada) to a depth of 1 km. The Marathon deposit is a circular (\u00f8 = 25 km) alkaline intrusion comprising gabbros at the rim and an overlying series of syenites in the centre. Cu-PGE mineralisation is hosted by gabbros close to the inward-dipping footwall of the intrusion. The country rocks are Archaean volcanic breccias that are seismically slower than the gabbros, and similar in velocity to the syenites. We used ANSWT to image the footwall contact that controls the location of the mineralisation. An array of 1024 vertical-component receivers were deployed for 30 days to record ambient noise required for surface wave analysis. Two overlapping grids were used: a 200 m x 6040 m dense array with node spacing of 50 m, and a 2500 m x 4000 m sparse array with node spacing of 150 m. The signal was down-sampled to 50 Hz, divided into segments of 30 minutes, cross-correlated and stacked. Surface wave analysis was conducted over the dense array and the sparse array data. We considered the fundamental mode of Rayleigh wave propagation for our frequency-wavenumber (F-K) analysis and focused on the phase velocity variation in the high-frequency ambient noise signal (up to 22 Hz). We reconstructed the shallow structure with progressively increased resolution using surface wave dispersion curves extracted from receiver arrays divided into segments of variable lengths. Several average dispersion curves were computed from individual dispersion curves belonging to different seismic lines. Each average dispersion curve was inverted to obtain S-wave velocity models using an McMC transdimensional Bayesian approach. The tomographic images reveal a shallow high-velocity anomaly, which we interpret as being related to the gabbro intrusion that hosts the mineralization. The large-wavelength structures in the S-wave velocity models are relatively consistent with the geological structures inferred from surface mapping and drill core data. These results show that the ANSWT, focused on the high-frequency signal provided by anthropogenic noise sources, is an efficient technique for imaging \u201cshallow\" (1 km depth) geological structures in a mineral exploration context.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"","Field Date":null,"Field Precise the type":null},{"Id":379540,"Creation Time":1620369094,"Link":"https://cmt.sym.place/knowledge/view/379540/pacific-activities-presented-at-a-virtual-seminar-organised-by-geological-survey-of-canada-natural-resources-canada","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"PACIFIC activities presented at a virtual seminar organised by Geological Survey of Canada, Natural Resources Canada.","Field Brief description":"At the invitation of Dr. Andrew Schaeffer (Geological Survey of Canada, Natural Resources Canada), Dr. François Lavoué (UGA) presented the PACIFIC work on the use of seismic signals generated by trains for passive seismic imaging and monitoring on May 5th, 2021. The presentation provided an overview of the activities carried out within the framework of both the PACIFIC and FaultScan EU-funded projects.
\r\nThe presentation was attended by around 40 people. Technical questions revolved around the parameters controlling signal amplitude, and a more general debate took place on the merits of excluding signals generated by trains from \"classic\" ambient noise datasets, as is done for earthquakes.
\r\n","Text Brief description":"At the invitation of Dr. Andrew Schaeffer (Geological Survey of Canada, Natural Resources Canada), Dr. Fran\u00e7ois Lavou\u00e9 (UGA) presented the PACIFIC work on the use of seismic signals generated by trains for passive seismic imaging and monitoring on May 5th, 2021. The presentation provided an overview of the activities carried out within the framework of both the PACIFIC and FaultScan EU-funded projects. The presentation was attended by around 40 people. Technical questions revolved around the parameters controlling signal amplitude, and a more general debate took place on the merits of excluding signals generated by trains from \"classic\" ambient noise datasets, as is done for earthquakes.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Event","Field File":false,"Field URL":null,"Field Date":"2021-05-05","Field Precise the type":null},{"Id":363959,"Creation Time":1616145189,"Link":"https://cmt.sym.place/knowledge/view/363959/pacific-workplan-structure-and-interactions","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"PACIFIC workplan structure and interactions","Field Brief description":"\r\n
Click here to download the press release (Pdf format) announcing the online event co-organised by INFACT, PACIFIC and the NHM on December 3-4, 2020.
\r\n","Text Brief description":"Click here to download the press release (Pdf format) announcing the online event co-organised by INFACT, PACIFIC and the NHM on December 3-4, 2020.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Press release","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363947,"Creation Time":1616144402,"Link":"https://cmt.sym.place/knowledge/view/363947/m-chmiel-a-mordret-p-boue-f-brenguier-t-lecocq-r-courbis-d-hollis-x-campman-r-romijn-w-van-der-veen-ambient-noise-multimode-rayleigh-and-love-wave-tomography-to-determine-the-shear-velocity-structure-above-the-groningen-gas-field-geophysical-journal-international-volume-218-issue-3-september-2019-pages-1781%E2%80%931795","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"M. Chmiel, A. Mordret, P. Bou\u00e9, F. Brenguier, T. Lecocq, R. Courbis, D. Hollis, X. Campman, R. Romijn, W. Van der Veen, Ambient noise multimode Rayleigh and Love wave tomography to determine the shear velocity structure above the Groningen gas field, Geophysical Journal International, Volume 218, Issue 3, September 2019, Pages 1781\u20131795","Field Brief description":"Ambient noise multimode Rayleigh and Love wave tomography to determine the shear velocity structure above the Groningen gas field
\r\nThe Groningen gas field is one of the largest gas fields in Europe. The continuous gas extraction led to an induced seismic activity in the area. In order to monitor the seismic activity and study the gas field many permanent and temporary seismic arrays were deployed. In particular, the extraction of the shear wave velocity model is crucial in seismic hazard assessment. Local S-wave velocity-depth profiles allow us the estimation of a potential amplification due to soft sediments.
\r\nAmbient seismic noise tomography is an interesting alternative to traditional methods that were used in modelling the S-wave velocity. The ambient noise field consists mostly of surface waves, which are sensitive to the Swave and if inverted, they reveal the corresponding S-wave structures.
\r\nIn this study, we present results of a depth inversion of surface waves obtained from the cross-correlation of 1 month of ambient noise data from four flexible networks located in the Groningen area. Each block consisted of about 400 3-C stations. We compute group velocity maps of Rayleigh and Love waves using a straight-ray surface wave tomography. We also extract clear higher modes of Love and Rayleigh waves.
\r\nThe S-wave velocity model is obtained with a joint inversion of Love and Rayleigh waves using the Neighbourhood Algorithm. In order to improve the depth inversion, we use the mean phase velocity curves and the higher modes of Rayleigh and Love waves. Moreover, we use the depth of the base of the North Sea formation as a hard constraint. This information provides an additional constraint for depth inversion, which reduces the S-wave velocity uncertainties.
\r\nThe final S-wave velocity models reflect the geological structures up to 1 km depth and in perspective can be used in seismic risk modelling.
","Text Brief description":"Ambient noise multimode Rayleigh and Love wave tomography to determine the shear velocity structure above the Groningen gas field The Groningen gas field is one of the largest gas fields in Europe. The continuous gas extraction led to an induced seismic activity in the area. In order to monitor the seismic activity and study the gas field many permanent and temporary seismic arrays were deployed. In particular, the extraction of the shear wave velocity model is crucial in seismic hazard assessment. Local S-wave velocity-depth profiles allow us the estimation of a potential amplification due to soft sediments. Ambient seismic noise tomography is an interesting alternative to traditional methods that were used in modelling the S-wave velocity. The ambient noise field consists mostly of surface waves, which are sensitive to the Swave and if inverted, they reveal the corresponding S-wave structures. In this study, we present results of a depth inversion of surface waves obtained from the cross-correlation of 1 month of ambient noise data from four flexible networks located in the Groningen area. Each block consisted of about 400 3-C stations. We compute group velocity maps of Rayleigh and Love waves using a straight-ray surface wave tomography. We also extract clear higher modes of Love and Rayleigh waves. The S-wave velocity model is obtained with a joint inversion of Love and Rayleigh waves using the Neighbourhood Algorithm. In order to improve the depth inversion, we use the mean phase velocity curves and the higher modes of Rayleigh and Love waves. Moreover, we use the depth of the base of the North Sea formation as a hard constraint. This information provides an additional constraint for depth inversion, which reduces the S-wave velocity uncertainties. The final S-wave velocity models reflect the geological structures up to 1 km depth and in perspective can be used in seismic risk modelling.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1093/gji/ggz237","Field Date":null,"Field Precise the type":null},{"Id":363944,"Creation Time":1616144330,"Link":"https://cmt.sym.place/knowledge/view/363944/f-brenguier-p-boue-y-ben%E2%80%90zion-f-vernon-cw-johnson-a-mordret-et-al-2019-train-traffic-as-a-powerful-noise-source-for-monitoring-active-faults-with-seismic-interferometry-geophysical-research-letters-46-9529%E2%80%93-9536","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"F. Brenguier, P. Bou\u00e9, Y. Ben\u2010Zion, F. Vernon, C.W. Johnson, A. Mordret, et al. (2019). Train traffic as a powerful noise source for monitoring active faults with seismic interferometry. Geophysical Research Letters, 46, 9529\u2013 9536.","Field Brief description":"Train traffic as a powerful noise source for monitoring active faults with seismic interferometry.
\r\nLaboratory experiments report that detectable seismic velocity changes should occur in the vicinity of fault zones prior to earthquakes. However, operating permanent active seismic sources to monitor natural faults at seismogenic depth is found to be nearly impossible to achieve. We show that seismic noise generated by vehicle traffic, and especially heavy freight trains, can be turned into a powerful repetitive seismic source to continuously probe the Earth's crust at a few kilometers depth. Results of an exploratory seismic experiment in Southern California demonstrate that correlations of train\u2010generated seismic signals allow daily reconstruction of direct P body waves probing the San Jacinto Fault down to 4\u2010km depth. This new approach may facilitate monitoring most of the San Andreas Fault system using the railway and highway network of California.
","Text Brief description":"Train traffic as a powerful noise source for monitoring active faults with seismic interferometry. Laboratory experiments report that detectable seismic velocity changes should occur in the vicinity of fault zones prior to earthquakes. However, operating permanent active seismic sources to monitor natural faults at seismogenic depth is found to be nearly impossible to achieve. We show that seismic noise generated by vehicle traffic, and especially heavy freight trains, can be turned into a powerful repetitive seismic source to continuously probe the Earth's crust at a few kilometers depth. Results of an exploratory seismic experiment in Southern California demonstrate that correlations of train\u2010generated seismic signals allow daily reconstruction of direct P body waves probing the San Jacinto Fault down to 4\u2010km depth. This new approach may facilitate monitoring most of the San Andreas Fault system using the railway and highway network of California.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1029/2019GL083438","Field Date":null,"Field Precise the type":null},{"Id":363941,"Creation Time":1616144214,"Link":"https://cmt.sym.place/knowledge/view/363941/florent-brenguier-aurelien-mordret-richard-lynch-romeo-courbis-xander-campbell-pierre-boue-malgorzata-chmiel-shujuan-mao-shujuan-mao-tomoya-takano-thomas-lecocq-wim-van-der-veen-sophie-postif-and-dan-hollis-monitoring-of-fields-using-body-and-surface-waves-reconstructed-from-passive-seismic-ambient-noise-seg-technical-program-expanded-abstracts-2019-august-2019-3036-3040","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"Florent Brenguier, Aur\u00e9lien Mordret, Richard Lynch, Rom\u00e9o Courbis, Xander Campbell, Pierre Bou\u00e9, Ma\u0142gorzata Chmiel, Shujuan Mao, Shujuan Mao, Tomoya Takano, Thomas Lecocq, Wim van der Veen, Sophie Postif, and Dan Hollis; Monitoring of fields using body and surface waves reconstructed from passive seismic ambient noise. SEG Technical Program Expanded Abstracts 2019. August 2019, 3036-3040","Field Brief description":"Monitoring of fields using body and surface waves reconstructed from passive seismic ambient noise
\r\nThere are important economic, environmental and societal reasons for monitoring production from oil, gas and geothermal fields. Unfortunately, standard microseismic monitoring is often not useful due to low levels of microseismicity. We propose to use body and surface waves reconstructed from ambient seismic noise for such monitoring. In this work, we use seismic data recorded from a dense sensor array at the Groningen gas field in northern Holland and show how direct P-waves can be extracted from the ambient noise cross correlations and then used to monitor seismic velocity variations over time. This approach has advantages over the use of coda wave interferometry due to the ability to localise such changes in the subsurface. We show how both direct and refracted (head) P-waves as well as Rayleigh surface waves can be used for such field monitoring, with changes of ∼1% being resolved. Both fundamental and first overtone Rayleigh waves are used to localise such changes, which correspond nicely to known geology to within 100 m.
","Text Brief description":"Monitoring of fields using body and surface waves reconstructed from passive seismic ambient noise There are important economic, environmental and societal reasons for monitoring production from oil, gas and geothermal fields. Unfortunately, standard microseismic monitoring is often not useful due to low levels of microseismicity. We propose to use body and surface waves reconstructed from ambient seismic noise for such monitoring. In this work, we use seismic data recorded from a dense sensor array at the Groningen gas field in northern Holland and show how direct P-waves can be extracted from the ambient noise cross correlations and then used to monitor seismic velocity variations over time. This approach has advantages over the use of coda wave interferometry due to the ability to localise such changes in the subsurface. We show how both direct and refracted (head) P-waves as well as Rayleigh surface waves can be used for such field monitoring, with changes of \u223c1% being resolved. Both fundamental and first overtone Rayleigh waves are used to localise such changes, which correspond nicely to known geology to within 100 m.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1190/segam2019-3216217.1","Field Date":null,"Field Precise the type":null},{"Id":363938,"Creation Time":1616144032,"Link":"https://cmt.sym.place/knowledge/view/363938/tomoya-takano-florent-brenguier-michel-campillo-aline-peltier-takeshi-nishimura-noise-based-passive-ballistic-wave-seismic-monitoring-on-an-active-volcano-geophysical-journal-international-volume-220-issue-1-january-2020-pages-501%E2%80%93507","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"Tomoya Takano, Florent Brenguier, Michel Campillo, Aline Peltier, Takeshi Nishimura, Noise-based passive ballistic wave seismic monitoring on an active volcano, Geophysical Journal International, Volume 220, Issue 1, January 2020, Pages 501\u2013507","Field Brief description":"Noise-based passive ballistic wave seismic monitoring on an active volcano
\r\nMonitoring temporal changes of volcanic interiors is important to understand magma, fluid pressurization and transport leading to eruptions. Noise-based passive seismic monitoring using coda wave interferometry is a powerful tool to detect and monitor very slight changes in the mechanical properties of volcanic edifices. However, the complexity of coda waves limits our ability to properly image localized changes in seismic properties within volcanic edifices. In this work, we apply a novel passive ballistic wave seismic monitoring approach to examine the active Piton de la Fournaise volcano (La Réunion island). Using noise correlations between two distant dense seismic arrays, we find a 2.4 per cent velocity increase and −0.6 per cent velocity decrease of Rayleigh waves at frequency bands of 0.5–1 and 1–3 Hz, respectively. We also observe a −2.2 per cent velocity decrease of refracted P waves at 550 m depth at the 6–12 Hz band. We interpret the polarity differences of seismic velocity changes at different frequency bands and for different wave types as being due to strain change complexity at depth associated with subtle pressurization of the shallow magma reservoir. Our results show that velocity changes measured using ballistic waves provide complementary information to interpret temporal changes of the seismic properties within volcanic edifices.
","Text Brief description":"Noise-based passive ballistic wave seismic monitoring on an active volcano Monitoring temporal changes of volcanic interiors is important to understand magma, fluid pressurization and transport leading to eruptions. Noise-based passive seismic monitoring using coda wave interferometry is a powerful tool to detect and monitor very slight changes in the mechanical properties of volcanic edifices. However, the complexity of coda waves limits our ability to properly image localized changes in seismic properties within volcanic edifices. In this work, we apply a novel passive ballistic wave seismic monitoring approach to examine the active Piton de la Fournaise volcano (La R\u00e9union island). Using noise correlations between two distant dense seismic arrays, we find a 2.4 per cent velocity increase and \u22120.6 per cent velocity decrease of Rayleigh waves at frequency bands of 0.5\u20131 and 1\u20133\u2009Hz, respectively. We also observe a \u22122.2 per cent velocity decrease of refracted P waves at 550\u2009m depth at the 6\u201312\u2009Hz band. We interpret the polarity differences of seismic velocity changes at different frequency bands and for different wave types as being due to strain change complexity at depth associated with subtle pressurization of the shallow magma reservoir. Our results show that velocity changes measured using ballistic waves provide complementary information to interpret temporal changes of the seismic properties within volcanic edifices.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1093/gji/ggz466","Field Date":null,"Field Precise the type":null},{"Id":363935,"Creation Time":1616143966,"Link":"https://cmt.sym.place/knowledge/view/363935/f-brenguier-r-courbis-a-mordret-x-campman-p-boue-m-chmiel-t-takano-t-lecocq-w-van-der-veen-s-postif-d-hollis-noise-based-ballistic-wave-passive-seismic-monitoring-part-1-body-waves-geophysical-journal-international-volume-221-issue-1-april-2020-pages-683%E2%80%93691","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"F. Brenguier, R. Courbis, A. Mordret, X. Campman, P. Bou\u00e9, M. Chmiel, T. Takano, T. Lecocq, W. Van der Veen, S. Postif, D. Hollis, Noise-based ballistic wave passive seismic monitoring. Part 1: body waves, Geophysical Journal International, Volume 221, Issue 1, April 2020, Pages 683\u2013691","Field Brief description":"Noise-based ballistic wave passive seismic monitoring. Part 1: body waves
\r\nUnveiling the mechanisms of earthquake and volcanic eruption preparation requires improving our ability to monitor the rock mass response to transient stress perturbations at depth. The standard passive monitoring seismic interferometry technique based on coda waves is robust but recovering accurate and properly localized P- and S-wave velocity temporal anomalies at depth is intrinsically limited by the complexity of scattered, diffracted waves. In order to mitigate this limitation, we propose a complementary, novel, passive seismic monitoring approach based on detecting weak temporal changes of velocities of ballistic waves recovered from seismic noise correlations. This new technique requires dense arrays of seismic sensors in order to circumvent the bias linked to the intrinsic high sensitivity of ballistic waves recovered from noise correlations to changes in the noise source properties. In this work we use a dense network of 417 seismometers in the Groningen area of the Netherlands, one of Europe's largest gas fields. Over the course of 1 month our results show a 1.5 per cent apparent velocity increase of the P wave refracted at the basement of the 700-m-thick sedimentary cover. We interpret this unexpected high value of velocity increase for the refracted wave as being induced by a loading effect associated with rainfall activity and possibly canal drainage at surface. We also observe a 0.25 per cent velocity decrease for the direct P-wave travelling in the near-surface sediments and conclude that it might be partially biased by changes in time in the noise source properties even though it appears to be consistent with complementary results based on ballistic surface waves presented in a companion paper and interpreted as a pore pressure diffusion effect following a strong rainfall episode. The perspective of applying this new technique to detect continuous localized variations of seismic velocity perturbations at a few kilometres depth paves the way for improved in situ earthquake, volcano and producing reservoir monitoring.
","Text Brief description":"Noise-based ballistic wave passive seismic monitoring. Part 1: body waves Unveiling the mechanisms of earthquake and volcanic eruption preparation requires improving our ability to monitor the rock mass response to transient stress perturbations at depth. The standard passive monitoring seismic interferometry technique based on coda waves is robust but recovering accurate and properly localized P- and S-wave velocity temporal anomalies at depth is intrinsically limited by the complexity of scattered, diffracted waves. In order to mitigate this limitation, we propose a complementary, novel, passive seismic monitoring approach based on detecting weak temporal changes of velocities of ballistic waves recovered from seismic noise correlations. This new technique requires dense arrays of seismic sensors in order to circumvent the bias linked to the intrinsic high sensitivity of ballistic waves recovered from noise correlations to changes in the noise source properties. In this work we use a dense network of 417 seismometers in the Groningen area of the Netherlands, one of Europe's largest gas fields. Over the course of 1 month our results show a 1.5 per cent apparent velocity increase of the P wave refracted at the basement of the 700-m-thick sedimentary cover. We interpret this unexpected high value of velocity increase for the refracted wave as being induced by a loading effect associated with rainfall activity and possibly canal drainage at surface. We also observe a 0.25 per cent velocity decrease for the direct P-wave travelling in the near-surface sediments and conclude that it might be partially biased by changes in time in the noise source properties even though it appears to be consistent with complementary results based on ballistic surface waves presented in a companion paper and interpreted as a pore pressure diffusion effect following a strong rainfall episode. The perspective of applying this new technique to detect continuous localized variations of seismic velocity perturbations at a few kilometres depth paves the way for improved in situ earthquake, volcano and producing reservoir monitoring.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1093/gji/ggz440","Field Date":null,"Field Precise the type":null},{"Id":363932,"Creation Time":1616143891,"Link":"https://cmt.sym.place/knowledge/view/363932/aurelien-mordret-romeo-courbis-florent-brenguier-malgorzata-chmiel-stephane-garambois-shujuan-mao-pierre-boue-xander-campman-thomas-lecocq-wim-van-der-veen-dan-hollis-noise-based-ballistic-wave-passive-seismic-monitoring-%E2%80%93-part-2-surface-waves-geophysical-journal-international-volume-221-issue-1-april-2020-pages-692%E2%80%93705","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"Aur\u00e9lien Mordret, Rom\u00e9o Courbis, Florent Brenguier, Ma\u0142gorzata Chmiel, St\u00e9phane Garambois, Shujuan Mao, Pierre Bou\u00e9, Xander Campman, Thomas Lecocq, Wim Van der Veen, Dan Hollis, Noise-based ballistic wave passive seismic monitoring \u2013 Part 2: surface waves, Geophysical Journal International, Volume 221, Issue 1, April 2020, Pages 692\u2013705","Field Brief description":"Noise-based ballistic wave passive seismic monitoring – Part 2: surface waves
\r\nWe develop a new method to monitor and locate seismic velocity changes in the subsurface using seismic noise interferometry. Contrary to most ambient noise monitoring techniques, we use the ballistic Rayleigh waves computed from 30 d records on a dense nodal array located above the Groningen gas field (the Netherlands), instead of their coda waves. We infer the daily relative phase velocity dispersion changes as a function of frequency and propagation distance with a cross-wavelet transform processing. Assuming a 1-D velocity change within the medium, the induced ballistic Rayleigh wave phase shift exhibits a linear trend as a function of the propagation distance. Measuring this trend for the fundamental mode and the first overtone of the Rayleigh waves for frequencies between 0.5 and 1.1 Hz enables us to invert for shear wave daily velocity changes in the first 1.5 km of the subsurface. The observed deep velocity changes (±1.5 per cent) are difficult to interpret given the environmental factors information available. Most of the observed shallow changes seem associated with effective pressure variations. We observe a reduction of shear wave velocity (–0.2 per cent) at the time of a large rain event accompanied by a strong decrease in atmospheric pressure loading, followed by a migration at depth of the velocity decrease. Combined with P-wave velocity changes observations from a companion paper, we interpret the changes as caused by the diffusion of effective pressure variations at depth. As a new method, noise-based ballistic wave passive monitoring could be used on several dynamic (hydro-)geological targets and in particular, it could be used to estimate hydrological parameters such as the hydraulic conductivity and diffusivity.
","Text Brief description":"Noise-based ballistic wave passive seismic monitoring \u2013 Part 2: surface waves We develop a new method to monitor and locate seismic velocity changes in the subsurface using seismic noise interferometry. Contrary to most ambient noise monitoring techniques, we use the ballistic Rayleigh waves computed from 30 d records on a dense nodal array located above the Groningen gas field (the Netherlands), instead of their coda waves. We infer the daily relative phase velocity dispersion changes as a function of frequency and propagation distance with a cross-wavelet transform processing. Assuming a 1-D velocity change within the medium, the induced ballistic Rayleigh wave phase shift exhibits a linear trend as a function of the propagation distance. Measuring this trend for the fundamental mode and the first overtone of the Rayleigh waves for frequencies between 0.5 and 1.1 Hz enables us to invert for shear wave daily velocity changes in the first 1.5 km of the subsurface. The observed deep velocity changes (\u00b11.5 per cent) are difficult to interpret given the environmental factors information available. Most of the observed shallow changes seem associated with effective pressure variations. We observe a reduction of shear wave velocity (\u20130.2 per cent) at the time of a large rain event accompanied by a strong decrease in atmospheric pressure loading, followed by a migration at depth of the velocity decrease. Combined with P-wave velocity changes observations from a companion paper, we interpret the changes as caused by the diffusion of effective pressure variations at depth. As a new method, noise-based ballistic wave passive monitoring could be used on several dynamic (hydro-)geological targets and in particular, it could be used to estimate hydrological parameters such as the hydraulic conductivity and diffusivity.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1093/gji/ggaa016","Field Date":null,"Field Precise the type":null},{"Id":363788,"Creation Time":1616143770,"Link":"https://cmt.sym.place/knowledge/view/363788/philippe-dales-laura-pinzon%E2%80%90ricon-florent-brenguier-pierre-boue-nick-arndt-john-mcbride-francois-lavoue-christopher-j-bean-sophie-beaupretre-rosemary-fayjaloun-gerrit-olivier-virtual-sources-of-body-waves-from-noise-correlations-in-a-mineral-exploration-context-seismological-research-letters-2020-91-4-2278%E2%80%932286","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"Philippe Dales, Laura Pinzon\u2010Ricon, Florent Brenguier, Pierre Bou\u00e9, Nick Arndt, John McBride, Fran\u00e7ois Lavou\u00e9, Christopher J. Bean, Sophie Beaupretre, Rosemary Fayjaloun, Gerrit Olivier; Virtual Sources of Body Waves from Noise Correlations in a Mineral Exploration Context. Seismological Research Letters 2020; 91 (4): 2278\u20132286.","Field Brief description":"Virtual Sources of Body Waves from Noise Correlations in a Mineral Exploration Context.
\r\nThe extraction of body waves from passive seismic recordings has great potential for monitoring and imaging applications. The low environmental impact, low cost, and high accessibility of passive techniques makes them especially attractive as replacement or complementary techniques to active\u2010source exploration. There still, however, remain many challenges with body\u2010wave extraction, mainly the strong dependence on local seismic sources necessary to create high\u2010frequency body\u2010wave energy. Here, we present the Marathon dataset collected in September 2018, which consists of 30 days of continuous recordings from a dense surface array of 1020 single vertical\u2010component geophones deployed over a mineral exploration block. First, we use a cross\u2010correlation beamforming technique to evaluate the wavefield each minute and discover that the local highway and railroad traffic are the primary sources of high\u2010frequency body\u2010wave energy. Next, we demonstrate how selective stacking of cross\u2010correlation functions during periods where vehicles and trains are passing near the array reveals strong body\u2010wave arrivals. Based on source station geometry and the estimated geologic structure, we interpret these arrivals as virtual refractions due to their high velocity and linear moveout. Finally, we demonstrate how the apparent velocity of these arrivals along the array contains information about the local geologic structure, mainly the major dipping layer. Although vehicle sources illuminating array in a narrow azimuth may not seem ideal for passive reflection imaging, we expect this case will be commonly encountered and should serve as a good dataset for the development of new techniques in this domain.
","Text Brief description":"Virtual Sources of Body Waves from Noise Correlations in a Mineral Exploration Context. The extraction of body waves from passive seismic recordings has great potential for monitoring and imaging applications. The low environmental impact, low cost, and high accessibility of passive techniques makes them especially attractive as replacement or complementary techniques to active\u2010source exploration. There still, however, remain many challenges with body\u2010wave extraction, mainly the strong dependence on local seismic sources necessary to create high\u2010frequency body\u2010wave energy. Here, we present the Marathon dataset collected in September 2018, which consists of 30 days of continuous recordings from a dense surface array of 1020 single vertical\u2010component geophones deployed over a mineral exploration block. First, we use a cross\u2010correlation beamforming technique to evaluate the wavefield each minute and discover that the local highway and railroad traffic are the primary sources of high\u2010frequency body\u2010wave energy. Next, we demonstrate how selective stacking of cross\u2010correlation functions during periods where vehicles and trains are passing near the array reveals strong body\u2010wave arrivals. Based on source station geometry and the estimated geologic structure, we interpret these arrivals as virtual refractions due to their high velocity and linear moveout. Finally, we demonstrate how the apparent velocity of these arrivals along the array contains information about the local geologic structure, mainly the major dipping layer. Although vehicle sources illuminating array in a narrow azimuth may not seem ideal for passive reflection imaging, we expect this case will be commonly encountered and should serve as a good dataset for the development of new techniques in this domain.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1785/0220200023","Field Date":null,"Field Precise the type":null},{"Id":363699,"Creation Time":1616142955,"Link":"https://cmt.sym.place/knowledge/view/363699/the-environmental-impact-of-pacific-report-1","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"The environmental impact of PACIFIC: Report 1","Field Brief description":"PACIFIC develops mineral exploration techniques that have a relatively low impact on the environment. This document is an assessment of this impact, but also of the environmental footprint of all activities related to the project. PACIFIC environmental footprint is still significant because of plane travels linked to transnational meetings. Learn more about it by reading the following document.
\r\n\r\nTechnique now possible due to improvements in lithium batteries which power monitoring equipment
\r\nArticle in the Canadian press by Jeff Walters · CBC News · Posted: Jun 12, 2019 1:28 PM ET https://www.cbc.ca/news/canada/thunder-bay/thunder-bay-pacific-new-exploration-1.5172168
","Text Brief description":"Technique now possible due to improvements in lithium batteries which power monitoring equipment Article in the Canadian press by Jeff Walters \u00b7 CBC News \u00b7 Posted: Jun 12, 2019 1:28 PM ET https://www.cbc.ca/news/canada/thunder-bay/thunder-bay-pacific-new-exploration-1.5172168","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Press release","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363693,"Creation Time":1616142227,"Link":"https://cmt.sym.place/knowledge/view/363693/pacific-poster","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"PACIFIC poster","Field Brief description":"Download PACIFIC poster presented at the American Geophysical Union (AGU) in Washington DC (10-14 December 2018)
\r\nhttps://www.pacific-h2020.eu/wp-content/uploads/PACIFIC-poster.pdf
\r\nAll you want to know about the PACIFIC project (Passive seismic techniques for environmentally friendly and cost efficient mineral exploration) is there !
\r\nPACIFIC - H2020 research project in mineral exploration (pacific-h2020.eu)
\r\nSometimes noise is incredibly helpful.
\r\nBy Rahul Rao, Popular Science (January 28, 2021)
\r\nFor the full article, please visit How trains can help scientists study what's underground | Popular Science (popsci.com)
","Text Brief description":"Sometimes noise is incredibly helpful. By Rahul Rao, Popular Science (January 28, 2021) For the full article, please visit How trains can help scientists study what's underground | Popular Science (popsci.com)","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Press release","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363640,"Creation Time":1616078771,"Link":"https://cmt.sym.place/knowledge/view/363640/2021-01-12-railways-could-double-as-a-tool-for-probing-earth%E2%80%99s-shallow-crust","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"2021-01-12 Railways could double as a tool for probing Earth\u2019s shallow crust","Field Brief description":"Seismologists prospect for mineral deposits in Canada by recording the humming vibrations from freight trains.
\r\nBy Rachel Berkowitz, Physics Today (12 Jan 2021 in Research & Technology)
\r\nFor the full online article, visit Railways could double as a tool for probing Earth’s shallow crust (scitation.org)
\r\nCheck out our project log on Research Gate: https://www.researchgate.net/project/PACIFIC-H2020
\r\nView the PACIFIC project video PACIFIC Project on sustainable mineral exploration - YouTube
\r\nDownload the PACIFIC project presentation https://www.pacific-h2020.eu/wp-content/uploads/PACIFIC-Project-presentation.pdf
\r\nDownload PACIFIC first press release (July 2018): PACIFIC first press release
","Text Brief description":"Download PACIFIC first press release (July 2018): PACIFIC first press release","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Press release","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363625,"Creation Time":1616077335,"Link":"https://cmt.sym.place/knowledge/view/363625/d85-pacific-winter-school","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D8.5: PACIFIC winter school","Field Brief description":"Executive summary: The Winter School on Sustainable Mineral Exploration was jointly organized by two European projects—PACIFIC and INFACT. The event was held at the International Campus of Andalusia in Huelva, Spain, between the 9th and 12th March 2020. The Winter School was divided in 3 lecture sessions, 1 practical session, and 2 visits to mining sites. The main goal of this school was to present the techniques and knowledge on sustainable mineral exploration that have been developed within the INFACT and PACIFIC projects. The school targeted an audience of European master students, PhDs and post-doctoral researchers. A total of 40 students, including 15 from the University of Huelva, physically attended the school. An additional 13 students participated in parts of the school via video conference, since unfortunately due to travel restrictions stemming from the COVID-19 pandemic those 13 students were unable to attend in person. Videoconferencing was a last-minute adaptation made by the Winter School to allow for the participation of individuals under travel bans, quarantine, or other restrictions. Students (both physical and remote attendees) came from 13 countries. The results of the anonymous survey conducted at the end of the school reveal that the event was a success, despite the ongoing COVID-19 crisis.
","Text Brief description":"Executive summary: The Winter School on Sustainable Mineral Exploration was jointly organized by two European projects\u2014PACIFIC and INFACT. The event was held at the International Campus of Andalusia in Huelva, Spain, between the 9th and 12th March 2020. The Winter School was divided in 3 lecture sessions, 1 practical session, and 2 visits to mining sites. The main goal of this school was to present the techniques and knowledge on sustainable mineral exploration that have been developed within the INFACT and PACIFIC projects. The school targeted an audience of European master students, PhDs and post-doctoral researchers. A total of 40 students, including 15 from the University of Huelva, physically attended the school. An additional 13 students participated in parts of the school via video conference, since unfortunately due to travel restrictions stemming from the COVID-19 pandemic those 13 students were unable to attend in person. Videoconferencing was a last-minute adaptation made by the Winter School to allow for the participation of individuals under travel bans, quarantine, or other restrictions. Students (both physical and remote attendees) came from 13 countries. The results of the anonymous survey conducted at the end of the school reveal that the event was a success, despite the ongoing COVID-19 crisis.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363622,"Creation Time":1616077206,"Link":"https://cmt.sym.place/knowledge/view/363622/d84-project-flyer","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D8.4: Project flyer","Field Brief description":"Executive summary: This report presents two versions of the flyer produced in the framework of the PACIFIC project. Both documents are included as annexes to this deliverable and can be downloaded on PACIFIC public website: https://www.pacific-h2020.eu/media/
\r\nThe project flyer is a means to introduce PACIFIC to the public and more specifically to stakeholders in the project research domain. The initial version of the PACIFIC flyer produced at the start of the project (see section 2 - first item) sums up the project objectives, background and expected results. It also includes the list of partners
involved, as well as contact details for the project. This version was printed and distributed at partners' premises and during the PACIFIC internal and external events organised in the first two years of the project.
A digital update of the PACIFIC flyer has been prepared at the beginning of the third year (see section 2 \u0374second item) to provide further information on the challenges addressed by the PACIFIC research activities, the expected results and their expected impact on mineral exploration. The list of project partners, the logo section and the coordination team section have also been updated as required.
Executive summary: This document describes the structure and contents of the public website set up for PACIFIC on 29th November 2018 with the URL http://www.pacific-h2020.eu and updated in August 2020 to give more visibility to the expected impact of the project on mineral exploration in Europe, and reflect changes in the consortium. The website is based on Responsive web design (RWD), which provides an optimal viewing and interaction experience — easy reading and navigation with a minimum of resizing, panning, and scrolling — across a wide range of devices (from desktop computer monitors to mobile phones).
\r\n
On the PACIFIC public website, you can find information about the project objectives and results, the concept, work plan and expected impact, together with the list of participants, external advisors and projects identified for clustering opportunities. The website also acknowledges the financial support received under the European Union’s Horizon 2020 research and innovation programme with the EU emblem as well as a specific statement. This is visible at the bottom of every webpage.
Throughout the project the PACIFIC public website will become a major tool to present the project research outcomes to a wide audience with: links to scientific peer-reviewed publications, project documentation, public deliverables and press releases available for download. On-going activities will also be regularly updated and communicated through news and events.
Executive summary: The passive seismic survey of the Kaiserstuhl test site was initiated during discussion between partners of the PACIFIC and HiTech AlkCarb H2020 projects in February 2019. The final survey design is similar to an already existing geophysical profile crossing the Kaiserstuhl volcanic edifice surveyed by electrical techniques. A total of 66 3-component nodes were deployed along of the profile, and at the center, above a fault, a few additional nodes were deployed away from the profile to be used for earthquake detection and localization.
\r\n
The nodes recorded during 25 days in October-November 2019. The raw data was of good quality with stable ambient noise records over the whole duration of acquisition. Cross-correlation showed Rayleigh and Love propagation with weak dispersion, testifying to a homogeneous medium in terms of seismic velocities. However individual correlations showed low signal to noise ratio.
We processed the correlations using a classical method of surface wave tomography, and we jointly inverted Rayleigh and Love wave dispersion curves in order to obtain a 3D S-wave velocity model.
The final Vs model showed three layers parallel to the surface with strong velocity contrasts. This is unexpected in such geological context and could be an edge effect of the inversion near the bottom of the model. Once removed, the Vs Anomaly model shows a homogeneous medium with only weak velocity changes (<5%). A positive anomaly dominates the model and coincides well with the location, size, and shape of the carbonatite pipe found in the existing geological and geophysical models.
Executive Summary: The passive seismic survey of the La Cruces mine site was initiated during discussion between partners of the PACIFIC and INFACT H2020 projects in December 2018. The initial design for the deployment covered a large area, about 7 x 4 km extending to the north and south of the mine but this was reduced to a smaller tighter 2 x 1 km array in February 2019. A collapse of the northside of the open pit then eliminated the possibility of placing nodes to the west of the pit and this resulted in an even smaller array. Data treatment proved to be very difficult for several reasons. The array was smaller than originally planned, but more importantly a significant proportion of the nodes, about 30%, were placed in the pit. The large differences in elevation between adjacent nodes and the differences in orientation of pit walls and terraces introduced unanticipated difficulties in processing the seismic data.
\r\nWe used 33 days of passive seismic records to retrieve the fundamental mode of Rayleigh waves propagating in the subsurface. We mostly used man-made ambient noise generated in the vicinity of the mine in the period band [0.3 - 1.5] s. Strong anthropogenic noise in the middle of the array forced us to use one-bit normalization and very intense pre-processing to retrieve usable cross-correlation signals. We were able to pick individual group and phase velocity dispersion curves from correlations computed between the majority of sensor pairs for stations separated by less than 2 km. We retained about 15% of all possible dispersion curves after a thorough quality check based on expert visual inspection. The aperture of the array and the frequency content of the noise allowed us to invert a velocity model down to 500 m depth. Long offsets are mainly discarded inducing a poor coverage of the central part of the pit. A high velocity anomaly beneath the northern part of the site where topography is not a problem and where the array is denser can be resolved and could correspond to the massive sulphide ore body at depth. The depth of cover in the north-eastern part of the study area is well represented by the iso-velocity surface of 750 m/s.
","Text Brief description":"Executive Summary: The passive seismic survey of the La Cruces mine site was initiated during discussion between partners of the PACIFIC and INFACT H2020 projects in December 2018. The initial design for the deployment covered a large area, about 7 x 4 km extending to the north and south of the mine but this was reduced to a smaller tighter 2 x 1 km array in February 2019. A collapse of the northside of the open pit then eliminated the possibility of placing nodes to the west of the pit and this resulted in an even smaller array. Data treatment proved to be very difficult for several reasons. The array was smaller than originally planned, but more importantly a significant proportion of the nodes, about 30%, were placed in the pit. The large differences in elevation between adjacent nodes and the differences in orientation of pit walls and terraces introduced unanticipated difficulties in processing the seismic data. We used 33 days of passive seismic records to retrieve the fundamental mode of Rayleigh waves propagating in the subsurface. We mostly used man-made ambient noise generated in the vicinity of the mine in the period band [0.3 - 1.5] s. Strong anthropogenic noise in the middle of the array forced us to use one-bit normalization and very intense pre-processing to retrieve usable cross-correlation signals. We were able to pick individual group and phase velocity dispersion curves from correlations computed between the majority of sensor pairs for stations separated by less than 2 km. We retained about 15% of all possible dispersion curves after a thorough quality check based on expert visual inspection. The aperture of the array and the frequency content of the noise allowed us to invert a velocity model down to 500 m depth. Long offsets are mainly discarded inducing a poor coverage of the central part of the pit. A high velocity anomaly beneath the northern part of the site where topography is not a problem and where the array is denser can be resolved and could correspond to the massive sulphide ore body at depth. The depth of cover in the north-eastern part of the study area is well represented by the iso-velocity surface of 750 m/s.","Field WP":"WP7 Clustering with other projects","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363597,"Creation Time":1616076667,"Link":"https://cmt.sym.place/knowledge/view/363597/d73-report-on-joint-events-with-other-research-projects-in-the-second-year","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D7.3: Report on joint events with other research projects in the second year","Field Brief description":"Executive summary: This report describes events that took place in collaboration with other research projects during the second year of the PACIFIC project, from June 2019 to June 2020. Clustering activities are central to Work Package 7 “Collaboration and clustering with other research initiatives”. To that end, the PACIFIC project has initiated and completed a number of activities with multiple research initiatives. In the second year of the project, clustering activities significantly accelerated, and the earlier links made with other European projects started to yield concrete results and concrete plans for further activities. This report is an update to D7.2 (M12)—Report on joint events with other research projects in the first year.
\r\nDuring this year PACIFIC has established a very strong collaboration with the H2020 project INFACT and this is reflected throughout this report.
","Text Brief description":"Executive summary: This report describes events that took place in collaboration with other research projects during the second year of the PACIFIC project, from June 2019 to June 2020. Clustering activities are central to Work Package 7 \u201cCollaboration and clustering with other research initiatives\u201d. To that end, the PACIFIC project has initiated and completed a number of activities with multiple research initiatives. In the second year of the project, clustering activities significantly accelerated, and the earlier links made with other European projects started to yield concrete results and concrete plans for further activities. This report is an update to D7.2 (M12)\u2014Report on joint events with other research projects in the first year. During this year PACIFIC has established a very strong collaboration with the H2020 project INFACT and this is reflected throughout this report.","Field WP":"WP7 Clustering with other projects","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363594,"Creation Time":1616076577,"Link":"https://cmt.sym.place/knowledge/view/363594/d72-report-on-joint-events-with-other-research-projects-in-the-first-year","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D7.2: Report on joint events with other research projects in the first year","Field Brief description":"Executive summary: To create synergies and optimise project results and impact, the PACIFIC project dedicates the Work Package 7 to collaboration and clustering with other research projects under the same call topic, and other relevant projects in the field funded by Horizon 2020 (H2020). PACIFIC partners thus collaborate with ongoing research initiatives in the mineral exploration area.
\r\n
During the first year of the project, the collaboration took several forms, that are developed in this deliverable according to the following axes:
This report must be understood as the first of three reports on joint events with other research projects, that will be produced through the duration of the project: D7.2 (M12), D7.3 (M24) and D7.4 (M36). Thus, the information provided, especially in the “Ongoing and future collaborations” section, will be reviewed or updated in next reports.
Executive summary: One of the PACIFIC’s goals is to support the European Innovation Partnership (EIP) on Raw Materials with its aim to translate its mission into concrete actions. To do so, PACIFIC will collaborate closely with the existing, recently finished or future H2020 projects funded under the same or similar topics.
This document includes a concrete plan for clustering with these projects, aiming to facilitate planning of joint online and physical events, sharing results and exchanging on the difficulties encountered.
The clustering plan is divided in three main sections:
\r\nThis clustering plan will be considered as a living document to be reviewed in each General Assembly meeting to monitor the progress made in its implementation and allow for regular updates to take into account the evolving European context and prioritisation.
","Text Brief description":"Executive summary: One of the PACIFIC\u2019s goals is to support the European Innovation Partnership (EIP) on Raw Materials with its aim to translate its mission into concrete actions. To do so, PACIFIC will collaborate closely with the existing, recently finished or future H2020 projects funded under the same or similar topics. This document includes a concrete plan for clustering with these projects, aiming to facilitate planning of joint online and physical events, sharing results and exchanging on the difficulties encountered. The clustering plan is divided in three main sections: Inventory of relevant H2020 projects: List of the on-going, recently finished and future projects Analysis of the identified projects\u2019 objectives and planned results Assessment of the potential similarities and/or synergies with PACIFIC List of all the projects\u2019 planned events and plan for possible joint events Identification of the potential entry points and established contacts Presentation of the common online space facilitating discussions and clustering Action list This clustering plan will be considered as a living document to be reviewed in each General Assembly meeting to monitor the progress made in its implementation and allow for regular updates to take into account the evolving European context and prioritisation.","Field WP":"WP7 Clustering with other projects","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363588,"Creation Time":1616076323,"Link":"https://cmt.sym.place/knowledge/view/363588/d63-recommendations-for-improved-communication","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D6.3: Recommendations for improved communication","Field Brief description":"Executive summary: This report summarises recommendations for improved communications surrounding mining-related activities, based on an overview of existing communications through a behavioural science lens (Deliverable 6.1), and a computer-based behavioural experiment run in 2019 (Deliverable 6.2).
The work was undertaken by the Behavioural Research Unit of the Economic and Social Research Institute, a research group specialising in understanding how people process complex information and use it to make decisions. This is pertinent in the context of the PACIFIC project as people’s comprehension of mining-relating activities (and attitudes towards the same) relies on individuals processing complex information about risks and benefits from a range of sources.
The goal of this research is not to design communication tools that will best ensure that a company can secure a ‘social license to operate’. Rather, it is to inform best practice for communication strategies that promote understanding and empower stakeholders to make well-informed decisions, whatever the outcome may be. This is particularly important at a time where misinformation is becoming more widespread.
Herein we have made a suite of recommendations for improved communication about mining-related activities that may be utilised by a range of end-users (agencies, geological surveys, companies, etc.). For this project the research has primarily considered the general public as the target audience. That said, many of the findings presented have relevance to communications with otherstakeholders, such as shareholders, policy makers, and regulators.
As mentioned above, the recommendations are based off an overview of existing communication materials, as well as the results of a first behavioural experiment. This experiment had some unexpected findings, which will be investigated further in follow-up experiments in early 2021. The results of these may provide further insights that will be communicated in due course.
Executive summary:
\r\nThis report details the design and result of a computer-based behavioural experiment to gauge how the format of information provided to the public affects their understanding and perception of mining[1]related activities. The experiment was undertaken by the Economic and Social Research Institute (ESRI – third party to GSI) in fulfilment of Deliverable 6.2, as part of WP6 of PACIFIC (Social acceptance & perception of risk for mining activities).
\r\nThe design of the experiment was informed by a previous evaluation of currently used mining-related communication materials (Deliverable 6.1), as well as the broader social science and psychology literature. Insights gained from the results will be used to inform the design of follow-on experiments and will be used to generate recommendations for future communications (Deliverable 6.3).
","Text Brief description":"Executive summary: This report details the design and result of a computer-based behavioural experiment to gauge how the format of information provided to the public affects their understanding and perception of mining[1]related activities. The experiment was undertaken by the Economic and Social Research Institute (ESRI \u2013 third party to GSI) in fulfilment of Deliverable 6.2, as part of WP6 of PACIFIC (Social acceptance & perception of risk for mining activities). The design of the experiment was informed by a previous evaluation of currently used mining-related communication materials (Deliverable 6.1), as well as the broader social science and psychology literature. Insights gained from the results will be used to inform the design of follow-on experiments and will be used to generate recommendations for future communications (Deliverable 6.3).","Field WP":"WP6 Social acceptance & perception of risk for mining activities","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363582,"Creation Time":1616076115,"Link":"https://cmt.sym.place/knowledge/view/363582/d61-report-describing-tests-of-current-forms-of-communication","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D6.1: Report describing tests of current forms of communication","Field Brief description":"Executive summary: As part of WP6 “Social acceptance & perception of risk for mining activities” the Economic and Social Research Institute (ESRI) will be conducting computer-based behavioural experiments designed to gauge how the format of information provided to the public affects their understanding and perception of mining-related activities (D6.2). The results will be used to generate recommendations for future communications (D6.3). The focus of this report concerns the evaluation of currently-used mining-related communication materials, and forms a part of the preparation process for these future deliverables.
The primary aim of this deliverable is to gain insights regarding written communications in order to inform the design of experiments, and the information content included. A number of other EU funded projects are undertaking a more thorough assessment of interactions with stakeholders and evaluating best practice on a more general level.
As the behavioural experiment will be conducted in Ireland, information was collected from companies operating in the Republic of Ireland and in Northern Ireland (UK). Although companies in Northern Ireland adhere to UK licensing and regulation, their interaction with local communities is largely comparable to that in the Republic. Their information materials are therefore useful to include.
Executive summary: This document reports on the risks identified during field operations carried out in the second year of the PACIFIC project, from June 2019 to June 2020. During this period, two surveys were carried out at the Kallak iron ore project in Sweden and another was conducted at the Kaiserstuhl site in Germany.
The document builds on D5.2 - Environmental and Safety Risk Database adopted in 2018, and D5.3 Annual Risk Management Report 1. The procedures outlined in these documents were implemented during the surveys. No injuries were reported in either survey and impact on the local environment was found to be minimal.
Executive summary: This document reports on the risks identified during field operations carried out in the first year of the PACIFIC project, from June 2018 to June 2019. During this period, two surveys were carried out, one at Stillwater Canada Inc. (SCI)’ s Marathon PGU-Cu Project (“Marathon”), and another one at the Las Cruces site in Spain, an operating mine run by Cobre Las Cruces. The document builds on D5.2 – Environmental and Safety Risk Database adopted in 2018.
The procedures outlined in these documents were implemented during the surveys. No injuries were reported in either survey and impact on the local environment was found to be minimal.
Executive summary: This deliverable gathers risks related to safety or environmental issues relevant for PACIFIC activities. For each type of issue, the risks/hazards are listed with their score before and after mitigation and the corresponding control measures. A safe working procedure is also described. This database will serve as reference for the ESMC – Environmental and Safety Risk Management Committee – for follow-up during the course of the project.
","Text Brief description":"Executive summary: This deliverable gathers risks related to safety or environmental issues relevant for PACIFIC activities. For each type of issue, the risks/hazards are listed with their score before and after mitigation and the corresponding control measures. A safe working procedure is also described. This database will serve as reference for the ESMC \u2013 Environmental and Safety Risk Management Committee \u2013 for follow-up during the course of the project.","Field WP":"WP5 Environmental and safety risk assessment","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363570,"Creation Time":1616075728,"Link":"https://cmt.sym.place/knowledge/view/363570/d51-environmental-health-safety-and-risk-management-committee-charter","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D5.1: Environmental, Health, Safety and Risk Management Committee Charter","Field Brief description":"An ultimate Charter governing the roles, responsibilities, composition and membership of the Committee will be outlined and implemented prior to the activation of PACIFIC programs.
","Text Brief description":"An ultimate Charter governing the roles, responsibilities, composition and membership of the Committee will be outlined and implemented prior to the activation of PACIFIC programs.","Field WP":"WP5 Environmental and safety risk assessment","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363567,"Creation Time":1616075573,"Link":"https://cmt.sym.place/knowledge/view/363567/d32-successful-extraction-of-body-wave-data","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D3.2: Successful extraction of body-wave data","Field Brief description":"Executive summary: A key goal of the PACIFIC project is to develop methodologies for the extraction of body waves from passive seismic data, for use in the environmentally sustainable environments. Recovering body waves from ambient noise data has proved to be challenging as they are usually weak and ambient noise fields are rich in surface waves. Here we propose and test a method, based on the Radon Transformation, that helps suppress surface waves and enhance reflected body waves. The method exploits the ‘moveout’ differences between reflected body (hyperbolic) and surface waves (linear) and is tested on synthetic 2D & 3D model data prior to its application to ambient noise field data. We refer to it as Radon Correlation. Synthetic tests are very encouraging, showing clear body wave recovery that cannot be seen in raw cross-correlated data. Using these synthetics to have a choice of parameters, we then move to field passive data from the Marathon site within PACIFIC. We generate virtual shot gathers by applying Radon Correlation to single virtual sources into a linear array of receivers. Again, results are very encouraging with clear reflected body wave recovery from the ambient noise data and determined by clear hyperbolic arrivals on the virtual shot gathers. There is a hint that using time windows that contain active blast seismic coda possibly further enhances body wave recovery. Finally, velocity analysis on these virtual shot gathers leads to a P-wave velocity model that compares well with models derived from surface wave dispersion analysis of the same ambient noise data. However, these models are not currently publicly available and hence are not shown here, in this report.
","Text Brief description":"Executive summary: A key goal of the PACIFIC project is to develop methodologies for the extraction of body waves from passive seismic data, for use in the environmentally sustainable environments. Recovering body waves from ambient noise data has proved to be challenging as they are usually weak and ambient noise fields are rich in surface waves. Here we propose and test a method, based on the Radon Transformation, that helps suppress surface waves and enhance reflected body waves. The method exploits the \u2018moveout\u2019 differences between reflected body (hyperbolic) and surface waves (linear) and is tested on synthetic 2D & 3D model data prior to its application to ambient noise field data. We refer to it as Radon Correlation. Synthetic tests are very encouraging, showing clear body wave recovery that cannot be seen in raw cross-correlated data. Using these synthetics to have a choice of parameters, we then move to field passive data from the Marathon site within PACIFIC. We generate virtual shot gathers by applying Radon Correlation to single virtual sources into a linear array of receivers. Again, results are very encouraging with clear reflected body wave recovery from the ambient noise data and determined by clear hyperbolic arrivals on the virtual shot gathers. There is a hint that using time windows that contain active blast seismic coda possibly further enhances body wave recovery. Finally, velocity analysis on these virtual shot gathers leads to a P-wave velocity model that compares well with models derived from surface wave dispersion analysis of the same ambient noise data. However, these models are not currently publicly available and hence are not shown here, in this report.","Field WP":"WP3 Pilot test of the passive reflection seismic technique at the GEN Marathon deposit","Field Type of information":"Deliverable","Field File":false,"Field URL":null,"Field Date":null,"Field Precise the type":null},{"Id":363564,"Creation Time":1616075466,"Link":"https://cmt.sym.place/knowledge/view/363564/d31-deployment-complete","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"D3.1: Deployment complete","Field Brief description":"Executive summary: Permitting of the seismic survey and the acquisition of data are the first steps in WP3, the pilot test of the passive reflection seismic technique in the Marathon deposit. The processing and development stages of the Work Package rely directly on the successful acquisition of ambient seismic noise data from the Marathon test site.
Between September 17th and October 26th of 2018, at the Marathon test site, a 1025 sensor passive seismic survey was completed. The sensors equipment was rented from SAExploration. 1024 sensors were successfully deployed; however, only 1019 were recovered. The loss of sensors was due to animal activity or being buried by a rock slide.
The grid design was composed of two overlapping grids, a 416-sensor array and a 609-sensor profile line. The array had a grid spacing of 150m, while the profile line had a grid spacing of 50m. Both grids designs were configured along the main noise source of Lake Superior in the direction of 250deg to the west.
The sensors selected for the survey were ZL and C1, vertical direction sensors with a 10hz range. Once the sensors were retrieved, they were shipped back to SAExploration for download. The data was successfully downloaded and shipped to Sisprobe for analysis.
Retrieving reflection arrivals from passive seismic data using Radon correlation
\r\nSince explosive and impulsive seismic sources such as dynamite, air guns, gas guns or even vibroseis can have a big impact on the environment, some companies have decided to record ambient seismic noise and use it to estimate the physical properties of the subsurface. Big challenges arise when the aim is extracting body waves from recorded passive signals, especially in the presence of strong surface waves. In passive seismic signals, such body waves are usually weak in comparison to surface waves that are much more prominent. To understand the characteristics of passive signals and the effect of natural source locations, three simple synthetic models were created. To extract body waves from simulated passive signals we propose and test a Radon-correlation method. This is a time-spatial correlation of amplitudes with a train of time-shifted Dirac delta functions through different hyperbolic paths. It is tested on a two-layer horizontal model, a three-layer model that includes a dipping layer (with and without lateral heterogeneity) and also on synthetic Marmousi model data sets. Synthetic tests show that the introduced method is able to reconstruct reflection events at the correct time-offset positions that are hidden in results obtained by the general cross-correlation method. Also, a depth migrated section shows a good match between imaged horizons and the true model. It is possible to generate off-end virtual gathers by applying the method to a linear array of receivers and to construct a velocity model by semblance velocity analysis of individually extracted gathers.
","Text Brief description":"Retrieving reflection arrivals from passive seismic data using Radon correlation Since explosive and impulsive seismic sources such as dynamite, air guns, gas guns or even vibroseis can have a big impact on the environment, some companies have decided to record ambient seismic noise and use it to estimate the physical properties of the subsurface. Big challenges arise when the aim is extracting body waves from recorded passive signals, especially in the presence of strong surface waves. In passive seismic signals, such body waves are usually weak in comparison to surface waves that are much more prominent. To understand the characteristics of passive signals and the effect of natural source locations, three simple synthetic models were created. To extract body waves from simulated passive signals we propose and test a Radon-correlation method. This is a time-spatial correlation of amplitudes with a train of time-shifted Dirac delta functions through different hyperbolic paths. It is tested on a two-layer horizontal model, a three-layer model that includes a dipping layer (with and without lateral heterogeneity) and also on synthetic Marmousi model data sets. Synthetic tests show that the introduced method is able to reconstruct reflection events at the correct time-offset positions that are hidden in results obtained by the general cross-correlation method. Also, a depth migrated section shows a good match between imaged horizons and the true model. It is possible to generate off-end virtual gathers by applying the method to a linear array of receivers and to construct a velocity model by semblance velocity analysis of individually extracted gathers.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":false,"Field URL":"https://doi.org/10.1093/jge/gxab004","Field Date":null,"Field Precise the type":null},{"Id":361548,"Creation Time":1614942926,"Link":"https://cmt.sym.place/knowledge/view/361548/2021-02-21-pacific-talk-at-the-toronto-geological-discussion-group","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"2021-02-21 PACIFIC talk at the Toronto Geological Discussion Group","Field Brief description":"Charlie Beard's presentation can be viewed on the link https://www.youtube.com/watch?v=g_qdwQGHNhs
","Text Brief description":"Charlie Beard's presentation can be viewed on the link https://www.youtube.com/watch?v=g_qdwQGHNhs","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Event","Field File":false,"Field URL":null,"Field Date":"2021-02-02","Field Precise the type":null},{"Id":361537,"Creation Time":1614941628,"Link":"https://cmt.sym.place/knowledge/view/361537/pacific-flyer","Author Id":48091,"Author Name":"Inactive User 48091","Author Link":"https://cmt.sym.place/profile/anon48091","Rating":null,"Votes":0,"Field Title":"PACIFIC flyer","Field Brief description":"Download the PACIFIC flyer https://www.pacific-h2020.eu/wp-content/uploads/pacific-flyer.pdf
\r\nExecutive summary: Active seismic sources such as explosives, air guns and vibroseis generate energetic P-waves well suited for reflection seismic studies. However, they can have negative environmental impacts and are expensive, both of which have motivated the development of passive seismic methods. Passive seismic methods utilise ambient noise from meteorological and anthropogenic activity. They have been successful for surface wave recovery but extracting body waves for reflection imaging is still a challenge. A key goal of the PACIFIC project is to develop methodologies for extracting body waves from passive seismic data, and for using these body waves for subsurface imaging. This report describes the development of synthetic velocity models that characterise the geological structure and seismic reflectivity at the Marathon Cu-PGE prospect Ontario, Canada. Synthetic seismic signals generated in these models will then be used to develop and test processing procedures for body wave recovery and body wave imaging. A first velocity model consists of two vertical sections obtained by interpolation of lithological contacts identified in drillholes. One section is perpendicular to the dip of the main gabbro intrusion, the other is parallel. A second model is obtained by blind 3D interpolation between drillholes and uses velocities measured on hand samples and drill core. Work in progress uses dedicated geological modelling software to generate a 3D block model that honors geological structures and cross-cutting relationships. A recently acquired downhole acoustic log avoids negative velocity biases from microfractures that can be introduced during depressurisation (e.g. of drill core). This will be used to calibrate a new velocity forward model.
\r\nExecutive Summary: Seismic methods provide high-resolution images of geologic structures hosting mineral deposits and, in a few cases, can be used for direct targeting of deposits. Active reflection techniques have been successfully used in the minerals sphere, especially for structural control on deep targets. Although useful, a disadvantage of this methodology is that it is expensive and logistically difficult in locations without easy access for source generation. In contrast to active seismology, passive methods exploit ambient seismic noise and do not require specific seismic sources. In this report, we compare active and passive seismic methods in general and discuss different data processing sequences that have been used in previous passive seismic studies. The quality of the results in passive seismic methods strongly depends on (1) the spatial-temporal properties of the noise source distribution and (2) the number and disposition of seismic receiver pairs on which the noise correlation is performed. We then discuss how to apply these processing sequences to extract body-waves in the PACIFIC project, with a view to developing reflection seismic images analogous to active reflection seismic work.
\r\nExecutive summary: The physical properties of rocks and minerals, particularly their density and elasticity, control the velocitywith which they transmit seismic waves. The acoustic impedance, which is the product of density and seismic velocity, is a useful property to characterize different lithologies. Available data indicates that there are strong contrasts in acoustic impedance between common types of rock and, most importantly, between common rocks and ore minerals. These differences provide a basis for relating passive seismic tomographic models with models based on geological and previously acquired geophysical data.
\r\nExecutive summary: Across the globe, the mineral industry is seeking new technologies to replace or complement existing geological, geochemical and geophysical methods to improve exploration efficiency at depth and to help design safer and more productive mines. These industries are increasingly using seismic methods for a wide range of commodities including base metals, uranium, diamonds, and precious metals. Seismic methods usually can be used for direct targeting of mineral deposits but particular care must be taken during acquisition and processing of the data. To achieve the best results, different processing sequences based on the target of the project are applied. Here we compare and discuss how such workflows are used when treating active seismic data in order to provide a basis for their use in the development of the passive seismic methods that form the basis of the PACIFIC project.
\r\nUnderstanding Seismic Waves Generated by Train Traffic via Modeling: Implications for Seismic Imaging and Monitoring.
\r\nTrains are now recognized as powerful sources for seismic interferometry based on noise correlation, but the optimal use of these signals still requires a better understanding of their source mechanisms. Here, we present a simple approach for modeling train\u2010generated signals inspired by early work in the engineering community, assuming that seismic waves are emitted by sleepers regularly spaced along the railway and excited by passing train wheels. Our modeling reproduces well seismological observations of tremor\u2010like emergent signals and of their harmonic spectra. We illustrate how these spectra are modulated by wheel spacing, and how their high\u2010frequency content is controlled by the distribution of axle loads over the rail, which mainly depends on ground stiffness beneath the railway. This is summarized as a simple rule of thumb that predicts the frequency bands in which most of train\u2010radiated energy is expected, as a function of train speed and of axle distance within bogies. Furthermore, we identify two end\u2010member mechanisms—single stationary source versus single moving load—that explain two types of documented observations, characterized by different spectral signatures related to train speed and either wagon length or sleeper spacing. In view of using train\u2010generated signals for seismic applications, an important conclusion is that the frequency content of the signals is dominated by high\u2010frequency harmonics and not by fundamental modes of vibrations. Consequently, most train traffic worldwide is expected to generate signals with a significant high\u2010frequency content, in particular in the case of trains traveling at variable speeds that produce truly broadband signals. Proposing a framework for predicting train\u2010generated seismic wavefields over meters to kilometers distance from railways, this work paves the way for high\u2010resolution passive seismic imaging and monitoring at different scales with applications to near\u2010surface surveys (aquifers, civil engineering), natural resources exploration, and natural hazard studies (landslides, earthquakes, and volcanoes).
\r\n\r\n
The accepted version and the supplementary material can be downloaded as a compressed file from this webpage.
\r\nThe link to the published version is provided below as well.
","Text Brief description":"Understanding Seismic Waves Generated by Train Traffic via Modeling: Implications for Seismic Imaging and Monitoring. Trains are now recognized as powerful sources for seismic interferometry based on noise correlation, but the optimal use of these signals still requires a better understanding of their source mechanisms. Here, we present a simple approach for modeling train\u2010generated signals inspired by early work in the engineering community, assuming that seismic waves are emitted by sleepers regularly spaced along the railway and excited by passing train wheels. Our modeling reproduces well seismological observations of tremor\u2010like emergent signals and of their harmonic spectra. We illustrate how these spectra are modulated by wheel spacing, and how their high\u2010frequency content is controlled by the distribution of axle loads over the rail, which mainly depends on ground stiffness beneath the railway. This is summarized as a simple rule of thumb that predicts the frequency bands in which most of train\u2010radiated energy is expected, as a function of train speed and of axle distance within bogies. Furthermore, we identify two end\u2010member mechanisms\u2014single stationary source versus single moving load\u2014that explain two types of documented observations, characterized by different spectral signatures related to train speed and either wagon length or sleeper spacing. In view of using train\u2010generated signals for seismic applications, an important conclusion is that the frequency content of the signals is dominated by high\u2010frequency harmonics and not by fundamental modes of vibrations. Consequently, most train traffic worldwide is expected to generate signals with a significant high\u2010frequency content, in particular in the case of trains traveling at variable speeds that produce truly broadband signals. Proposing a framework for predicting train\u2010generated seismic wavefields over meters to kilometers distance from railways, this work paves the way for high\u2010resolution passive seismic imaging and monitoring at different scales with applications to near\u2010surface surveys (aquifers, civil engineering), natural resources exploration, and natural hazard studies (landslides, earthquakes, and volcanoes). The accepted version and the supplementary material can be downloaded as a compressed file from this webpage. The link to the published version is provided below as well.","Field WP":"WP8 Dissemination training innovation management and exploitation","Field Type of information":"Publication","Field File":"https://cmt.sym.place/serve-file/e0/l1619441110/di/c1/DX3iiIXDGMR9K2Wt7ust19uRUPrpa9zit11RDDVhtQQ/:MzYwMDAwLzM2MTUyMi9fX2NtdGZpZWxkXzE2MTAwOTQ2MTcxMzQyL1BBUEVSX0xhdm91ZS1ldC1hbF8yMDIwX1NSTF9hY2NlcHRlZC1TdXBwbGVtZW50YXJ5X01hdGVyaWFsLnppcA","Field URL":"https://doi.org/10.1785/0220200133","Field Date":null,"Field Precise the type":null}]