Seismic noise monitoring of the water table in a deep-seated, slow-moving landslide

2016 ◽  
Vol 4 (3) ◽  
pp. SJ67-SJ76 ◽  
Author(s):  
Christophe Voisin ◽  
Stéphane Garambois ◽  
Chris Massey ◽  
Romain Brossier
Keyword(s):  
Water Table ◽  
Frequency Band ◽  
Seismic Noise ◽  
Seismic Velocity ◽  
Slip Surface ◽  
Ground Surface ◽  
Velocity Change ◽  
Fluid Saturation ◽  
Limited Frequency ◽  
Velocity Changes

Daily correlations of ambient seismic noise on a large landslide at Utiku, New Zealand, reveal seismic velocity changes up to [Formula: see text] that follow a summer/winter cycle consistent with the pore-water pressures monitored at the basal slip surface in the landslide. The annual pattern of velocity changes is borne by a limited frequency band (6–8 Hz typically) that suggests a localized change in the medium. The Rayleigh waves that form the seismic signal within this frequency band have a maximum sensitivity at a depth of 2–3 m below the ground surface, consistent with the water table level. Fluid saturation changes in the landslide modeled using the Biot-Gassmann theory explain the limited frequency band and the amplitude of the seismic velocity change. This set of arguments suggests that seismic noise correlations are sensitive to water table oscillations through saturation changes and could be used as a nondestructive hydrologic monitoring tool.

scholarly journals Monitoring southwest Greenland’s ice sheet melt with ambient seismic noise

2016 ◽  
Vol 2 (5) ◽  
pp. e1501538 ◽  
Author(s):  
Aurélien Mordret ◽  
T. Dylan Mikesell ◽  
Christopher Harig ◽  
Bradley P. Lipovsky ◽  
Germán A. Prieto
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Sea Level ◽  
Seismic Noise ◽  
Seismic Velocity ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Sea Level Changes ◽  
Ice Sheet Mass Balance ◽  
Velocity Changes

The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth’s crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. Seasonal loading and unloading of glacial mass induces strain in the crust, and these strains then result in seismic velocity changes due to poroelastic processes. Our method provides a new and independent way of monitoring (in near real time) ice sheet mass balance, yielding new constraints on ice sheet evolution and its contribution to global sea-level changes. An increased number of seismic stations in the vicinity of ice sheets will enhance our ability to create detailed space-time records of ice mass variations.

Spatial Evaluation of Pore Pressure Variations Related to Rainfall from Seismic Velocity Changes

2021 ◽  
Author(s):  
Rezkia Dewi Andajani ◽  
Takeshi Tsuji ◽  
Roel Snieder ◽  
Tatsunori Ikeda
Keyword(s):  
Pore Pressure ◽  
Negative Correlation ◽  
Ambient Noise ◽  
Seismic Velocity ◽  
Diffusion Mechanism ◽  
Velocity Change ◽  
Diffusion Parameters ◽  
The Status ◽  
Seismic Velocity Changes ◽  
Velocity Changes

<p>Crustal pore pressure, which could trigger seismicity and volcanic activity, varies with fluid invasion. Various studies have discussed the potential of using seismic velocity changes from ambient noise to evaluate pore pressure conditions, especially due to rainfall perturbations. Although the influence of rainfall on seismic velocity changes has been reported, consideration of the spatial influence on rainfall towards seismic velocity and its mechanism have not been well understood. We investigated the mechanism of rainfall-induced pore pressure diffusion in southwestern Japan, using seismic velocity change (Vs) inferred from ambient noise. We modeled pore pressure changes from rainfall data based on a diffusion mechanism at the locations where infiltration is indicated. By calculating the correlation between Vs changes and the modeled pore pressure with various hydraulic diffusion parameters, the optimum hydraulic diffusion parameter was obtained. We estimated the diffusion parameters with the highest negative correlation between pore pressure and Vs change because a negative correlation indicates pore pressure increase due to diffusion induced by groundwater load. Furthermore, the spatial variation of the hydraulic diffusivity infers the heterogeneity of the rocks in different locations. This finding suggests that the response of pore pressure induced by rainfall percolation depends on location.  We show that seismic velocity monitoring can be used to evaluate the status of pore pressure at different locations, which is useful for fluid injection, CO<sub>2</sub> wellbore storage, and geothermal development.</p>

Ambient seismic noise monitoring: an online application for decision makers – example of various applications for different slopes configurations.

2020 ◽  
Author(s):  
Alexandra Royer ◽  
Mathieu Le Breton ◽  
Antoine Guillemot ◽  
Noélie Bontemps ◽  
Eric Larose ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Seismic Velocity ◽  
Early Warning Systems ◽  
Soil Liquefaction ◽  
Decision Makers ◽  
Velocity Variation ◽  
Ambient Seismic Noise ◽  
Landslide Monitoring ◽  
Velocity Change ◽  
Online Application

<p>Monitoring landslides is essential to understand their dynamics and to reduce the risk of human losses by detecting precursors before failures. In general, surface observations need to be complemented by observation at depth, in the bulk of the material. A decade ago, the ambient seismic noise interferometry method was proposed to monitor changes in the seismic surface wave velocity. As seismic wave velocities are directly related to the rigidity of the material, any reduction of seismic velocity can be associated to a loss of rigidity with high probability (a route toward soil liquefaction or to high fracturation). This technique led to detect a velocity decrease several days before the failure of a clayey landslide [1], paving the way to a novel precursor signal that could serve for alert or early warning systems. Here we report at least five different landslides that have been monitored, over several years [2]. In this paper, we detail the standard experimental configuration, the basic signal processing procedure, the sensitivity and resolution of the method, together with its advantages and possible limitations. Environmental effects on the relative seismic velocity change are discussed.</p><p>In order to make the technology operational for decision makers, we built an online application with web portal displaying daily evolution of seismic velocity variation. This portal also integrates other available observations like environmental parameters (weather, precipitations) or surface observation (photogrammetry, gps, extensometers…).</p><p>[1] G. Mainsant, E. Larose, C. Brönnimann, D. Jongmans, C. Michoud, M. Jaboyedoff, <em>Ambient seismic noise monitoring of a clay landslide : toward failure prediction</em>, J. Geophys. Res. <strong>117</strong>, F01030 (2012).</p><p>[2] M. Le Breton, N. Bontemps, A. Guillemot, L. Baillet, E. Larose,<sup> </sup><em>Landslide Monitoring Using Seismic Ambient Noise In-terferometry: Challenges and Applications,</em> Earth Science Review (under review) (2020)</p>

Temporal seismic velocity changes during the 2020 rapid inflation at Mt. Thorbjorn-Svartsengi, Iceland, using ambient seismic noise

2021 ◽  
Author(s):  
Yesim Cubuk Sabuncu ◽  
Kristin Jonsdottir ◽  
Corentin Caudron ◽  
Thomas Lecocq ◽  
Michelle Maree Parks ◽  
...  
Keyword(s):  
Seismic Wave ◽  
Seismic Noise ◽  
Seismic Velocity ◽  
Ambient Seismic Noise ◽  
Magmatic Activity ◽  
Volcanic Unrest ◽  
Seismic Velocity Changes ◽  
Magmatic Intrusions ◽  
Reykjanes Peninsula ◽  
Velocity Changes

<p>The Reykjanes peninsula, SW Iceland, was struck by intense earthquake swarm activity that occurred in January-July 2020 due to repeated magmatic intrusions in the Reykjanes-Svartsengi volcanic system. GPS and InSAR observations confirmed surface deformation centered near Mt. Thorbjorn, and during the unrest period, approximately ~14,000 earthquakes (-2≤M≤4.9) were reported at the Icelandic Meteorological Office (IMO). We investigate the behavior of the crust as a response to these repeated intrusions to provide insights into volcanic unrest in the Reykjanes peninsula. Our study presents temporal seismic wave velocity variations (dv/v, in percent) based on ambient noise seismic interferometry using continuous three-component waveforms collected by IMO, (http://www.vedur.is) for the period from April 2018 to November 2020. The state-of-the-art MSNoise software package (http://www.msnoise.org) is used to calculate cross-correlations of ambient seismic noise and to quantify the relative seismic velocity variations. We observe that magmatic intrusions in the vicinity of Mt. Thorbjorn-Svartsengi have considerably reduced the seismic wave velocities (dv/v, -1%) in the 1-2 Hz frequency band. Seismic velocity changes were compared with local seismicity, GPS and InSAR data recorded close to the repeated intrusions, and modelled volumetric strain changes. We found a good correlation between the dv/v variations and the available deformation data. The Rayleigh wave phase-velocity sensitivity kernels showed that the changes occurring at depths down to ~3-4 km in the crust were captured by our measurements. We interpret the relative seismic velocity decrease to be caused by crack opening induced by intrusive magmatic activity. Monitoring the Mt. Thorbjorn-Svartsengi volcanic unrest is crucial for successful early warning of volcanic hazards since the center of uplift is only 2km away from a fishing village and major infrastructure in the area, such as water supply and geothermal power. For the first time in Iceland, we have provided near-real-time dv/v variations to obtain a more complete picture of this magmatic activity. Our findings are supported by the analysis of other primary monitoring streams. We propose that this technique may be useful for early detection of future intrusions/increased magmatic activity. This study is supported by the Icelandic Research Fund, Rannis (Grant No: 185209-051).</p>

InSAR, seismic noise, and geotechnical data to assess landslide activity and geometry: the Villa de Independencia (Cochabamba, Bolivia) case study

2021 ◽  
Author(s):  
Veronica Pazzi ◽  
Matteo Del Soldato ◽  
Chuang Song ◽  
Chen Yu ◽  
Zhenhong Li ◽  
...  
Keyword(s):  
Time Series ◽  
Seismic Noise ◽  
Slip Surface ◽  
Ground Surface ◽  
Spectral Ratio ◽  
Failure Surface ◽  
Inversion Method ◽  
Geotechnical Data ◽  
Landslide Volume ◽  
Noise Measurements

<p>Interferometric Synthetic Aperture Radar (InSAR) enables detailed investigation of surface landslide movements but lacks information about subsurface recognition/identification. It can be obtained by means of direct measurements (e.g., geotechnical data) and geophysical techniques. InSAR observations, seismic noise measurements, and geotechnical data were integrated to assess the deformation on the ground surface and to determine the depth of the failure surface of the Villa de Independencia landslide, Cochabamba (Bolivia) affecting the village. It is a compound slow-moving landslide (total area approximatively 3.8·10<sup>6</sup> m<sup>2</sup>) composed by three sub-blocks slide exhibiting diverse geometries, multiple failure surfaces, and magnitudes.</p><p>For investigating the spatiotemporal characteristics of the landslide motion, Sentinel-1 time series from October 2014 to December 2019 were analysed. A new geometric inversion method was also proposed to determine the best-fit sliding direction and inclination of the landslide. Results of the Sentinel-1 time series show two substantial accelerations in early 2018 and 2019, coinciding with an increment of precipitations in the late rainy season. It allows supposing the rainy as the most likely triggers of the identified accelerations.</p><p>The seismic noise measurements (more than one hundred spreaded over the whole landslide), analysed according to the Vertical to Horizontal Spectral Ratio technique (H/V), were calibrated and validated by means of the geotechnical data derived by three boreholes and 13 between rock and soil samples. H/V data allowed identifying the different dynamic characteristics of the three sub-blocks: movements are possibly due to the different properties of shallow and deep slip surfaces. The landslides caused damage on the edifices, probably mainly caused by the shallow slip interface (located at a mean depth of 5 m) since the foundation depth of the buildings is at most 2 m. In the town centre a deeper failure surfaces, approximatively with depth between 15 and 75 m, can be identified which may be responsible for its different direction and acceleration magnitude of sliding (inferred by InSAR) compared to the other parts of the landslides. Finally, the determination of the slip surface depths allowed to estimate the overall landslide volume assessed approximatively 9.18·10<sup>7</sup> m<sup>3</sup>.</p><p>The study shows the great potential for landslide motion characterization and mechanism investigation by combing InSAR, seismic noise and geotechnical measurements.</p>

Application of passive and active seismic methods to subsurface investigation of Just-Tegoborze landslide (Outer Carpathians, Poland)

2020 ◽  
Author(s):  
Paulina Harba ◽  
Krzysztof Krawiec
Keyword(s):  
Wave Velocity ◽  
Seismic Noise ◽  
Slip Surface ◽  
Seismic Refraction ◽  
Seismic Interferometry ◽  
Geological Medium ◽  
S Wave ◽  
Passive Seismic ◽  
Outer Carpathians ◽  
Velocity Changes

<p>The study presents the results of seismic measurements on the Just-Tegoborze landslide located in Outer Carpathians in the southern region of Poland. The aim of the study was to investigate the landslide geological subsurface and define S-wave velocity changes within geological medium using passive seismic interferometry (SI) and active multichannel analysis of surface waves (MASW). Additionally, seismic refraction and numerical slip surface calculations were carried out in order to combine the results.</p><p>Measurements of SI were conducted based on local high-frequency seismic noise generated by heavy vehicles passing state road which intersects Just-Tegoborze landslide. Seismic noise registration was made using three-component broadband seismometers installed along a seismic profile. Measurements were repeated in a few series in different season and hydration conditions.</p><p>Seismic sections show different velocity layers within the landslide medium. Comparing them with geological cross-section of the studied area, we can distinguish the main lithological boundaries. First near-surface seismic layers may correspond to clayey colluvium and clayey-rock colluvium. The deepest seismic layer probably correlates to less weathered flysch bedrock made of shales and sandstones. It can be identified as the main slip surface of the studied landslide.</p><p>S-wave velocities within seismic profiles significantly varies between each measurement series of SI. It can be observed a decrease of S-wave velocity in March and July which is connected to seasonal weather and hydration conditions. Strong increase of hydration during melting snow cover in March and after heavy rainfalls in July resulted in loss of rigidity what presumably led to drop of S-wave velocity. Changes in hydration could also cause the variation of the course of the less weathered flysch bedrock boundary.</p><p>Presented results of passive seismic interferometry measurements show that study of seismic noise can be applicable to subsurface identification of an active landslide. The example of Just-Tegoborze site indicates that based on seismic interferometry it is possible to observe changes in elastic properties of geological medium. It is worth to underline that SI and MASW complement each other in retrieving the information of Rayleigh surface wave. Combining the results with seismic refraction and numerical calculations allows to better image the landslide geological subsurface. Such observations may be helpful in assessing landslide threat.</p>

Instantaneous phase variation for seismic velocity monitoring from ambient noise at the exploration scale

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. Q37-Q44 ◽  
Author(s):  
Margherita Corciulo ◽  
Philippe Roux ◽  
Michel Campillo ◽  
Dominique Dubucq
Keyword(s):  
Seismic Noise ◽  
Seismic Velocity ◽  
Phase Measurement ◽  
Signal To Noise Ratio ◽  
Phase Variation ◽  
Computation Time ◽  
Real Data ◽  
Velocity Change ◽  
Data Set ◽  
Instantaneous Phase

Recent studies in geophysics have investigated the use of seismic-noise correlations to measure weak-velocity variations from seismic-noise recordings. However, classically, the existing algorithms used to monitor medium velocities need extensive efforts in terms of computation time. This implies that these techniques are not appropriate at smaller scales in an exploration context when continuous data sets on dense arrays of sensors have to be analyzed. We applied a faster technique that allows the monitoring of small velocity changes from the instantaneous phase measurement of the seismic-noise crosscorrelation functions. We performed comparisons with existing algorithms using synthetic signals. The results we have obtained for a real data set show that the statistical distribution of the velocity-change estimates provides reliable measurements, despite the low signal-to-noise ratio obtained from the noise-correlation process.

Interpreting seismic velocity changes observed with ambient seismic noise correlations

2016 ◽  
Vol 4 (3) ◽  
pp. SJ77-SJ85 ◽  
Author(s):  
Gerrit Olivier ◽  
Florent Brenguier
Keyword(s):  
Seismic Noise ◽  
Relative Velocity ◽  
Dynamic Stress ◽  
Seismic Velocity ◽  
Ambient Seismic Noise ◽  
Seismic Velocity Changes ◽  
Velocity Variations ◽  
Velocity Changes ◽  
Pressure Changes

Recent results have shown that crosscorrelating ambient seismic noise recorded in underground mines can successfully extract the seismic Green’s function between sensors. We have revisited an earlier experiment that showed that these virtual seismic sources can be used to measure changes in seismic velocity accurately enough to monitor the short- and long-term influences of a blast in an underground mine. To use this method routinely, it is important to determine the cause of velocity variations in the absence of large dynamic stress perturbations (such as blasts). It also is important to calibrate the seismic velocity changes in terms of known stress changes so the effect of mining activities can be quantified in units that can be used by geotechnical engineers. To this end, we used coda-wave interferometry to measure relative velocity variations during times where no significant blasting or microseismic activity occurred and compared it to atmospheric air pressure changes, temperature variations, and modeled tidal strain. The results indicate that atmospheric air pressure changes have a measurable influence on the long-term seismic velocity variations at depth in the absence of large dynamic stress perturbations. This influence enabled us to determine the sensitivity of the relative velocity changes to stress, where a value of [Formula: see text] was found. This calibration essentially enables us to turn each sensor pair in an underground mine into a stress meter, paving the way for geotechnical engineers to use ambient seismic noise correlations to monitor the evolution of stress and to assess seismic hazard in conjunction with conventional microseismic methods.

Analysis of ballistic waves in seismic noise monitoring of water table variations in a water field site: added value from numerical modelling to data understanding

2019 ◽  
Vol 219 (3) ◽  
pp. 1636-1647 ◽  
Author(s):  
S Garambois ◽  
C Voisin ◽  
M A Romero Guzman ◽  
D Brito ◽  
B Guillier ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Surface Waves ◽  
Water Table ◽  
Seismic Noise ◽  
Seismic Velocity ◽  
Signal To Noise Ratio ◽  
Numerical Approach ◽  
P Wave ◽  
Added Value ◽  
Observation Window

SUMMARY Passive seismic interferometry allows to track continuously the weak seismic velocity changes in any medium by correlating the ambient seismic noise between two points to reconstruct the Green’s function. The ballistic surface waves of the reconstructed Green’s functions are used to monitor the changes of water table induced by a controlled experiment in the Crépieux-Charmy (France) exploitation field. Viscoelastic numerical modelling of the monitoring experiment reproduces quite satisfactorily the sensitivity of the surface waves to the water table previously observed with seismic noise data. This numerical approach points out that this sensitivity is controlled by mode mixing of Rayleigh waves. It also made it possible to identify the refracted P wave and to extract its anticorrelated sensitivity to water table variations. Depending on the offset between receivers, it was observed numerically that the interferences between the different waves (with different velocities) composing the seismic wavefield slightly affect the quantitative sensitivity to water table changes. This suggests the use of an optimal spatial and temporal observation window for which wave interference is minor and does not blur the quantitative response to water table variations. We were thus able to determine the relationship between velocity and water table variations for all waves involved. From numerical computations, we identify a weak signal-to-noise ratio phase in the noise correlograms, with a anticorrelated sensitivity to the water table: the reconstructed refracted waves.

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