Seismologically understanding the basal sliding depth and groundwater level for deep-seated landslide

2020 ◽  
Author(s):  
Wei-An Chao ◽  
Chun-Hung Lin ◽  
Che-Ming Yang ◽  
Keng-Hao Kang ◽  
Yu-Ting Kuo ◽  
...  
Keyword(s):  
Surface Wave ◽  
Groundwater Level ◽  
Seismic Noise ◽  
Seismic Station ◽  
Shear Zones ◽  
Ambient Seismic Noise ◽  
Depth Range ◽  
Frequency Dependent ◽  
Additional Tool ◽  
Basal Sliding

<p>Deep-seated landslide is one of most catastrophic and disastrous geohazards. Probing the spatial extent and basal sliding interface of the deep-seated landslide is not only particularly critical for understanding landslide size (i.e., volume and collapsed area), but also crucial for landslide hazard assessment. The conventional investigations such as the borehole drilling and seismic profiles are usually challenging for investigating landslide body comprehensively in space due to the expensive cost and the limitations of geophysical exploration. Recent studies of ambient seismic noise monitoring have provided an additional tool to monitor the subsurface medium in a non-invasive and relatively inexpensive way, which advances the investigating landslide geological structure. Here, we applied the ambient seismic noise monitoring technique to deep-seated landslide at Fanfan, Ilan area in northeastern Taiwan. The multiple geophysical, geotechnical and geodetic approaches including active multi-channel analysis of surface wave (MASW), real-time kinematic (RTK) measurement, campaign GPS, borehole time-domain reflectometer (TDR) and groundwater level (GWL) gauge are adopted during our monitoring period. A series of relation analysis found that the variations of frequency-dependent seismic velocity changes (dv/v), TDR sliding behavior, time series of groundwater level associated to two heavy rainfall episodes concurrently. With the available shear-wave velocity model (V<sub>S</sub>) derived from MASW, the depth range sensitive to different frequency band for surface wave can be certainly determined. Clear 3-5 Hz dv/v measurement at seismic station of V01 collocated with GWL gauge can be found with the largest reduction of ~ 1%, coinciding with 1 m GWL increasing. Models with different thickness layer (H), basal depth (d), V<sub>s</sub> perturbation (dV<sub>s</sub>) were exercised, and a good fit between predicted spectral dv/v and the frequency-dependent dv/v measurements at seismic station V02 with H = 0.5 m, d = 21 m and dV<sub>s </sub>= 0.5. TDR measurement showed the obvious sliding signals is consistent with the shear zones identified by borehole log with the depth ranging from 48 to 50 m. These results demonstrate that multidisciplinary perspectives are needed to increase a better understanding of landslide structure. Consequently, a model linking variations of dv/v and TDR measurements is proposed to better understand sliding characteristics, which could potentially toward failure prediction of deep-seated landslide.</p>

scholarly journals Systematic recovery of instrumental timing and phase errors using interferometric surface-waves retrieved from large-N seismic arrays

2020 ◽  
Vol 224 (2) ◽  
pp. 1028-1055
Author(s):  
Cornelis Weemstra ◽  
Janneke I de Laat ◽  
Arie Verdel ◽  
Pieter Smets
Keyword(s):  
Surface Wave ◽  
Seismic Noise ◽  
Arrival Time ◽  
Weighted Least Squares ◽  
Ambient Seismic Noise ◽  
Frequency Dependent ◽  
Timing Errors ◽  
Phase Errors ◽  
Large N ◽  
Cross Correlations

SUMMARY Instrumental timing and phase errors are a notorious problem in seismic data acquisition and processing. These can be frequency independent, for example due to clock drift, but may also be frequency dependent, for example due to imperfectly known instrument responses. A technique is presented that allows both types of errors to be recovered in a systematic fashion. The methodology relies on the time-symmetry usually inherent in time-averaged cross-correlations of ambient seismic noise: the difference between the arrival time of the direct surface-wave at positive time and the arrival time of the direct surface-wave at negative time is quantified. Doing this for all eligible receiver–receiver pairs of a large-N seismic array, including one or more receivers devoid of instrumental timing errors, the instrumental timing errors of all incorrectly timed receivers can be determined uniquely. Most notably, this is accomplished by means of a weighted least-squares inversion. The weights are based on the receiver–receiver distances and decrease the adverse effect of inhomogeneities in the noise illumination pattern on the recovered instrumental timing errors. Inversion results are furthermore optimized by limiting the inversion to receiver couples that (i) exceed a specific receiver–receiver distance threshold and (ii) whose time-averaged cross-correlations exceed a specific signal-to-noise ratio threshold. Potential frequency dependence of the timing errors is incorporated by means of an iterative, frequency-dependent approach. The proposed methodology is validated using synthetic recordings of ambient seismic surface-wave noise due to an arbitrary non-uniform illumination pattern. The methodology is successfully applied to time-averaged cross-correlations of field recordings of ambient seismic noise on and around the Reykjanes peninsula, SW Iceland.

Near‐surface VSstructure by inversion of surface wave estimated from ambient seismic noise

2015 ◽  
Vol 13 (5) ◽  
pp. 447-455 ◽  
Author(s):  
Taghi Shirzad ◽  
Z. Hossein Shomali ◽  
Mojtaba Naghavi ◽  
Rahim Norouzi
Keyword(s):  
Surface Wave ◽  
Seismic Noise ◽  
Ambient Seismic Noise ◽  
Near Surface

scholarly journals Surface wave tomography of China from ambient seismic noise correlation

2008 ◽  
Vol 9 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Sihua Zheng ◽  
Xinlei Sun ◽  
Xiaodong Song ◽  
Yingjie Yang ◽  
Michael H. Ritzwoller
Keyword(s):  
Surface Wave ◽  
Seismic Noise ◽  
Ambient Seismic Noise ◽  
Noise Correlation ◽  
Surface Wave Tomography ◽  
Wave Tomography

scholarly journals Using ambient seismic noise to study temporal and spatial surface wave velocity structures and ambient noise field characteristics of central South Island, New Zealand

2021 ◽  
Author(s):  
◽  
Rachel Heckels
Keyword(s):  
New Zealand ◽  
Surface Wave ◽  
Wave Velocity ◽  
Seismic Noise ◽  
Shear Velocity ◽  
Southern Alps ◽  
Ambient Seismic Noise ◽  
Near Surface ◽  
Surface Wave Velocity ◽  
Velocity Changes

<p>Ambient seismic noise is used to examine the spatial and temporal surface wave velocity structures and ambient seismic noise fields in the vicinity of different fault zone environments. This study focuses on two distinct regions of central South Island, New Zealand. The Canterbury Plains is a sedimentary basin with many minor faults, which was considered to have low seismic hazard prior to the 2010 – 2011 Canterbury earthquake sequence. We focus on the time period immediately following the 2010 Darfield earthquake, which ruptured the previously unmapped Greendale Fault. The second region of interest is the central Southern Alps. The locked portion of the Alpine Fault currently poses one of the largest seismic hazards for New Zealand. The wealth of data from both permanent and temporary seismic deployments in these regions make them ideal areas in which to assess the effectiveness of ambient noise for velocity modelling in regions surrounding faults at different stages of their seismic cycles.  Temporal velocity changes are measured following the Mw 7.1 Darfield earthquake of 4 September 2010 in the Canterbury Plains. Nine-component cross-correlations are computed from temporary and permanent seismic stations lying on and surrounding the Greendale Fault. Using the Moving-Window Cross-Spectral method, surface wave velocity changes are calculated for the four months immediately following the earthquake until 10 January 2011, for 0.1 — 1.0 Hz. An average increase in seismic velocity of 0.14 ± 0.04 % is determined throughout the region, providing the first such estimate of postseismic relaxation rates in Canterbury. Depth analyses further showed that velocity changes are confined to the uppermost 5 km of the subsurface and we attribute this to postseismic relaxation via crack-healing of the Greendale Fault and throughout the surrounding region.  Rayleigh and Love wave dispersion is examined throughout the Canterbury region. Multi-component cross-correlation functions are analysed for group and phase dispersion curves. These are inverted using frequency-time analysis for 2-D phase and group velocity maps of Rayleigh and Love waves. A high-velocity zone to the southeast of the region coincides with volcanic rocks of Banks Peninsula. Dispersion curves generated from the surface wave tomography are further inverted for one-dimensional shear velocity profiles. These models show a thin, low-velocity near surface layer consistent with the basin sediments, which thins towards the foothills of the Southern Alps. A near-surface damage zone is identified along the length of the Greendale Fault, with consistent reduced Vs velocities to depth of up to 5 km.  Surface and shear wave velocity maps are computed for the central Southern Alps to image the seismic structure of the region. Tomographic surface maps at periods of 5 – 12 s are produced from dispersion measurements of three-component cross-correlation functions. At periods of 5 – 8 s a strong NE-SW trending velocity contrast highlights the Alpine Fault. One-dimensional shear velocity models, computed from the surface wave maps, are in agreement with previous models produced by other conventional methods. An analysis of surface wave amplitudes through signal-to-noise ratios of cross-correlations reveals strong directional effects. Calculated signal-to-noise ratios are up to eight times higher for surface waves travelling north-west than for waves travelling to the south or east. We attribute this to a combination of more energetic ocean wave signals from the Southern Ocean compared to the Tasman Sea.</p>

scholarly journals Reflection images from ambient seismic noise

Geophysics ◽  
2009 ◽  
Vol 74 (5) ◽  
pp. A63-A67 ◽  
Author(s):  
Deyan Draganov ◽  
Xander Campman ◽  
Jan Thorbecke ◽  
Arie Verdel ◽  
Kees Wapenaar
Keyword(s):  
Surface Wave ◽  
Green’S Function ◽  
Green's Function ◽  
Seismic Noise ◽  
Seismic Exploration ◽  
Ambient Seismic Noise ◽  
Reflection Data ◽  
Parallel Lines ◽  
Reflection Image ◽  
Sirte Basin

One application of seismic interferometry is to retrieve the impulse response (Green’s function) from crosscorrelation of ambient seismic noise. Various researchers show results for retrieving the surface-wave part of the Green’s function. However, reflection retrieval has proven more challenging. We crosscorrelate ambient seismic noise, recorded along eight parallel lines in the Sirte basin east of Ajdabeya, Libya, to obtain shot gathers that contain reflections. We take advantage of geophone groups to suppress part of the undesired surface-wave noise and apply frequency-wavenumber filtering before crosscorrelation to suppress surface waves further. After comparing the retrieved results with data from an active seismic exploration survey along the same lines, we use the retrieved reflection data to obtain a migrated reflection image of the subsurface.

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