scholarly journals Estimation of Deep S-wave Velocity Structure in Osaka Plains Urban Area by Using Microtremor Survey Method

2011 ◽  
Vol 52 (5) ◽  
pp. 192-198
Author(s):  
Yuichiro MINAMI ◽  
Tatsurou MATSUOKA ◽  
Tsuyoshi HARAGUCHI ◽  
Kenta MOTOKI
Keyword(s):  
Urban Area ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Survey Method ◽  
S Wave ◽  
Microtremor Survey

Deep S-wave Velocity Structure in Osaka Plains Urban Area Estimated by Microtremor Survey Method

2014 ◽  
Vol 55 (3) ◽  
pp. 110-117 ◽  
Author(s):  
Yuichiro MINAMI ◽  
Yukihiro MIZUOCHI ◽  
Tatsurou MATSUOKA ◽  
Tsuyoshi HARAGUCHI ◽  
Kenta MOTOKI
Keyword(s):  
Urban Area ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Survey Method ◽  
S Wave ◽  
Microtremor Survey

scholarly journals Estimation of shallow subsurface S-wave velocity structure in urban area based on inversion of apparent dispersion curve

2020 ◽  
Vol 17 (6) ◽  
pp. 940-955
Author(s):  
Zhiwei You ◽  
Peifen Xu ◽  
Suqun Ling ◽  
Yanan Du ◽  
Ruohan Zhang ◽  
...  
Keyword(s):  
Spatial Autocorrelation ◽  
Urban Area ◽  
Wave Velocity ◽  
Simulated Annealing Algorithm ◽  
Velocity Structure ◽  
Dispersion Curves ◽  
Survey Method ◽  
S Wave ◽  
Geological Surveys ◽  
Autocorrelation Method

Abstract Due to its efficiency, convenience, non-destructive nature and strong anti-interference capability, the microtremor survey method (MSM) has found wide applications in urban geological surveys. The spatial autocorrelation method is diffusely applied to extract the dispersion curves from microtremor signals, which needs to satisfy the assumption that the energy of the fundamental Rayleigh wave is dominant. However, for layered media containing a layer with a significant low- or high-velocity contrast, this assumption is distinctly incorrect for certain frequency ranges. We present a processing methodology comprising the extraction and inversion of the apparent dispersion curves based on extended spatial autocorrelation method and fast simulated-annealing algorithm. We analyse synthetic microtremor signals for three selected geological models, and then compare the S-wave velocity structures estimated from their inversions with the actual models. Subsequently, a filed data example is given to detect the shallow stratigraphic structures in Guangzhou city, China, in which the new MSM was used. The estimated two-dimensional S-wave velocity model provided an accurate description of the thickness and depth of the strata in the study area, based on a priori information. Moreover, the S-wave velocity structures estimated from the MSM and the results from the drilling match very well, indicating that MSM is a reliable geophysical technique in urban geological surveys. Combined with available borehole information, MSM can be a very robust and effective method for detecting the shallow three-dimensional velocity structures in an urban area.

Building a geothermal formation model using microtremor array measurement

Geophysics ◽  
2021 ◽  
pp. 1-34
Author(s):  
Baoqing Tian ◽  
You Zhiwei ◽  
Guangjie Wang ◽  
Jiangjie Zhang
Keyword(s):  
Heat Flow ◽  
Wave Velocity ◽  
Geophysical Methods ◽  
Correlation Method ◽  
Survey Method ◽  
Geothermal System ◽  
Formation Model ◽  
S Wave ◽  
Geothermal Resources ◽  
Microtremor Survey

A comprehensive understanding of the internal structure and building a geomechanical formation model plays an important role in developing and utilizing geothermal resources. Formation models help in identifying the channel and cycling modes of the heat flow. Due to the urban sprawl and development, constructing a formation model of geothermal resources based on data from traditional geophysical methods is challenging. The Microtremor survey method was adopted to obtain critical information in Jimo, which is famous for rare seawater geothermal resources in China. Three microtremor survey lines were deployed to identify subsurface structures up to 2 km into the ground. Dispersion curves of Rayleigh waves with frequencies from 0.4 Hz to 10 Hz were extracted using the spatial auto-correlation method. An empirical equation was adopted to obtain the apparent S-wave velocity of each survey point, and plot the apparent S-wave velocity sections. The obtained sections reveal the development of two interacting faults. They form a channel for the heat-flow cycle. Two conceptual models were established to depict the formation and cycling modes of seawater geothermal resources in Jimo, based on the results and analysis. The proposed model will help verify the geothermal system and scientifically guide the development of unique geothermal resources . Moreover, the developed model verified that the microtremor survey method is effective and dependable for identifying fracture zones and strata.

scholarly journals Rapid assessment of S-wave profiles from the inversion of multichannel

1998 ◽  
Vol 41 (1) ◽  
Author(s):  
G. A. Tselentis ◽  
G. Delis
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Velocity Structure ◽  
Rapid Assessment ◽  
Detailed Knowledge ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Wave Profiles ◽  
Shear Wave Velocity Structure

The importance of detailed knowledge of the shear-wave velocity structure of the upper geological layers was recently stressed in strong motion studies. In this work we describe an algorithm which we have developed to infer the 1D shear wave velocity structure from the inversion of multichannel surface wave dispersion data (ground-roll). Phase velocities are derived from wavenumber-frequency stacks while the inversion process is speeded up by the use of Householder transformations. Using synthetic and experimental data, we examined the applicability of the technique in deducing S-wave profiles. The comparison of the obtained results with those derived from cross-hole measurements and synthesized wave fields proved the reliability of the technique for the rapid assessment of shear wave profiles during microzonation investigations.

Microtremor exploration for shallow S-wave velocity structure in Bandung Basin, Indonesia

2017 ◽  
Vol 48 (4) ◽  
pp. 401-412 ◽  
Author(s):  
Andi Muhamad Pramatadie ◽  
Hiroaki Yamanaka ◽  
Kosuke Chimoto ◽  
Kazuki Koketsu ◽  
Minoru Sakaue ◽  
...  
Keyword(s):  
Wave Velocity ◽  
Velocity Structure ◽  
S Wave

Tuning S-Wave Velocity Structure of Deep Sedimentary Layers in the Shimousa Region of the Kanto Basin, Japan, Using Autocorrelation of Strong-Motion Records

2020 ◽  
Vol 110 (6) ◽  
pp. 2882-2891
Author(s):  
Kosuke Chimoto ◽  
Hiroaki Yamanaka
Keyword(s):  
Wave Velocity ◽  
Velocity Structure ◽  
Strong Motion ◽  
S Wave ◽  
Reflected Waves ◽  
Arrival Times ◽  
Strong Motion Records ◽  
Kanto Basin ◽  
Determination Of Parameters

ABSTRACT The autocorrelation of ambient noise is used to capture reflected waves for crustal and sedimentary structures. We applied autocorrelation to strong-motion records to capture the reflected waves from sedimentary layers and used them for tuning the S-wave velocity structure of these layers. Because a sedimentary-layered structure is complicated and generates many reflected waves, it is important to identify the boundary layer from which the waves reflected. We used spectral whitening during autocorrelation analysis to capture the reflected waves from the seismic bedrock with an appropriate smoothing band, which controls the wave arrival from the desired layer boundary. The effect of whitening was confirmed by the undulation frequency observed in the transfer function of the sedimentary layers. After careful determination of parameters for spectral whitening, we applied data processing to the strong-motion records observed at the stations in the Shimousa region of the Kanto Basin, Japan, to estimate the arrival times of the reflected waves. The arrival times of the reflected waves were found to be fast in the northern part of the Shimousa region and slow in the western and southern parts. These arrival times are consistent with those obtained using existing models. Because we observed a slight difference in the arrival times, the autocorrelation function at each station was used for tuning the S-wave velocity structure model of the sedimentary layers using the inversion technique. The tuned models perfectly match the autocorrelation functions in terms of the arrival time of the reflected waves from the seismic bedrock.

Estimating deep S-wave velocity structure in the Los Angeles Basin using a passive surface-wave method

2013 ◽  
Vol 32 (6) ◽  
pp. 620-626 ◽  
Author(s):  
Koichi Hayashi ◽  
Antony Martin ◽  
Ken Hatayama ◽  
Takayuki Kobayashi
Keyword(s):  
Surface Wave ◽  
Los Angeles ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Wave Method ◽  
S Wave ◽  
Los Angeles Basin ◽  
Surface Wave Method
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