scholarly journals Surface Wave Path Corrections and Source Inversions in Southern California

2010 ◽  
Vol 100 (6) ◽  
pp. 2891-2904 ◽  
Author(s):  
Y. Tan ◽  
A. Song ◽  
S. Wei ◽  
D. Helmberger
Keyword(s):  
Surface Wave ◽  
Southern California ◽  
Wave Path

scholarly journals Vp/Vs tomography in the southern California plate boundary region using body and surface wave traveltime data

2018 ◽  
Vol 216 (1) ◽  
pp. 609-620 ◽  
Author(s):  
Hongjian Fang ◽  
Huajian Yao ◽  
Haijiang Zhang ◽  
Clifford Thurber ◽  
Yehuda Ben-Zion ◽  
...  
Keyword(s):  
Surface Wave ◽  
Southern California ◽  
Plate Boundary ◽  
Boundary Region

Measurement of interstation phase and group velocities and Q using Wiener filtering

1982 ◽  
Vol 72 (1) ◽  
pp. 73-91
Author(s):  
Steven R. Taylor ◽  
M. Nafi Toksöz
Keyword(s):  
Surface Wave ◽  
Green’S Function ◽  
Green's Function ◽  
Amplitude Spectrum ◽  
Wiener Filter ◽  
Wave Path ◽  
Phase And Group Velocities ◽  
Filtering Technique ◽  
Surface Wave Data ◽  
Group Velocities

abstract A method for calculating interstation phase and group velocities and attenuation coefficients using a Wiener (least-squares) filtering technique is presented. The interstation Green's (or transfer) function is estimated from surface wave data from two stations laying along the same great circle path. The estimate is obtained from a Wiener filter which is constructed to estimate the signal recorded at the station further from the source from the signal recorded at the nearer station. The interstation group velocity is obtained by applying the multiple-filtering technique to the Green's function, and the interstation phase velocity from the phase spectrum of the Green's function. The amplitude spectrum of the Green's function is used to calculate average attenuation between the two stations. Using synthetic seismograms contaminated by noise, it is shown that the Q values calculated from the Green's function are significantly more stable and accurate than those obtained by taking spectral ratios. The method is particularly useful for paths involving short station separations and is applied to a surface wave path crossing the Iranian Plateau.

Retrieving 2D structures from surface-wave data by means of space-varying spatial windowing

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. EN39-EN51 ◽  
Author(s):  
Paolo Bergamo ◽  
Daniele Boiero ◽  
Laura Valentina Socco
Keyword(s):  
Surface Wave ◽  
Real Data ◽  
Processing Technique ◽  
Dispersion Curves ◽  
Data Sets ◽  
Local Dispersion ◽  
Wave Data ◽  
Survey Line ◽  
Wave Path ◽  
Surface Wave Data

Surface-wave techniques are mainly used to retrieve 1D subsurface models. However, in 2D environments, the 1D approach usually neglects the presence of lateral variations and because the surface-wave path crosses different materials, the resulting model is a simplified or misleading description of the site. We tested a processing technique to retrieve 2D structures from surface-wave data acquired with a limited number of receivers. Our technique was based on a two-step process. First, we extracted several local dispersion curves along the survey line using a spatial windowing based on a set of Gaussian windows with different shapes; the window maxima span the survey line so that we were able to extract a dispersion curve from the seismic record for every window. This provided a set of local dispersion curves each of them referring to a different subsurface portion. This space varying spatial windowing provided a good compromise between wavenumber resolution and the lateral resolution of the obtained local dispersion curves. In the second step, we inverted the retrieved set of dispersion curves using a laterally constrained inversion scheme. We applied this procedure to the processing of synthetic and real data sets and the method proved to be successful in reconstructing even complex 2D structures in the subsurface.

Regional bias in estimates of earthquake MS due to surface-wave path effects

1994 ◽  
Vol 84 (2) ◽  
pp. 377-382
Author(s):  
Rachel E. Abercrombie
Keyword(s):  
Surface Wave ◽  
Tectonic Setting ◽  
High Surface ◽  
Earthquake Source ◽  
Plate Boundaries ◽  
Source Type ◽  
Shallow Earthquakes ◽  
Seismic Strain Rate ◽  
Seismic Strain ◽  
Wave Path

Abstract Continental earthquakes have long been known to have anomalously high surface-wave magnitudes relative to their seismic moments. A recent global study of shallow earthquakes by Ekström and Dziewonski (1988) confirmed this and found other regional, systematic anomalies in the MS-M0 relationship. It is important to determine the source of these anomalies in order to understand the controls on earthquake-source radiation and to obtain accurate estimates of historical seismic strain rates. In this study the magnitudes of 82 earthquakes from eight different tectonic regions are recalculated using a simple surface-wave path correction to determine whether path effects are responsible for the observed anomalies. The magnitudes of continental earthquakes are reduced by an average of 0.2 magnitude units, an improvement in fit to the global average significant at the 98% level. Surface-wave path effects are clearly responsible for the high MS observed in continental areas. There is a small decrease in scatter in the other areas, but lateral refraction of the surface waves at plate boundaries prevents the simple correction from having a significant effect. There is no evidence in the observed anomalies, however, for any dependence of earthquake-source type on tectonic setting. It is clear that to obtain reliable, unbiased estimates of regional seismic strain rate and hazard, a local moment-magnitude relationship should be preferred to a global one.

scholarly journals Surface wave tomography from microseisms in Southern California

2005 ◽  
Vol 32 (14) ◽  
pp. n/a-n/a ◽  
Author(s):  
Karim G. Sabra ◽  
Peter Gerstoft ◽  
Philippe Roux ◽  
W. A. Kuperman ◽  
Michael C. Fehler
Keyword(s):  
Surface Wave ◽  
Southern California ◽  
Surface Wave Tomography ◽  
Wave Tomography
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