Open AccessRefinements to the method of epicentral location based on surface waves from ambient seismic noise: introducing Love waves
Author(s) -
Levshin Anatoli L.,
Barmin Mikhail P.,
Moschetti Morgan P.,
Mendoza Carlos,
Ritzwoller Michael H.
Publication year - 2012
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2012.05631.x
Subject(s) - rayleigh wave , geology , seismology , love wave , seismic noise , ambient noise level , noise (video) , geodesy , surface wave , rayleigh scattering , seismic wave , microseism , geophysics , wave propagation , longitudinal wave , physics , mechanical wave , optics , sound (geography) , geomorphology , artificial intelligence , computer science , image (mathematics)
SUMMARY The purpose of this study is to develop and test a modification to a previous method of regional seismic event location based on Empirical Green's Functions (EGFs) produced from ambient seismic noise. Elastic EGFs between pairs of seismic stations are determined by cross‐correlating long ambient noise time‐series recorded at the two stations. The EGFs principally contain Rayleigh‐ and Love‐wave energy on the vertical and transverse components, respectively, and we utilize these signals between about 5 and 12 s period. The previous method, based exclusively on Rayleigh waves, may yield biased epicentral locations for certain event types with hypocentral depths between 2 and 5 km. Here we present theoretical arguments that show how Love waves can be introduced to reduce or potentially eliminate the bias. We also present applications of Rayleigh‐ and Love‐wave EGFs to locate 10 reference events in the western United States. The separate Rayleigh and Love epicentral locations and the joint locations using a combination of the two waves agree to within 1 km distance, on average, but confidence ellipses are smallest when both types of waves are used.