Path-specific, dispersion-based velocity models and moment tensors of moderate events recorded at few distant stations: Examples from Brazil and Greece

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F16%3A10330100" target="_blank" >RIV/00216208:11320/16:10330100 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1016/j.jsames.2016.07.004" target="_blank" >http://dx.doi.org/10.1016/j.jsames.2016.07.004</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jsames.2016.07.004" target="_blank" >10.1016/j.jsames.2016.07.004</a>

Result language

angličtina

Original language name

Path-specific, dispersion-based velocity models and moment tensors of moderate events recorded at few distant stations: Examples from Brazil and Greece

Original language description

Centroid moment tensor (CMT) determination in intraplate regions like Brazil can be very difficult, because earthquakes are often recorded just at few and distant stations. This paper introduces a methodology for datasets like that. The methodology is based on waveform inversion in which each source-station path has its own velocity model. The 1-D path-specific velocity models are derived from the Rayleigh- and Love-wave dispersion curves. The waveform inversion is accompanied by posterior check of numerous P-wave first-motion polarities. An important innovation is the use of so-called frequency range test. The test basically consists in calculating CMT's for many different frequency ranges to assess the stability and uncertainty of the solution. The method is validated on two Brazilian earthquakes and a well-known Greek event. An offshore event (mb 5.2) in SE Brazil is inverted with four stations, at epicentral distances 300-400 km. The other Brazilian earthquake (mb 4.8 in Central Brazil) is even more challenging only two broadband stations at 800-1300 km are at disposal for waveform inversion. The paper unambiguously demonstrates that the path-specific velocity models significantly increase the reliability of the CMT's. While standard models (e.g. IASP91) typically allow waveform modeling up to epicentral distances of the order of a few (similar to 10) minimum shear wavelengths (MSW), using the path specific velocity models we successfully inverted waveforms up to > 20 MSW. Single-station waveform inversions are thoroughly tested, but multi-station joint inversions are shown to be preferable. The new methodology of this paper, providing a reasonable estimate of focal mechanisms and their uncertainties in case of highly limited waveform data, may find broad applicability in Brazil and elsewhere. (C) 2016 Published by Elsevier Ltd.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

DC - Seismology, volcanology and Earth structure

OECD FORD branch

—

Project

<a href="/en/project/GA14-04372S" target="_blank" >GA14-04372S: Multiscale spatial-temporal complexity of tectonic earthquake sources</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of South American Earth Sciences

ISSN

0895-9811

e-ISSN

—

Volume of the periodical

71

Issue of the periodical within the volume

-

Country of publishing house

GB - UNITED KINGDOM

Number of pages

15

Pages from-to

344-358

UT code for WoS article

000385322400026

EID of the result in the Scopus database

2-s2.0-84979019846