THE CRUSTAL ANISOTROPY PATTERN IN THE EPICENTRAL AREA OF THE 2008 MW 6.4 EARTHQUAKE IN NORTHWEST PELOPONNESE, GREECE

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Published: Jul 27, 2016
DOI: https://doi.org/10.12681/bgsg.11823
Keywords:
shear wave splitting stress field wave propagation
D. Konstantinopoulos
University of Patras, Department of Geology, Seismological Laboratory
D. Giannopoulos
University of Patras, Department of Geology, Seismological Laboratory
E. Sokos
University of Patras, Department of Geology, Seismological Laboratory
K.I. Konstantinou
University of Patras, Department of Geology, Seismological Laboratory;Department of Earth Sciences, National Central University
G.A. Tselentis
Institute of Geodynamics, National Observatory of Athens,
Abstract

An anisotropic upper crust has been revealed in the W. Gulf of Corinth with potentially changing properties. During 2013, a unique opportunity to conduct a shear-wave analysis was presented, as a combination of the significantly increased seismicity in the area, including a seismic swarm between May and August, and the existence of local seismological networks. The Hellenic Unified Seismological Network (HUSN) and the Corinth Rift Laboratory Network (CRLN) provided invaluable data during the unrest period. While shear-waves travel through an anisotropic medium, the splitting phenomenon takes place and, as a result, their propagation is characterized by two discernible components: the fast (Sfast) and the slow (Sslow) one, which arrives to the station in a subsequent temporal point. Modern advances in seismology and geophysics have rendered shear-wave splitting a valuable tool in determining properties of the anisotropic propagation media. One of the predominant causes of this phenomenon is the existence of microcracks throughout the upper crust. The current study presents results for 8 stations from 535 analyzed events that are in agreement with the anisotropy models of EDA and APE.

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  • Geophysics and Seismology
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