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Imaging crustal structure around the western segment of the Atotsugawa fault system, central Japan
Author(s) -
Kato Aitaro,
Kurashimo Eiji,
Hirata Naoshi,
Iwasaki Takaya,
Iidaka Takashi
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl025841
Subject(s) - geology , seismology , fault (geology) , tilt (camera) , tectonics , clockwise , geometry , rotation (mathematics) , mathematics
The velocity structure at the western segment of the Atotsugawa fault system is elucidated by inverting arrival times from local earthquakes and explosive sources using double‐difference tomography. Bodies with high P‐wave velocities ( V p ) are imaged at depths greater than 2 km beneath surface traces of the Atotsugawa fault system. The high velocity bodies, which tilt gently to the south, markedly coincide with zones of high electrical resistivity. Quite low resistive zones at shallower depths in the vicinity of the fault correspond to bodies with low V p and high V p / V s . The top of the high‐velocity bodies is deeper in the northern and southern areas than that in the center of the fault system, showing a convex upward‐shape within the Niigata‐Kobe Tectonic Zone (NKTZ). Lateral variations in upper crustal structures could partially contribute to the observed large increase in compressional strain within the NKTZ.