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Evidence for pre‐seismic crustal movement in China and Japan
Author(s) -
Cao Lide,
Fujii Yoichiro
Publication year - 1989
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1989.tb00435.x
Subject(s) - seismology , geology , aftershock , fujita scale , levelling , interplate earthquake , intraplate earthquake , slip (aerodynamics) , fault (geology) , foreshock , geodetic datum , geodesy , tectonics , oceanography , physics , thermodynamics
Some recent Chinese observations on precursory crustal movements detected by geodetic measurements such as short‐range levelling or base‐line survey across the active fault corroborate the three gamma phases model of Fujita and Fujii: Gamma 1 phase is pre‐slip along the imminent faulting, gamma 2 is coseismic slip and gamma 3 is post‐slip along the main or subsidiary faulting after an earthquake. Typical of these are the results of short‐range levelling across the earthquake fault that ruptured during the 1976 Tangshan earthquake (M s = 7.8). Associated with the occurrence of the Tangshan earthquake or the subsequent Ninghe earthquake (M s = 6.9), remarkable gamma 2 phases were observed. At this same location abnormal gamma 1 or gamma 3 phases were detected from the Lulong 1982 earthquake (M s = 6.2) that originated from the north end of the Tangshan Fault and was one of the aftershocks of the Tangshan earthquake. These phases are interpreted by analogy with the recent experimental results of stick‐slip motion of the frictional sliding of rock.