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Earthquake triggering during preparation for great earthquakes
Author(s) -
Habermann R. E.,
Wyss M.
Publication year - 1984
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/gl011i004p00291
Subject(s) - epicenter , seismology , quake (natural phenomenon) , geology , stress field , foreshock , slow earthquake , seismic gap , earthquake prediction , interplate earthquake , aftershock , induced seismicity , engineering , structural engineering , finite element method
Seismic quiescence has been proposed as a precursor to many large earthquakes. In this paper we present two cases in which precursory quiescence is interrupted several years prior to great earthquakes by triggered events in the upcoming rupture areas. This triggering results in complex precursory patterns which include seismic quiescence and triggered events. Prior to the Kermadec earthquake of 1976 ( M s = 8.0) events in the rupture zone were triggered by a quake on the outer rise and one near the future mainshock epicenter. Events were triggered by an earthquake on an adjacent segment of the plate interface and by one near the epicenter of the New Hebrides earthquake of 1980 ( M s = 8.0). We propose that two preconditions must be fulfilled for triggering to occur. First the stress in the region must be close to the failure stress and second nearby events must occur which are large enough to affect the stress field but not large enough to cause an immediate mainshock.