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Tsunami earthquakes possibly widespread manifestations of frictional conditional stability
Author(s) -
Bilek S. L.,
Lay T.
Publication year - 2002
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 - 10.1029/2002gl015215
Subject(s) - tsunami earthquake , seismology , geology , subduction , interplate earthquake , remotely triggered earthquakes , intraplate earthquake , moment magnitude scale , earthquake swarm , earthquake rupture , seismic moment , slow earthquake , induced seismicity , fault (geology) , tectonics , scaling , geometry , mathematics
Tsunami earthquakes, shallow events that produce larger tsunamis than expected given their surface wave magnitudes (M s ), typically have long durations and a source spectrum depleted in short period energy. Seven cases of underthrusting tsunami earthquakes provide information on the rupture processes, but little constraint on geographic distribution or frequency. We compare their rupture characteristics with smaller magnitude earthquakes on circum‐Pacific interplate thrust faults. Comparable moment release time histories are found for large tsunami earthquakes and for many smaller shallow subduction zone earthquakes, with significantly longer durations and additional source complexity than for events deeper than 15 km. Thus, very shallow interplate earthquake ruptures are scale invariant, with variable frictional properties on the plate interface controlling the depth dependent rupture process. Widespread occurrence of small shallow interplate earthquakes with long durations suggests that many subduction faults have frictional properties that may enable large tsunami‐generating earthquakes to occur; fortunately, large shallow ruptures are infrequent.