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A possible explanation for difference in stress drop between intraplate and interplate earthquakes
Author(s) -
Kato Naoyuki
Publication year - 2009
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 - 10.1029/2009gl040985
Subject(s) - intraplate earthquake , geology , seismology , drop (telecommunication) , interplate earthquake , asperity (geotechnical engineering) , stress (linguistics) , geotechnical engineering , tectonics , engineering , telecommunications , linguistics , philosophy
It is known from observations that stress drop of intraplate earthquakes is larger than that of interplate earthquakes on average. I present a mechanical model for explaining the difference in stress drop, where an intraplate fault is assumed to be loaded uniformly, while a locked area (an asperity) on a plate boundary is nonuniformly loaded by surrounding aseismic sliding. A numerical simulation is conducted to quantitatively evaluate the difference in stress drop for different loading processes. Because the model intraplate fault is uniformly loaded, stress drop is uniform over the fault with a larger average value. In contrast, stress concentration is generated at a boundary region between locked area and aseismic sliding area for a model interplate earthquake. This stress concentration hastens earthquake occurrence, resulting in lower average stress drop. The stress drop of simulated intraplate earthquakes is several tens percent larger than that of simulated interplate earthquakes.