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Pore pressure distribution along plate interface that causes a shallow asperity of the 2011 great Tohoku‐oki earthquake
Author(s) -
Yoshida Shingo,
Kato Naoyuki
Publication year - 2011
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 - 10.1029/2011gl048902
Subject(s) - asperity (geotechnical engineering) , geology , pore water pressure , hydrostatic pressure , hydrostatic equilibrium , permeability (electromagnetism) , overpressure , overburden pressure , stress (linguistics) , mechanics , seismology , geotechnical engineering , thermodynamics , biology , genetics , linguistics , philosophy , physics , quantum mechanics , membrane
Kato and Yoshida (2011) conducted a numerical simulation for understanding the mechanics of the 2011 Tohoku‐oki earthquake. In this model, a strong asperity with higher effective normal stress was assumed at a shallower part of the plate interface. This shallow strong asperity controls the occurrence cycle of great earthquakes. The present paper discusses pore pressure distribution along the interface at the Pacific plate subducting beneath northern Honshu (Tohoku), Japan. Assuming that the permeability is exponentially dependent on effective stress and that the proportional constant drops to a lower value at a critical effective stress due to pore collapse, we obtained nearly hydrostatic pore pressure at a shallow part and nearly lithostatic pressure at a deep part of the plate interface. Assuming a different permeability model, in which increase of confining pressure has a larger effect than decrease of pore pressure, we obtained similar results. Such pore pressure distributions provide a possible generation mechanism for a shallow strong asperity.