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Interaction between two subducting plates under Tokyo and its possible effects on seismic hazards
Author(s) -
Wu Francis,
Okaya David,
Sato Hiroshi,
Hirata Naoshi
Publication year - 2007
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 - 10.1029/2007gl030763
Subject(s) - geology , seismology , subduction , induced seismicity , lithosphere , pacific plate , mantle (geology) , tectonics , geophysics
Underneath metropolitan Tokyo the Philippine Sea plate (PHS) subducts to the north on top of the westward subducting Pacific plate (PAC). New, relatively high‐resolution tomography images the PHS as a well‐defined subduction zone under western Kanto Plain. As PAC shoals under eastern Kanto, the PHS lithosphere is being thrusted into an increasingly tighter space of the PAC‐Eurasian mantle wedge. As a result, zones of enhanced seismicity appear under eastern Kanto at the top of PHS, internal to PHS and also at its contact with PAC. These zones are located at depths greater than the causative fault of the disastrous 1923 Great Tokyo “megathrust” earthquake, in the vicinity of several well‐located historical, damaging (M6 and M7) earthquakes. Thus a rather unique interaction between subducting plates under Tokyo may account for additional seismic hazards in metropolitan Tokyo.