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Permeability structure around an ancient exhumed subduction‐zone fault
Author(s) -
Kato Aitaro,
Sakaguchi Arito,
Yoshida Shingo,
Yamaguchi Haruka,
Kaneda Yoshiyuki
Publication year - 2004
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 - 10.1029/2003gl019183
Subject(s) - geology , permeability (electromagnetism) , subduction , seismology , petrology , fault (geology) , pore water pressure , turbidite , tectonics , geochemistry , geotechnical engineering , sedimentary rock , genetics , membrane , biology
We conducted permeability measurements on rocks sampled from an exhumed ancient subduction zone fault in the Cretaceous Shimanto accretionary complex of Japan. The permeability under seismogenic environment conditions shows a heterogeneous structure across the fault zone. Permeability of the sandstone in turbidite sequence is the lowest, whereas the highly sheared zone has the largest permeability. A combination of permeability contrast between these two zones and fluid pressure source, including tectonically driven burial and dehydration, could result in a concentration of pore fluids along the fault, which causes Deep Seismic Reflections during underplating stage as delineated in seismic reflection studies. Following a rise of temperature up to 250°C, the permeability of all the sampled rock types became smaller than at room temperature, and also gradually decreased with increasing hold time.