TY - JOUR
T1 - Tomographic evidence for hydrated oceanic crust of the Pacific slab beneath northeastern Japan
T2 - Implications for water transportation in subduction zones
AU - Tsuji, Yusuke
AU - Nakajima, Junichi
AU - Hasegawa, Akira
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/7/28
Y1 - 2008/7/28
N2 - We estimate detailed seismic-velocity structure around the Pacific slab beneath northeastern Japan by double-difference tomography. A remarkable low-velocity zone with a thickness of ∼10 km, which corresponds to much hydrated oceanic crust, is imaged coherently along the arc at the uppermost part of the slab. The zone gradually disappears at depths of 70-90 km, suggesting the occurrence of intensive dehydration reactions there. The concentration of intraslab earthquakes at these depths supports dehydration-embrittlement hypothesis as a mechanism for generating intraslab earthquakes. A low-velocity zone imaged immediately above the slab at depths >70 km probably reflects a hydrous layer that absorbs water expelled from the slab and carries it to deeper depths along the slab. Our observations suggest that an along-arc variation in arc volcanism might be related to that in the development of the hydrous layer above the slab.
AB - We estimate detailed seismic-velocity structure around the Pacific slab beneath northeastern Japan by double-difference tomography. A remarkable low-velocity zone with a thickness of ∼10 km, which corresponds to much hydrated oceanic crust, is imaged coherently along the arc at the uppermost part of the slab. The zone gradually disappears at depths of 70-90 km, suggesting the occurrence of intensive dehydration reactions there. The concentration of intraslab earthquakes at these depths supports dehydration-embrittlement hypothesis as a mechanism for generating intraslab earthquakes. A low-velocity zone imaged immediately above the slab at depths >70 km probably reflects a hydrous layer that absorbs water expelled from the slab and carries it to deeper depths along the slab. Our observations suggest that an along-arc variation in arc volcanism might be related to that in the development of the hydrous layer above the slab.
UR - http://www.scopus.com/inward/record.url?scp=53749100291&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=53749100291&partnerID=8YFLogxK
U2 - 10.1029/2008GL034461
DO - 10.1029/2008GL034461
M3 - Article
AN - SCOPUS:53749100291
VL - 35
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 14
M1 - L14308
ER -