TY - JOUR
T1 - Along-trench structural variation and seismic coupling in the northern Japan subduction zone
AU - Fujie, Gou
AU - Miura, Seiichi
AU - Kodaira, Shuichi
AU - Kaneda, Yoshiyuki
AU - Shinohara, Masanao
AU - Mochizuki, Kimihiro
AU - Kanazawa, Toshihiko
AU - Murai, Yoshio
AU - Hino, Ryota
AU - Sato, Toshinori
AU - Uehira, Kenji
N1 - Funding Information:
Acknowledgments. We thank Greg Moore and an anonymous reviewer for their thorough reviews and very helpful comments that greatly improved our manuscript. This study was partly funded by the Ministry of Education, Culture, Sports, Science and Technology as “A Pilot study on the Miyagi-ken oki earthquake”.
PY - 2013
Y1 - 2013
N2 - Large destructive interplate earthquakes, such as the 2011 Mw 9.0 Tohoku-oki earthquake, have occurred repeatedly in the northern Japan subduction zone. The spatial distribution of large interplate earthquakes shows distinct along-trench variations, implying regional variations in interplate coupling. We conducted an extensive wide-angle seismic survey to elucidate the along-trench variation in the seismic structure of the forearc and to examine structural factors affecting the interplate coupling beneath the forearc mantle wedge. Seismic structure models derived from wide-angle traveltimes showed significant along-trench variation within the overlying plate. In a weakly coupled segment, (i) the sediment layer was thick and flat, (ii) the forearc upper crust was extremely thin, (iii) the forearc Moho was remarkably shallow (about 5 km), and (iv) the P-wave velocity within the forearc mantle wedge was low, whereas in the strongly coupled segments, opposite conditions were found. The good correlation between the seismic structure and the segmentation of the interplate coupling implies that variations in the forearc structure are closely related to those in the interplate coupling.
AB - Large destructive interplate earthquakes, such as the 2011 Mw 9.0 Tohoku-oki earthquake, have occurred repeatedly in the northern Japan subduction zone. The spatial distribution of large interplate earthquakes shows distinct along-trench variations, implying regional variations in interplate coupling. We conducted an extensive wide-angle seismic survey to elucidate the along-trench variation in the seismic structure of the forearc and to examine structural factors affecting the interplate coupling beneath the forearc mantle wedge. Seismic structure models derived from wide-angle traveltimes showed significant along-trench variation within the overlying plate. In a weakly coupled segment, (i) the sediment layer was thick and flat, (ii) the forearc upper crust was extremely thin, (iii) the forearc Moho was remarkably shallow (about 5 km), and (iv) the P-wave velocity within the forearc mantle wedge was low, whereas in the strongly coupled segments, opposite conditions were found. The good correlation between the seismic structure and the segmentation of the interplate coupling implies that variations in the forearc structure are closely related to those in the interplate coupling.
KW - Forearc mantle interplate coupling.
KW - Japan trench
KW - Wide-angle seismic survey
UR - http://www.scopus.com/inward/record.url?scp=84876246653&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84876246653&partnerID=8YFLogxK
U2 - 10.5047/eps.2012.06.003
DO - 10.5047/eps.2012.06.003
M3 - Article
AN - SCOPUS:84876246653
VL - 65
SP - 75
EP - 83
JO - Earth, Planets and Space
JF - Earth, Planets and Space
SN - 1343-8832
IS - 2
ER -