title: Weak interplate coupling by seamounts and repeating M approximately 7 earthquakes.
abstract: Subducting seamounts are thought to increase the normal stress between subducting and overriding plates. However, recent seismic surveys and laboratory experiments suggest that interplate coupling is weak. A seismic survey in the Japan Trench shows that a large seamount is being subducted near a region of repeating earthquakes of magnitude M approximately 7. Both observed seismicity and the pattern of rupture propagation during the 1982 M 7.0 event imply that interplate coupling was weak over the seamount. A large rupture area with small slip occurred in front of the seamount. Its northern bound could be determined by a trace of multiple subducted seamounts. Whereas a subducted seamount itself may not define the rupture area, its width may be influenced by that of the seamount.
authors.affiliation: Earthquake Research Institute, University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. kimi@eri.u-tokyo.ac.jp
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Mochizuki
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Yamada
authors.forename: Masanao
authors.initials: M
authors.lastname: Shinohara
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Yamanaka
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kanazawa