Technical Note 20/6
LEG 186
WEST PACIFIC SEISMIC NETWORK
Modified by K. Suyehiro from Proposal 431 Submitted by:
K. Suyehiro, H. Fujimoto, T. Kanazawa, J. Kasahara, Y. Fukao, H. Momma,
K. Fujioka, T. Matsumoto, J. Kinoshita, S. Sacks, A. Linde, R. Hino, A.
Hasegawa, M. Shinohara, and I. Kawasaki
Staff Scientist: Gary Acton --- Co-Chief Scientists: Kiyoshi Suyehiro and Selwyn Sacks
ABSTRACT
During Leg 186, we will drill two sites from the deep-sea terrace on the landward side of the Japan
Trench off northeast Japan to monitor crustal response to stable (aseismic) or unstable (seismic)
sliding of the subducting Pacific Plate. This will be the first attempt to establish such a long-term
seafloor borehole observatory in one of the world's most active and most studied subduction
zones. Near-field data from an active plate boundary are crucial in quantifying the plate's elastic and
anelastic behaviors in relation to earthquakes. Borehole strainmeters and broadband seismometers
will be installed at the bottom of the two holes to continuously monitor strain changes and seismic
activities associated with episodic plate motions. Secondary objectives include (1) determining the
forearc subsidence history and placing constraints on the subduction mass balance at this tectonic
erosional environment and (2) obtaining arc volcanism reference since 3 Ma.
To 186 FY99 Complete Text
To FY99 Table of Contents
ODP Publications
ODP Science Services
ODP Home