Nonvolcanic deep tremor associated with subduction in southwest Japan.
Deep long-period tremors were recognized and located in a nonvolcanic region in southwest Japan. Epicenters of the tremors were distributed along the strike of the subducting Philippine Sea plate over a length of 600 kilometers. The depth of the tremors averaged about 30 kilometers, near the Mohorovic discontinuity. Each tremor lasted for at most a few weeks. The location of the tremors within the subduction zone indicates that the tremors may have been caused by fluid generated by dehydration processes from the slab.
Obara
Kazushige
K
National Research Institute for Earth Science and Disaster Prevention, Tenno-dai 3-1, Tsukuba, Ibaraki, 305-0006, Japan. obara@bosai.go.jp