HR: 0800h
AN: S31A-0218    [Abstracts]
TI: Metropolitan Seismic Observation Network (MeSO-net) in Japan
AU: * Nakagawa, S
EM: nakagawa@eri.u-tokyo.ac.jp
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Kasahara, K
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Sakai, S
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Tsuruoka, H
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Urabe, T
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Takano, K
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Sasaki, S
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Kato, A
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AU: Sekine, S
AF: National Research Institute for Earth Science and Disaster Prevention, Japan, 3-1, Tennodai, Tsukuba-shi, Ibaraki, 305-0006, Japan
AU: Obara, K
AF: National Research Institute for Earth Science and Disaster Prevention, Japan, 3-1, Tennodai, Tsukuba-shi, Ibaraki, 305-0006, Japan
AU: Tanada, T
AF: Hot Springs Research Institute of Kanagawa Prefecture, 586, Iryuda, Odawara-shi, Kanagawa, 250-0031, Japan
AU: Hirata, N
AF: Earthquake Research Institute, the University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113- 0032, Japan
AB: Beneath the metropolitan Tokyo area, the Philippine Sea Plate (PSP) subducts and causes damaged mega- thrust earthquakes. The Dai-Dai-Toku Project revealed the geometry of the upper surface of PSP, and estimated a rupture process and a ground motion of the 1923 Kanto earthquake. However, these results are not sufficient for the assessment of the entire picture of the seismic hazards beneath the metropolitan Tokyo area including those due to an intra-slab M7+ earthquake. So, we have started a new project, the Special Project for Earthquake Disaster Mitigation in the Metropolitan Tokyo area. Proving the more detailed geometry and physical properties (e.g. velocities, densities, attenuation) of PSP is very important to attain this issue. The core item of this project is the dense seismic array observation in metropolitan area, which is called the MeSO-net (Metropolitan Seismic Observation network). The MeSO-net consists of 400 stations including those in Hakone, a Data Center at ERI (Earthquake Research Institute, the University of Tokyo), and a Sub-Center at NIED (National Research Institute for Earth Science and Disaster Prevention), at which the data are backuped and integrated with the Hi-net data. In order to obtain the high resolution images of a velocity and Q structure, it is requested to construct a seismic network with a spacing of 2-5 km. The total number of seismic stations of the MeSO-net will be about 400. The MeSO-net is to be deployed in 4 years and will provide useful datasets. Since the metropolitan area is surrounded with cultural noises, seismographs are installed at the bottom of the 20-m-deep borehole. Seismographs, data of which are digitized at the bottom of observation well, are three- component acceleration type with the maximum measurable acceleration of ±2G (dynamic range of 135 dB or more). The seismic data with a sampling rate of 200 Hz are telemetered to the Data Center using UDP/IP protocol. We adopt an autonomous cooperative seismic telemetry system, which is a newly developed for the reliable data transmission in a large seismic observation network, such as the MeSO-net. The new system enables us to easily maintain and quickly recover from troubles.
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: 2007 Fall Meeting