HR: 08:40h
AN: S21D-03    [Abstracts]
TI: Home Seismometer
AU: * Horiuchi, S
EM: horiuchi@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai Ibaraki, Tsukuba, 305-0006, Japan
AU: Yamamoto, S
EM: syama@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai Ibaraki, Tsukuba, 305-0006, Japan
AU: Nakmaura, H
EM: manta@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai Ibaraki, Tsukuba, 305-0006, Japan
AU: Wu, C
EM: wu@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai Ibaraki, Tsukuba, 305-0006, Japan
AU: Rydelek, P
EM: par@ceri.memphis.edu
AF: National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai Ibaraki, Tsukuba, 305-0006, Japan
AU: Kachi, M
EM: mark@a-2.co.jp
AF: A2 Corp., 2-4-10, Nakanobu Tokyo, Shinagawa, 142-0052, Japan
AB: We have developed an automated system for analyzing Hi-net seismograms for earthquake early warning (EEW) in Japan. Because of limitations imposed by station spacing, our system generally cannot issue an EEW to areas within about 30 km distance of the earthquake's hypocenter. We estimate that about 10 times the number of stations would be needed to issue an EEW in these areas, but the overhead would be cost prohibitive for governmental agencies. The practical deployment of EEW in Japan has started in October, 2007 and millions of people are expected to purchase and install the receiving/alarm unit of EEW. Since most of these units are connected to internet and equipped with a CPU and memory, we realized that the addition of an inexpensive seismometer and digitizer would transform the receiver into a real-time seismic observatory, which we are calling a home seismometer; these modifications only cost about $20. The home seismometer can help to generate alerts at the time of the occurrence of a large local earthquake by using locally observed data. Also, home seismograms can be used to estimate the amplification factor in sedimentary layers, which will be used to determine the site correction for shaking intensity by comparing the waveform data from the home seismometer against those from nearby Hi-net or K-NET stations. This amplification factor, which is essentially the basis of a shake-map with very-high spatial resolution, will help to establish a safety index of houses/buildings for large earthquakes, since a structure located at a site with large seismic amplification can be damaged more seriously than those with small amplification factors. The installation of home seismometers will create an extremely dense seismic network that is without precedence. We are developing an automatic system that collects waveform data from all home seismometer installations, calculates earthquake parameters in real-time, and then sends back alarms signals based on computed results in order to provide an accurate estimate of the expected shaking level at each house or building.
UR: http://www.bosai.go.jp/e/index.html
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: 2007 Fall Meeting