No. +1,-.+,*++ Technical Research Report, Earthquake Research Institute, the University of Tokyo, No. +1, pp.,-.+,,*++.,- * * Deployment of online broadband seismic stations in Chiba and Ibaraki Prefectures after the,*++ o# the Pacific coast of Tohoku Earthquake Koji MIYAKAWA* and Atsushi WATANABE* Abstract After the,*++ o# the Pacific coast of Tohoku Earthquake, we deployed fifteen online broadband seismic stations in Chiba and Ibaraki Prefectures. The area we deployed is located close to the main slip area of the earthquake and the area of Boso slow slip events which occur about every six years. The purpose of the deployment is to study post-seismic activity and slow slip events using broadband seismic waves. They are composed of ten existing stations in Chiba Prefecture, and five newly constructed stations in Ibaraki Prefecture. First we repaired four existing stations since they had troubles by power outage after the earthquake. Then we started site survey for new stations. We conducted temporal seismic observations at all the thirteen candidate sites for about one week to evaluate ground noise levels, and selected five sites. Construction started in July and four stations have been completed and went online by mid-september, but the last station (E. IBR) remained completion until mid-october caused by the delay of the electric power service. Key words : Broadband seismometer, Seismic station, Site survey, Ground noise level +/,*++ - ++ +..0 Mw 3*. / /** km,** km +. ++ Mj 1.* +32* 0,**2,*++ +*,*++ +.,*++.,+,*++ ++.,*++ ++ +. miyakawa@eri.u-tokyo.ac.jp * * Technical Supporting Section for Observational Research, Earthquake Research Institute, the University of Tokyo. 23
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