HR: 0803h
AN: NS11D-0800    [Abstracts]
TI: Microtremor array measurement in Metropolitan Beijing
AU: Wang, W
EM: wjwang@seis.ac.cn
AF: Institute of Earthquake Science, China Earthquake Administration, 63 Fuxing Avenue, Beijing, 100036, China
AU: * Liu, L
EM: Lanbo.Liu@UConn.edu
AF: Institute of Earthquake Science, China Earthquake Administration, 63 Fuxing Avenue, Beijing, 100036, China
AU: * Liu, L
EM: Lanbo.Liu@UConn.edu
AF: Dept. Civil & Environ. Engineering, University of Connecticut, 261 Glenbrook Road, U-2037, Storrs, CT 06269-2037, United States
AU: Chen, Q
EM: chenqf@seis.ac.cn
AF: Institute of Earthquake Science, China Earthquake Administration, 63 Fuxing Avenue, Beijing, 100036, China
AU: Rohrbach, E
EM: eric.rohrbach@uconn.edu
AF: Dept. Civil & Environ. Engineering, University of Connecticut, 261 Glenbrook Road, U-2037, Storrs, CT 06269-2037, United States
AB: High-resolution near-surface geologic information is essential for seismic hazard reduction in urban areas. Traditionally, a seismic source within the area of study is always desirable for getting the high-resolution information. However, natural earthquake does not usually conveniently occur during periods of seismic observation. Meanwhile, explosive and/or vibrating sources are prohibited to be used in cities. To overcome these limitations for addressing urban seismic hazard reduction, microtremors, the ambient noise of micro-motions in the ground, are becoming valuable sources for extracting the much needed earthquake engineering parameters in urban settings. Using 30 three-component seismometers we have collected microtremor data at more than 1,000 sites in metropolitan Beijing area in the summer of 2007. The data were collected in two ways: 1) along two major roads running roughly orthogonal in NW and NE directions centered in the city center with 200-m seismometer spacing and minimum measurement duration of 1 hour; and 2) seismometer spacing of approximately 1-km that covered the entire area inside Beijing's 5th Beltway. The data are processed with both the horizontal to vertical spectral ratio method (H/V) and space correlation method. The delineated shear wave velocity and the bedrock interface mapping are compared with results by other means. Meanwhile, the newly obtained information on ground motion fundamental frequency and amplification factor will provide further constraints on seismic hazard analysis to those critical structures of the 2008 Summer Olympic Game. This project is supported by the Ministry of Science and Technology of China.
DE: 1599 General or miscellaneous
DE: 1810 Debris flow and landslides
DE: 7212 Earthquake ground motions and engineering seismology
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting