HR: 1330h
AN: S22B-0456    [PDF]
TI: Coda Q Factor of the Hong Kong Region and Tectonic Implications
AU: * Mak, S
EM: titan@graduate.hku.hk
AF: Dept. of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, 000 Hong Kong
AU: Chan, L S
EM: chanls@hkucc.hku.hk
AF: Dept. of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, 000 Hong Kong
AU: Chandler, A
EM: amchandl@hkucc.hku.hk
AF: Dept. of Civil and Structural Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, 000 Hong Kong
AB: The coda-Q factor of the Hong Kong Region has been estimated using 25 local earthquakes of ML=2.7-4.6 and with epicentral distances within 200 km digitally recorded by eight short-period stations in Hong Kong. FFT and regression analysis were conducted on the coda waves within a 35 s window starting at t=2ts to obtain Q values for 10 frequencies from 2 Hz to 20 Hz for each record. Records with a S/N ratio $<5.0$ during the last 5 sec of the coda window, and Q values with a correlation coefficient $<0.45$ were rejected from the data set. A total of 260 data points yielded a Q-f relation of . The data were also divided into three groups based on epicentral distance (R), resulting in Q0 (Q at f=1 Hz) values of 224 (R$<50$ km), 342 (R=50-100 km) and 262 (R=100-200 km). The results are consistent with the spatial variations of the Q factor in the wider region of South China, and yield useful information on the crustal attenuation conditions in the Pearl River Delta region. In spite of the lack of major historical seismic events in the region, the relatively low Q-factor implies a tectonic setting more akin to areas with active seismicity, giving support to the existence of a major tectonic boundary between South China and the adjacent plates. (Support from HKU and PROCORE programme is gratefully acknowledged.)
DE: 7205 Continental crust (1242)
DE: 7212 Earthquake ground motions and engineering
DE: 7230 Seismicity and seismotectonics
DE: 8107 Continental neotectonics
SC: Seismology [S]
MN: 2003 Fall Meeting