Coda Q estimates in the Hong Kong region

Abstract

Complementing a series of recent seismic hazard studies for Hong Kong, we have estimated the Q factor using 25 local earthquakes, within 200 km of Hong Kong, digitally recorded from January 1998 to July 2000 by eight short-period stations of the Hong Kong Observatory seismic monitoring network. By analyzing the coda wave at frequencies 2-20 Hz, we obtained a Q-f relation of Q=256f 0.7. The values of Q 0 (Q at 1 Hz) determined for three distance ranges (R) are 224 for R≤50 km, 342 for 50<R<100 km and 262 for 100≤R≤200 km. The results are consistent with the spatial variations of the Q factor in the wider region of South China. The results fill an important gap in knowledge about the Q factor and associated crustal attenuation conditions in the Pearl River Delta region including Hong Kong, and provide useful insight into the influence of epicentral distance range in coda-Q measurements, allowing better understanding of the degree of complexity in the crustal structure of the region. © 2004 Elsevier Ltd. All rights reserved.