• journal_title：Bulletin of the Seismological Society of America
• Contributor：Shunping Pei ; Zhongxiong Cui ; Youshun Sun ; M. Nafi Toksöz ; Charlotte A. Rowe ; Xing Gao ; Junmeng Zhao ; Hongbing Liu ; Jiankun He ; F. Dale Morgan
• Publisher：Seismological Society of America
• Date：2009-
• Format：text/html
• Language：en
• Identifier：10.1785/0120080029
• journal_abbrev：Bulletin of the Seismological Society of America
• issn：0037-1106
• volume：99
• issue：1
• firstpage：428
• section：Short Notes

Seismic attenuation (Q-value) can be estimated by extracting the amplitude-frequency information contained in seismic waveforms. We apply the attenuation tomography method of Pei et al. (2006) using M_L amplitude data to estimate attenuation within the upper crust in Japan. More than 60,000 Sg-wave maximum amplitude readings from 5559 events, recorded by 971 stations, were selected from the dense High-Sensitivity Seismography Network (Hi-net) under the condition that epicentral distance is less than 2º and event depth is less than 10 km. The lateral S-wave Q variations of the upper crust at 1 Hz in Japan were obtained. The results indicate that low Q-values exist in the central Japanese islands, with almost the same distribution as volcanoes, while high Q-values exist mainly between the front of volcanoes and the Japanese east coast. In addition, a low Q was found between the eastern coast and the subducted trench. Most large crustal earthquakes occur in or around zones of low Q or the boundaries between areas of low and high Q, which will be very helpful in estimating the risk of large earthquakes.