Abstract :
Byline: Won Sang Lee (1), Haruo Sato (2), Sukyoung Yun (1,3) Keywords: coda; seismic envelope; ScS; Q .sub.C .sup.-1 ; mantle Abstract: Coda envelope reflects heterogeneity in the Earth medium. Examining seismogram envelopes of regional earthquakes over the world in 1--20 s periods for a wide lapse time range up to 2000 s, we classified them focusing on the envelope characteristics around ScS arrivals. We found that coda decay gradient decreases after ScS arrival irrespective of focal depths and epicentral distances on a semi-logarithmic scale plot. Amplitude offset behavior observed in seismic envelopes is an evidence that scattered waves of ScS waves sometimes dominate over scattered S waves and scattered surface waves. Such an offset associated with ScS arrival is not clear for shallow events ( Author Affiliation: (1) Division of Polar Earth System Sciences, Korea Polar Research Institute, Incheon, 406-840, Korea (2) Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Japan (3) School of Earth and Environmental Sciences, Seoul National University, Sillim-Dong, Gwanak-Gu, Seoul, 151-747, Korea Article History: Registration Date: 11/01/2009 Received Date: 11/01/2009 Accepted Date: 13/06/2009 Online Date: 14/01/2010