Attenuation of high frequency body waves in the crust of western Tibet

Publication date: Available online 28 October 2019Source: Physics of the Earth and Planetary InteriorsAuthor(s): Rahul Biswas, Chandrani SinghAbstractThe attenuation characteristics of western Tibet have been analyzed by estimating the seismic attenuation parameters (Qp−1 and Qs−1) at five different central frequencies (1.5, 3, 6, 12 and 18 Hz). The extended coda normalization method has been used on 469 three component local earthquakes which are recorded at Y2 network of broadband stations deployed in western Tibet during 2007-2011 years. We have estimated the frequency dependent Qp−1 and Qs−1 values at each station. The results indicate strong body wave attenuation in the medium below western Tibet. The highest attenuation is observed at WT19 and WT13 stations located near to the Karakoram fault (KKF) and Indus-Yarlung suture (IYS). Across the KKF, we have subdivided the entire study area into two regions to explore the lateral variations of crustal attenuation properties. First part covers the northeastern of KKF referred as Region 1 while second part covers southwestern of KKF referred as Region 2. The frequency dependent relations are found as follows: Qp−1 = (19.4 ± 4.4).10−3f−(0.9±0.2), Qs−1 = (13.3 ± 2.1).10−3f−(0.8±0.1) for Region 1 and Qp−1 = (18.4 ± 1.8).10−3f−(0.8±0.1), Qs−1 = (13.2 ± 2.2).10−3f−(0.8±0.1) for Region 2. Both the regions show strong frequency dependent nature of Q−1 values with no significant lateral variat...

Source: Physics of the Earth and Planetary Interiors - October 28, 2019 Category: Physics Source Type: research