Attenuation of high-frequency P and S waves in Garhwal Himalaya, India

Abstract Tectonics of a region plays important role on the attenuation characteristics of the region. Attenuation characteristics have been estimated to understand the effect of the heterogeneity of the region in a tectonically active Garhwal region of Himalaya. Seismic body wave attenuation characteristics in the region is studied using 234 short-period, seismic observations from local events. The P-wave attenuation ( Q P − 1 ) and S-wave attenuation ( Q S − 1 ) were estimated by applying the state-of-the-art, extended coda normalization method for the frequency range from 1.5 to 24 Hz. Estimates of Q P − 1 and Q S − 1 decrease from (15.86 ± 0.90) × 10 − 3 and (5.35 ± 0.51) × 10 − 3 at 1.5 Hz to (0.54 ± 0.11) × 10 − 3 and (0.34 ± 0.06) × 10 − 3 at 24 Hz, respectively. The values of Q P − 1 and Q S − 1 show strong frequency dependence and fit the power-law relation Q P − 1 ( f ) = (27.43 ± 3.15) × 10 − 3 f (− 1.16 ± 0.06) and Q S − 1 ( f ) = (8.05 ± 0.74) × 10 − 3 f (− 0.93 ± 0.05) , respectively. Obtained results are in the range of those reported for Q P − 1 and Q S − 1 of the other seismically active regions. The ratio of Q P − 1 / Q S − 1 is larger than unity in the entire analyzed frequency range and may suggest high degree of heterogeneity in the region.