Attenuation of coda waves in southern Tibet

The alternation characteristics of the crust in the southernmost Tibetan plateau are determined from analysis of S-wave coda recorded at a temporary broadband station deployed during the 1994 INDEPTH-II experiment. A method for determining Qc is developed which utilizes the coda spectrogram observed at a single station. The average S-wave coda quality factor for this continent-continent collision zone is Qc(f) = (160 ± 69) (f/ f₀)^1.11±0.19, 1 < (f/f₀) < 4, where f₀ = 1Hz. The results are consistent with other measurements of Qc(f) in continental collisional environments which typically exhibit low values of Qc(f) at 1 Hz and a strong dependence on frequency. In particular, the attenuation characteristics obtained for the Arabian-Eurasian continental collisional boundary in western Turkey are quite similar to the results reported here for the southern Tibetan plateau.