Coda Q in Eastern Indian shield

Abstract

We have analyzed 16 earthquake waveform data recorded during the period from 2006 to 2013 at broadband station lying at the premises of Indian School of Mines, Dhanbad in the Eastern Indian Shield region. Coda window lengths of 30, 40 and 50 s were selected after thorough analysis of the waveforms. The Coda Q (Qc) values were computed using single back scattered method. The earthquakes parameters were compiled from catalogue of Indian Meteorological Department (Nodal agency under Govt. of India for record keeping and data sharing), New Delhi. The estimated average Qc values for three coda windows 30, 40 and 50 s are Qc = 259.1f0.808, Qc = 275.9f0.764 and Qc = 397.1f0.651, respectively. The average Qc value estimated from the Qc values for the time windows 30, 40 and 50 s is found to be Qc = 313.2f0.73. Thus, the attenuation follows the power law relationships (e.g., Qc = Q0fn), and the moderate to higher values of frequency parameters (n) obviously show that the Qc value is a strong function of frequency. The increasing values of Q0 with increasing lapse time indicating the depth dependency of attenuation, and accounts for decreasing heterogeneity towards deeper level beneath the study area.