TITLE:
Software to Estimate Earthquake Spectral and Source Parameters
AUTHORS:
Arjun Kumar, Ashwani Kumar, Himanshu Mittal, Ashok Kumar, Rakhi Bhardwaj
KEYWORDS:
Spectral Parameters; Source Parameters; EQ_SRC_PARA; Garhwal; Uttarkashi
JOURNAL NAME:
International Journal of Geosciences,
Vol.3 No.5,
November
29,
2012
ABSTRACT: A software (EQK_SRC_PARA) has been developed to estimate spectral parameters of earthquake source spectrum, namely: low frequency displacement spectral level (Ω0), corner frequency above which spectrum decays with a rate of 2 (fc), the cut-off frequency above which the spectrum again decays (fmax) and the rate of decay above fmax (N). A Brune’s source model [1,2] that yield a fall-off of 2 beyond corner frequency is considered with high cut-off frequency factor presented by Boore [3] that fits well for frequencies greater than fmax. The software EQK_SRC_PARA is written in MATLAB and uses input data in Sesame ASCII Format (SAF) format. The obtained spectral parameters have been used to estimate source parameters (e.g., seismic moment, source dimension and stress drop etc.) and to develop scaling laws for the study region. The cut-off frequency “fmax” can also be studied and interpreted to confirm about its origin.