TITLE:
Characterization of Source Parameters and Some Empirical Relations between Them for Kachchh Region, Gujarat, India: Implication of January 26, 2001 Bhuj Earthquake and Its Aftershock Sequence
AUTHORS:
Parul C. Trivedi, Imtiyaz A. Parvez
KEYWORDS:
Source Parameters, Bhuj Earthquake, Aftershock Sequence, Empirical Relations
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.10,
October
28,
2015
ABSTRACT: Study of source parameters of small to
moderate and large earthquakes is important to understand the differences and
similarities between dynamic ruptures of different earthquakes and clarifying
the scaling relations. In the present study, we have characterized source
parameters and presented new and revised empirical relationships between
various source parameters for Kachchh region of Gujarat, India to facilitate to
draw first-order conclusions regarding the trends in the region. We have
studied total 202 aftershocks of shallow-focus (hypo central depth less than 40
km) and moderate magnitude recorded over the Kachchh region during January 2001
to December 2012 by different seismological observatories of India
Meteorological Department. We have adopted the spectral technique for source
parameter estimation, where S-wave displacement spectra are considered and
applied Fast Fourier Transform (FFT) to compute displacement spectra. We have
followed the Brune’s source model for our estimation and the estimated values
of source parameters show close approximation to the global values. While derived
empirical relations between different source parameters, they demonstrate
direct or inverse proportion to linear or power scale. Interrelation between
seismic moment, rupture parameters, corner frequency and radiated seismic
energy can be summarized as , , and ER μ M0 and ER μ Mw for our analysis. Stress
drop distribution over the Kachchh region is very scattered and due to its
peculiar behavior, it is difficult to derive its empirical relation with other
source parameters. Sufficient accuracy on measuring source parameters like
corner frequency stress drop, rupture dimensions, radiated seismic energy etc.
helps to understand earthquake processes in the region. This is the first ever
attempt to establish empirical relation between different source parameters for
Kachchh region for longer aftershock sequence and they are useful to assess
future earthquake potential over the region.