Application of Omori’s Decay Law to the 2001 Bhuj Aftershock Sequence for Kachchh Region of Western India

Parul C Trivedi

doi:10.4236/ojer.2015.43009

Abstract

In the present study, the temporal behavior of 2001 Bhuj aftershock sequence in Kachchh region of western peninsular India is studied by the modified Omori law. The Omori law parameters p, c and K are determined with the standard errors by the maximum likelihood estimates using ZMAP algorithm in MatLab environment. The entire aftershock sequence is analyzed by diving it into three separate series with respect to time to weigh up the bigger earthquake of magnitude M 5.7 occurring on March 7, 2006 at Gedi fault. This study helps to understand the cumulative effect of the aftershocks generated by this bigger earthquake of the mainshock sequence. The results of this analysis are discussed with other studies of the different earthquake sequence for the different parts of the world and suggest that all the three series of Bhuj aftershock sequence follow the Omori relation. Values of parameter p vary significantly from series 1 to series 3, i.e., p-value varies significantly with time. Similarly, other two Omori law parameters K and c are also found to change significantly with time. These parameters are useful to describe temporal behavior of aftershocks and to forecast aftershock activity in time domain. Aftershock decay rate provides insight into stress release processes after the mainshock, thus helping to understand the heterogeneity of the fault zone properties and evaluate time-dependent seismic hazard analysis over the region.

Highlights

Earthquakes are the deadliest natural hazards amongst all other natural hazards that cause lots of casualties andHow to cite this paper: Trivedi, P.C. (2015) Application of Omori’s Decay Law to the 2001 Bhuj Aftershock Sequence for Kachchh Region of Western India
The p-value is 1.19 and 1.006 for the deep 1994 Tonga and Bolivia earthquakes respectively. 2001 Bhuj earthquake of Mw 7.7 is the example of large SCR earthquake and it is of shallow focused and the aftershock activity is still ongoing over the Kachchh region
The analysis of aftershock sequence of the 2001 Bhuj earthquake (Mw 7.7) suggests that the seismic activity associated with some moderate events in 2006 had an influence on the future seismicity in the area, in particular on the temporal distribution of p-values observed for the aftershocks of 2001 Bhuj earthquake

Summary

Introduction

How to cite this paper: Trivedi, P.C. (2015) Application of Omori’s Decay Law to the 2001 Bhuj Aftershock Sequence for Kachchh Region of Western India. (2015) Application of Omori’s Decay Law to the 2001 Bhuj Aftershock Sequence for Kachchh Region of Western India. When we look back to Reid’s elastic rebound theory, the basic physical process involved in the generation of earthquake is slow building up and rapid release tectonic stress in a cyclic process This theory provides insight into aftershock activity after the occurrence of a large earthquake. The aftershock sequence of 2001 Bhuj earthquake of Mw 7.7 for Kachchh region of western peninsular India is studied by the modified Omori law. The results presented in this study are very useful to understand temporal behavior of aftershocks and to forecast aftershock activity in the future It has significant implications on seismic hazard analysis since the study gives idea on stress release processes after the mainshock

Data and Method

Results and Discussion

Conclusion