Spatial variation of the aftershock activity across the Kachchh Rift Basin and its seismotectonic implications

Journal of Earth system science

A P Singh1²  R B S Yadav4⁴  Santosh Kumar1²  Dinesh Kumar3³  O P Mishra2¹ 

[1] SAARC Disaster Management Centre, New Delhi 110 002, India.$$;Institute of Seismological Research (ISR), Raisan, Gandhinagar 382 009, Gujarat, India.$$;Department of Geophysics, Kurukshetra University, Kurukshetra 136 119, Haryana, India.$$;Indian National Centre for Ocean Information Services (INCOIS), Hyderabad, India.$$

关键词: Aftershocks;    𝑏-value;    fractal dimension;    frequency–magnitude;    slip ratio.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

We analyzed 3365 relocated aftershocks with magnitude of completeness (𝑀𝑐) ≥ 1.7 that occurred in the Kachchh Rift Basin (KRB) between August 2006 and December 2010. The analysis of the new aftershock catalogue has led to improved understanding of the subsurface structure and of the aftershock behaviour. We characterized aftershock behaviour in terms of 𝑎-value, 𝑏-value, spatial fractal dimension (𝐷s), and slip ratio (ratio of the slip that occurred on the primary fault and that of the total slip). The estimated 𝑏-value is 1.05, which indicates that the earthquake occurred due to active tectonics in the region. The three dimensional 𝑏-value mapping shows that a high 𝑏-value region is sandwiched around the 2001 Bhuj mainshock hypocenter at depths of 20–25 km between two low 𝑏-value zones above and below this depth range. The 𝐷s-value was estimated from the double-logarithmic plot of the correlation integral and distance between hypocenters, and is found to be 2.64 ± 0.01, which indicates random spatial distribution beneath the source zone in a two-dimensional plane associated with fluid-filled fractures. A slip ratio of about 0.23 reveals that more slip occurred on secondary fault systems in and around the 2001 Bhuj earhquake (Mw 7.6) source zone in KRB.

【 授权许可】

Unknown