Aftershock activity of Bhuj earthquake of January 26th, 2001

Journal of Earth system science

Ashwani Kumar1¹  Sanjay Jain1¹  A K Jindal1¹  Vandana1¹  S C Gupta1¹ 

[1] Department of Earthquake Engineering, Indian Institute of Technology Roorkee, Roorkee 247 667, India$$

关键词: Bhuj earthquake;    aftershocks;    local network;    temporal distribution;    b-value.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Following a large-sized Bhuj earthquake (𝑀𝑠 = 7.6) of January 26th, 2001, a small aperture 4- station temporary local network was deployed, in the epicentral area, for a period of about three weeks and resulted in the recording of more than 1800 aftershocks (-0.07 ≤ 𝑀𝐿 < 5.0). Preliminary locations of epicenters of 297 aftershocks (2.0 ≤ 𝑀𝐿 < 5.0) have brought out a dense cluster of aftershock activity, the center of which falls 20km NW of Bhachau. Epicentral locations of after-shocks encompass a surface area of about 50 × 40km2 that seems to indicate the surface projection of the rupture area associated with the earthquake. The distribution of aftershock activity above magnitude 3, shows that aftershocks are nonuniformly distributed and are aligned in the north, northwest and northeast directions. The epicenter of the mainshock falls on the southern edge of the delineated zone of aftershock activity and the maximum clustering of activity occurs in close proximity of the mainshock. Well-constrained focal depths of 122 aftershocks show that 89% of the aftershocks occurred at depths ranging between 6 and 25km and only 7% and 4% aftershocks occur at depths less than 5 and more than 25km respectively. The Gutenberg-Richter (GR) relationship, log 𝑁 = 4.52-0.89 𝑀𝐿, is fitted to the aftershock data (1.0 ≤ 𝑀𝐿 < 5.0) and the 𝑏-value of 0.89 has been estimated for the aftershock activity.

【 授权许可】

Unknown