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The 12 May 2015 Kodari Earthquake (Mw 7.3) in Central Nepal:Delayed Triggering by the 25 April 2015 Gorkha Earthquake (Mw 7.8)


Affiliations
1 CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
2 Department of Earth and Atmospheric Sciences, National Institute of Technology Rourkela, Rourkela 769 008, India
3 National Centre for Seismology, Ministry of Earth Sciences, New Delhi 110 003, India
 

The 12 May 2015 earthquake of Mw 7.3 occurred in the Kodari region, Central Nepal, 17 days after the 25 April 2015 Gorkha earthquake (Mw 7.8) along the Himalayan plate boundary. Both the earthquakes were associated with predominantly thrust faulting on the Main Himalayan Thrust (MHT). This is the largest aftershock of the 2015 Gorkha earthquake which occurred approximately 150 km east of it. Our analysis suggests that the 2015 Gorkha earthquake significantly increased the Coulomb stress on the shallow unruptured and updip part of the MHT, further west of the 2015 rupture and also in the hypocentre region of 12 May 2015 Mw 7.3 aftershock. In the following 17 days period, Coulomb failure stress increased further by the relaxation of coseismic pore pressure on the eastern side of its coseismic rupture, where the 12 May 2015 aftershock had occurred.

Keywords

Coseismic Rupture, Delayed Triggering, Earthquakes, Failure Stress, Thrust Faulting.
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  • The 12 May 2015 Kodari Earthquake (Mw 7.3) in Central Nepal:Delayed Triggering by the 25 April 2015 Gorkha Earthquake (Mw 7.8)

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Authors

Rajeev Kumar Yadav
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
Bhaskar Kundu
Department of Earth and Atmospheric Sciences, National Institute of Technology Rourkela, Rourkela 769 008, India
Kalpna Gahalaut
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
V. K. Gahalaut
National Centre for Seismology, Ministry of Earth Sciences, New Delhi 110 003, India

Abstract


The 12 May 2015 earthquake of Mw 7.3 occurred in the Kodari region, Central Nepal, 17 days after the 25 April 2015 Gorkha earthquake (Mw 7.8) along the Himalayan plate boundary. Both the earthquakes were associated with predominantly thrust faulting on the Main Himalayan Thrust (MHT). This is the largest aftershock of the 2015 Gorkha earthquake which occurred approximately 150 km east of it. Our analysis suggests that the 2015 Gorkha earthquake significantly increased the Coulomb stress on the shallow unruptured and updip part of the MHT, further west of the 2015 rupture and also in the hypocentre region of 12 May 2015 Mw 7.3 aftershock. In the following 17 days period, Coulomb failure stress increased further by the relaxation of coseismic pore pressure on the eastern side of its coseismic rupture, where the 12 May 2015 aftershock had occurred.

Keywords


Coseismic Rupture, Delayed Triggering, Earthquakes, Failure Stress, Thrust Faulting.

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DOI: https://doi.org/10.18520/cs%2Fv114%2Fi07%2F1534-1539