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An Appraisal of Recent Earthquake Activity in Palghar Region, Maharashtra, India


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1 CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
 

The present study focuses on the recent earthquake activity in Palghar region, Maharashtra, India. Until 31 August 2019, a total of 4854 earthquakes have been located here, whose local magnitude (ML) varied from 0.1 to 4.1. Majority of the earthquakes (~94%) were located in the depth range 4–16 km. The precise earthquake relocations reveal two clusters. The N–S trending cluster north of 20.04°N extends to a depth of 10 km, whereas the NE–SW trending cluster to the south of 20.04°N extends to 16 km depth. The shallow northern cluster is noticed to be sandwiched between two mapped mafic intrusions, whereas the deeper southern segment shows earthquakes clustering around the mafic intrusion. The modelled composite focal mechanism solutions for both the north and south clusters suggest normal faulting with a minor strike–slip component as the dominant deformation mode for the Palghar region. From relocated seismici-ty, we have detected a deeper seismically active zone (with M> 3) at 4–16 km depth, occupying a crustal volume of 1440 km 3 (i.e. 20 km (in N–S) ×6 km (in E– W) and 12 km (in depth)) that dips toward 20°S and 70°W. This could be attributed to the large crustal stresses induced by the mafic intrusive body below the region.

Keywords

Crustal Stress, Deformation Mode, Earth-quake, Mafic Intrusion, Relocations, Seismic Activity.
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  • An Appraisal of Recent Earthquake Activity in Palghar Region, Maharashtra, India

Abstract Views: 524  |  PDF Views: 130

Authors

D. Srinagesh
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
Dhiraj Kumar Singh
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
G. Vikas
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
B. Naresh
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
Sunil Roy
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
Y. V. V. B. S. N. Murthy
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
P. Solomon Raju
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
G. Suresh
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
Prantik Mandal
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
A. N. S. Sharma
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
M. Shekar
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India
V. M. Tiwari
CSIR-National Geophysical Research Institute, Hyderabad 500 007, India

Abstract


The present study focuses on the recent earthquake activity in Palghar region, Maharashtra, India. Until 31 August 2019, a total of 4854 earthquakes have been located here, whose local magnitude (ML) varied from 0.1 to 4.1. Majority of the earthquakes (~94%) were located in the depth range 4–16 km. The precise earthquake relocations reveal two clusters. The N–S trending cluster north of 20.04°N extends to a depth of 10 km, whereas the NE–SW trending cluster to the south of 20.04°N extends to 16 km depth. The shallow northern cluster is noticed to be sandwiched between two mapped mafic intrusions, whereas the deeper southern segment shows earthquakes clustering around the mafic intrusion. The modelled composite focal mechanism solutions for both the north and south clusters suggest normal faulting with a minor strike–slip component as the dominant deformation mode for the Palghar region. From relocated seismici-ty, we have detected a deeper seismically active zone (with M> 3) at 4–16 km depth, occupying a crustal volume of 1440 km 3 (i.e. 20 km (in N–S) ×6 km (in E– W) and 12 km (in depth)) that dips toward 20°S and 70°W. This could be attributed to the large crustal stresses induced by the mafic intrusive body below the region.

Keywords


Crustal Stress, Deformation Mode, Earth-quake, Mafic Intrusion, Relocations, Seismic Activity.

References





DOI: https://doi.org/10.18520/cs%2Fv118%2Fi10%2F1592-1598