EGU21-1636
https://doi.org/10.5194/egusphere-egu21-1636
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Estimation of Source Parameters and their scaling relationship of small to moderate magnitude earthquakes for northeast India

Prosanta Kumar Khan1 and Bandana Baruah2
Prosanta Kumar Khan and Bandana Baruah
  • 1Indian Institute of Technology (Indian School of Mines), Dhanbad, IIT (ISM), Dhanbad, Applied Geophysics, Dhanbad, India (khanprosanta1966@gmail.com)
  • 2Seismo-Geodetic data receiving and Processing Centre, Central Head Quarters, Geological Survey of India, Kolkata - 700091, India

We investigate the source parameters of 87 local earthquakes (3.5 ≤ ML ≤ 5.0) that occurred in West Brahmaputra basin and its neighbouring area, using body wave displacement spectra. Seismic moment, corner frequency, source dimension and static stress drop are estimated using a grid search method based on the model of circular source. The measured seismic moments, corner frequency and moment magnitude ranges from   to  N-m, 0.7 to 12.1 and 3.0 to 4.8, respectively. The average ratio of corner frequency of P - and S - waves is 2.21. The scaling relationship of seismic moment against corner frequency is also studied for various tectonics regimes separately. Median stress drop values of individual earthquake vary from ~ 0.1 to 38.5 MPa, with an average value of about ~ 6 MPa. Spatial variation of stress drop observed for different tectonic unit reveals a higher stress drop values associated with West Brahmaputra basin, Shillong-Mikir plateau and Indo-Myanmar subduction zone suggesting a higher stress accumulation that may increase the probability of higher magnitude earthquake. The empirical relationship between ML and MW scale is also derived for hazard assessment.

How to cite: Khan, P. K. and Baruah, B.: Estimation of Source Parameters and their scaling relationship of small to moderate magnitude earthquakes for northeast India, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1636, https://doi.org/10.5194/egusphere-egu21-1636, 2021.

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