Abstract
An earthquake of magnitude 5.0 with its epicenter in the West Sikkim district occurred on the evening of 20th May 2007. The macroseismic study revealed an ENE-WSW isoseismal pattern indicating a trend conforming to that of the major tectonic discontinuities in this part of the Himalaya.
The relatively moderate event, felt even at far away places like, Siliguri, Darjeeling, etc induced a maximum intensity of VI (MSK) in the form of development of cracks in the walls, fall of thick chunks of plaster in Type A or even Type B-C structures at localities like Tashiding, Ralang, Rabang, Keozing, Sakyong, etc.
The study also revealed that the NW-SE trending Tista lineament is playing an important role in the release of the tectonics strain in this region and that the rupture initiated under the influence of the northward directed tectonic stresses at an asperity formed at one of the decollements within the crust by the intersection of this tectonic discontinuity was interpreted to be responsible for this seismic event.
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Joshi, K.C., Sengupta, S. & Kandpal, G.C. Macroseismic study of 20th May 2007 Sikkim earthquake — Its seismotectonic implications for the region. J Geol Soc India 75, 383–392 (2010). https://doi.org/10.1007/s12594-010-0034-8
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DOI: https://doi.org/10.1007/s12594-010-0034-8