Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Sushil Gupta ¹, S. K. Arora ²

Affiliations
1 Seismology Section, Reactor Safety Analysis (RSA) Group, Nuclear Power Corporation, Vikram Sarabhai Bhavan, Anushaktinagar, Mumbai - 400094, IN
2 National Institute of Rock Mechanics, Champion Reefs, Kolar Gold Fields (KGF)-563 117, IN

Abstract

The best available data from different compilations have been consolidated and homogenised for the Indian peninsular shield. These historical and instrumental data of 410 years (1586 - 1995) have been subjected to statistical completeness test to determine time - intervals in which the data sets are complete in different ranges (classes) of magnitude. The analysis reveals that the data are complete for the last about 40 years, 60 years and 120 years from present in the magnitude cIasses 4.0≤M<5.0, 5.0≤M<6.0 and M≥6.0 respectively. The two significant parametric constants of seismicity (a and b values) obtained by regression analysis of these data sets turn out to be 4.59 and 0.94 respectively that are typically indicative of a moderately active zone such as the continental interior of southern India is indeed so. Based on this deduction, the recurrence time-interval for a Latur type earthquake (M 6.3) in the Indian shield region works out to be close to 21.5 years. The magnitude of Design Basis Earthquake (DBE), assumed to occur not more than once in 50 years in the peninsular shield region, works out to be close to 6.7.

Keywords

Earthquake, Magnitude Class, Data Completeness, Seismicity Parameters, Recurrence Time-Interval, Peninsular India.

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Brijesh K. Bansal ¹, Sushil Gupta ¹

Affiliations
1 Nuclear Power Corporation, Vikram Sarabhai Bhavan, Anushaktinagar, Mumbai 400094, IN

Abstract

This paper reports the status of seismicity of the Peninsular Indian region based on historical earthquake data from 1200 to 1995 AD. A list of earthquakes occurring within the geographical area between latitude 8° N-24° N and longitude 70° E-86° E has been compiled. The current seismic activity in Peninsular region shows evidence of neotectonic movements. Based on the knowledge of the geotectonics of the area and the epicentral distribution of earthquakes, seismogenic zones in the region have been demarcated. Among the 11 such zones Western Ghat. Narmada~Son and °Rann of Kutch are relatively more active.

Keywords

Seismicity, Peninsular India, Seismogenic Zone.

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