A Statistical Analysis of Completeness of Earthquake Data of Peninsular India and its Implications for Seismicity Evaluation

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.