Estimation of Strong Ground Motion from a Great Earthquake Mw 8.5 in Central Seismic Gap Region, Himalaya (India) Using Empirical Green? Function Technique

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• 作者：Babita Sharma (1)
  Sumer Chopra (1)
  Anup Kumar Sutar (1)
  B. K. Bansal (1)
  
• 关键词：Simulation ; PGA ; central seismic gap ; empirical green function
• 刊名：Pure and Applied Geophysics
• 出版年：2013
• 出版时间：December 2013
• 年：2013
• 卷：170
• 期：12
• 页码：2127-2138
• 全文大小：
• 作者单位：Babita Sharma (1)
  Sumer Chopra (1)
  Anup Kumar Sutar (1)
  B. K. Bansal (1)
  
  1. Geosciences/Seismology Division, Ministry of Earth Sciences, New Delhi, India
  
• ISSN：1420-9136

文摘

In the present study ground motions for a Mw 8.5 scenario earthquake are estimated at 13 sites in Kumaun-Garhwal region using the empirical Green? function technique. The recordings of 1991 Uttarkashi earthquake of Mw 6.8 at these sites are used as an element earthquake. A heterogeneous source model consisting of two asperities is considered for simulating the ground motions. The entire central seismic gap (CSG) can expect acceleration in excess of 100?cm/s2 with NW portion in excess of 400?cm/s2 and SE between 100 and 200?cm/s2. The central portion can expect peak ground acceleration (PGA) between 200 and 400?cm/s2. It has been observed from simulation of strong ground motion that sites located near the rupture initiation point can expect accelerations in excess of 1g. In the present analysis, Bhatwari and Uttarkashi can expect ground accelerations in excess of 1g. The estimates of the PGA are compared with earlier studies in the same region using different methodologies and it was found that the results are comparable. This has put constrains on the expected PGAs in this region. The obtained PGA values can be used in identifying the vulnerable areas in the central Himalaya, thereby facilitating the planning, design and construction of new structures and strengthening of the existing structures in the region.