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Asperity interaction and dependence of frequency-size distribution of earthquakes in brittle-ductile transition zone in Central Himalaya
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  • Anil Tiwari,
  • Ajay Paul,
  • Rakesh Singh,
  • Rajeev Upadhyay
Anil Tiwari
Wadia Institute of Himalayan Geology

Corresponding Author:anilgeox93@gmail.com

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Ajay Paul
Wadia Institute of Himalayan Geology
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Rakesh Singh
Graphic Era Hill University
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Rajeev Upadhyay
Kumaun University
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We explore the hypothesis that b-value act as stress meter which varies inversely with differential stress and decreases until it reached the depth of brittle-ductile transition. Correlation of seismogenic asperity and brittle-ductile contact (BDC) with b-value is of special interest. Lowest b- and Dc-values coincides with transition depth and interpreted as seismogenic asperities. Moderate ruptures (ML≥5.0) nucleate in vicinity of transition zone where stress concentration is highest. We illustrate behavior of mid-crustal detachment and dependence of topographic elevation above Mid-Crustal Ramp (MCR). The depth 10-15 km is marked as MCR which coincides with fluids, seismogenic asperity and shows seismic clustering. The composite trend in abrupt escalation of b-value is observed at depth ≈12 km and ≈7 km for Garhwal and Kumaun region respectively. These depth ranges is demarcated as BDC which coincides with proposed MCR and exhibiting as an alarming asperity zone (12-15 km) for future great earthquake in Garhwal-Himalaya.