Active fault topography along Kangra Valley Fault in the epicentral zone of 1905 Mw7.8 earthquake NW Himalaya, India

作者：Sahoo, Santiswarup; Malik, Javed N.

来源：Quaternary International, 2017, 462: 90-108.

DOI：10.1016/j.quaint.2017.03.020

• Active fault
• Right-lateral strike-slip
• Stream-offset
• Fault directivity
• NW Himalaya

The 1905 CE Kangra earthquake (Mw7.8) was one of the most damaging earthquakes in Himalaya. Malik et al (2015) suggested that the Kangra Valley Fault (KVF) from the epicentral zone was the source of the 1905 Kangra earthquake. In this article we discuss the active fault topography along KVF marked by distinct right lateral strike-slip movement, extends for about 60 km between Patka Village in NW and Tanda Village in SE. The prominent offset of streams ranging from 10 m to 340 m have been identified along the fault trace; the lateral offset of 10 m may be indicative of displacement during a single event. Lateral as well as the vertical offset of alluvial fan surfaces and fluvial terraces, resulted in formation of the north as well as south facing fault scarps ranging in height from 1.2 to 14 m. KVF between two major thrust systems i.e., Main Boundary Thrust (MBT) and Jawalamukhi Thrust (JMT), suggest that slip-partitioning is taking place between the thrust and strike-slip faults and is a net result of oblique convergence in NW Himalaya. The end points of the fault traces exhibit typical "Y" shape because of stepping and branching out of rupture from the main fault. Considering the pre-stress axis from the GPS velocity vectors from Banerjee and Burgman, (2002), the branching scenario we obtained for KVF, is not consistent with the simulated models by Kame et al., (2003) and Poliakov et al., (2002) for other faults. This could be attributed to the ongoing oblique convergence in NW Himalaya. Based on the "Y" shape pattern, and the upthrown and downthrown sides mapped along the fault trace, we suggest two possibilities for surface rupture, (1) the fault rupture initiated from Pathiyar-Malan side and propagated unilaterally towards west, (2) taking into account the "Y" shape on both the end sections of the fault trace, it can be inferred that the rupture during most recent event probably started in the center at Miniana and propagates bilaterally in E-W.

• 出版日期2017-12-30