Kashmir Basin Fault could host 7.6 earthquake

THE recent earthquakes near Doda region of Jammu and Kashmir has once again forced us to realize that we live in one of the seismically active and vulnerable, regions of the world. Therefore, it is very crucial to understand the active tectonics of the valley, so that adequate measures could be taken in advance to prevent the repetition of Muzaferabad type devastation, which occurred in 2005.

Though earthquake studies in Kashmir are still accumulating, however, some progress has been made in last few years. In one of my recent articles, published in 2013 in the International Journal of Earth Sciences, I have identified two major traces of active thrust faults in the Kashmir Basin (KB) by using satellite images and mapping active geomorphic features. Similar faults have also been identified by Chris Madden, Shabir and others in their teams. Thus, it is very important for us to understand these faults and plan a comprehensively strategy to minimize the destruction, which might be caused by earthquake on these faults in the near future.

Through this article, I will highlight my own research to make it simple and easy for people to understand the active tectonics of the Kashmir valley. Therefore, I have extracted most of the information from my published paper, which can be reached at: http://link.springer.com/article/10.1007%2Fs00531-013-0874-8

As we are aware that the continent–continent collision of Indian and Eurasian plates is responsible for the earthquakes along the Himalayan arc, these two tectonic plates collide at geologic and geodetic convergence rates of 30–50 mm/yr. This convergence is partly absorbed by the active faults of the Kashmir Basin (KB), which is clearly shown by a variety of geomorphic evidences preserved. Using the satellite images, traces of active faults are mapped in the KB and these faults are trending in ~N130E, which is quite consistent with the regional ~NE–SW convergence along the Indian–Eurasian collision zone. The ~ NE dipping thrust faults have uplifted the young alluvial fan surfaces at the SW side of the KB.This created a major tectono-geomorphic boundary along the entire strike length of the KB that is characterized by (1) a low relief with sediment-filled sluggish streams to the SE and (2) an uplifted region, with actively flowing streams tothe SW. The overall tectono-geomorphic expression suggests that recent activity along these faults has tilted the entire Kashmir valley towards NE.

Further, the Mw 7.6 earthquake, which struck Northern Pakistan and Kashmir on 8 October 2005, also suggests a similar strike and NE dipping fault plane, which could indicate that the KB fault is continuous over a distance of ~210 km and connects on the west with the Balakot Bagh fault. However, the geomorphic and the structural evidences of such a structure are not very apparent on the north-west, which thus suggest that it is not a contiguous structure with the Balakot Bagh fault. Therefore, it is more likely that the KB fault is an independent thrust, a possible ramp on the Main Himalayan Thrust, which has uplifting the SW portion of the KB and drowning everything to the NE.

Furthermore, it seems very likely that the KB fault could be a right-stepping segment of the BalakotBagh fault, similar to RiasiThrust, as proposed by Thakur et al. in 2010. The earthquake magnitude is measured by estimating the fault rupture parameters (e.g. as in Wells and Coppersmith, 1994). Therefore, the total strike length of the mapped KB fault is ~ 120 km and by assuming a dip of 29 (as in Avouac et al., 2006) and a down-dip limit of 20 km, a Mw of 7.6 is possible on this fault. Therefore, in the coming future, the Kashmir Basin Fault could produce a similar earthquake of what we have witnessed in Muzaferabad in year 2005.

Further, detailed studies are required to understand the behavior of the mapped active faults, which could be achieved by using paleoseismic knowledge on these faults. Therefore, I would suggest, that Jammu and Kashmir should invest in earthquake research facility to facilitate the active tectonics research in the state. This will benefit the people of the state and will simultaneity, make us aware of the faults in our backyard and will teach us to stay with faults and be safe, just like in Japan. Therefore, we must organize ourselves to work as a team and understand the nature of the faults and think of various remedies.

 Dr. Afroz Ahmad Shah is Senior Lecturer, Department of Applied Geology, School of Engineering and Science, Curtin University, Sarawak Malaysia. He can be reached at:  <[email protected]>

Follow this link to join our WhatsApp group: Join Now

MONTHLY	Rs 100
YEARLY	Rs 1000
LIFETIME	Rs 10000

CLICK FOR DETAILS