NEW DELHI : Two Indian seismologists have feared that a massive earthquake is likely to take place in the Himalayas, between Srinagar and Chamba in Himachal Pradesh, which is similar to the 2005 Kashmir earthquake of 7.6 magnitude that devastated the eastern Kashmir, killing more than 85,000, mostly in north Pakistan.
Their claim is based on the discovery that a 1555 earthquake with its epicentre in the Srinagar valley had hit Chamba locate 200 km away. They said the region is not struck by any major earthquake for the last 451 years, but it may have one because of the building up stress in the region.
Tilted pillars, cracked steps, and sliding stone canopies in a number of 7th-century A.D. temples in and around Chamba are among the telltale signs the seismologists used to reconstruct the extent of some of the region’s larger historic earthquakes.
In their report published online July 27 in Seismological Research Letters, Mayank Joshi and V.C. Thakur of the Wadia Institute of Himalayan Geology, Dehradun, show how the signs of destructive earthquakes are imprinted upon the ancient stone and wooden temples.
The temples in the Chamba district lie within the Kashmir “seismic gap” of the Northwest Himalaya range, an area that is thought to have the potential for earthquakes with magnitude of 7.5 or larger. The new analysis extends rupture zones for the 1905 Kangra earthquake (magnitude 7.8) and the 1555 Kashmir earthquake (possibly a magnitude 7.6 quake) within the Kashmir gap. The type of damage sustained by temples clustered around two towns in the region–Chamba and Bharmour–suggests that the Chamba temples may have been affected by the 1555 earthquake, while the Bharmour temples were damaged by the 1905 quake, the seismologists conclude.
To better understand the historical earthquake record in the region, Joshi and Thakur examined several temples in the region to look for telltale signs of earthquake damage. It can be difficult at first to distinguish whether a tilted pillar, for example, is due to centuries of aging or to earthquake deformation. But Joshi noted that archaeoseismologists are trained to look for regular kinds of deformation to a structure–damages “that have some consistency in their pattern and orientation,” said Joshi. “In the cases of aging and ground subsidence, there is no regular pattern of damage.” At the temples, the researchers measured the tilt direction, the amount of inclination on pillars and the full temple structures, and cracks in building stones, among other types of damage. They then compared this damage to historic accounts of earthquakes and information about area faults to determine which earthquakes were most likely to have caused the damage.