Science News

Ancient Himalayan temples reveal evidence of historic earthquakes

A survey of ancient temples in the northwest of India has revealed signatures of historic earthquakes — one in 1555 and another in 1905 — evidence that the region is especially prone to massive seismic ruptures.

An accurate timeline of earthquakes helps scientists understand the type of rumbles a fault system is capable of producing, as well as when a rupture is most likely to happen again.

The earthquake-damaged temples were built in the 7th century. They’re located in the Chamba district of Himachal Pradesh, part of what’s known as the Kashmir “seismic gap,” a segment of an active fault in the northwest Himalayas.

Scientists say the temples’ cracked stones and crooked pillars were caused by the 1905 Kangra earthquake, a measured magnitude 7.8 rupture, and the 1555 Kashmir earthquake, believed to be a magnitude 7.6 quake.

“In the Chamba-area temples, there are some marker features that indicate that the body of the temple structure has suffered some internal deformation,” Mayank Joshi, seismologist with the Wadia Institute of Himalayan Geology, said in a news release. “The pillars and temple structures are tilted with respect to their original positions. The rooftop portions show tilting or displacement.”

Joshi and his research partner V.C. Thakur compared their analysis of the local temples to historical accounts of the two quakes to confirm which quakes caused what damage.

The two historic quakes expand the rupture zone of the Kashmir seismic gap, and offer further evidence that the region is capable of producing large earthquakes.

The new analysis, detailed in the journal Seismological Research Letters, also reveals a segment of the seismic gap where tension has been building since 1555.

“This further implies that the eastern Kashmir Himalaya segment between Srinagar and Chamba has not been struck by a major earthquake for the last 451 years,” Joshi said.

When this building tension is finally released, the two researchers suggest, the result could be analogous to the 7.6 magnitude earthquake that killed some 85,000 people in northern Pakistan in 2005.