Need to brace against more Himalayan quakes
When Kiren Rijiju, the Union minister of earth sciences, told the Lok Sabha last December that there had been an increase in earthquakes in India between January and November 2023, experts wasted no time in questioning the possible causes. It was a fairly tough question to answer. But a few days later, a new study presented at the annual meeting of the American Geophysical Union attempted an answer.
It pointed to the shocking effect of the tectonic shift that horizontally split the Indian Plate as it pushed into the Eurasian Plate at the geologically-significant speed of 2 mm a year. The split is not like that unfolding in East Africa, which is vertical and gradually giving birth to a new micro-continent. Here, it is like the top layer getting peeled off while the bottom layer of the crust is moving into the Earth’s mantle—like a block of cheese when pushed into a horizontally-held blade.
This process has been at work over millions of years. It explains the rapidly increasing elevation of the Tibetan plateau and parts of the Eastern Himalayas. The Indian Plate pushing into the Eurasian Plate is not a revelation, but the top and bottom layers getting split horizontally has shocked geologists. This process is mostly likely behind the increasing frequency of earthquakes reported, especially in North and Northeast India, as a thinner top layer—100 km thick—is getting peeled.
This must make the Indian government wake up to its huge responsibility of ensuring the safety of almost half its population that is dependent on the Himalayan rivers’ basin drainage. Attention must shift to the fragility of the Himalayan ecosystem, where hydro-power projects and tunnelling works are going on with the military and civil infrastructure in mind, while the possible catastrophic impact of the tectonic movements are being ignored. Realisation must dawn on the possible shifts in riparian paths, or rivers drying up due to massive earthquakes.
There is an urgent need to promote earthquake-proof housing and structures, while adopting better earthquake management practices to minimise loss of life, property, forest cover, wildlife and the ecosystem. Tectonic shifts proceed over millions of years, but they cannot be stopped or wished away. It is time we braced ourselves against the catastrophes-in-waiting and at least started having their impacts minimised.