India pushing north prompts quakes

India pushing north prompts quakes

The remote area of north-western China, in the Tianshan mountains, where Monday's powerful earthquake struck, is well used to seismic upheaval.

Disturbance in the earth's crust has been going on here for more than 50 million years, as the Indian tectonic plate pushes roughly in a north-easterly direction, converging with the Eurasia plate.

"India is ploughing into Eurasia at the rate of up to five centimetres a year, pretty fast, pushing mid-China to the east," Dr Mike Pettersen of the British Geological Survey told BBC News Online.

"The Tianshan mountain range has to accommodate much of this movement."

But the effects of this activity spread well beyond the mountains. A huge area of Central Asia suffers relatively frequent earthquakes, with different parts of the earth's crust accommodating the push at different times.

The movement of India has put enormous pressure on the Asian continent, as demonstrated by the emergence of the Himalayas more than 40 million years ago.

The 3,000 kilometre (1,864 miles) long mountain range, the highest in the world, was formed when the India and Eurasia landmasses first collided, driven by plate movement.

As with the Tianshan mountains further north, the pressure could only be relieved by thrusting skyward.