Pakistan's new island was created by a 'mud volcano'

As we reported yesterday, a new island measuring 40 feet high and about 200 feet across suddenly appeared off the coast of Pakistan following a devastating 7.7 magnitude quake. Geologists now say that it formed after the temblor triggered a mud volcano.

The new island, which is likely temporary, now sits about 2,000 feet (600 meters) off the Gwadar coastline in the Arabian Sea. This region is known for its mud volcanoes. And in fact, a similar island appeared in 1968 following an earthquake — dissipating back into the sea a year later. And in 2001, a magnitude 7.7 quake in Pakistan produced a mud volcano about 300 miles (480 km) away.

Mud volcanoes form when jets of mud, sand, and water are pressurized and squeezed out of underlying sediment, which spreads a brown mush over the immediate area. Sandy layers underground are shaken, causing sand grains to jiggle, settle, and become more compact. This geological process, the liquefaction of sand and mud layers, can happen after any kind of earthquake. But it typically takes a magnitude 7 to 8 quake to produce a new island.

Here's a video from last year showing a mud volcano erupting:

As an aside, it is possible for an earthquake to push up entirely new land features. But again, it would take a powerful seismic event, like a 7 or 8 magnitude.

And as for the immediate aftermath of the recent Pakistan earthquake, the official death toll has risen to 327, but it's expected to rise considerably in the coming days. Pakistan's army has airlifted hundreds of soldiers to the affected areas, with a thousand more set to go.

[Sources: Nature News and NBC; top image: Latif Baloch]