Pakistan’s New Island Is Flammable and Temporary

Just half an hour after a 7.7 magnitude earthquake shook Pakistan last Tuesday, a new island surfaced in ocean, roughly half a mile offshore. Even though the quake’s epicenter was 230 miles away, the seismic wave disturbed a pocket of pressurized gas, which erupted as a “mud volcano,” forcing the seafloor of fine sand, solid rock and mud up 60 to 70 feet above the water.

As residents along the coast came out to explore, they found stranded sea creatures that had found themselves suddenly be hundreds of feet from the very ocean they were swimming in a moment ago. Journalist Bahram Baloch told the BBC that island was covered in dying fish and he could hear the hiss of escaping gas. At the end of the first-hand account video below someone lights one of the vents on fire.

The escaping gas, which is probably methane, is proof that Pakistan’s newest island is above the ocean only temporarily. As the underground gas cools, compresses, or escapes, the crust will settle back down and collapse, and currents in the sea will wash the sediment away.

"It's a transient feature," Bill Barnhart, a research geophysicist with the US Geological Survey told National Geographic. "It will probably be gone within a couple of months. It's just a big pile of mud that was on the seafloor that got pushed up."

Several of these islands have come and gone along the Makran coast in recent years—at least four since 1945, and the third in 15 years according to Rashid Tabrez at the National Institute of Oceanography. In November 2010, fisherman came across an uncharted island, but by February the next year, the ocean reclaimed it. Satellite pictures captured that island’s brief life, just as, two days after the earthquake, NASA caught images of the new island.

Pakistan sits on—and is formed by—the slow, on-going collision of two tectonic plates. The Arabian tectonic plate is slowing being driven under the Eurasian plate, at a pace of about four centimeters each year. Some of the land is sloughed off, forming Pakistan's coastal plain, the Makran Desert.

But mud volcanoes show up elsewhere. When they appear on land, they stay around much longer, although most are shorter than a meter or two. The largest mud volcano is Indonesia's Lusi, which has been continuously errupting since 2006.

The local residents who have explored the island off Pakistan's coast are exploring terra nova and an island that will soon be returned to the seafloor.