View from space: Earthquake island before and after
Earthquake island, via National Institute of Oceanography
“The island is really just a big pile of mud from the seafloor that got pushed up.” – Bill Barnhart, USGS geologist
The deadly earthquake that struck Pakistan on September 24, 2013 – leaving 515 people dead and 100,000 homeless – also created a new earthly landform. A new mud island now lies offshore in the Paddi Zirr (West Bay) near Gwadar, Pakistan. It is some 380 kilometers (230 miles) from the earthquake’s epicenter. It’s being called being called Zalzala Jazeera – orearthquake island. The first image below shows the new island from space, as seen by NASA’s Earth Observing-1 satellite on September 26. The second image shows the same area on April 17; no sign of an island could be seen at that time.
Earthquake island in Paddi Zirr (West Bay) near Swadar, Pakistan. This island rose from the sea following the September 24, 2013 deadly earthquake in Pakistan. NASA Earth Observatory image via Earth-Observing-1 satellite. Read more about the September 24 earthquake.
Here is the same area as in the photo above, on April 17, 2013. No island. NASA Earth Observatory image via Landsat 8 satellite.
The water depth around the new island is roughly 15 to 20 meters, according to marine geologist Asif Inam of Pakistan’s National Institute of Oceanography.
Bill Barnhart, a geologist at the U.S. Geological Survey who studies earthquakes in Pakistan and Iran, told NASA’s Earth Observatory:
The island is really just a big pile of mud from the seafloor that got pushed up. This area of the world seems to see so many of these features because the geology is correct for their formation. You need a shallow, buried layer of pressurized gas—methane, carbon dioxide, or something else—and fluids. When that layer becomes disturbed by seismic waves (like an earthquake), the gases and fluids become buoyant and rush to the surface, bringing the rock and mud with them.
The underground pressure, in this case, seems to have come from expanding natural gas. Asif Inam said:
The main driving force for the emergence of islands in this part of the world is highly pressurized methane gas, or gas hydrate. On the new island, there is a continuous escape of the highly flammable methane gas through a number of vents.
Close-up of the new island, estimated to stretch 75 to 90 meters (250 to 300 feet) across and standing 15 to 20 meters (60 to 70 feet) above the water line. The surface is a mixture of mud, fine sand, and solid rock. Image via NASA Earth Observatory via National Institute of Oceanography.
The 700-kilometer-long Makran coast has had several of islands similar to the one that appeared September 24, over the past century. In this region, according to NASA’s Earth Observatory:
… the Arabian tectonic plate is pushed northward and downward to go underneath the Eurasian continental plate. The thick layer of mud and rock on the Arabian Plate is scraped off and has formed the land in southwestern Pakistan, southeastern Iran, and the shallow underwater area offshore.
Asif Inam said said these mud volcanoes and islands are:
… a natural hazard and threat to navigation.
It’s thought that the new island will last a few months to a year before sinking back below the water line. It appeared to have survived another strong earthquake in Pakistan – in the same region as the one on September 24 – this time on September 28. That second earthquake is being called an aftershock of the first.
Meanwhile, the relief effort in Pakistan is ongoing, with the situation said to be “desperate.”
Bottom line: The new island offshore in the Paddi Zirr (West Bay) near Gwadar, Pakistan is being called being called Zalzala Jazeera – or earthquake island. This post shows before and after images from space of this bay, plus a closer aerial view of the new island.