How long it takes to compile up that chunk of mud volcano island? Anyone knows? Is it a period of time? Or couple of months? Or couple of weeks? Or a few days?
Photograph from Gwadar Government/AP
Published September 25, 2013
On Tuesday, a 7.7-magnitude earthquake struck a remote part of western Pakistan, killing more than 260 people and displacing hundreds of thousands. It also triggered formation of a new island off the coast, which has quickly become a global curiosity.
But scientists say the island won't last long.
"It's a transient feature," said Bill Barnhart, a research geophysicist with the U.S. Geological Survey. "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."
Indeed, such islands are formed by so-called mud volcanoes, which occur around the world, and Barnhart and other scientists suspect that's what we're seeing off the Pakistani coast.
News organizations have reported that the Pakistani island suddenly appeared near the port of Gwadar after the quake. The island is about 60 to 70 feet (18 to 21 meters) high, up to 300 feet (91 meters) wide, and up to 120 feet (37 meters) long, reports the AFP.
Media reports have located the new island at just a few paces to up to two kilometers off the coast of Pakistan. It is about 250 miles (400 kilometers) from the epicenter of the earthquake.
Map by National Geographic maps. Source: USGS
The island appears to be primarily made out of mud from the seafloor, although photos show rocks as well, Barnhart told National Geographic. He has has been studying images and media accounts of the new island from his lab in Golden, Colorado.
"It brought up a dead octopus, and people have been picking up fish on [the island]," he said.
A similar mud island appeared off Pakistan after a 2011 earthquake there, Barnhart said: "It lasted a month or two and then washed away."
How Mud Volcanoes Work
Though mud volcanoes have been seen elsewhere, they don't always produce islands.
Such volcanoes were seen in California after a 2010 earthquake, Barnhart noted, when the tremors caused carbon dioxide to bubble up through the ground, but the result was "vigorous boiling," not new islands.
Barnhart said Pakistani scientists will soon be measuring the new landmass to better understand how it formed.
Photograph from Gwadar Government/AP
"We don't know much about it so far," he added. "We haven't had a satellite pass over it yet to really identify it."
Seismic waves from the quake likely caused some fluid material under the seafloor to expand, Barnhart said. The crust holding that pressurized fluid ruptured, and mud spewed up.
The whole process is similar to liquefaction, Barnhart said, which is when seismic waves turn normally solid layers of soil into a flowing fluid, often with disastrous results for the buildings and people above.
He was skeptical of media reports that the underlying fluid was methane hydrates.
"We don't know exactly what this was, whether it was free methane, carbon dioxide, water, or some other kind of fluid," he said. But methane hydrates are offshore in much deeper water, he said.
A Local Event
Although earthquakes have been known to radically reshape coastlines, the mud volcano off Pakistan is highly localized, Barnhart said. The epicenter was too far from the coast to cause any widespread changes, and the earthquake was the wrong type to cause big uplifts.
A 9.5-magnitude earthquake off Chile in 1960 pushed whole villages several feet up in the air. But that was from a dip-slip earthquake, when tectonic plates are colliding vertically.
This week's Pakistan earthquake was a strike-slip type, meaning there was only movement horizontally.
I ve heared that it emits flammable gas... some ppl visited the island and it was releasing some kindof gas, they put the flame at that spot and suddendly it was on fire. Fire so strong that u need buckets of water to kill it.
Very revealing article.
Sad to learn so many lives were lost and hundreds of thousand displaced.
Hope the people walking on the mud island are safe though.
Wish data could be gathered on all organisms found on this mud Island.
Thanks NaGoe for this too.
Nice info map of Pakistan is not shown properly Kashmir is a disputed region and u have shown it as a part of Endia..... Kindly review the map
Mud volcano.? Interesting. We can only stand in awe as we small humans ponder the power of the natural world.
Well, its a facinating place even if it is only temporary. And you know, I bet if Obama had an island.....it would look like this.
Enjoy your day. TD.
Barnhart has very nicely explained the creation of this island but he has not given the reasons as he says this will wash away in a month or two. We can clearly see it is all rocks not mud.
In a few seconds, on one side an island appeared as a result of 7.7 earthquake but on the other side many people were killed /injured and thousands rendered homeless. Don't know how much time it will take for poor people to make their homes. May Allah Almighty help the poor still without help/food /shelter.
So many people dying, so many rendered homeless, so many still buried under the derbies! It is all painful. May God help those sleeping in the open! Where are the world disaster managers?
est ce qu'elle est attachée au fond de la mer? ou est ce qu'elle flotte ? si elle est attachée ave ses 21m de hauteur sur 91m largeur sur 37m de longueur; elle ne risque pas de disparaitre, et si elle n'est pas attachée va t-elle partir au large ? avec ses dimensions " ils en feront sûrement une escale touristique"
Our Earth's catastrophies are getting more interesting and concerning by the day. Thankyou Nat. Geo. for your research. You have outstanding reporters, and I look forward to your Magazine each month, along with news online. I now know the specific term for some Earthquakes..!! We are so far lucky here in Australia, but one must be a Scout - Be Prepared. !!
I appreciate the information. Since I live on the Wastch Fault in Utah, I am very interested in earthquakes and their causes. Thanks!
The information was a great help to understand the sudden appearance of the New island.
But i would request you to change the MAP which you have shown in this report because you have shown territory of Pakistan going beyond Indian Territory.
Indeed, as we seek to understand and quantify our home the Earth, she changes the scene again to keep us captivated.
Our home landscape is a fractal of fractals of change. Fascinating story...
From Trinidad and Tobago
The Mysterious Wilkey Island
One hundred years ago, in Trinidad and Tobago there was a similar, but more spectacular geological phenomenon in the waters off Chatham, Cedros.
Villagers reported a mysterious disturbance on October 31, 1911. Fishermen in the area had reported to the police at Erin that an unusual amount of bubbles were seen in the sea and they were afraid to continue fishing in the area. With no explanation as to the cause of the sudden change in sea conditions they dragged their boats onto the nearby Erin beach and waited until conditions at Chatham improved.
Later on the bubbles became larger and rumblings from the sea became so loud that fishermen feared they were in danger. After three days of suspense an island suddenly appeared out of the water. It was the first of its kind, and as the news spread through the village hundreds of curious spectators, newspaper reporters, seismologists, geologists and police and fire officers were on hand to witness the unfolding event.
Among the visitors on site was George A Macready, a geologist from Stanford University, USA, who had arrived in Trinidad a few days before to take up an appointment with General Asphalt Ltd to carry out surveys at Chatham to determine the possibility of finding crude oil. Also on site was police sergeant AFG Wilkey of the Erin Police Station.
Wilkey said at the time a report was made at the police station by fisherman Freddy James of Chatham.
As the drama continued Wilkey got into a fishing boat and headed towards the island to carry out investigations. Taking a flag with him he landed on the island and planted it in the soil, naming it Wilkey Island as he was the first person to land on the mysterious island. Wilkey had barely returned to shore after inspecting the island when a loud explosion was heard. Pandemonium reigned and people were asked to pray. Many knelt on the bare earth with chaplets in hand and prayed to the Virgin Mary to have the eruption subsided. A priest was called to join the prayers but by the time he arrived the smoke had become a raging fire.
Historians record that flames from the volcano lit up the sky, reaching a height of between 500 and 1000 feet. Chatham and its environs were illuminated, and the flare was visible for miles. With no further explosions the island gradually increased in size from one acre to approximately 8.5 acres.
Visitors from Erin arrived in large numbers on board the coastal steamer SS Kennet which was tied up at Erin Bay during the drama. The visitors were not allowed to land on the island but were allowed to circle around for short durations. Meanwhile the fire services stood guard on shore to assist visitors who might be affected by the smoke. This went on for two weeks as more and more people flocked to Chatham hoping to collect samples of anything related to the island.
After three weeks it quietly melted into the bosom of the ocean. In a report submitted by Macready he stated "The gas coming from the formation was definitely petroleum gas."
But there was more to come as some people had predicted. Fifty years later in 1961, what remained of Wilkey Island caused a near accident which could have been disastrous. A 600 tonne boat called the Sea Search was conducting seismic surveys in the same area where the island had emerged. The officer in charge had miscalculated the depth of the water in which the boat was travelling. When the captain realised the boat was in danger he ordered an immediate halt, the boat shuddered to a stop. It had struck the island. One officer fell backwards down the gangway, broke his arm and had to be taken to Moruga and then to the hospital in Pointe-a-Pierre. The captain used his skill and extricated the boat from the island. Little damage was reported.
Wilkey Island again appeared in 1928, 1964 and 2001. In 1964 it had moved from the last location and was located one and half miles from the Chatham coastline where it rose to a height of 25 feet above sea level. Two days later it disappeared again. But before its disappearance spectators had already collected samples from the crater that looked like silver. Some of it was sold to unsuspecting collectors of mineral and rocks.
Curtis Archie, President of the Geological Society of Trinidad and Tobago said there is no fixed time for mud volcanoes to appear.
There are many factors governing the behaviour of these events. He said these underwater mud volcanoes have several means of formation. Usually they are due to pressure building up underground due to rising natural gas, water and mud.
Eventually it will be expelled to form a cone if on land and an island if in the sea. He said fisherfolk in the certain parts of Trinidad should always exercise caution when fishing in areas previously affected by underwater volcanoes. The shiny minerals usually collected after these eruptions has no real value, commonly it is called "fool's gold" or pyrite.
@Usman Latif 9th paragraph: "A similar mud island appeared off Pakistan after a 2011 earthquake..."
@nasir chaudhri If you look closely, you will see a combination of rounded rocks, which would have been brought to the ocean via continental runoff. The rest of the material that appears jagged is ocean sediments, and may be mostly made up of silt clay. It appears jagged and angular like rock when it is compacted and then forced to move, especially if dry or near-dry. Because silt and clay are not strongly joined particle to particle, water dissolves the mixture very quickly. Ocean currents and surface waves will erode the island in geologically no time at all.
While I am not sure of the age of the deposit, gem and mineral hunters may find the island a "gold mine" especially if the deposit contains runoff from mountainous regions known to contain gold. Also look for igneous gems common to the area that supplied the runoff.
@Tina Bertram well said.
I have had to separate pyrite from gold flakes as they can be in the same spot. It's easy (Get a magnet.). But they most definitely can be found together, so look closely.
@r. shaheen We don't even understand why Pakistanis always think in terms of war, there is more than that for human kind to do.
@Hal McCombs wait what? Iron pyrite is generally non-magnetic, and gold is also generally non-magnetic (if not repulsive to a magnet).
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