Geologists have recorded almost 1,000 small earthquakes at the Cotopaxi volcano since Monday and say large explosions or even an eruption could be imminent. Only small amounts of gas and steam are escaping from the crater, they say, indicating a blockage in the volcano’s central vent.
Ecuador’s Geophysical Institute says that the large number of earthquakes is due to magma rising from the magma chamber, three to four kilometers under the volcano. “Specifically, they are caused by the fracturing of rock due to increased pressure,” the institute reports. “We are also seeing some outward distortion of the mountain due to the pressure.”
Most of the earthquakes register between 1.5 and 2.2 on the Richter scale.
On Thursday afternoon, small plumes of gas rose to 1,000 meters above the crater.
“This is a very dangerous time for the volcano,” says U.S. geologist George Lassiter. “It’s better that the pressure is released sooner than later since the longer it builds the more violent the explosion or an eruption will be.”
Lassister said he is pleased that the Geophysical Institute is providing more information about what is occurring inside the volcano and saying that the danger level is increasing. “I was seeing some reports that people living close to the mountain were thinking that the danger was subsiding when, in fact, the opposite is true.”
On Thursday, risk management officials extended the area of preparation to Ambato, 60 kilometers south of Cotopaxi. They say that rivers and streams flowing from the volcano could carry eruption outflow into the region. They plan meetings with local officials on Friday.
In addition to Cotopaxi, Ambato is also keeping an eye on the Tungurahua volcano, which is only 18 kilometers away. Tungurahua is also in an eruptive stage.