![]() Now imagine dropping the bottle and cracking the cap. If the cap is on and the soda is under pressure, it can't go anywhere. Then these faults created conduits that the rhyolite magma followed to extrude the rhyolite lava flow. This allowed the magma that was residing in the volcano to rapidly move towards the surface, creating the explosive phase of the eruption. What Novoa and others propose is that local faults on the volcano that produced a M5 earthquake in early June may have changed the stress the volcano was feeling from compression to extension. Unlike that 1980 blast, Puyehue-Cordón Caulle not only had massive explosive phase, but it also produced one of the few rhyolite lava flows in historic times. It ranks as a VEI 5, putting it on par with the 1980 eruption of Mount St. The eruption of Puyehue-Cordón Caulle that started in June 2011 was one of the largest of the 21st century. ![]() A new study by Camila Novoa and colleagues published in Earth and Planetary Science Letters suggests that the 2011-12 eruption of Puyehue-Cordon Caulle in Chile may have had an earthquake trigger. Yet, on a planet as complex as the Earth, there are always exceptions to the rule. The initial ash plume (tan) from the eruption of Puyehue-Cordón Caulle on Jby Aqua's MODIS imager. Did an earthquake lead to a big blast in Chile? ![]() Even in the case of the Chilean earthquake in 1960 (the largest historic earthquake), the potentially triggered eruptions happened days to weeks after the fact. There is no example of a volcano that was dormant suddenly roaring back just because a large earthquake occured. There is some weak correlation between nearby big earthquakes and volcanic eruptions, but in those cases the earthquakes was big, we're talking M9 and most likely the volcano was already primed to erupt. However, it takes a lot to release that pressure. Magma under pressure can hold more dissolved gas, so if you release the pressure, the gas forms bubbles like when you pop open a bottle of soda. ![]() Much of what is controlling whether an eruption happens is pressure - too much then a quick release. Now, this clearly simplifies eruption triggers. The magma might also just keep rising and erupt. This rejuvenates (as we call it) the magma and could move the magma from uneruptable to eruptable. Magma is created tens of miles beneath the volcano and it can rise and intersect older magma that has been sitting and crystallizing. Combine this is the idea that magma needs to be eruptable - that is, liquid enough to get out of the ground - then you can see that a little shaking even from a large earthquake likely won't change that condition.Ĭurrently, the most popular explanation for eruptions is the injection of new, hot magma into the volcano from below. However, at most volcanoes, magma is stored miles beneath the ground. These might include occasional small earthquakes, hot gasses escaping (fumaroles), hot springs and deformation of the ground up or down. Most volcanoes are in repose, meaning that they might show signs of being a potentially active volcano. Second, earthquakes and volcanoes are both part of the processes of plate tectonics, so if something massive happens in one place, could it start a chain reaction? The problem is that the connection is not as direct as it might seem and exactly what can trigger an eruption is still hotly debated.įirst off, the idea that all or most volcanoes are sitting there, primed to erupt, is a misconception. First, earthquakes will shake the ground and volcanoes appear to be vats of magma waiting to explode. Usually this happens when a large earthquake happens somewhere on the planet (especially if it was near any volcano). I get asked quite often if earthquakes can trigger volcanic eruptions.
0 Comments
Leave a Reply. |