March 18, 2014
Earthquakes Could Be Indicator Of Volcanic Eruption
Lee Rannals for redOrbit.com - Your Universe OnlineAugustine Volcano in Alaska looked at how earthquakes caused by mounting volcanic pressure could be an early indicator of an eruption about to take place.
Scientists detected a swarm of 54 earthquakes across 13 station seismic networks on Augustine Island 36 hours before the first magmatic explosions in 2006. The team found that these earthquakes were actually triggered from a block in the lava flow.
“Our article talks about a special type of volcanic earthquake that we think is caused by lava breaking, something that usually can't happen because lava is supposed to flow more like a liquid, rather than crack like a piece of rock,” Dr. Helena Buurman from the University of Alaska Fairbanks, said in a statement. “Much like breaking a piece of chewing gum by stretching it really fast, lab tests show that hot lava can break when stretched quickly enough under certain pressures like those that you might find in the conduit of a volcano."
The scientists discovered that over the course of two hours, the earthquakes moved 115-feet deeper down into the magma conduit, which indicates that the conduit was becoming clogged.
“We think that these earthquakes happened within the lava that was just beginning to erupt at the top of Augustine. The earthquakes show that the lava flow was grinding to a halt and plugging up the system. This caused pressure to build up from below, and resulted in a series of large explosions 36 hours later," said Dr. Buurman. “We believe that these types of earthquakes can be used to signal that a volcano is becoming pressurized and getting ready to explode, giving scientists time to alert the public of an imminent eruption."