June 18 (UPI) – An earthquake alarm is what it sounds like: many earthquakes contain a fault system over a short period of time. The phenomenon helps scientists uncover the connection between descending tectonic plates and volcanoes.
Recently, researchers discovered a few earthquake swarms while exploring the Pacific Mariana and Izu Bonin arch systems. When scientists mapped the swarm's seismic signatures in 3D, they discovered a sort of pipeline that connects the descending tectonic plates and a pair of magma chambers.
The discovery – described this week in the journal Earth and Planetary Science Letters ̵
Mariana and Izu Bonin arch systems are found along the border of two tectonic plates, the Philippine sea plate and the Pacific plate. As the Pacific plate sinks below the earth's mantle, it carries water deep beneath the earth's crust. As the water gets deeper and deeper, the heat and pressure water gets overheated. When it tries to escape, crush stone and melt, it creates a pipeline through which molten stone can rise.
"In fracking used by the petroleum industry, they drill into the soil up to a few kilometers deep, and then continue to pump liquid down until the pressure grows and the rocks break and create a path for petroleum or natural gas to flow through the rocks and into a pipe back to the surface, "says Lloyd White, an earth scientist at the University of Wollongong in Australia, in a press release. "In this case, the tectonic plate transports the water very deep into the ground, down to about 200 kilometers below the surface. When the plate goes down, it gets warmer and the pressure gets higher, driving water out of the submerged plate."  The new research suggests that the subdued water causes rocks to break and melt, create the magma itself and create a path through which the molten stone can travel. The activity also generates a series of small earthquakes or earthquakes.
"It resembles fracking, but to a much greater extent and completely driven by the earth's natural processes, rather than being man-made," White said.
Scientists estimate that the seismic activity is generated either by fracturing stones as overheated water spills or as the pipeline collapses when the molten stone has migrated through.
"Geologists have always assumed that the water in this system goes up, but we have never had a good way of imaging it," White said. "These examples – a freak occurrence that we have stumbled upon – show very clearly where the water should travel."
The new research could help scientists identify the volcanoes supplied with large amounts of molten rock, and are therefore at greater risk of eruptions.