The two earthquakes that struck Japan and Chile in 2010 and 2011 have yielded new evidence to scientists on the potential damage that so-called “megaquakes” can cause – in addition to spawning tsunamis, crumbling buildings, massive loss of life, and opening up holes in the surface of the Earth. In addition to the billions of dollars in damage and the loss of human lives, the earthquakes in Chile and Japan caused a number of big volcanoes to sink up to six inches into the ground, according to the study’s authors.
Following the 8.8 magnitude Maule earthquake in Chile in 2010, and the 9.0 magnitude Tohoku earthquake in Chile in 2011, scientists analyzed captured satellite data to look for markers of increased volcanic activity. What they found instead was that the volcanoes appeared to react to the earthquakes by sinking slightly. These two teams of scientists, who worked independently on researching volcanoes in Chile and Japan, published their respective papers in the online journal Nature Geoscience, which came out on June 30, 2013.
According to Matthew Pritchard of Cornell University, lead author of “Subsidence without eruption of Chilean volcanoes induced by the 2010 Maule earthquake,” “We use satellite Interferometric Synthetic Aperture Radar (InSAR) and night-time thermal infrared data to [analyze] subtle changes in ground deformation and thermal activity at volcanoes in the southern volcanic zone since 2010. We document unprecedented subsidence of up to [6 inches] in five volcanic areas within weeks of the earthquake, but no detectable thermal changes. We suggest that the deformation is related to coseismic release of fluids from hydrothermal systems documented at three of the five subsiding regions. The depth and shape of these hydrothermal reservoirs can also be constrained by our deformation data, implying that coseismic volcano subsidence could be used to prospect for geothermal resources. Similar subsidence observed at Japanese volcanoes following the 2011 Tohoku earthquake suggests this phenomenon is widespread.”
The scientists used satellite data to look for misshapen ground around the volcanoes before and after the massive Tohoku earthquake in Japan and Maule earthquake in Chile. However, Pritchard stated that the find may have been nothing more than a fluke, saying, “There’s probably nothing special about it…Similar subsidence is probably happening after the biggest quakes in Alaska, Indonesia and other major subduction zones in which megaquakes are possible. These two events are just the first to be detected because they happened when the right instruments were in orbit to get the data.”