Earthquake-induced static stress change on magma pathway in promoting the 2012 Copahue eruption

- I studied the effect of 2010 Chile earthquake on the Copahue volcano- The normal stress change was resolved on the reconstructed subvolcanic magma pathway
- Magma pathway unclamping encouraged the unrest at a distance of 257 km- Magma pathway unclamping could favor eruptions up to at least 3 years after an earthquake
- The NE-striking plane suffers the highest value of unclamping

It was studied how tectonic earthquake-induced static stress changes could have contributed to favouring the 22 December 2012 major eruption at Copahue volcano, Chile. Numerical modelling indicates that the vertical N60°E-striking magma pathway below Copahue was affected by a normal stress reduction induced by the Mw 8.8 Chile earthquake of 27 February 2010. A sensitivity analysis suggests that N-, NE- and E-striking vertical planes are affected by normal stress decrease (maximum at the NE-striking plane), and that also a possible inclined N60°E plane is affected by this reduction. Copahue did not have any magmatic event since 2000. Seismic signals of awakening started in April 2012 and the first volcanic event occurred on July 2012. Thus, it is here suggested a possible earthquake-induced feedback effect on the crust below the volcanic arc up to at least 3 years after a large subduction earthquake, favouring new eruptions.