Influence of the March 11, 2011 M w 9.0 Tohoku-oki earthquake on regional volcanic activities

Abstract

Two days after the March 11, 2011, M w 9.0 Tohoku-oki earthquake, Shinmoedake volcano, located on the Japanese island of Honshu, erupted. Was this eruption triggered by the Tohoku-oki earthquake? Could Mount Fuji and Changbaishan volcanoes also be triggered to erupt? By calculating changes in the regional stress-strain field that resulted from the earthquake, we find that Mount Fuji, Shinmoedake and Changbaishan volcanoes are all located in regions of volumetric expansion. The volumetric expansions at a depth of 10 km are up to ∼220 nano-strain, ∼8 nano-strain, and ∼14 nano-strain, respectively, for the three volcanoes. The strain changes inferred from GPS co-seismic displacements also suggest that these three volcanoes are located in regions with surface areal expansion. Considering that the expansional stress may cause the opening of magma channels, exsolution of CO2 gases stored in magma, and a series of positive feedback effects, the Tohoku-oki earthquake may result in an increase in the activity of these volcanoes. Attention should be paid to potential triggering of volcanic eruptions by stress changes induced by the Tohoku-oki earthquake.