¿Was the volcanic eruption triggered by the earthquake?¿ The answer to this question usually
is ¿maybe¿ or ¿a coincidence¿. A region like Central America, is an adequate area to find hints to
answer this question because have the necessary ingredients: the frequent occurrence of large
earthquakes (M5+) and dozens of active volcanoes. This research focuses
on whether the
uncommon occurrence of three large earthquakes in the subduction zone of Central America,
within a time span of ten weeks in 2012, promoted enhanced volcanic activity. The time window
analyzed is from 2000 to 2019, which includes a total of 50 volcanic eruptions with a VEI¿2.
Before the 2012 earthquakes, 22 eruptions occurred.
The Monte Carlo statistical simulation
method allowed to demonstrate that this increase in the number of volcanic eruptions after the
three large earthquakes of 2012 it is not a temporal coincidence. We analyzed the characteristics
of each earthquake and described how they could disturb the volcanic systems. Although Central
America hosts 24 volcanoes with historical eruptions, only 11 of them erupted after the 2012
earthquakes. Why did only these volcanoes erupt? To answer this question, we calculated the
dynamic and static stress in each volcano and the level of volcanic unrest (the change in volcanic
activity beyond background behavior to worrisome levels) prior to the earthquakes. We found
that volcanoes in a unrest stage before the earthquakes but, without experiencing explosive
eruptions before, erupted after receiving the seismic shocks. This fact suggests that the
earthquakes by themselves did not transfer enough energy to generate the volcanic eruptions
when volcanoes were not ready to erupt. However, earthquakes could promote volcanic
eruptions when volcanoes were already at unrest. This research offers a tool for forecasting
volcanic activity when a large earthquake hits a region, if the volcanic activity
is previously
monitored
