Increasing seismic activity recorded under San Miguel volcano, El Salvador

In a report released on April 18, 2017, the country's Ministry of Environment and Natural Resources (MARN) reported a sudden increase in internal seismic vibration under San Miguel volcano, between 00:20 and 00:30 UTC on April 18. 

The number of earthquakes recorded in a period of 10 minutes under San Miguel volcano reached 356. According to MARN, "these variations are associated with the movement of magma inside the crater, typical situation in an active volcano".

Due to the behavior recorded during the past few days, the emission of gasses and/or magma from the central crater or from the flanks of the volcano is considered very possible. Authorities have issued warnings towards the population to stay away from the volcano.

San Miguel volcano, also known as Chaparrastique, is one of the most active volcanoes in El Salvador. Rising from near sea level, the basaltic-andesitic volcano reaches a height of 2130 m. The last major eruptive phase of the volcano started on December 29, 2013, and ended in August 2014. The explosive eruption that began at 10:30 local time on December 29, 2013, led to a dense ash plume that rose from the crater and eventually reached an altitude of 9.7 km above sea level; the eruption forced the evacuation of 1400 - 2600 people.