Report on San Miguel (El Salvador) — 25 June-1 July 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
25 June-1 July 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on San Miguel (El Salvador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 June-1 July 2014. Smithsonian Institution and US Geological Survey.
13.434°N, 88.269°W; summit elev. 2130 m
All times are local (unless otherwise noted)
MARN issued a special report on 27 June and related the unstable system at San Miguel as RSAM values decreased then climbed to fluctuate between 118 and 335. Concentrations of sulfur dioxide (SO2) values measured over the past 24 hours have fluctuated between good and unhealthy.
Geological Summary. The symmetrical cone of San Miguel, one of the most active volcanoes in El Salvador, rises from near sea level to form one of the country's most prominent landmarks. A broad, deep, crater complex that has been frequently modified by eruptions recorded since the early 16th century caps the truncated unvegetated summit, also known locally as Chaparrastique. Flanks eruptions of the basaltic-andesitic volcano have produced many lava flows, including several during the 17th-19th centuries that extended to the N, NE, and SE. The SE-flank flows are the largest and form broad, sparsely vegetated lava fields crossed by highways and a railroad skirting the base of the volcano. Flank vent locations have migrated higher on the edifice during historical time, and the most recent activity has consisted of minor ash eruptions from the summit crater.