Report on San Miguel (El Salvador) — 31 January-6 February 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
31 January-6 February 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on San Miguel (El Salvador). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 31 January-6 February 2018. Smithsonian Institution and US Geological Survey.
13.434°N, 88.269°W; summit elev. 2130 m
All times are local (unless otherwise noted)
On 2 February SNET reported that seismicity at San Miguel was decreasing, along with a decrease in emissions. RSAM values fluctuating between 63 and 114 units; normal values are between 50 and 150. Small pulses of gas near the crater rim were visible.
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.