Report on San Miguel (El Salvador) — 11 February-17 February 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 11 February-17 February 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on San Miguel (El Salvador). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 11 February-17 February 2004. Smithsonian Institution and US Geological Survey.
13.434°N, 88.269°W; summit elev. 2130 m
All times are local (unless otherwise noted)
According to a news article, a tectonic earthquake near San Miguel on the evening of 8 February caused landslides within the crater and on the volcano's flanks. One of the landslides threatened retention walls in the community of Carretos near the volcano. Citizens feared that heavy rains in the future could mix with the landslide material and overload the retention walls, causing them to fail.
Geologic Background. The symmetrical cone of San Miguel volcano, one of the most active in El Salvador, rises from near sea level to form one of the country's most prominent landmarks. The unvegetated summit rises above slopes draped with coffee plantations. A broad, deep crater complex that has been frequently modified by historical eruptions (recorded since the early 16th century) caps the truncated summit, also known locally as Chaparrastique. Radial fissures on the flanks of the basaltic-andesitic volcano have fed a series of historical lava flows, including several erupted during the 17th-19th centuries that reached beyond the base of the volcano on the N, NE, and SE sides. 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. The location of flank vents has migrated higher on the edifice during historical time, and the most recent activity has consisted of minor ash eruptions from the summit crater.
Source: La Prensa Grafica