Report on San Miguel (El Salvador) — 14 May-20 May 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 May-20 May 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, 14 May-20 May 2014. 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 SNET, the Ministerio de Medio Ambiente y Recursos Naturales (MARN) reported on 19 May that activity at San Miguel had increased significantly in the previous few days. The activity was characterized by an increase in the frequency and magnitude of gas emissions, rumbling in the crater, and small explosions followed by juvenile ashfall. On 18 May between 2230 and 2300 less than 1 mm of ash fell to the WNW in San Jorge. On 19 May the webcam recorded periodic pulses of gray gas plumes that rose 300 m and drifted W. On 20 May seismicity remained high and gray emissions rose 300 m.
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.