The volcano has been relatively quiet recently. Only few volcanic quakes, weak tremor and (probably) rockfall signals show up now and then.
[details]
San Miguel volcan éruptions
stratovolcan 2130 m / 6,988 ft El Salvador, 13.43°N / -88.27°W Liste des éruptions: 2002, 1997, 1995, 1985-86, 1976-77, 1970, 1967, 1966 (Jul), 1966 (Feb), 1964, 1954, 1939, 1936(?), 1931, 1930, 1929, 1919-20, 1890-91, 1884, 1882, 1867-68, 1862, 1857, 1855, 1854(?), 1844-48, 1819, 1811(?), 1798(?), 1787, 1769, 1762, 1699, 1510 ± 5 years
2002-2006 unrest and seismic activity
Following the small eruption in January 2002, San Miguel volcano remained restless for over 4 years, with periods of increased seismic activity, landslides inside the crater, increased fumarole activity, and lahars triggered by heavy rains. The volcano was on alert several times, but no eruption occurred in this period.
[cacher] In January 2005 observers saw new fumaroles as well as small landslides on the N and SW wall of the crater. Lahars occurred in March 2005 after heavy rains.
Fumarolic activity increased following intense rainfall during the tropical storm Adrian in May 2005.
A spike in seismic activity occurred during August 2005, with 7,048 long-period earthquakes, compared to July 2005, with 2,239 long-period earthquakes.
Lahars occurred on the N slope in October 2005, and in November, major landslides were detected to have taken place in the summit crater.
In April 2006, an increase in fumarole degassing within the crater and small landslides contributed to the instability of the deposits on the NW flanks of the volcano.
A sudden increase in seismicity occurred on 9 October 2006 but no landslides or rock falls were associated with the event and it was attributed to gas emissions in the crater. The volcano was put on yellow alert, but no eruption followed, and the seismic activity calmed down after October.
---
Source: Smithsonian / GVP monthly reports
2002 eruption
On 16 January, gas and steam emissions with some ash were observed at San Miguel, reaching a few 100 meters above the summit crater
2000-2001 lahars
A large lahar occurred on 26 August 2000 and damaged houses and a highway north of the volcano. On 6 September 2001, another lahar damaged a highway.
1997 eruption
A small eruption occurred on 31 December 1997 and produced minor ashfall.
[cacher] "New fumaroles were found near the central vent in early January, followed by an increase in seismic activity from an average of 20-30 events/day. On 8 February there were 52 recorded earthquakes. Seismicity increased to 73 events on 19 February, 100 on the 20th, and peaked at 267 on the 21st. This activity then declined on 22 February to an average of 76 events/day, a rate which continued through at least 24 March. Minor ashfall was reported on 23 March within ~100 m of the crater."
(from: Smithsonian / GVP monthly reports)
1976-77 eruption
After 6 years of dormancy, San Miguel started erupting on 2 December 1976. The eruption built a new spatter cone in the central crater and continued until 12 December. It paused for 56 days and resumed on 28 February the following year and ended on 1 March.
1970 eruption
An eruption of San Miguel volcano started on 30 March 1970 and lasted until 4 April. It consisted of small ash emissions, sometimes accompanied by loud explosions.
The first ash eruption could be heard 4 km away and produced an ash plume rising 400 m above the crater. Light ashfall occurred at up to 10 km distance.
