mercredi, janv. 22, 2014
The volcano continues to be at yellow alert (one of 6 in Colombia) as seismic activity remains elevated, but at low energy levels. [details]
Machin volcanCerro Machín volcano is a small stratovolcano about 20 km WNW of the city of Ibagué, Colombia. Although there are no historic eruptions, Machin is considered one of the most dangerous volcanoes in Colombia, because it has produced devastating explosive eruptions in its past and will likely to continue so. Pyroclastic flow deposits have been found up to 40 km and mud flow deposits (lahars) up to 109 km distance from the volcano along the Coello and Magdalena rivers.
The last known activity took place about 800 years ago.
Introduction:The small Machín stratovolcano forms the southern end of the Ruiz-Tolima massif. It contains a 3-km-wide caldera breached to the south. There are 3 forested dacitic lava domes inside the caldera.
The number of earthquakes increased at Machin volcano on 31 December 2010. Over the next 4 days, 367 volcano-tectonic earthquakes were recorded south and southwest of the main lava dome in the summit caldera.
The largest event occurred at 5:22 pm on 1 January 2011, with a magnitude 2.3 at a depth of 3.3 km. The earthquake was felt by residents in vicinity of the volcano and in the town of Cajamarca (Tolima).
(USGS / GVP weekly reports)
2008 seismic unrest
An earthquake swarm occurred at Machín volcano on 9 November 2008. The increase in earthquakes was accompanied by an increase in fumarolic activity and there was damage to some buildings (USGS / GVP weekly reports).
2004 seismic unrest
In April 2004, a swarm of earthquakes occurred at Machín volcano. More than 60 earthquakes occurred daily, in comparison to the normal number of 1-10 quakes. (USGS/GVP weekly updates)