Machin volcano (Colombia): magnitude 4.6 earthquake on 7 Oct triggers seismic swarm
Tuesday Oct 09, 2012 09:07 AM | BY: T
Seismic signal this morning October 9 (CIMA station, INGEOMINAS)
On 7 October at 21:32 and 21:35 (local time) 2 volcano-tectonic quakes with local magnitude 4.6 and 3.9 occurred beneath Cerro Machin at 12 km depth to the southeast of the main dome.
Seismic signal with the 2 mag 4.6 and 3.9 earthquakes on 7 Oct (CIMA station, INGEOMINAS)
These earthquakes were felt by residents near the volcano, in the municipalities of Cajamarca and Ibague (Tolima), and in some municipalities in the departments of Risaralda, Quindio and Caldas.
These two events triggered in an increase in seismic activity which continued for a day, but seems to have calmed down for now.
As earthquake-report mentioned, Machin has not had any historic eruptions, but there are records of large explosive events in the past. The volcano awakened from a long period of dormancy in the 1990s with numerous earthquake swarms similar to the current ones, but so far has not produced an eruption.
The past several years have been relatively quiet ones at the volcano, but in the past few months, seismicity has again increased. Most of this activity is in the same region 12-15 km below the volcano and could indicate magma intruding there. It will be interesting to follow this volcano's activity in the coming months or years.
Wednesday, Oct 03, 2012
Some weak seismic activity was located south of the main dome at depths ranging between 3 and 5 km. Additionally, there were earthquakes located to the southeast of the dome in the sector between Moral and Moralito. The earthquake of greatest magnitude during the week was a 1.0 (Local Magnitude ML) on September 29 at 10:15 (local time). No other changes were noted at the volcano. [more]
Wednesday, Sep 26, 2012
During the last week Cerro Machin volcano continued to record seismic events associated with the fracturing of rock inside the volcano, located in the main dome and south of it, at depths ranging between 2.5 and 5 km. Additionally, other events were located to the southeast of the dome in the sector between Moral and Moralito. [more]
Wednesday, Sep 19, 2012
Elevated seismic activity continues with 82 events registered over the past 7 days, out of which 45 shallow volcanic quakes up to magnitude 1.3 and frequent tremor pulses of weak energy. Visual observations reveal strong degassing generating a plume rising less than 1 km. [more]
Wednesday, Sep 12, 2012
At the moment, seismicity Machin is calm again. INGEOMINAS summarizes the recent 2 earthquake swarms on 9 Sep between 7:30 and 8:30 (local time) and the following day 10 Sep between 07:20 and 14:00. ... [more]
Tuesday, Sep 11, 2012
Another small swarm of quakes occurred on 10 Sep and then ceased. At the moment, seismicity is again low. [more]