Volcan Nevado del Ruiz, en Colombie centrale, à 130 km WNW de Bogota, est un vaste volcan du glacier couvert. Une éruption relativement faible en 1985 a provoqué une coulée de boue dévastatrice qui a tué près de 25.000 personnes dans la ville d'Armero, marquant l'une des pires catastrophes volcaniques de l'histoire. Malheureusement, cette tragédie aurait pu être facilement évités si des avertissements clairs par les volcanologues ont été prises au sérieux.
Current seismic signal from Ruiz volcano (OLL station, INETER)
The frequency and size of earthquakes has diminished, but is still above normal levels, and suggests that the intrusion of fresh magma is not yet over. A volcanic-tectonic earthquake of magnitude 2.9 occurred this morning at a depth of 7.24 km NW of the Arenas crater. ...plus
The other Colombian volcanoes have not shown significant variations in activity: Weak seismic unrest continues at Machin, Cumbal and Sotara volcanoes with no surface activity. Nevado del Huila has remained in a degassing state with average low seismicity during the past weeks, while Galeras volcano produces occasional steam and ash emissions. [moins]
Current seismic recording from Nevado del Ruiz (OLL station, INGEOMINAS)
The earthquakes swarm at depths between 5-9 km continues with increasingly strong quakes, and accompanied by continuous volcanic tremor (since 10 April), indicating an ongoing magmatic intrusion. Some of the recent earthquakes were above magnitude 4 and felt in areas near Manizales town. ...plus
The volcano is now producing a plume of gas and ash rising to about 800 meters and light ash fall has occurred in various parts of Tolima. [moins]
Yesterday evening's seismic recording from Nevado del Ruiz showing the M4 earthquake (OLL station, INGEOMINAS)
A magnitude 4 earthquake occurred last night under the volcano, marking the so far largest event during the ongoing earthquake swarm, which in turn is likely a result of a shallow magma intrusion at depths of 5-9 km SW of Arenas crater. The earthquake was felt by many inhabitants of the area.
Current seismic recording from Nevado del Ruiz (OLL station, INGEOMINAS)
Strong degassing and minor ash venting continue creating a plume reaching 1000 m above the crater today. The seismic swarm has decreased in strength, but goes on.
Today's seismic recording from Nevado del Ruiz (OLL station, INGEOMINAS)
SO2 plume from Nevado del Ruiz (NOAA)
An eruption is underway at the volcano. The seismic swarm has continued and is increasing, with quakes as large as magnitude 3.2 this morning. The hypocenters of the seismic swarm, caused by intruding magma, is at 5-9 km depth 6 km NW below the Arenas craters. ...plus
INGEOMINAS reports ongoing strong degassing and ash venting. A modest SO2 anomaly is visible on the latest (yesterday's) NOAA satellite data, which confirms fresh magma rising below the volcano. [moins]
Seismic signal from Ruiz this morning (OLL station, INGEOMINAS)
The earthquake swarm with weak volcanic tremor continues, associated with internal fluid movements and steam and ash venting, creating a plume observed rising 630 m above the volcano this morning. ...plus
The volcano-tectonic earthquakes , i.e. the likely location of new intruding magma, are located in northwest of Arenas crater, at an average depth of 7 km. The largest recorded quake was a magnitude 2.6 event at 22:43 (local time) last night, felt by officials of the Colombia National Parks in the area of Brisas. [moins]
Steam plume rising from Ruiz yesterday (INGEOMINAS)
Current seismic signal from Nevado del Ruiz (OLL station, INGEOMINAS)
A (probably shallow) seismic swarm is in progress at the volcano. As INGEOMINAS mentioned in its latest report yesterday, a weak continuous tremor signal continues to be recorded, associated with elevated steaming and light ash venting, creating a plume rising about 1600 m above the volcano.
This morning's seismic signal from Ruiz (OLL station, INGEOMINAS)
Current seismic signal
The Manizales volcano observatory published a special bulletin because of increased activity from Ruiz. Starting at 02:18 (local time) this morning, continuous volcanic tremor has been recorded. This is similar to signals recorded between 8 and 21 March 2013, although this new episode of tremor is of lower energy level than in March. ...plus
Very often, such seismicity is associated with emissions of gas and / or ash. Volcano webcams showed a steam/gas column rising 1600 m above the volcano and drifting NW, and possibly containing some ash in it. [moins]
Today's seismic recording from Nevado del Ruiz (OLL station, INGEOMINAS)
SO2 plume from Nevado del Ruiz (NOAA)
No significant changes in activity have been reported in recent days. Small bursts of small volcanic-tectonic earthquakes, indicators of frequent small magma intrusions, continue to show up almost daily, and are clustered mostly in an area northeast and northwest of the Arenas crater at shallow depths between 0.5-8 km. ...plus
Strong degassing accompanies this process at the surface. A large SO2 plume was visible on yesterday's NOAA satellite data. [moins]
Yesterday's seismic recording from Nevado del Ruiz (OLL station, INGEOMINAS)
Seismic activity has been generally low. INGEOMINAS published some photos showing strong degassing from the volcano. ...plus
The seismic recordings show small clusters of higher amplitude volcano-tectonic and volcanic earthquakes as well as continuous low-level tremor during the recent days. [moins]
During the last few days, INGEOMINAS has been recording weak continuous tremor of low energy and observed increased gas emissions, which produced a plume reaching up to about 1.5 km above the crater. The increased SO2 emission is also visible on NOAA's satellite images. ...plus
Earthquakes associated with rock fracturing (caused by intruding magma at depth) remain in the same area as before, to the northeastern sector of Arenas crater, and to a lesser extent under the crater itself at depths between 2 and 6 km. [moins]
Steaming Nevado del Ruiz yesterday morning (INGEOMINAS)
SO2 plume from Nevado del Ruiz (NOAA)
A phase of increased degassing and weak ash venting is taking place. INGEOMINAS observed a continuous steam-gas-ash plume rising about 300 m high and drifting southwest. ...plus
This activity was accompanied by weak volcanic tremor and volcanic-tectonic earthquakes, located northeast of Arenas Crater with magnitudes less than 1.5 on the Richter scale at depths less than 3 km. [moins]
Since Friday, activity has been elevated. Ash emissions have been causing light ash falls in areas near the volcano. Strong degassing and odor of sulfur was noted in parts of the National Park. INGEOMINAS reports continuous volcanic tremor, and keeps the alert level at yellow (2 on a scale 1-4).
Current seismic recording from Nevado del Ruiz (OLL station, INGEOMINAS)
An increase in seismic activity was recorded by the Manizales Observatory today. Several relatively large volcanic earthquakes (but still less than mag 2 on the Richter scale) occurred and are thought to be related to a new intrusion of magma. ...plus
The new quakes occurred in the area of the Olleta crater at a depth of 2 - 4.5 kilometers, accompanied by seismicity typical for fluid movements at shallow depth beneath Arenas crater. [moins]
Seismic recording this morning from Ruiz (OLL station, INGEOMINAS)
The volcano experienced a phase of increase tremor and small quakes yesterday, probably related to some magma intrusion at depth, which resulted in increased SO2 emissions.
