Subject: Activity Bulletin of the Nevado del Ruiz volcano.
The level of activity continues at:
Activity level Yellow or (III): changes in the behavior of volcanic activity.
Regarding the monitoring of the activity of the Nevado del Ruiz, the SERVICIO Geologico COLOMBIANO reports:
During the last week the seismic activity of the Nevado del Ruiz volcano was mostly associated with rock fracturing within the volcanic edifice, showing a decrease in both the number of events and the energy released by them . Earthquakes were mainly located in the North distal area, 7.0 km away compared to the Arenas crater at depths between approximately 6.0 and 8.0 km.
And in the northern area of the crater to 4.0 km, with depths between 4.0 and 6.0 km and to a lesser extent in the Arenas crater and in the South of it. The maximum energy of the week corresponds to an event of magnitude 1.2ML (local magnitude), recorded on April 19 at 18:09 (local time), located in the North distal area at a depth of 7.05 km. Seismic activity related to fluid dynamics in volcanic conduits, characterized by the occurrence of earthquakes long period (LP) and very long period (VLP), as well as episodes of continuous volcanic tremor, weak, is also recorded, with an energy level and a pulse mode having different energy levels, some associated with process of emission of gas and ash. These events were in the Arenas crater, near the South-East and North-West.
The volcanic deformation measured from electronic inclinometers, global navigation satellite systems (GNSS) and satellite images to track changes in the tilt, the position and shape of the volcano (respectively), continues to record changes.
The volcano continues to emit into the atmosphere large amounts of water vapor and gases, including sulfur dioxide (SO2), as it was felt by the permanent stations SCANDOAS installed in the Volcano area and by satellite imagery.
In satellite surveillance images provided by the portal Mirova he identified a thermal anomaly in the vicinity of Arenas crater, reported on 20 April, with a value of 6 MW during the week. The persistence of these anomalies confirms the instability of the Nevado del Ruiz volcano and confirmed that the volcanic process continues to evolve.
The column of gas, steam and ash reached a height of 1,700 meters above the summit of the volcano. This height corresponds to the vapor column of April 21. The direction of the dispersion of the column was in line with the prevailing wind in the area, which during the week showed a predominant direction towards the northwest and to a lesser extent to the southwest of the volcano .
April 28 , 2016.Nevado Del Ruiz , Colombia :
Source : SGC.