Weekly bulletin of activity of the volcano Nevado del Ruiz, from 15 February to 22 February 2016
The level of activity continue at level : Activity Level Amarillo or (III): changes in the behavior of volcanic activity.
Regarding the monitoring of the activity of the Nevado del Ruiz, the Colombian Geological Service reports that:
During the last week, the volcanic system continued to show unstable behavior. The recorded seismic activity was mainly associated with rock fracturing in the volcanic structure. This type of seismicity was located mainly in the North distal sector (7.9 kilometers away from the crater) and, less numerous and scattered, in areas of the North, North East and South West of the Arenas crater. The depths of earthquakes during the week ranged from 0.6 to 7.9 km. The biggest event of the week was 2.9 ML (local magnitude), on February 17 at 5:22 p.m. (local time), located north of Arenas crater at a depth of 6.38 km.
The volcano presented on 23 February 2 ash emissions, the first quickly scattered by the wind, at 5:14 p.m. local, the second at 9:19 p.m. local, who was accompanied by expulsion of incandescent material.
Seismic activity related to fluid dynamics inside volcanic conduits, was characterized by the occurrence of earthquakes long period (LP), short pulses of tremors and episodes of continuous volcanic tremors to short duration and low energy levels. These seismic signals were mainly located near the Arenas crater and in the South and Southeast of the volcano area. These processes were accompanied by small ash emissions limited near the crater.
The volcanic deformation measured from electronic inclinometers, global navigation satellite systems (GNSS) and satellite images, which record changes in the tilt, the position and shape of the volcano (respectively) during the last period evaluated showed some changes.
The volcano continues to emit into the atmosphere large amounts of water vapor and gases, including sulfur dioxide (SO2) which is distinguished, as has been estimated by the permanent stations SCAN DOAS installed in the region of the volcano and satellite imagery.
The gas column of steam and ash reached a height of 850 meters above the summit of the volcano on February 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 over the volcano.
It is considered that the volcanic system continues to evolve. No new events that may indicate an acceleration of the process, involving greater instability of it and therefore the change in the level of activity is present. While the instability of the volcano covers more than five years, it is essential not to get used to a seemingly monotonous behavior of the volcano and monitoring official information to be published by the Colombian Geological Service.
February 26, 2016. Nevado Del Ruiz, Colombie :
Source : SGC
Photos : SGC ( archives) .