Subject: internal activity level of the Nevado del Ruiz volcano.
The level of activity continues at:
Yellow activity level or (III): changes in the behavior of volcanic activity.
Regarding the monitoring of the activity of the Nevado del Ruiz volcano, the Colombian Geological Service reports:
During the last week, the volcanic system continued to show unstable behavior. The recorded seismic activity was mainly associated with the fracturing of the rock in the volcanic structure. This type of seismicity was located mainly in the Southwest areas, Northeast, North distal and in Arenas crater. The depths of earthquakes during the week ranged from 1.42 to 7.70 km. The maximum recorded was magnitude 1.2 ml (local magnitude), corresponding to an earthquake on January 24 at 12:04 (local time), located in the northeast sector of the Arenas crater at a depth of 2.82 km.
Seismic activity related to fluid dynamics in volcanic conduits, was characterized by the appearance of continuous tremors and earthquakes long period (LP). These two types of signals were mainly located near the Arenas crater and areas in South and Southeast of the volcano. The continuous tremor signal, had varying levels and low energy. Do not rule out that new episodes of high levels of energy of this signal and the output of gas and ash in the atmosphere can reproduce. These processes were accompanied by thermal anomalies, which were recorded by monitoring satellite images provided by the Italian universities (portal Mírová) of Turin and Florence. Moderate thermal anomalies on the 20, 22, 23 and 25 January, which have been identified near the Arenas crater, confirming the instability of the volcano.
The volcanic deformation measured from electronic inclinometers, global navigation satellite systems (GNSS) and satellite images, which record changes in tilt, position and shape of the volcano (respectively) in the last evaluated period, showed no significant changes.
The volcano continues to emit into the atmosphere a significant amounts of water vapor and gases, including sulfur dioxide (SO2), as has been estimated by the permanent stations SCAN DOAS installed in the volcano area and by satellite imagery.
The column of gas, steam and ash reached a height of 1300 meters above the summit of the volcano on January 22. The direction of the dispersion of the column is in line with the regime of prevailing winds in the region, who, during the week showed a predominant direction towards the west and northwest of the volcano.
It is considered that the volcanic system continues to evolve and new events may indicate an acceleration of the process, involving greater instability of it and consequently changes in activity level. While the instability of the volcano has been smoldering for more than five years, it is essential not to get used to an apparently monotonous behavior of the volcano and watch the official information that will be published by the Colombian Geological Service.
January 28, 2016. Nevado Del Ruiz , Colombia :
Source : SGC