Subject: Activity Bulletin of Nevado del Ruiz.
The level of activity continue at level:
Activity level Amarillo or (III): changes in the behavior of the volcanic activity.
Regarding the monitoring of the activity of the Nevado del Ruiz volcano, the Colombian Geological Service reports that:
During the last week, the volcanic system continued to show unstable behavior. The recorded seismic activity is mainly associated with the fracturing of the rock in the volcanic structure. This type of seismicity was located in the distal areas of the North over the volcano and dispersed to a lesser extent in the Southeast , Northeast and Northwest areas compared to the Arenas crater.
The depth of earthquakes during the week was between 1.1 and 8.7 km. The maximum value recorded was magnitude 0.9 ML (Magnitude Locale), corresponding to an earthquake occurred on January 28 at 01:00 (local time), located in the distal northern sector at a depth of 3.2 km .
Seismic activity related to fluid dynamics inside volcanic conduits, was characterized by the appearance of several episodes of continuous tremor and earthquakes long period (LP). These two signals are mainly located near the Arenas crater and southern – Southeast sector of the volcano. The continuous tremor signal had varying levels and low energy. Do not rule out that new episodes of increased levels of this signal and the output of gas and ash in the atmosphere can reproduce. These processes were accompanied by temperature anomalies, low to moderate as monitoring by satellite images provided by the system Mírová, from Italian universities of Turin and Florence highlighted. These moderate thermal anomalies on 27 and 31 January and 1 February, were identified near the Arenas crater, confirming the instability of the volcano.
The volcanic deformation measured from electronic inclinometers, satellite global navigation 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 no significant changes.
The volcano continues to emit into the atmosphere of 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 850 meters above the summit of the volcano on January 26. The direction of the dispersion of the column is 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 and no new events that would indicate an acceleration of the process, involving greater instability of it .Therefore there is no change in the level of activity. While the instability of the volcano drags for more than five years, it is essential not to get used to a apparently monotonous behavior of the volcano and monitoring official information to be published by the Colombian Geological Service.
February 04, 2016. Nevado Del Ruiz, Colombia :
Source : SGC.
Photos : SGC.