Weekly activity report of the Nevado del Ruiz volcano.
Subject: internal activity level 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 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 distal areas at North, South, West and East of Arenas crater and, to a lesser extent in the crater itself and its surroundings. The depths of earthquakes during the week ranged from 0,78 to 8,83 kilometers, the maximum recorded was magnitude 2.6 ml (local magnitude), corresponding to an earthquake on January 6 , 2h06 p.m. (local time) in the Arenas crater at a depth of 0,78 km.
Regarding seismic activity related to fluid dynamics in volcanic pipes, this type of seismicity was characterized by the appearance of continuous tremors and earthquakes long period (LP), located mainly in the vicinity of Arenas crater and in the Southeast region of the volcano. The continuous tremor signal, had low energy levels and remained constant throughout the week. Do not rule out that new episodes of high energy levels of this signal and the gas expulsion and ash in the atmosphere may occur.
These processes were accompanied by thermal anomalies noted through monitoring by satellite images provided by different organizations, such as the Italian universities of Turin and Florence (Mírová portal). Moderate thermal anomalies on the 06, 09 and 11 January, which have been identified near the Arenas crater, confirming the instability of the Nevado del Ruiz volcano and confirming that the volcanic process continues to evolve.
The volcanic deformation measured from electronic inclinometers, satellite global navigation systems (GNSS) and satellite images, which record changes in tilt, position and shape of the volcano (respectively) during the last period evaluated, showed no significant changes.
The volcano continues to emit into the atmosphere large quantities of steam and gas, including sulfur dioxide (SO2), as has been estimated by the permanent stations SCAN DOAS installed in the volcano area and by imaging satellite.
The column of gas, steam and ash reached a height of 1400 meters above the summit of the volcano, January 9. The direction of the dispersion of the column is in line with the regime of prevailing winds in the area, which, during the week, showed a predominant direction towards North over the volcano.
January 14, 2016. Nevado Del Ruiz, Colombie :
Source : Sgc.gov.co.