Subject: Activity level of Nevado del Ruiz volcano.
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 SERVICIO Geologico COLOMBIANO through the OBSERVATORIO VULCANOLÓGICO Y SISMOLÓGICO OF MANIZALES reports:
During the last week, the volcanic system continued to show unstable behavior. The recorded seismic activity was mainly due to the fracturing of the rock in the volcanic structure. This type of seismicity was located in the north, northwest, southwest and northeast of Arenas crater and to a lesser extent, in the southeast sector and near this one, at depths between 1 , 3 km to 8.2 km. The maximum magnitude recorded during the week was 1.3 ML (local magnitude), corresponding to an earthquake on October 31 at 2:09 p.m. (local time), 3.2 km to the southwest of Arenas crater at a depth of 2.6 kilometers.
Seismic activity associated with fluid dynamics in volcanic conduits, was characterized by the recording of LP type earthquakes (long period) and episodes of volcanic tremor of short duration. Some of these events were associated with emissions of gases and ash in the atmosphere, verified by web cameras installed in the volcano area, official reports Pnnn and technical staff in field mission in the region of influence the volcano. Seismicity related to fluid circulation is mainly located in the southern sector of Arenas crater and near this one. The volcanic deformation measured from electronic inclinometers, GNSS stations and satellite images, which record changes in position and shape of the volcano during the last assessment period showed no major change .
The volcano continues to emit into the atmosphere of significant amounts of water vapor and gases, including sulfur dioxide (SO2). The column of gas, steam and ash reached a height of 1700 meters above the volcano’s summit on October 30. The dispersion direction of the column was in harmony with the wind regime, which during the week showed a variable direction between southwest and northwest over the volcano.
The Colombian Geological Service through the Volcanological and Seismological Observatory of Manizales is preparing to mark the 30th anniversary of the eruption of the Nevado del Ruiz volcano in 1985, which resulted in the loss of about 25,000 people in the departments of Caldas and Tolima . « Lessons of a disaster for Colombia and the world. The story should be the basis to build a better future. »
The Colombian Geological Service through the Volcanological and Seismological Observatory of Manizales closely follows the evolution of the volcanic phenomenon and will continue to report timely to the changes that may occur.
November 07, 2015. Nevado Del Ruiz, Colombie :
Source : SGC