Weekly Activity Bulletin volcano Nevado del Ruiz, from October 13 to October 19, 2015.
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 SERVICIO Geologico COLOMBIANO through the OBSERVATORIO VULCANOLÓGICO Y SISMOLÓGICO OF MANIZALES, reports that:
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 in the North, Northeast, Southeast and Southwest, and to a lesser extent near the Arenas crater. The depths vary between 0.9 and 8.5 kilometers. The maximum magnitude recorded during the week was 1.8 ML (local magnitude), corresponding to an earthquake on October 13 to 11:28 p.m. (local time) at a depth of 2.7 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. These episodes were associated with emissions of gases and ash in the atmosphere, which could be verified by web cameras installed in the volcano area, the official reports of NNNP and technical staff during field work in the area of ??influence of the volcano. Seismicity related to fluid circulation is mainly located in the southeast area of ??the Arenas crater and nearby. The volcanic deformation measured from electronic inclinometers, GNSS stations and satellite images, which record changes in tilt, position and shape of the volcano, during the last assessment period showed no change major.
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 1800 meters above the volcano’s summit on October 17. The direction of the dispersion of the column was in harmony with the wind regime, which during the week showed a variable direction, but with a tendency towards the northwest flank of the volcano.
The SERVICIO Geologico COLOMBIANO through the OBSERVATORIO VULCANOLÓGICO Y SISMOLÓGICO OF MANIZALES, continued to lead the process of socialization of technical information with various stakeholders in the risk management; communities who have been informed during the last week were the municipalities of Ambalema and Venadillo in the department of Tolima. Thereupon, the Colombian Geological Service has been able to achieve all the different municipalities of the region on the threat of the Nevado del Ruiz volcano.
While the volcano Nevado del Ruiz to date remains at yellow activity, it is possible that additional changes occur in the behavior of volcanic activity, indicating greater system instability and may imply changes in the activity level.
October 22 , 2015. Nevado del Ruiz , Colombie .
Source : SGC ( http://www2.sgc.gov.co/Manizales/Publicaciones/)
Photos : Ingeominas, SGC