Weekly activity report of the volcano Nevado del Ruiz, from May 10 to 16 May 2016
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, the SERVICIO Geologico COLOMBIANO reports:
During the last week the seismic activity of the Nevado del Ruiz volcano was mostly associated with rock fracturing within the volcanic edifice, showing a slight decrease in the number and energy released from the previous week. Earthquakes are located mainly in North proximal seismogenic zones , distal North and Northeast compared to the Arenas crater , in its neighborhood and in the crater itself. To a lesser extent, it was recorded activity in the southern areas of South-East and West of the volcanic structure.
The maximum magnitude recorded during the week corresponded to the earthquake registered on May 13 at 16:21 (local time) with a magnitude of 1.0 ML (local magnitude) at a depth of 4.14 km. It was located 2.1 km northeast of the Arenas crater. During the week, a seismicity episode type “Drumbeat” low energy and short durationon May 13, from 11:47 to 11:54 (local time) was recorded. Seismic activity related to fluid dynamics in volcanic conduits characterized by the appearance of long period earthquakes (LP) and very long period (VLP), as well as episodes of continuous volcanic tremor of low level energy, were also recorded. Tremor pulses with different energy levels were noted, some of these signs were associated with the gas and ash emissions. These events were mainly located in Southeast sector of the volcano and near the Arenas crater. The registration of new seismic signals of this type with high levels of energy and ash emissions in the atmosphere are not excluded.
The volcanic deformation measured from electronic inclinometers, satellite global navigation systems (GNSS) and satellite images to track changes in the tilt, the position and shape of the volcano (respectively), continues to record changes.
The volcano continues to emit into the atmosphere large amounts of water vapor and gases, including sulfur dioxide (SO2), as has been estimated by the permanent stations SCANDOAS installed in the Volcano area and by satellite imagery.
On monitoring satellite images supplied by the site Mirova, thermal anomalies were identified during the week, in the vicinity of Arenas crater on 11 and 12 May, with a maximum value of 5 MW. The persistence of these anomalies confirms the instability of the Nevado del Ruiz volcano and confirmed that the volcanic process continues to evolve.
The gas column of steam and ash reached a height of 1700 m, measured from the top of the volcano, on May 12 The direction of the dispersion of the column was in line with the prevailing wind in the area, which, during the week showed the predominant direction towards the West, Northwest and occasionally to the South west of the volcano.
May 20 , 2016.Nevado Del Ruiz , Colombia :
Source : SGC.