February 24 , 2017. EN. Nevado Del Ruiz , Nevados de Chillan , Tungurahua , Piton de la Fournaise .
February 24 , 2017.
Nevado Del Ruiz , Colombia :
Weekly activity bulletin of the volcano Nevado del Ruiz, from 14 February to 20 February, 2017
The level of activity continues at the level of activity yellow or (III): changes in the behavior of volcanic activity.
Regarding the monitoring of the activity of the volcano Nevado del Ruiz, the Colombian Geological Survey reports that:
During the week, the different control parameters showed that the volcano Nevado del Ruiz remains unstable. Seismic activity related to fracturing of volcanic rocks showed an increase in the number of recorded earthquakes and seismic energy released compared to the previous week. This seismicity has been located mainly in the North-East, North, South-East, South-West and to a lesser extent in the Arenas crater. The depth of the earthquakes was between 1.1 and 7.7 km. The maximum magnitude recorded during the week was 1.4 ML (local magnitude), which corresponds to the earthquake recorded on 14 February at 19:59 (local time), at 3.1 km depth and located at 2, 5 km south-west of the crater Arenas.
Seismicity related to fluid dynamics in the volcanic structure ducts was characterized by the appearance of earthquakes with varying levels of energy, long period (LP) and very long period (VLP), Tremor pulses and multiple fluid earthquakes. This type of seismicity showed an increase in the number of earthquakes and seismic energy released compared to the previous week. The earthquakes were mainly located in the Arenas crater and to a lesser extent in the Southeast sector. Some of these seismic signals have been associated with the emission of gases and ash into the atmosphere, as confirmed by the cameras installed in the volcano region and the reports of the managers of the Los Nevados Natural Park (Pnnn) . The recording of such seismic signals is not excluded, with higher energy levels, which may be associated with emissions of gases and ash. It is important to remember that ash emission processes can occur over several days and sometimes several times a day, without involving an individual report for each episode.
Volcanic deformation, measured from electronic inclinometers, Global Navigation Satellite Systems (GNSS) and satellite images to determine changes in tilt, position and shape of the volcano, continues to record In recent months a deflationary process and intermittent inflation / deflationary impulses linked to gas and ash emissions.
The volcano continues to emit significant amounts of water vapor and gases, including sulfur dioxide (SO2), as evidenced by the values obtained by the SCANDOAS stations installed in the volcanic analysis area and Satellite images. In the monitoring of the information provided by the Mirova site, 6 thermal anomalies, on 14, 16, 17, 19 and 20 February with different energy values were identified, the most important of which was recorded on 17 February with a value of 30 MW.
The column of gas, steam and ash from time to time reached a maximum height of 1200 m measured on the top of the volcano on 18 February. The direction of dispersal of the column was in line with prevailing wind patterns in the area, which predominated during the week northeast, southeast and sometimes northwest of the volcano.
The volcano Nevado del Ruiz continues to activity level Amarillo.
Source : Ingeominas
Nevados De Chillan , Chile :
1053 seismic events were recorded, of which 76 were classified as volcano – tectonic (VT) in relation to rocks fracturing processes, with local magnitudes less than or equal to 1.9 ML. The largest energy event was located 1.2 km south-east of the active crater at a depth of 3.9 km. Similarly, 922 long-period (LP) earthquakes associated with fluid movements within the volcano were registered with a maximum magnitude of 2.4 ML. The higher energy event showed a reduced displacement value equal to 27 cm2. Finally, 51 long-term Tornillos (TO) events related to the resonance oscillations of the magmatic and / or hydrothermal fluids within the volcanic ducts were recorded. In addition, four (4) tremors (TR) episodes with reduced displacement values (RDC) of less than 3 cm2 and dominant frequencies between 2 and 4hz were recorded.
The images obtained thanks to cameras installed near the volcanic complex, showed a low degassing around the craters currently active with heights that do not exceed 100 m.
According to data obtained from five (5) GNSS stations, which measure the deformation of the volcano surface, no significant changes were observed. The lengths of control lines that cross the volcano have remained stable, suggesting that there is no significant change in the internal dynamics of the volcano. The data provided by two (2) inclinometers did not indicate any significant variations in the morphology of the volcano.
No emissions of sulfur dioxide (S02) into the atmosphere in the volcano sector have been reported, according to data published by OMI monitoring instruments OMI, Sulfur Dioxide Group (http: //so2.gsfc .nasa.gov /) and NESDIS, (http://satepsanoine.nesdis.noaa.gov).
No thermal alerts were reported in the area associated with the volcano according to the data processed by the infrared observations Mirova (http://www.mirovaweb.it/) and MODVOLC (http://modis.higp.hawaii.edu /), Remote sensing systems that indicate significant changes in the earth surface temperature from Moderate Resolution Imaging spectroradiometer MODIS data.
Although superficially the activity has remained weak and without explosions, the dynamics linked to the magmatic and hydrothermal circulation of the fluids inside the volcanic conduits continues to evolve. Moreover, the presence of volcano-tectonic seismic activity in the vicinity of the active crater and a persistent long-term seismicity very close to the surface suggests that the volcanic system is still unstable and may evolve into new explosive phases of type Phreatic and / or phreatomagmatic of a higher intensity of active craters. Therefore, the level of volcanic alert remains at:
YELLOW LEVEL: changes in the behavior of volcanic activity – probable time for a rash: weeks / months.
Note: It is recommended as a preventive measure to apply access restrictions from the area near the crater with a radius of 3 kilometers.
Source : Sernageomin
Tungurahua , Ecuador :
From Thursday, February 16 to Friday, February 17, 2017, IGEPN staff climbed the Tungurahua volcano to conduct on – site monitoring of the current volcano conditions.
1. Climate situation
During the visit of the volcano Tungurahua, on the 16th and 17th of February of this year, the weather conditions are not very favorable. The volcano has remained covered most of the time. On Thursday 16, heavy rains in the upper zone, even complicated the ascent to the shelter and in the late afternoon did not allow to directly observe the volcano. According to service personnel at the Tungurahua Volcano Observatory (OVT), no reports of the descent of lahars in one of the volcano’s streams had been received.
The technical team (figure 1) was formed by volcanologists from the Geophysics Institute (Ecuador), volcanologists who are members of the « Trail by Fire » (France, Canada and Portugal) and a mountain guide. The ascent started at 2:30 am on Friday the 17th. The volcano was covered at the top and completely covered with snow up to about 500 meters below the crater. The climb lasted about 4 hours to the crater of the volcano. At the arrival of the team, there was a small window of clarity which allowed for a few minutes to do the work in the zone. The ambient temperature was about -1 ° C centigrade below zero, a relative humidity of 50%.
Figure 1: Technical team during the descent into the crater of the Tungurahua volcano. Photography: R Toapanta. IG-EPN. 17/02/2017.
An activity of fumaroles was observed, very weak and pulsatile, on the NW and N flanks, which was presented as small gas plumes, possibly constituted for the major part of water vapor. Inside the crater of the volcano, small fields of fumarole, with very little activity, where one could hardly distinguish the exit of gases in very small quantities, were observed, at a height that failed to Over the edge of the crater (Figure 2).
It is impossible to perceive a smell of sulfur at all the stages of the ascent, and during the work done in the upper zone of the volcano (crater).
Figure 2: Northeast edge of the Tungurahua volcano crater, very low intensity fumaroles are observed. Photo: M Almeida. IG-EPN. 17/02/2017.
In addition, as part of the mission, they were able to obtain new measurements by means of a device that allows the measurement of distances from a distance (rangefinder). The new crater measurements are 363 m in diameter, the maximum crater depth is 228 m and the difference in height in the north-western edge is 61 m from the 4895-m altitude. This time, no craters associated with the phreatic explosions were observed.
The results of the measurements can also be seen in the diagrams shown in FIG3.
Figure 3: Diagram of the measurements obtained in the crater of the Tungurahua volcano. Photo: M Almeida, IG-EPN.
3. Thermal monitoring:
By analyzing the thermal images captured in the volcano crater the following TMA (apparent maximum temperature) values were obtained:
1. Inner edge South-West, TMA = 110.8 ° C
2. Current crater bottom, TMA = 68, 6 ° C
3. Northwest edge, TMA = 111 ° C
In other areas inside the crater, which have shown thermal anomalies, variable temperature was calculated with values between 35 ° C and 50 ° C
In general, all temperatures obtained in these surveys are considered to be low and could be mainly related to hydrothermal activity (Figure 4).
Source : IGEPN
Piton de la Fournaise , La Reunion :
The eruption begun on January 31, 2017 at 7:40 pm local time continues. The volcanic tremor (indicator of surface eruptive intensity) remains at a stable level (Figure 1).
Figure 1: Evolution of the RSAM (volcanic and volcanic eruption indicator) between January 31st and February 23rd (4:30 pm local time) on the seismic station of Château Fort, located on the southern flank of the volcano.
– No seismicity was recorded during the day under the summit of Piton de la Fournaise.
– The inflation of the volcano in its summit area continues. A slight inflation at the base of the cone (bottom of the Enclos ) is now perceptible. On the other hand, outside the Enclos , no deformation is currently observable.
The visual observations made this day from the Piton de Bert, as well as the measurements made on gas plume, indicate moderate and stable activity. No significant change in surface activity was observed compared to yesterday.
Source : Ovpf
Photo : Timaoul