February 19 , 2017. EN. Cayambe , Piton de la Fournaise , Bogoslof , Sabancaya.
February 19 , 2017.
Cayambe , Ecuador :
Since the publication of 28 December (Special Report No. 5), the Cayambe volcano has been experiencing abnormal seismic activity characterized by fracture-type volcano-tectonic earthquakes and long-period events (fluid movements) between 2 and 8 Km downstream from the summit. In January, an average of 15 LP-type events and 36 VT events per day was recorded, where as so far this month there has been an average of 15 LP events and 21 type events VT per day so far, indicating a slight decline that began during the last week of January. Climbers reported that the smell of sulfur, which was at a high level from October to December, decreased significantly today.
Overflights of the volcano were made, but due to poor conditions and amount of snow, observations of cracks observed in December, are not very clear.
Due to the type of recorded earthquakes and their locations, it is believed that the internal anomaly of the volcano is likely to have a magmatic origin. In the medium term, an eruption (weeks to months) is possible, although unlikely if acceleration or sudden changes do not occur in the monitoring parameters.
Since the first signs of commotion have been received, the Institute of Geophysics has installed additional stations [1 GPS 1 inclinometer, 1 DOAS (gas sensor)], with plans for another seismic station in the near future, And updated one of the existing stations [the ANGU seismic station was changed from short to broadband – increasing its capacity to measure the parameters of larger events] to ensure surveillance capabilities. The institute also holds weekly meetings to discuss and interpret the data received, ensuring that any changes on the volcano are detected.
The Cayambe volcano remains at a higher than normal seismic level (with mainly volcano-tectonic events (fracture) and long-term events (fluid movements) since the beginning of September (Figures 1 and 2). The last few weeks show a slight downward trend since the last week of January and that persists. It should be noted that activity is still significantly higher than normal.
Fig. 1: Cumulative number of Cayambe volcano events since January 2016 (blue line). The orange line corresponds to the previous trend of typical swarm of June 2016. The gray line corresponds to the same trend post-June and pre-September 2016.
The locations and extent of events over the last few weeks, compared to the previous activity (November and December 2016), are presented below.
VOLCANIC GAS DETECTION and visual observations.
We have had reports from climbers indicating that the smell of sulfur, which has been reported as alarming in the last months of 2016, has been significantly reduced. The most intense smell was felt above the Cayambe refuge, at 4670 meters above sea level, at Picos Jarrin (the strongest area) and at the crest before the summit. Currently, the smell of sulfur near the top is not perceived, but still the odor varies with time between moderately strong and weak near the Jarrin Picos.
During the flyover on January 28, 2017, the volcano was partially cloudy, limiting direct observation of the summit. During the follow-up work, no apparent emissions of volcanic gases could be observed, nor the perception of sulfur odor. Despite adverse weather conditions, it was possible to demonstrate the presence of the « new » crack observed during the flight of December 23, 2016, with no apparent changes in its structure
Fig. 7: Cayambe volcano seen from the west, no surface activity is observed. (Photo: P. Ramon – IG / EPN, 16/01/2017).
Similar to the analysis performed in the last flyby, the volcano shows no thermal anomaly; The measurements obtained relate mainly to rock heated under the influence of solar radiation, this time with maximum temperatures of approximately 28.5 ± 5 ° C apparent in areas without snow accumulation or without the presence of ice cap .
Photograph and corresponding thermal image, captured on the eastern flank of the Cayambe volcano. The yellow zones correspond to rocks which have been heated mainly by the action of solar radiation (see large scale analysis on the right side of the thermal image) (Photo and thermal imaging: P. Ramon – IG / EPN; 2017).
In relation to the report published on 28 December, where a slight increase in seismic activity was indicated, there was a slight decrease in seismicity but remained within the limits of the anomaly observed since September. The origin of this anomaly may originate from the hydrothermal system, but more probably a magmatic origin due to the characteristics of the earthquakes. Volcano eruption in the medium term (weeks to several months) is possible, but very unlikely if there is no change in monitoring parameters.
Source : IGEPN
Piton de la Fournaise , La Reunion :
Eruption begun on January 31, 2017 at 7:40 pm local time continues. The volcanic tremor (surface eruptive indicator) remains at a relatively constant intensity level for 3 days, at a level equivalent to that at the onset of the eruption (Figure 1).
Figure 1: Evolution of the RSAM (volcanic tremor and eruption intensity indicator) between January 31st and February 18th (18h local time) on the seismic station of Château Fort, located on the southern flank of the volcano. (© OVPF / IPGP)
– No seismicity was recorded during the day under the summit of Piton de la Fournaise.
– A trend towards a rebound in inflation under the volcano seems to be emerging. This parameter will be confirmed in the next few days.
The activity is visible on the eruptive cone, which now measures more than 30 meters in height!
Source : Ovpf, Fournaise info.
Photo : Timaoul
Bogoslof , Aleutians Islands , Alaska :
53°55’38 » N 168°2’4″ W,
Summit Elevation 492 ft (150 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: RED
The eruption of Bogoslof volcano continues. After the explosion the morning of 17 February, a subsequent minor explosion was observed in seismic and infrasound data at around 15:46 AKST (00:46 UTC). The resulting volcanic cloud was observed in satellite views with cloud tops at around 25,000 ft asl.
The morning of 18 February, at around 4:50 AKST (13:50 UTC), an explosion occurred producing a cloud again. The explosion was detected by seismic, infrasound, lightning and satellite observations. This volcanic cloud traveled south-west at around 25,000 ft asl.
Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition. Additional explosions producing high-altitude volcanic clouds could occur at any time. Some previous explosions have been preceded by an increase in earthquake activity that allowed for short-term forecasts of imminent significant explosive activity. Although we are able to detect energetic explosive activity in real-time, there is typically a lag of tens of minutes until we can characterize the magnitude of the event and the altitude of the volcanic cloud. Low-level explosive activity that is below our ability to detect in our data sources may be occurring. These low-level explosions could pose a hazard in the immediate vicinity of the volcano. When such low-level activity occurs, it is considered to be consistent with Aviation Color Code ORANGE and Volcano Alert Level WATCH.
Source : AVO
Sabancaya , Peru :
In the week, there was an average of 23 explosions per day, with DR values reduced to a maximum of 77 cm2 (DR: the area that was moved by earthquakes in the source).
• Eruptive ash and gas columns reached about 3000 meters above the edge of the crater and then spread over more than 40 kilometers to the south, northwest and south-east of the volcano.
The tendency of deformation is weak and negative.
The volcanic gas flow (SO2) reached a maximum of 2360 tons / day on 01 February.
8 thermal anomalies were detected, with values between 1 and 31 MW of GRP (volcanic radiated power).
Source : Ingemmet