December 29 , 2016. EN. Bogoslof , Sabancaya , Cayambe .

Home / Alaska / December 29 , 2016. EN. Bogoslof , Sabancaya , Cayambe .

December 29 , 2016. EN. Bogoslof , Sabancaya , Cayambe .

December 29 , 2016.


Bogoslof , Aleutian Islands , Alaska :

53°55’38 » N 168°2’4″ W,
Summit Elevation 492 ft (150 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Bogoslof volcano remains in a state of elevated unrest. Seismic data from neighboring islands detected an increase in volcanic tremor at Bogoslof beginning at 17:55 AKST today (02:55 Dec 29 UTC), with the largest burst occurring at 18:07 AKST (03:07 Dec 29 UTC). The tremor signal lasted for approximately 50 minutes, ending around 18:46 AKST (03:46 Dec 29 UTC). This type of seismic activity has accompanied each of the previous explosions at Bogoslof volcano since the eruption began last week, prompting AVO to issue a Volcano Activity Notice and Volcano Observatory Notice for Aviation. It is unknown if this event produced airborne ash. Continued analysis of data from the Worldwide Lightning Location Network shows no indication of lightning strikes associated with an ash cloud, and infrasound sensors from nearby islands did not detect signals associated with ash emissions. Regional high cloud cover to 35,000 ft asl, however, is obscuring satellite views of the surrounding area preventing confirmation of the presence or absence of an ash cloud. The volcanic seismicity has subsided, for the moment, and the status of the volcano remains at Aviation Color Code ORANGE and Alert Level WATCH.


AVO Image

AVO has no ground-based volcano monitoring equipment on Bogoslof volcano. We continue to monitor satellite images, data from distant seismic and infrasound instruments, and information from the Worldwide Lightning Location Network for indications of significant activity.

Source : AVO

Photo : Harding, Ann


Sabancaya , Peru :

The seismicity showed a significant increase in the number of events associated with the movements and / or the rise of magmatic material (LP, TRE, HIB). In addition, this can be seen in DRC values (reduced displacement values in cm2). These values tend to increase.
-Eruptive columns of gas and ash have reached up to about 3000 meters above the crater, spreading over a large radius of more than 35 km in the North, North-West, South-East and South directions of the volcano .
-The deformation is minimal, almost imperceptible.
-The volcanic gas flow (SO2) recorded a maximum of 3400 tons / day, similar to the previous week.


Keep up-to-date with reports published jointly by OVI and OVS.
Do not approach within 12 km of the volcano.
If ash falls: cover your nose and mouth with a damp cloth or a mask.
Wipe the eyes and cool the throat with pure water.
Avoid wearing contact lenses.
Keep the windows of housing closed.
Implement prevention and mitigation of increased activity.

The Scientific and Technical Committee for Volcanic Risk Management in the Arequipa Region, composed of the IGP South Volcanological Observatory (OVS-IGP) and the INGEMMET Volcanological Observatory (OVI), issued a new official statement on the  Sabancaya eruptive activity. This report recommends raising the  alert level from yellow to ORANGE and avoiding approaching the volcano within 12 km due to the observed steady increase in volcanic monitoring parameters between  November 8 and  December 26


Source : OVI


Cayambe , Ecuador :

Activity Update

Since the publication on December 13 of the Special Report No. 4, the Cayambe volcano has been experiencing an abnormal seismic activity characterized by volcano-tectonic (rock fracturing) and long-term (fluid movement) earthquakes between 2 and 8 km downstream from the summit. In the past two weeks there have been an average of 40 earthquakes per day, noting that since 24 December the number of events has increased, especially the volcano-tectonic type, which also generated a swarm on the 27th, when they counted 100 small earthquakes.
On the other hand, the persistent and strong smell of sulfur that was reported by the climbers during their ascent to the summit and confirmed the presence of new cracks in the glacier near the top of the volcano persists.


Concerning the deformation of the flanks, it is observed that the anomaly, now a little lighter in the GPS data, has been maintained.
An overflight of the volcano was carried out and no thermal anomaly was observed, but it was possible to visualize the crack described by the climbers in recent days.

Due to the type of recorded earthquakes and their locations, it is estimated that the internal anomaly and agitation of the volcano is of magmatic origin. In the medium term, an eruption (weeks to months) is possible, but unlikely if acceleration or sudden changes do not occur in the monitoring parameters. The eruptive scenarios detailed in the previous reports remain valid: A / a very small phreatic eruption whose influence would be near the crater; B / a small magmatic eruption like the event that took place in 1785.


Since the beginning of September, the seismic activity of the Cayambe volcano has remained on normal events / power rates for this volcano, compared to those observed at the beginning of 2016 (Figures 1 and 2). In the last week, there was an average of ~ 40 events / day, mainly volcano-tectonic (fracture) and long-period (fluid movement), which is greater than that observed in previous weeks, see Fig. 3. On 27 December, the number of recorded events was more than 100, located between three to five kilometers west of the summit, they were presented as a swarm, which lasted about 2 hours. The earthquake of greater magnitude was M2.6 degrees. The locations and magnitudes of events over the past two weeks are shown in the figures. 4 and 5 respectively.

Informe Especial Cayambe N. 5 - 2016

Fig. 1: Cumulative number of events on the Cayambe volcano 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 tendency after June and pre-September 2016.

Informe Especial Cayambe N. 5 - 2016

Fig 2 :. Recording of earthquakes on the Cayambe volcano in 2016.
 Informe Especial Cayambe N. 5 - 2016

Fig. 3: Localization of earthquakes (blue dots) in the last two weeks.


Reports indicate that several climbers still perceived a strong smell of SO2 above the Cayambe refuge at 4670 meters above sea level, especially along the way to reach the summit. On the other hand, the SO2 measurement station (DOAS) installed in the second week of December on the western flank of the Cayambe volcano indicates an average SO2 flow rate measured between 20 and 27 December of 180 ± 146 t / d . It should be noted that these are the only SO2 data measured on the Cayambe volcano and due to the low number of daily measurements, it can not be concluded that this SO2 flow corresponds to a type or anomaly in this volcano value.

With the support of the US Geological Survey, it was possible to carry out an analysis of the crack reported near the summit, which indicates a North-South and Northeast-South-East direction. The crack is about a few hundred meters long and its current width is about 5 meters (Figure 7). Near the main, two small perpendicular cracks were observed.

Informe Especial Cayambe N. 5 - 2016

Fig. 7. image of the main crack in the northern part of the volcano (red line). The blue arrows indicate the tendency of the slope. Image USGS.

It has not yet been precisely determined the origin of this crack in the glacier, but apparently in 2007 there was a trace of it, but it was not that size.

Visual Observations:
On December 23, during the flight of the volcano, at the time of approach, it was clear (Figure 8). No degassing was observed in any area of it. The different fronts of the glaciers on all sides of the volcano show no sign that betrays an increase in their rate of fusion. In the highest peak of the volcano (5790 m) as previously reported, the crack that cuts the ice cap (Figure 8) was observed.

Informe Especial Cayambe N. 5 - 2016

Fig. 8: Cayambe volcano seen from the east, no surface activity, or melting of the fronts of the glaciers is observed. (Photo: M. Almeida – IG / EPN, 23/12/2016).

Thermal monitoring:
Thermal monitoring on the Cayambe did not show thermal anomalies on the volcano, measurements in rocky areas where steep slopes not allowing snow accumulation and therefore ice formation show that The temperatures are less than 35 ° C. (FIG. 9) and are related to the influence of the solar radiation, but do not correspond to thermal anomalies.

Informe Especial Cayambe N. 5 - 2016

Fig. 9: Photography, thermal imaging and Google Earth image (January 21, 2016), you can see the crack formed on the highest peak of the Cayambe volcano. (Photo and thermal imaging: M. Almeida – IG / EPN, 23/12/2016 Satellite image: Google Earth.).

It is important to note that this overview could not see the thermal anomalies in the crack which is discussed in the chapter on « visual observations ». In other words, we still can not confirm that the origin of this crack is related to the abnormal hydrothermal activity of the highest peak (Figure 9).


As for the report published on 13 December, where an increase in seismic activity was indicated, there is an increase in seismicity, but it remains within the limits of the anomaly observed since September. On Monday of this week, a regrouping took place in the number of seismic events, which resulted in a swarm. The origin of these internal disturbances is probably magmatic because of the characteristics of the earthquakes. Volcano eruption in the medium term (weeks to several months) is possible, but unlikely if there is no change in monitoring parameters.

Source : IGEPN

Recommended Posts
Showing 2 comments
  • Pamela Gay Conley

    Why is there no detection equipment on Bogoslof Volcano? It seems big enough to be able to add a few monitoring instruments on the island. It looks like they might even be able to put a small structure on there to house some research equipment.

    • ADMIN

      Many volcanoes do not have surveillance devices: isolated trops, no population around (Ertaale in Ethiopia, Lengai in Africa etc …)

Leave a Comment

Nous contacter

Nous ne sommes pas disponibles pour le moment. Mais vous pouvez nous envoyer un email a l'aide du formulaire ci-dessous.

Not readable? Change text. captcha txt

Start typing and press Enter to search