February 11 , 2017. EN. Piton de la Fournaise , Bogoslof , Turrialba , Pacaya .
February 11 , 2017.
Piton de la Fournaise , La Réunion :
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 high intensity level (Figure 1).
Figure 1: Evolution of the RSAM (volcanic tremor and eruption intensity indicator) between January 31st and February 10th (5pm 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.
– The inflation of the building continues, reflecting the pressurization of the surface reservoir and the maintenance of a rise of fluids.
– SO2 fluxes are relatively low.
The observations and observations made on the ground this morning by a team from the Observatory enabled:
– Monitoring of surface activity and erection of the eruptive cone.
A cone 30-35 m high (in its maximum height) and 190 m wide was built (Figure 2). A single active mouth is observed at the top of this cone, from which escape regular projections covering its external walls and thus contributing to its growth. The lava level inside the cone is relatively low (about half the height of the cone at 08:50 this morning).
Most of the activity is done in lava tunnel, and surface flows are therefore low (estimates between <1 and 2.4 m3 / s according to the satellite data of the HOTVOLC platforms (OPGC – Clermont Ferrand) And MIROVA (University of Turin)). Only a few small arms are visible at the exit of some tunnels. These observations are consistent with the low flux of SO2.
Shooting of the eruptive site on 10/02/2017 at 8:50 am, local time. (© OVPF / IPGP)
– The cartographic follow-up of the flows.
The photographs taken today have made it possible to more accurately map the extent of lava flows (Figure 3). The thickness of the lava accumulation at the outlet of the vent (FIG. 2) is about 14 m. The flow front at the top of the « Grandes Pentes » is fixed and no longer progresses (Figure 4).
Figure 3: Approximate tracing of lava flows as of 10/02/2017, 8:50 local time, deduced from aerial images (IGN background map). (© OVPF / IPGP)
Figure 4: Shooting of the front of flow on 10/02/2017 at 7:30, local time. (© OVPF / IPGP)
– Shooting thermal images.
Outlet temperatures at the vent are between 1200 and 1250 ° C. Larger shots identified main channels and highlighted tunnel areas (Figure 5).
Figure 5: Thermal image of the eruptive site taken in aerial view on 10/02/2017, 8:45 am local time. (© OVPF / IPGP)
Bogoslof ,Aleutians 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
Volcanic unrest at Bogoslof continues. One low-level eruptive event was detected at Bogoslof since our last Weekly Update. It occurred last Friday, February 3, at 16:41 AKST (1:41 February 4 UTC), and produced a small volcanic ash plume below 25,000 ft asl, as seen in satellite observations and confirmed by pilot reports. Weakly elevated surface temperatures were observed in satellite imagery on February 7 and 8, possibly related to hot eruptive deposits from last Friday’s explosive activity.
Annotated photograph of Bogoslof Island showing the cumulative effects of 2016-17 eruptive activity. A layer of fine muddy appearing ash drapes most of the landscape and covers pre-existing vegetation. The dashed line indicates the area excavated by explosive eruptive activity so far. A prominent zone of upwelling is probably the surface expression of a shallow submarine vent. Photograph taken by Dan Leary, Maritime Helicopters, January 10, 2017.
It has been 7 days since the last detected explosive activity at Bogoslof. This is the longest repose time between explosive eruptive events since the eruption began on Dec 12, 2016. The longer repose, along with the fact that the last two eruptive events were less energetic and produced relatively low-level ash clouds (<25,000 feet asl), may indicate that the eruption is waning. It is also possible that significant explosive eruptive activity could resume with little or no warning. A satellite image from February 8 shows the vent location at Bogoslof remains underwater, suggesting that if future explosive eruptive activity occurs, it will likely be similar in character to that observed over the past 2 months.
Source : AVO
Photo : Waythomas, chris , 10 Janvier 2017 , 12:00 AM
Turrialba , Costa Rica :
Activity report of the Turrialba volcano, 10/02/2017
On 10/02/2017 at 15:31 local time, an eruption on the Turrialba volcano is recorded, the height reached by the column is unknown due to the poor visibility of the site.
Duration of the activity: Ongoing.
The winds blow northwest.
There are no reports of ash falls.
No sulfur odor reported.
The Turrialba volcano in the light of the moon:
Incandescent vs. Heat Radiation
Incandescence is the change of color towards the red (in the visible spectrum of light to which the human eye is sensitive) that emit heated materials. Beyond red, these changes can be detected by infrared glasses.
The webcam of the Ovsicori-Una in the crater of the turrialba volcano operates in the visible spectrum during the day or in conditions of high brightness (night clear at full moon) and in the infrared spectrum in low light conditions.
These pictures are taken at two moments of the morning of Friday, February 10, 2017: at 4:09 am when the full moon (at the bottom) activated the camera in the visible spectrum and we clearly see the incandescence that leaves the crater by high temperatures of the gases and rocks inside the crater and at 4:45 h when the moon fell on the horizon and the camera reactivates in the infrared spectrum showing in lighter shades the higher temperatures. With the sole infrared, one can not make sure that there is incandescence; Just that there are high temperatures.
Despite the density of water vapor in the gas and aerosol plume, it is permissible to appreciate red light in the active crater of Turrialba, signaling a high flow of thermal energy inside the active crater from a semi-crystallized magma body and relatively poor in magmatic volatiles (gas) near the earth’s surface.
Images: webcam located at the top of Turrialba volcano about 950 meters south-east of the active crater.
Sources : Ovsicori , Marino Protti ,
Pacaya , Guatemala :
Activity type: Strombolian.
Morphology: Stratovolcan composite
Geographical location: 14 ° 22’50˝ Latitude N; 90 ° 36’00˝ Longitud W.
The activity of the Pacaya volcano has increased in its crateric part, with a cone which generates incandescent pulses at altitudes of 25 to 50 m, filling a large part of the crater, and which generated an overflow in the northwest part , Where one meets the crack of the eruption of 2010. This lava flow is approximately 300 m long and runs northwest towards the crater of Cerro Chino.
This new activity cycle of lava flows will continue as well, and in the next few days it will even increase, giving moderate to strong explosions, more than 300 m above the crater
The RSAM graph shows an internal tremor remaining in 2000/3000 Units ranges, being produced by the expulsion of gases and magma.
Guatemala’s civil protection authorities continue to monitor the Pacaya volcano, following an increase in eruptions with strong explosions and lava flows, an official source said on Thursday. « It is expected that in the next few days moderate to strong explosions will continue, more than 300 meters above the crater, » said David de Leon, spokesperson for the National Disaster Prevention Coordinator (Conrad). According to the official, the 2552-meter-high volcano, located 20 km south of the capital, presents lava flows that descend to the northwest of the crater. « Monitoring and communication is maintained with authorities and leaders in areas of the volcano, with those who have made visits to observe the direction and length of the lava flows surrounding it, » De Leon said. The authorities restrict access to hikers on the volcano.
Source : Insivumeh , El telegrafo .
Photo : Photovolcanica ( 2007) , Dr R. Roscoe.