October 08, 2015. English . Copahue, Grimsvötn , Nevado Del Ruiz .

Home / blog georges Vitton / October 08, 2015. English . Copahue, Grimsvötn , Nevado Del Ruiz .

October 08, 2015. English . Copahue, Grimsvötn , Nevado Del Ruiz .

October 08, 2015.

 

Copahue, Chili :

Special volcanic activity report (CSR)
REGION OF BIO BIO – October 6 2015 13: 00 HL


The National Geology and Mining Service (SERNAGEOMIN) Volcano Observatory and the southern Andes (OVDAS) announces that:
Earlier today October 6 at 2:02 local time (5:02 GMT), the Copahue volcano showed sporadic nocturnal glow, suggesting an area of activity associated with small explosions in the crater, engaging in intense degassing process and lower seismic amplitude.

 copahue


When lighting conditions are permitted, there was the issue continues with the release of particulate matter and a low power level, from the El Agrio crater. This activity is the result of a process described in REAV issued on October 1 at 16:00 HL. The emission column has a gray color, reaching a height of 200 m above the crater and moves to the south – east of the volcano.

copahue

At the time of publication of this report, there is no further significant change in the activity described above.
In the present scenario, volcanic risks are limited to the adjacent proximal areas of the crater. Therefore, we recommend maintaining an exclusion zone of 2.5 km around the crater El Agrio, the level of technical Amarillo alert is maintained.
SERNAGEOMIN OVDAS continue online monitoring and timely inform on changes in the activity of the volcano.

Source : SERNAGEOMIN – OVDAS

Photo : , Sernageomin , virgienargentine.canalblog.com

 

 

Grimsvotn, Islande:

64.42 ° N, 17.33 ° W

Elevation 1725 m

According to the Icelandic Meteorological Office, the water level of the Skaftá river at Sveinstindur (the closest gauging station at 28 km downstream from the ice margin) and electrical conductivity both rose on 29 September, indicating the beginning of a glacial outburst flood (jökulhlaup), originating from Grímsvötn’s Eastern Skaftá ice cauldron. GPS measurements indicated that the ice surface above the lake began to subside late on 27 September; the rate progressively increased reflecting increased discharge from the lake.

grimsvotn

At 0330 on 1 October the discharge rate detected at Sveinstindur was higher than 1,300 m³/s, the highest rate recorded since the station was established in 1971. At around 1000, floodwater was also detected in Skaftárdalur at a discharge rate of ~400 m³/s and was rising quickly. GPS data from the eastern ice cauldron showed over 66 m of subsidence since 1800 on 27 September. IMO warned that hydrogen sulfide released from the floodwater as it drains is particularly potent at the river outlet from the ice margin, where concentrations may reach poisonous levels. The cauldrons drain every two years on average, producing floods of up to 1,500 cubic meters per second. During fieldwork later that day volcanologists observed where the jökulhlaup had burst through the glacier at several locations 1-2 km from the terminus. Ice fragments a few tens of centimeters in diameter were scattered near the terminus; ice blocks 3-5 m high and 10 m long were deposited close to the outflow points.

skafta04

Ice Cauldron Skaftárjökull – Photo: RAX via mbls

On 2 October IMO noted that the jökulhlaup was possibly the largest to have occurred from the Skaftá cauldrons. The discharge rate peaked at 0200, just short of 2,100 m³/s, however true discharge rate was thought to have been considerably greater (3,000 m³/s) since water flooded outside of the gauged area. The discharge rate peaked at 1300 at Eldvatn near Ásar at an approximate rate of 2,200 m³/s. According to a news article, the high waters in the Skaftá River damaged the bridge over Eldvatn prompting authorities to close the bridge during 4-5 October.

Sources: Icelandic Met Office, Islande Magazine

Photo : Rax / Ragnar Axelsson via IMO

 

 

Nevado del Ruiz , Colombie :

 

Internal activity level of the Nevado del Ruiz volcano.

Activity level Yellow or (III): changes in the behavior of volcanic activity.

Regarding the monitoring of the activity of the Nevado del Ruiz volcano, the SERVICIO Geologico COLOMBIANO through the OBSERVATORIO VULCANOLÓGICO Y SISMOLÓGICO OF MANIZALES, reports that:

During the last week, the volcanic system continued to present instability in his behavior. The recorded seismic activity was mainly due to the fracturing of the rock in the volcanic structure. This type of seismicity was located in the North East areas, South-West and near the Arenas crater, and to a lesser extent in areas of the North West and South East of the volcano. The depths were recorded from 0.6 to 7.0 km. The maximum magnitude recorded during the week was 1.4 ML (local magnitude), corresponding to an earthquake on October 4 at 1:38 (local time) at a depth of 4.3 kilometers. It showed a slight increase on 3 and 4 October in the northeast section of Arenas crater and in the Azufrado River Canyon area.

 

nevado-del-ruiz

Regarding the seismic activity associated with fluid dynamics in volcanic conduits, it was characterized by the recording of seismic activity type LP (long period) and shorts episodes of volcanic tremor , they showed a slight decrease regarding the final weeks evaluated. These episodes were associated with emissions of gases and ash in the atmosphere, which could be verified by web cameras installed in the volcano area, officials and technical staff during field work in the area of influence of the volcano. Combined with the reduction in tremor signal, it was noted the decrease in the amount of ash emitted into the atmosphere.

Seismicity related to fluid circulation is situated mainly in the Southeast sector and near the Arenas crater. The above processes mentioned were usually accompanied by thermal anomalies (another typical feature of active volcanoes), which can be tracked using satellite images provided by different agencies such as the portal Mírová, from Italian universities of Turin and Florence . During this week were reported on 28 and 30 September, two thermal anomalies in the Arenas crater of minor nature. The volcanic deformation measured from electronic inclinometers, GNSS stations and satellite images, which record changes in tilt, position and shape of the volcano during the last evaluation period showed stable performance.

 

The volcano continues to emit into the atmosphere a significant amounts of water vapor and gases, including sulfur dioxide (SO2). The column of gas, steam and ash reached a height of 2000 meters above the summit of the volcano on September 29, 2015. The direction of the dispersion of the column was in harmony with the wind regime, which showed during the week a variable but tended toward the northwest area of the volcano.

 

Source :  SGC ( http://www2.sgc.gov.co/Manizales/Publicaciones/Reportes-de-actividad/Reportes-semanales/2015/Septiembre/Boletin-Semanal-de-Actividad-del-Volcan-Nevado-4.aspx )

Photo : SGC ( 2012 ), Ingeominas ( 2011)

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