July 30, 2015. English . Piton de la Fournaise , Poas, Karymsky .

Home / blog georges Vitton / July 30, 2015. English . Piton de la Fournaise , Poas, Karymsky .

July 30, 2015. English . Piton de la Fournaise , Poas, Karymsky .

July 30, 2015.

 

Piton de la Fournaise , La Réunion .

 

The volcanic vigilance is more than ever in force and there is no question of restoring access to the summit of the volcano as was envisaged last week in light of the apparent stabilization of the activity of Piton de la Fournaise.

Since this weekend, the parameters recorded by the Volcano Observatory have evolved: seismicity increases again and the swelling of the top of the volcano took over.
On July 6, the prefecture had activated the alarm volcano Orsec 1 and closed the enclos due to the probability of an eruption « more or less imminent«  in an hour, the monitoring network had logged more than 90 earthquakes of moderate magnitude at a shallow depth below the summit.

 

piton

This isolated crisis remained unanswered. L’enclos was reopened on July 9, with the limitation: since, hikers should not go further than the Rosemont chapel, located at the foot of the terminal cone. The volcano continues to swell and shallow magma stays below the summit, explained the prefecture announcing the return of volcanic vigilance phase. In this context, the ascent of magma could take place very quickly with the risk of destabilizing the edges of the Dolomieu crater where the observation platform is located.

Since last weekend, the seismicity is again on the increase: the observatory counted up to 67 earthquakes on Monday (with a maximum magnitude of M 1.4), but their average number is around of forty to fifty (against fifteen per day of the month of July). The summit of the volcano inflation accelerated and also the pressure source (the place alleged of the storage of magma) is estimated between one and two kilometers below the summit. More sensitive gas emissions are detected by the sensors of the observatory.

After two eruptions already this year, in February (12 days) and in May (14 days), the third is still in preparation.

 

Source : Clicanoo.

Photo : Jean Guichard

 

Poas , Costa Rica :

During the visit to the Poas Volcano, July 21, 2015 some observations described below were performed. With favorable conditions in the direction of the gas plume it was possible to visit the western part of the dome in its top and bottom. Because the eruptive activity was concentrated in the lake in recent years, there are no abrupt changes in the morphology of the dome; as happened in other eruptive periods.

poas

The lower dome on the north side (lakeside) is partially covered by rising lake level. Some morphological characteristics produced in recent years have not been observed on this side. Fumaroles with abundant water outlet (geyser-type) for the reason that these vents are completely flooded were not observed. Despite the abundant water activity, the water level of the lake is very high. This is related to heavy rains in recent months on the tops of the volcanic Sierra.

One of the most noticeable changes is depression that remains in the north wall, with the collapse that partially covered the eastern mouth; formed in the second half of 2011. The scar on the wall shows chaotic highly weathered materials.

This eastern mouth has maintained for many months a deep and vigorous exit of gas and steam. The slide buried almost the entire depression and has almost completely erased its features. The abundant water outlet activity is stopped even if the lake level is several meters above the level it was in 2012.

 

poas

 The turbine classic sound of some vigorous fumaroles of the dome is understood. The convective activity on the lake showed only one main cell, unlike previous visits. The main cell displays a rich mixture of sediment and produces no noise to reach the surface. In general, it can be concluded that the activity of the lake and dome seems to be relatively low. The fact that the lake maintain the temperature between 35 and 40 ° C is quite normal given the dynamics observed on the volcano for decades.

 

Source : Ovsicori.
Photo : Robin Campion, Maria Martinez .

 

Karymsky, Kamchatka :

54.05 N, 159,44 E;
Altitude : 4874 pi (1 486 m)
Code couleur Aviation : ORANGE

 

Satellite data showed an ash plume is extending about 35km to the east of the volcano.
Distance of ash plume/cloud of the volcano: 22 mi (35 km)
Direction of drift of ash plume/cloud of the volcano: E / azimuth 84 deg

Karymsky

Satellite data showed: ash cloud in size 8×5 km drifted about 113 km to the east of the volcano on July 17; and a thermal anomaly over the volcano on July 17. The volcano was obscured by clouds in the other days of week.

Moderate eruptive activity of the volcano continues. Ash explosions up to 19,700 ft (6 km) a.s.l. could occur at any time. Ongoing activity could affect low-flying aircraft.

 

Source : Kvert
Photo : V. Yaschuk. KB GS RAS
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