17/03/2015. Lewotobi, Sangay, Sheveluch.

17/03/2015. Lewotobi, Sangay, Sheveluch.
17/03/2015.

Lewotobi, Indonesie :

Information on the activity level of the G Lewotobi, East Nusa Tenggara (16-Mar-2015)

The Lewotobi volcano is in alert level Waspada Activity (Level II) since 30 September 2013. This is based on visual and instrumental observations from the observation post of Lewotobi (Laki-laki & Perempuan), which indicate still unstable volcanic activity. For a month, a trend of shallow volcanic seismicity on G. Lewotobi experienced an average increase of 4 earthquake / day to an average of 12 earthquakes / day. The surface volcanic seismicity indicates that the volcanic rocks are fractured due to magma movement on the surface.

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Earthquakes low frequency , called internationally “low frequency / long-period events” are also on the rise these days. These earthquakes indicate under Lewotobi liquid movement. These changes do not occur significantly to the surface.

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The twin “Husband and Wife” volcanoes of Lewotobi Lakilaki (left) and Lewotobi Perempuan (right) rise above forests on their western flanks. The twin volcanoes were constructed along a NW-SE-trending line. Both the conical Lakilaki and the broad Perempuan volcanoes have erupted during historical time, but the sharper-peaked and sparsely vegetated Lakilaki has been the more active

However, compared to the level of activity of G. Lewotobi which is Waspada (level II), PVMBG recommends that residents and visitors / climbers do not move in a radius of 1 km from the summit. It is difficult to predict when an eruption will occur and its impact can not be established. Communities must remain calm and follow the directions of PVMBG and local government.

Source : PVMBG .
Photo : ndesoadventure / Aris yanto

 

Sangay, Equateur :

Evaluation of the eruptive activity

Sangay (2.002 ° S, 341 ° W 78, 5230 m) is the last volcano in southern Ecuador. It is located in the province of Morona Santiago in the Sangay National Park. It is one of the most active volcanoes in Ecuador, and has been operating since 1628.

From the first days of January 2015, there has been new lava flows that descended from the crater on the south side of the summit. Lava flows have a length of about 900 m from the original crater. In addition, blocks and ash deposits extend to the ESE 2.5 km to the lava flow. We can also note the presence of blocks and ash on the south side up to 1.5 km from the summit. Blocks, pyroclastic materials and volcanic ash is the product of the explosive activity of the volcano.

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Figure 1. The new block and volcanic deposits of ash and lava flows on the Sangay since the beginning of 2015.

Ash plumes emissions were observed by villagers centers located several kilometers from the Sangay without ashes does affect people.

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Figure 2. The Sangay emitting ash plume reaching about 2 km height above the crater. Photo by Gustavo Cruz, taken during the month of January 2015.

On the other hand, the Mirova system, which detects the thermal anomalies associated with volcanic activity using an almost real time infrared heat thermal radiation system located 21 anomalies low to moderate from January 31 to February 25, 2015. From 02.27.2015 until 12.03.2015, have been registered:
839 events long period (LP), 165 events Tornillo, 118 explosions, three episodes of harmonic tremor and 3 emissions. These data indicate a high activity of the volcano. Figure 3 shows an example of the observed seismic record from 08 to 09 March via station SAGA broadband.

Figure 3. seismic recording of station SAGA March 08-09, 2015.

In general, the activity of the Sangay volcano could be affected by ash falls mainly cities like Macas in the East, or Cebadas, Palmira or Alausí west-southwest and even Riobamba. Ashes in these cities depend on the size of the explosions, the amount of ash and the wind direction. Finally, in case of explosive activity, keep in mind that some columns may be high enough to affect the airways.

Source : IGEPNInstitut de géophysiqueEcole Nationale Polytechnique
Photo : Gustavo Cruz

 

Sheveluch , Kamchatka :

An explosion occurred a few hours ago. Webcam images show bright blow from incandescent material ejected. VAAC Tokyo estimates an ash plume was produced that rose to 25,000 ft (7.5 km) altitude.

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Source : Kvert
Photo : Yu Demyanchuk, IVS FEB RAS , KVERT

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