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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié le par Bernard Duyck
Publié dans : #volcanic activity
Sinabung - 18.05.2019 / 12:09 WIB - Doc. PVMBG / Magma Indonesia - a click to enlarge

Sinabung - 18.05.2019 / 12:09 WIB - Doc. PVMBG / Magma Indonesia - a click to enlarge

The level of activity of Sinabung is revised downward from May 20th at 10am WIB, at level 3 / siaga.

After the last eruption in June 2018, no other was observed for 10 months. Volcanic activity is visible only in the form of gusts of white smoke and thick - low pressure and thick, with a maximum height of 500 m above the peak. The color and intensity of the gusts showed that the gas content was dominated by water vapor. No rock was detected and transported to the surface.

On May 7th and 12th, 2019, there were 2 relatively small and short ash eruptions and a lava eruption located in the small hole of the crater, of low pressure. It would have been induced by a small volume of shallow magma.

Seismicity up to 20 May 2019 at 06:00 WIB tends to decrease even though there are fluctuations associated with sources of low fluid / magma volume.

Deformation data (inclination and EDM) fluctuate stably, indicating that at present the activity is dominated by the release of fluid (essentially low pressure gas) without detecting a continuous feed .

Geochemical data for the SO2 gas flow in May 2019 showed a decrease after the eruption of May 12, 2019, up to a value of 500 tonnes / day.

 

The potential for explosive eruptions still exists, as well as the risk of pyroclastic flows. In the event of an eruption, the danger zone covers a radius of 3 km for the north-west-south sector, a radius of 5 km for the south-east sector and a radius of 4 km for the northeast sector from from the summit of Sinabung. Potential secondary hazards are lahars likely to borrow from drainages in case of heavy rains.

 

Source: PVMBG, Magma Indonesia

Sinabung - ash eruption of 07.05.2019 / 8:43 - photo Sadrah Peranginangin

Sinabung - ash eruption of 07.05.2019 / 8:43 - photo Sadrah Peranginangin

The Anak Krakatau has erupted on May 19, 2019 at 4:17 WIB, but the height of the ash column was not observed. This eruption is recorded on a seismogram of maximum amplitude of 44 mm and a duration of ± 2 minutes 41 seconds.

Currently, G. Anak Krakatau is at level 2 / Waspada, with recommendations not to approach the crater within 2 km of the crater

 

Source: PVMBG

Anak Krakatau - summary of seismicity on 19.05.2019 - Doc. Magma Indonesia

Anak Krakatau - summary of seismicity on 19.05.2019 - Doc. Magma Indonesia

According to the available data, Sangay, in Ecuador, presents a new impulse of activity which, as has happened on other occasions, could be the beginning of a new eruptive phase since March 2018.

The Geophysical Institute recommends to people who frequent the areas of the upper flanks of the volcano to avoid approaching the craters and the top of the volcano, especially it is recommended to make no ascents for whatever reason the crater or flanks located in the upper part of the volcano.

Sangay - moderate thermal anomalies on 20.05.2019 - Doc. Mirova

Sangay - moderate thermal anomalies on 20.05.2019 - Doc. Mirova

Mirova reports moderate thermal anomalies since May 10th (see table) and the May 17th Sentinel images show a gas plume from the central crater towards the southwest and a lava flow at the start from a lateral vent on the southeast flank.

 

Source: IGEPN

Sangay - image Sentinel 2 bands 12,11,4 from 17.05.2019 - plume from the central crater to the SW, hot spots at the central crater and a lateral vent, which feeds a pour towards the SE - a click to enlarge

Sangay - image Sentinel 2 bands 12,11,4 from 17.05.2019 - plume from the central crater to the SW, hot spots at the central crater and a lateral vent, which feeds a pour towards the SE - a click to enlarge

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