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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
 Kerinci - GVP archive photo / Luke Mackin flickr / 06.09.2016 - CC-BY-NC-SA 2.0.

Kerinci - GVP archive photo / Luke Mackin flickr / 06.09.2016 - CC-BY-NC-SA 2.0.

On August 7, 2020, a brown ash emission was observed at 03:24 UTC (10:24 local time) in Kerinci, on Sumatra.

The best estimate of ash cloud top by a ground observer is about 4405 meters above sea level, may be higher than what can be clearly observed. Emissions of ash move East-South-East-North-East.

The main plume of the crater is brown, with fine to moderate high intensity about 50-300 meters from the summit.

 

The seismicity of August 6 is characterized by:

- 155 blast earthquakes, with an amplitude of 0.5 to 5 mm and an earthquake duration of 10 to 25 seconds.

- 1 episode of continuous tremor, with an amplitude of 0.5-2 mm, dominant 1 mm.

 

The activity level is 2 / waspada, with a yellow aviation code, and a ban on entering a 3 km rayon around the active crater .

 

Sources: Magma Indonesia and VAAC Darwin

Kerinci - Volcanic ash advisory for 07.08.2020 - Doc. VAAC Darwin

Kerinci - Volcanic ash advisory for 07.08.2020 - Doc. VAAC Darwin

An eruption occurred in Dukono, in the Moluccas, with the emission of a cloud of volcanic ash at 11:17 UTC (08:17 local). Best estimate of ash cloud top is around 1.629 meters above sea level, may be higher than what can be seen clearly, the observation was made from the ground. The ash cloud is moving east.

The main plume of the crater is white and gray, with a thick high intensity about 200-500 meters from the summit.

 

The seismicity of August 6 consists of

- 2 distant tectonic earthquakes, with an amplitude of 28-30 mm, S-P 19.81-20.67 seconds and earthquake duration of 55-78.82 seconds.

- 1 episode of continuous tremor with an amplitude of 0.5 to 6 mm, dominant 2 mm.

 

The activity level is at 1 / waspada, with a ban on approaching Malupang Warirang crater within a radius of 2 km.

 

Sources: Magma Indonesia and VAAC Darwin

Dukono - activity from 08/01/2020 / 8:12 a.m. - photo PVMBG

Dukono - activity from 08/01/2020 / 8:12 a.m. - photo PVMBG

The Kīlauea volcano is not erupting. The alert level is normal and the aviation code is green.

Monitoring data for the month of July shows varying but typical rates of seismicity and soil deformation, low rates of sulfur dioxide emissions, and only minor geological changes since the end of eruptive activity in September 2018 .

In the past month, summit inclinometers recorded 16 deflation and inflation events - an increase from last month's total. In the Middle East Rift Zone, increased strain rates that began in March 2020, consistent with an episode of rift inflation west of Highway 130, and which eased and flattened in May , have returned to their pre-March trend. The long-term deformation trend at the summit of Kilauea and in the Middle East Rift Zone continues to show inflation, consistent with the supply of magma to the volcano's shallow storage system.

GPS stations on the southern flank of Kīlauea continue to show high rates of seaward movement. Of the recorded earthquakes, two were greater than magnitude 4, with focal mechanisms compatible with sliding along the basal flank detachment. South.

Sulfur dioxide emission rates are low at the top, which corresponds to the absence of significant areas of magma. A certain amount of sulfur dioxide is dissolved in the shallow groundwater and the crater lake at the bottom of Halema'uma'u.

A higher resolution thermal imager was used and showed maximum temperatures around 80–85 degrees Celsius of the lake waters present in the crater.

Globally, only a few volcanic lakes have surface temperatures above 80 degrees Celsius. So why is Kīlauea water lake so hot ? One likely factor is the residual heat in the rubble from the collapse at the base of Halema'uma'u, from rock that was heated by the lava column before the 2018 collapse. The hot gas vents ( at least 150 degrees Celsius) nearby (fumaroles) are another potential explanation for the high temperatures.

 

Source: HVO- USGS monthly update & Volcano Watch

This thermal image of the water lake at the summit of Kīlauea was taken from the western caldera rim on July 31, 2020. Warmer colors (yellow-orange) show higher temperatures, while cooler colors (blue) show lower temperatures. The image indicates that the maximum temperatures on the lake surface at this time are about 82 degrees Celsius (180 degrees Fahrenheit). The cooler zones on the lake surface are patches of rising steam. - USGS photo.

This thermal image of the water lake at the summit of Kīlauea was taken from the western caldera rim on July 31, 2020. Warmer colors (yellow-orange) show higher temperatures, while cooler colors (blue) show lower temperatures. The image indicates that the maximum temperatures on the lake surface at this time are about 82 degrees Celsius (180 degrees Fahrenheit). The cooler zones on the lake surface are patches of rising steam. - USGS photo.

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