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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
Sabancaya - activity summary from 30.12.2019 to 05.01.2020 - doc. IG Peru

Sabancaya - activity summary from 30.12.2019 to 05.01.2020 - doc. IG Peru

The Peruvian Geophysical Institute (IGP) reports that the eruptive activity of the Sabancaya volcano is maintained at moderate levels; that is, with the continuous recording of moderate explosions and the resulting ash emission.

- During the period from December 30, 2019 to January 5, 2020, the IGP recorded and analyzed the occurrence of approximately 1,179 earthquakes of volcanic origin, the highest percentage of which is associated with the circulation of fluids (magma, gas, etc.) inside the volcano.

- During this period, there were on average 9 explosions per day of medium to low intensity, accompanied by columns of gas and ash up to 2 km high above the summit of the volcano, scattered to the north, at southeast and east of Sabancaya.

- The monitoring of the deformation of the volcanic structure, using GNSS data (processed with fast orbits), does not record any significant anomalies.

- A 4 MW thermal anomaly, associated with the presence of a lava dome in the crater of the volcano, around 280 m in diameter. It should be noted that the number of anomalies has been reduced due to the high cloudiness in the region.

It is recommended to maintain the volcanic alert level at orange, with a prohibited zone of 12 km radius around the crater.

Ubinas - summary of the activity between 29.12.2019 and 05.01.2020 - Doc. IG Peru

Ubinas - summary of the activity between 29.12.2019 and 05.01.2020 - Doc. IG Peru

The eruptive activity of the Ubinas volcano remains at low levels.

To date, the energy of earthquakes which would be associated with the rise of magma on the surface has considerably decreased.

Likewise, there are weak and sporadic emissions of bluish gases (of magmatic origin) and water vapor, observed through surveillance cameras.

According to this scenario, the possibility of volcanic explosions and / or ash emissions is low.

It is recommended to lower the volcanic alert level from orange to yellow, and not to approach within a radius of less than 6 km from the crater of the volcano.

 

Source: I.G. Peru

Yellowstone - seismicity during the year 2019 - Doc. Michael Poland / USGS

Yellowstone - seismicity during the year 2019 - Doc. Michael Poland / USGS

The USGS / YVO took stock of Yellowstone activity in 2019:

- The seismic activity of the year was generally weak. There were 1,217 earthquakes located in 2019, which is far below the average of 1,500 to 2,500 earthquakes per year. About half of these earthquakes occurred in 11 separate earthquake swarms.

- Yellowstone deformation patterns have mostly followed established trends. The Yellowstone caldera GPS stations have shown a continuous sinking of the resurgent domes, with small fluctuations probably related to seasonal weather conditions.

Unlike the caldera, the area around the Norris Geyser basin had been increasing since 2015, but this uplift gradually slowed down and stopped at the end of 2018. After no movement of ascent or descent during the first 9 months of 2019, the Norris area started to calm down in September / October, sinking about 3 cm at the end of 2019.
 

Yellowstone N.P. - Aerial view of the new spa area, center left. The existing thermal zone of Lake Tern is the bright white patch of soil in the upper central part of the image. - Doc. M.Poland / USGS

Yellowstone N.P. - Aerial view of the new spa area, center left. The existing thermal zone of Lake Tern is the bright white patch of soil in the upper central part of the image. - Doc. M.Poland / USGS

- The year 2019 also saw the first visit to the all-new Yellowstone thermal area near Lake Tern on the east side of the caldera. Boiling temperatures were just below the surface in a few places, and there had vents releasing hot gas which included hydrogen sulfide (H2S). But there was no water on the surface.

- In 2019, the Steamboat geyser broke its own record, with 48 eruptions! The longest period between flares was just over 17 days, while the shortest was 3 days and 3 hours - itself a record for the shortest time between large water flares in the geyser.

 

Source : Yellowstone volcano Observatory, caldera chronicles - Yellowstone, the year 2019 in review

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