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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 : #Actualités volcaniques

The JMA has raised the level of volcanic alert of the Satsuma-Iojima, to "2 / do not approach the crater", on March 19 at 11:45 JST.

Seismicity has increased since mid-February, reaching 12 volcanic earthquakes on March 15, and 51 on March 19 (at 11:30 am)

On March 16th, the JMA confirms a type of tremor associated with underground magmatic activity.

An area of ​​1 km around the crater could be affected by bombs in case of eruption.

Satsuma-Iojima - Iwodake Dome is the highest point on the island; the smaller and lush green Inamuradake cone is located on the right of the photo - Doc. Kyodo news

Satsuma-Iojima - Iwodake Dome is the highest point on the island; the smaller and lush green Inamuradake cone is located on the right of the photo - Doc. Kyodo news

Satsuma-Iojima forms part of the edge of the largely submerged Kikai caldera, 19 km wide, and located at the northern end of the Ryuku volcanic arc, south of Kyushu Island / Japan.

Two post-caldera structures contributed to its current morphology: Mt.Iwodake, a rhyolitic lava dome, and the small Inamuradake scoria cone.

The historical eruptions of the 20th century have mainly concerned Iwodake, which is marked by a fumarolic activity of high temperature (up to 900 ° C).

The summit zone, of 400 over 140 meters, includes several craters, result of the explosive activity following the installation of the dome. The small crater Kintsuba is located southwest of the central crater Oana, a place of mining sulfur . Small ash eruptions were observed in 1999, 2001, 2002-2204, and 2013.

Sources: JMA, Kyodo news, Global Volcanism Program, Photovolcanica.
 

Bathymetry of the Kikai Caldera - Satsuma-Iojima Island is located on the edge of the Kikai caldera, largely submerged (red dotted) - Doc. Geological Survey of Japan / GVP

Bathymetry of the Kikai Caldera - Satsuma-Iojima Island is located on the edge of the Kikai caldera, largely submerged (red dotted) - Doc. Geological Survey of Japan / GVP

Geological map of Satsuma-Iojima - Doc. Geological Survey of Japan / GVP

Geological map of Satsuma-Iojima - Doc. Geological Survey of Japan / GVP

The activity of the Reventador seems to increase in power. The IGEPN reports the observation of a plume of steam and ash rising to a height of 600 meters, on March 18 at 8:57 local / 11:57 UTC

During the night, the incandescence in the crater is accompanied by fall of blocks on the flanks of the volcano on 800 meters.

At the seismicity level, 31 LP earthquakes, 25 explosion-related earthquakes, 15 tremor of emissio and 7 harmonic tremor episodes were recorded for the period from 18.03 / 11h to 19.03 / 11h. Other parameters are reported without changes.

Source: IGEPN
 

Reventador - 18.03.2018 / 11:57 UTC - webcam IGEPN

Reventador - 18.03.2018 / 11:57 UTC - webcam IGEPN

The Gunung Sundoro, located with its neighbor Gunung Sumbing, in the center of the island of Java, has since March 18 in the morning a small white plume of steam and gas.

Although its level remains "green / normal", the approach of the crater is prohibited.

Its historical eruptions are generally of phreatic type. The last data of 1971.

Sources: PVMBG, Global Volcanism Program

Sundoro - 18.03.2018 / 6h36 loc. - photo webcam PVMBG

Sundoro - 18.03.2018 / 6h36 loc. - photo webcam PVMBG

Seismicity of Sundoro on 18.03.2018 - Doc. Magma Indonesia

Seismicity of Sundoro on 18.03.2018 - Doc. Magma Indonesia

Sufficiently rare to talk about, the Steamboat Geyser erupted on March 15, 2018, at 5:37 pm. This eruption was recorded by the seismic network and temperature taking. The roads being closed, the observation of the episode remained confidential.

The temperature is taken in the outlet channel downstream of the vent; rapid increases in temperature in the geyser outlet channels generally reflect increases in flow due to eruptions of the nearby thermal structure.

Nearby trees were covered with mud; National Park staff took pictures the next day of rock fragments ejected during this episode.

Steamboat geyser - steam emission and surrounding area covered with rocks - photo 16.05.2018 / USGS- YVO

Steamboat geyser - steam emission and surrounding area covered with rocks - photo 16.05.2018 / USGS- YVO

Steamboat geyser - the area of ​​the vent covered with rocks - photo 16.05.2018 / USGS- YVO

Steamboat geyser - the area of ​​the vent covered with rocks - photo 16.05.2018 / USGS- YVO

Temperature measured in the exit channel of the geyser Steamboat, between 12.03 and 19.03.2018 - to notice the peak of 15.03 - Doc. USGS - YVO

Temperature measured in the exit channel of the geyser Steamboat, between 12.03 and 19.03.2018 - to notice the peak of 15.03 - Doc. USGS - YVO

Located at the eastern end of the Norris Basin in Yellowstone National Park, it is known as the largest active geyser; it rarely has major eruptions, but they are powerful when they occur, propelling hot water columns up to over a hundred meters, followed by a vapor phase that can last longer than one day.

The Steamboat has been more active in the early 21st century than in the early 1980s. Between late 1991 and 2000, there were no major eruptions. However, since May 2000, Steamboat has experienced 9 major eruptions, the last one on September 3, 2014. Its eruptions can not be predicted.

The YVO points out, to the attention of the sensational news carriers, that the volcano is not about to erupt.

Sources: USGS - YVO / Yellowstone Volcano Observatory
 

Eruption of Steamboat geyser on 23.05.2005 - photo Hsing-Mei Wu

Eruption of Steamboat geyser on 23.05.2005 - photo Hsing-Mei Wu

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