31/05/2015. Shindake , Piton de la Fournaise, Villarrica .

31/05/2015. Shindake , Piton de la Fournaise, Villarrica .

Shindake , île Kuchinoerabujima , Japon :

Continued eruptions of Mount Shindake , on the island Kuchinoerabujima in Kagoshima Prefecture, which likely paused at 10:50 on Saturday, announced the Japan Meteorological Agency. After the massive eruption of the volcano 626 meters high on Friday, all residents of the island were evacuated. However, its volcanic activity has not ended, and the agency calls for vigilance because there is a possibility that an explosive eruption could happen again in the future. The volcano has been maintained at the level of volcanic alert 5, which calls for the evacuation.


The black smoke that had continued after the eruption until Saturday morning have apparently dissipated, the agency said. The number of volcanic earthquakes, which occurred nearly 200 times since explosive eruption of Friday, fell sharply, with only three from midnight to 9 am on Saturday. “Although it is difficult to predict eruptions in future, the situation has become more stable now, “said an official of the agency.

Meanwhile, around 4:10 Saturday the agency observed that an area on the slope of Mount Shindake shone red. Pyroclastic flows have expanded in all directions from the crater and spread along areas that represent about 20 percent of the island of 36 square kilometers, the agency said.


A mission from the government, including Ryosei Akazawa, a Minister of State for the Cabinet Office, entered the town of Yakushima Saturday. Of the 137 people who had been on the island, including people evacuated from Kuchinoerabujima to the island of Yakushima and tourists, 83 people spent the night in evacuation centers, while 54 others remained in their families and other places, according to sources.

Source : the-japan-news.com
Photo : Sankei Shimbun , Kyodo News , AP.

Piton de la Fournaise, La Réunion :


Phenomena: End of tremor

At 8:50 p.m. (local time) after several hours of classical phase variations of intensity, the Tremor disappeared. The Tremor is a sign of geophysical surfacing and / or sub-surface magmatic fluids, stopping this signal shows the end of the magma supply.



RESULTS: The OVPF does not exclude any hypothesis regarding the evolution in the coming hours that can be characterized either by a stop of all phenomena or a recovery in activity.


But the volcano has not really deflated …
This detail is important because it could signal a possible resumption of activity quickly enough! We must therefore remain vigilant , la Fournaise erupted after many hesitations, expect the following events.

Source : OVPF , Fournaise info.
Photo : Pascal Dorr

Villarica , Chili :

One hundred and twenty six (126) long period events [LP, recorded seismic signal associated with the fluid dynamics inside the volcano], maximum local magnitude of M1,7 and reduced movement [DR, parameter indicating the size of the seismic signal originally] maximum of 5.9 cm2, values considered moderate for this volcano have been recorded. The type of tremor signal, mainly associated with fluid dynamics inside the volcano reaches reduced displacement values (DR) maximum equal to 4.2 cm2 and a mean of 2.4 cm2, values considered as low. The spectral content of the LP events and tremor continued on dominant frequencies between 0.7 and 6.0 Hz, with a more persistent group between 1.0 and 2.0 Hz.
Type VT events are not recorded during the day.


Data from monitoring stations that measure the deformation around the volcano suggests a process of slight lifting of the surface. The volcanologist Hugo Moreno explains that inflation is about 1.75 cm per month, but on a little more than a year, that’s significant. It is a variable data and one can not know if the trend will continue or whether it will stabilize but by one estimate, in ten months could reach over 15 cm.This elevation is measured on the slopes of current volcanic edifice and the old (Villarrica 1) .This uprising is uneven, a difference between the slopes of the current cone was also recorded, located west and the slope of the old edifice..
But the funny thing is that it increases in the eastern sector, namely, on the slopes of the ancient volcano. The old Villarica was higher than the current one, but collapsed when its magma chamber emptied, creating a caldera of 6 km in diameter. Hugo Moreno explained that this could be a residual magma chamber of the ancient volcano that is replenished.

Source : Sernageomin, AVCAN .
Photo : C. Brooks

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