October 21, 2015. EN. Ubinas, Piton de la Fournaise, Turrialba.

Home / blog georges Vitton / October 21, 2015. EN. Ubinas, Piton de la Fournaise, Turrialba.

October 21, 2015. EN. Ubinas, Piton de la Fournaise, Turrialba.

After two days in the family ,  back in business .

 

October 21, 2015.

 

Ubinas, Perou :

Earthquakes LP type , associated with fluid movements, continued to record an increase in their average activity this week. We observed a peak value of 422 LP during the day of 17 October and a daily rate of 293 LP / day.  These events have greatly decreased in number and energy in the last three days of this week. The energy values also increased mainly during the October 15 and 16, low levels, however, are always saved.
As regards the hybrid seismic activity associated with magma ascent, there was an average of 20 Hybrid / day until 15 October; while from October 16 to 19, the number of hybrid events decreased significantly. The energy levels of these events is very low.

ubinas


The type of VT seismicity (earthquakes type rock fracturing) recorded an average of 130 earthquakes at the beginning of the week, but then from 16 to 19 October dropped significantly. A major peak of VT events was recorded on October 15 with   161 VT / day.
The activity of Tremor rose last week following ash emissions caused by the exhalations stored on October 15, then declined until the end of this report.
During this period, there were five explosions / expirations.

 

ubinas-caldeira

 

During the last 7 days, and through the camera Campbell Scientific, the IGP has registered the emission of steam vents and various ash emissions from the Ubinas volcano .
On October 15, in the afternoon, the exhalations of ash associated with the volcanic degassing system were observed. These exhalations amounted to 2,000 meters.
Subsequently, between 17 and 18 October, intense clouds covered the volcano. At the same time, sporadic emissions of steam does not exceed 300 meters above the base of the crater.
Finally, this past week 5 exhalations were recorded on the Ubinas volcano.

Source : IGP Perou.
Photo : Go2peru

 

Piton de la Fournaise, La Réunion :

 

Activity Bulletin Monday, October 19, 2015 at 10:00 am (local time)

On october 18 at 8:02, the Tremor disappeared in a very brutal way.
The Tremor is a geophysical sign of surfacing and / or sub-surface magmatic fluids, the stop of this signal shows the end of the feed of lava.

Subsequently, however, we probably recorded sporadic signals   in connection with the arrival of « puffs » of surface fluids (probably only gaseous). At present we still note the presence of background noise (tremor) on the Bory station.
The abrupt end of the supply is not an exceptional fact, this has already been observed in the past by the OVPF (in August 2003 for example).
Since Sunday the seismic activity picked up in the volcano also under the level of the sea.

 

piton

Under these conditions, the Prefect of La Réunion decided the transition on phase SAFEGUARD of the specific device ORSEC on the Volcano Piton de la Fournaise, as of 8:00 this Tuesday, October 20, 2015.

Despite the termination of activity on the geo-physical point of view and the stop of the magma supply, an eruption is not excluded in the days or weeks ahead. Consequently, the prohibition of access to the top of the Enclos and helicopter landing in the volcano area remain in force until further notice.

During the safeguard phase, site investigations will be conducted to define the post-eruption dangerous areas and study the terms of a return in phase of vigilance.

 

Source : OVPF, Fournaise info.

Photo: Fournaise info / Mamz’l Ha

 

Turrialba, Costa-Rica :

 

Report on field observations after the eruption of October 16, 2015.


The deposits indicate a moderate energy eruption similar to those that occurred last year.
On October 18, officials of the OVSICORI visited the Turrialba volcano, to maintain permanent gas monitoring stations and study the deposits of the eruption that took place on October 16, 2015 at 17:49.
The researchers found deposits of thin (<1 mm) of fine ash near the Mirador and in the direction of Silvia. Bombs up to a diameter of 20 cm were found in the southwestern edge of the crater, and a solar panel located in a west side of monitoring station of the active crater was destroyed by ballistic fall / lapilli (~ 2 cm in diameter).

turrialba

By the number of observed impacts on the solar panel, it can be calculated that about 20 lapilli (1 cm to several centimeters in diameter) per square meter fell to 250 m to the south-west of the active crater. In the same place we find ~ 0.5 cm of ash. To the northwest edge of the active crater, a layer of fine ash from 8 cm thickness was measured, and this layer is deposited on top of a small pyroclastic flow in the southwest of the central crater. Justifiants elements are the size characteristics, the presence of gas ducts during the sedimentation and temperature (> 70 ° C to 40 cm deep in a place without fumarole). This pyroclastic flow was observed by webcam, on April 23, 2015.

 turrialba

The preliminary observation of ash in the laboratory of petrology reveals characteristics closely resembling those of previous eruptions with a major presence of weathered material and possibly of about 5-10% by volume of fresh material.
Also, it is observed with evidence on the ground a recent landslide in the active crater. Rock falls are very common with the instability of very vertical walls, but the size of the slide and the absence of ash covering the wall suggests that it occurred in recent days.

 

Source : OVSICORI
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