December 06, 2015. EN. Etna, Copahue .
December 06, 2015.
Etna, Sicily :
Update ETNA, December 5, 2015, 21:00 UTC
In the last 24 hours there were two episodes of paroxysms from the crater of Voragine, one in the evening of December 4, 2015, between 20h30 and 21h15 UTC (local time = -1), and the second in the afternoon December 5, between 14h35 and 15h 55 GMT. These paroxysms repeated in almost every detail those that occurred in the early hours of December 3 and the morning of December 4, with large lava fountains and high eruption columns of several kilometers.
This morning, the tremor is always important, and it seems that it is now the turn of southeastern crater that would establish a new peak since the new « pit crater » at the top of its eastern flank.
At 11 hours, the tremor resumed its march upwards, activity on the new « pit crater » at the top of the New South East Crater cone is well marked on the thermal camera images.
Source : INGV
Photo : Veronica Testa
Copahue, Chile :
Based on the analysis of information gathered through monitoring equipment and volcano observators, the National Geology and Mining (SERNAGEOMIN) – Observatorio Volcanológico de Los Andes del Sur (OVDAS), communicates the following:
-During This period were recorded two hundred and nine (209) seismic events , Ninety-nine (99) of them were classified as volcano
-tectonics (VT) associated with fracturing processes of rigid material.
Similarly, one hundred ten (110) events ,associated to the fluid dynamics inside the volcano were recorded, seventy (70) of them were identified as earthquakes long-period (LP) and forty (40) events as very long period (VLP).
Regarding the type of VT seismicity, their local magnitude (ML) was less than 2.3 M and location of epicenters shows a wide distribution. The highest energy event was located on the North side (NE), 13.4 km from the crater El Agrio and deep under 1km.-
As for LP type of events, they presented a maximum local magnitude (ML) of 1.4, mostly located around the crater with epicentral distances of less than 3.5 km.
The Tremor remained in oscillating values DRC, generally below 1,5cm2, with an average of 0.4 cm2 considered as low for this volcano. The dominant frequencies remained concentrated between 1.0 to 4.5 Hz.
IP cameras installed near the volcano showed the presence of constant ash emissions from the active crater accompanied by incandescence before the explosions.
. These emissions are mostly characterized by a grayish color showing the presence of particulate matter.
Finally, the column reached a height of 1300m above the November 29.
The information obtained in the overflights conducted November 28, show a completely empty acid lake, with formation of a pyroclastic cone emerging from pyroclastic material accumulation around him.
On its surface, there was impact craters, probably generated by ballistic fragments ejected during minor explosions.
The thermal images showed no significant change from the previous overview, the eruption column reached a maximum temperature of 550 ° C
The process appears to be related to the rise of a small amount of magma that progressively destabilizes the hydrothermal system, keeping it at temperatures which maintain a significant eruptive activity and maintaining the possibility of small explosions in the crater.
Sulfur dioxide (SO2) recorded on the volcano Copahue equipment by DOAS (Differential Optical Absorption Spectrometry), Twins Station, located 5 km to the east – north – east of the active crater , have an average value monthly of 929 ± 118 t / d and a maximum of 2 076 t / d, on November 20.
Satellite anomaly was observed on November 28.
A heat alert was observed on November 29 with a volcanic radiative power value (VRP) of 2 MW.
According to the data collected, this scenario corresponds to a small eruption, with persistent emission of particulate matter to the surface.
Ballistic fragments on the impact area do not exceed the 300 m radius around the active crater.
Therefore, restricted access to the proximal area is recommended 1.5 km around the crater and the level of technical alert remains at YELLOW
Source : Sernageomin
Photos : Alto Valle-Valle Medio , Latercera , archives Sernageomin .