The level of activity of the volcano is at: YELLOW; changes in the behavior of volcanic activity – likely time for an eruption weeks / months.
Based on the analysis of information obtained by monitoring equipment and the observation of the volcano, the National Service of Geology and Mining (SERNAGEOMIN) – Volcanológico Observatorio de Los Andes del Sur (OVDAS) announces:
During this period, sixty-two (62) seismic events were recorded, thirty-three (33) were classified as volcano-tectonic (VT) associated with rigid materials fracturing processes.
Similarly, twenty-nine (29) were recorded as events associated with the fluid dynamics inside the volcano and were identified as volcanic earthquakes long period (LP) and very long period (VLP).
Concerning the seismic activity , the local magnitudes (ML) do not exceed M 2.2 . The higher energy event was located on the North-East side (ENE) at 12.4 km of the crater El Agrio, at a depth of 8.4 km.
Concerning the events related to fluid dynamics (LP), they presented local magnitudes (ML) below M1,9 and a reduced displacement value (DRC) below 7,7cm2. VLPs events presented local magnitudes (ML) below M1,5 and reduced displacement value (DRC) of less than 10.4 cm2. These events are located around the crater.
Throughout the month, there was a constant tremor signal, primarily associated with the release of particulate matter (gas and ash) of El Agrio crater, recording DRC oscillating values ??generally below 3cm2, values ??considered as intermediate for this volcano. The dominant frequencies are concentrated in a bandwidth between 1 and 2 Hz.
From the data obtained from five (5) GNSS stations, which seek to measure the deformation of the surface of the volcano, it was observed that the horizontal and vertical components showed variations in a small scale, with a tendency to hold rates previously reported. The highest rate of change of the vertical components is at 0.2cm / month, recorded at the nearest station of the crater. Compared to the line that crosses the volcano, it was observed that this low value showed no changes, remaining stable over the period.
The sulfur dioxide emissions (SO2) recorded on the Copahue volcano by the team DOAS (Differential Optical Absorption Spectrometry) Triplets Station, located 5 km to the east-northeast (ENE) of the active crater has a mean value of 921 ± 37 t / day and a maximum of 2 323 t / day, April 4. IP cameras installed near the volcano recorded the constant emission of material from the active crater (El Agrio), accompanied by incandescence. These emission present mostly, a gray color, showing the presence of particulate matter.
Although a downward trend of seismic energy is recorded by the volcano monitoring indicators described above, they indicate the continuation of the activity associated with the interaction of a magma body of small volume, at more or less deep levels under the volcano and the volcanic hydrothermal system , without unbalancing the system, keeping it in what is called a “meta-stable” balance. This activity may continue for a long period with an oscillating manner, without excluding specific increases related to small phreatic explosions and / or low strombolian activity in the crater area. Therefore, the limitation of access to the proximal zone of a radius of 1.5 km around the crater El Agrio is recommended. The level of technical alert level remains at Yellow.
SERNAGEOMIN -OVDAS continues to be alert, and report timely to the changes in the activity that may occur.
April 20, 2016.Copahue , Chile :
Source : SERNAGEOMIN -OVDAS