Volcanic Activity Report (RAV)
The National Geology and Mining Service (SERNAGEOMIN) described below information obtained through the national network of monitoring teams, processed and analyzed by the Volcanological Observatory of Southern Andes, interpretation center of monitoring data of the Nevados de Chillan volcano:
The level of activity of the volcanic complex is at:
LEVEL YELLOW: changes in the behavior of volcanic activity – likely time for an eruption weeks / months.
Three hundred eighty-twenty-seven (387) seismic events were recorded , forty-eight of which (48) were related to rigid materials fracturing process , called volcano-tectonic earthquakes (VT) with a local maximum magnitude (ML) of 1.9. These events were located 1.4 km East-Southeast (ESE) of the active crater at a depth of 2 km.
In addition, three hundred and thirty nine (339) earthquakes associated with fluid dynamics inside the volcano have been recorded, called long-period events (LP). The event LP largest was an earthquake of magnitude (ML) of 2.1, with a little reduced displacement value (DRC) of 25,3cm2.
– The sulfur dioxide emissions (SO2) recorded on Nevados de Chillan volcanic complex by the equipment DOAS (Differential Optical Absorption Spectrometry), Chillán Station, located 3 km to the North-East ( ENE) of the active crater measurements taken only two days during the second half of the month showed a mean value of 544 ± 17 t / day. Note that due to the pulsatile nature of the data of the eruptive process, they will show great variability and intermittent reception.
However, a decrease was observed in sulfur dioxide emissions compared to previous months.
– According to data provided by four (4) GNSS stations that monitor the deformation of the surface of the volcanic complex, some variations are observed, low amplitude in the horizontal and vertical components, which do not exceed 0.25 cm / week and 0 35 cm / month, respectively. In turn, the control lines that cross the complex did not show higher rates to 0.5 cm / month. Further data from two (2) inclinometers installed around the complex show no internal deformation related to the evolution of the volcano and observed for small-scale variations.
The images obtained by the network of cameras in the region showed weak pulsatile activity surface, mainly characterized by a whitish emission plume associated with the water vapor.
It has not been observed nightglow.
– The images published by the Group Sulphur dioxide (ozone monitoring instrument – http://so2.gsfc.nasa.gov/) and NESDIS (National Environmental Satellite, Data, and Information – IMO Group http: // satepsanone .nesdis.noaa.gov) reported no abnormality in sulfur dioxide (SO2) into the atmosphere of the the volcanic complex sector.
– Thermal radiation released by the MODVOLC (Moderate Resolution Imaging Spectroradiometer) MODIS on its website (http://modis.higp.hawaii.edu/) and Mirova (Middle InfraRed Observation of volcanic activity) on its website ( http: / /www.mirovaweb.it/), surveillance systems that indicate important changes in surface temperature, have not reported thermal alerts in the zone associated with volcanic complex.
The monitoring parameters for fifteen days indicate a decrease in activity, suggesting stable trend of the volcanic system, indicating that the interaction between the magma body in surface and the hydrothermal system was lower maybe due to the dynamics of a lower caloric intake and a low volume of the magma body underneath.
In this scenario, it is still possible to see appear new phreatic explosions and / or Freato-magmatic eruptions of currently active craters given pulsatile characteristics indicated in the current activity.
Therefore the level of volcanic alert remains at LEVEL YELLOW.
Considering as a high-risk area the area within 2 km from the active craters, it is recommended to limit access to this zone.
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June 08 , 2016 : Nevados de Chillan , Chile :
Source : Sernageomin