April 20 , 2017. EN. Etna , Bogoslof , Poas , Ubinas .
April 20 , 2017.
Etna , Sicily :
ETNA, ACTIVITY REPORT, 15-19 April 2017
The episode of effusive activity of an eruptive fracture system on the side and south base of the Southeast Crater (SEC), which began on the evening of 13 April 2017, ended at night between 14 and 15 April. Subsequently, the volcano remained in a state of calm for four and a half days, returning to business with a new eruptive episode in the late morning of April 19, 2017.
While the previous episode had been announced by a strong increase in the amplitude of the volcanic tremor, followed by a short phase of strombolian activity and the opening of eruptive fractures, this new episode began with a small emission of lava from the Crater pit « which is placed just below the mouth rim of the old saddle between the old and the new SEC cone », at 09:34 UTC (= local time -2). After a few minutes, began from a vent a little further upstream, a modest strombolian activity; and only after a sudden increase in the amplitude of the volcanic shock accompanied by « superficialization » features of the tremor source.
The descent of the lava on the steep slope to the south of the SEC cone resulted in a few small collapses which generated, for a few minutes, modest plumes of reddish brown ash that are rapidly dispersed in the leeward atmosphere Which blows eastward.
At the time of this update (13:30 UTC on April 19), strombolian and effusive activity continues. The main lava flow follows the same route as the previous two streams (10-11 and 13-15 April), in the direction of the western edge of the Valle del Bove (see the image on the left, taken from Thermal surveillance camera on the Montagnola, « EMOT »).
Source : INGV
Photos : INGV , Alessandra Pozzana
Bogoslof , Aleutians , Alaska :
Current Volcano Alert Level: ADVISORY
Previous Volcano Alert Level: WATCH
Current Aviation Color Code: YELLOW
Previous Aviation Color Code: ORANGE
Issued: Wednesday, April 19, 2017, 12:23 PM AKDT
Source: Alaska Volcano Observatory
Location: N 53 deg 55 min W 168 deg 2 min
Elevation: 492 ft (150 m)
Wide view of Bogoslof Volcano taken from the M/V Miss Alyssa. April 7, 2017 12:20 PM
Volcanic Activity Summary:
No new volcanic activity has been observed at Bogoslof Volcano in satellite, seismic or infrasound data since a short-lived increase in seismicity on April 15. The last major explosive event occurred on March 8, 2017, and occasional high-spatial resolution satellite images show no significant surficial changes due to eruptive activity since that time. Based on the absence of detected activity over the past several days, AVO is lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. Bogolsof is not monitored by a real-time seismic network and this inhibits AVO’s ability to detect unrest that may lead to an explosive eruption. Rapid detection, and possible forecasting, of an ash-producing eruption may be possible using a combination of data from seismic and infrasound networks on neighboring islands and satellite and lightning detection data.
Source : AVO
Photo : Read, Cyrus
Poas , Costa Rica :
Poas Volcano Activity Report, 19 April 2017, updated at 11:00
Volcanic activity in the last 24 hours:
There have been a number of small phreatic eruptions interspersed with varying amplitudes of a weak to moderate tremor over the last 24 hours.
The largest began at 06:05 (local time), lasting 2.5 hours, with eruptions on an almost continuous basis.
This eruption consisted of the emission of water, gas, fine particles and aerosols from the main crater lake.
Other major eruptions took place at 03:31, 04:22 and 08:30 (local time). All of these eruptions have been identified by the seismic network. Volcanic earthquakes (LP) continue to occur at low frequency, but are of low amplitude.
Under the present conditions of the Poas volcano, it is possible to expect more short-term eruptions.
The OVSICORI-A remains vigilant on the volcanic activity and will publish periodic reports on the evolution of its behavior and at each important changes.
During the day, the gas and aerosol plumes were scattered mainly westward.
Source : Ovsicori
Photo : Ovsicori
Ubinas , Peru :
The Volcanological Observatory of the Southern Geophysical Institute of Peru (OVS-IGP) analyzed the recent images obtained from the Ubinas volcano crater, confirming that fumaroles (mainly water vapor and gas Quantities) remains constant in this part of the volcano.
This material was provided by Mr. Melquiades Álvarez, observer of the Ubinas District Municipality and OVS collaborator, who last Friday, April 14 made a brief inspection of the crater of the volcano located at 5676 m. « Although we have not recorded any explosive events since November 2016, we continue to see steam and magmatic gas emissions sporadically. We must remain vigilant despite the low level of activity of the volcano, « said Dr. Orlando Macedo, director of OVS-IGP.
This Monday, the South Volcano Observatory published the Ubinas activity report which analyzes its behavior in the first half of April. The report notes that the number of earthquakes is up to 85% lower than in the last half of March, recording an average of 3 events per day.
At present, the Ubinas volcano remains at the yellow alert level. The Scientific Committee on Permanent Monitoring of this volcano, composed of OVS-IGP, the INGEMMET Volcanological Observatory, monitors its activity 24 hours a day in real time.
Source : IGP