November 18 , 2017. EN. Cleveland , Öræfajökull , Kanlaon , Nevados de Chillan .
November 18 , 2017.
Cleveland , Alaska :
52°49’20 » N 169°56’42 » W,
Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
The eruption of Cleveland volcano continues. Two small explosions were detected in seismic and infrasound data on November 14 and 16. These recent events are less energetic than those seen previously, and no volcanic cloud was observed following either explosion. A number of small earthquakes were observed in seismic data on November 14. Satellite observations of the summit indicate that a lava dome remains in the crater, with recent explosions sourced from a vent in the middle of the dome. Elevated surface temperatures at the Cleveland summit were recorded in satellite data for much of the week and are consistent with lava at or near the surface.
Lava effusion is typically confined to the summit crater at Cleveland, with the last significant lava flow (that extended to the ocean) occurring in 2001. The lava domes that have been erupted since 2001 have all been destroyed by explosive activity within weeks to months after lava effusion. These explosions typically produce relatively small volcanic ash clouds that dissipate within hours, however more significant ash emissions have occurred.
Cleveland volcano is monitored with a limited real-time seismic network, which inhibits AVO’s ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.
Cleveland volcano forms the western portion of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. The volcano is located about 75 km (45 mi) west of the community of Nikolski, and 1500 km (940 mi) southwest of Anchorage. The most recent significant period of eruption began in February, 2001 and produced 3 explosive events that generated ash clouds as high as 39,000 ft above sea level. The 2001 eruption also produced a lava flow and hot avalanche that reached the sea. Since then, Cleveland has been intermittently active producing small lava flows, often followed by explosions that generate small ash clouds generally below 20,000 ft above sea level. These explosions also launch debris onto the slopes of the cone producing hot pyroclastic avalanches and lahars that sometimes reach the coastline.
Source : AVO
Photo : Schaefer, Janet ( Aout 2017.)
Öræfajökull , Iceland :
A new ice-cauldron in Öræfajökull volcano . 17.11.2017
New satellite images of Öræfajökull volcano shows that a new ice-cauldron has formed within the caldera in the last week. Pilot flying over the area took pictures of the cauldron today and sent them to the Icelandic Meteorological Office. The cauldron is about 1 km in diameter and it reflects a recent increase in geothermal activity within the caldera.
It seems that geothermal water has been slowly released from underneath the cauldron to the glacial river of the Kvíárjökull outlet-glacier (SE flank of Öræfajökull volcano). Associated with this water release sulphur smell has been reported nearby Kvíárjökull since last week. Most of the water has probably already been released. An increase in the seismic activity has been recorded for the last few months, but for the past days it has been low.
This data indicates increased activity of the volcano which has not erupted since 1727. Currently there are no signs of an imminent eruption.
The Icelandic Coast Guard will fly over the area with scientists tomorrow to collect additional data and samples. The Icelandic Meteorological Office has increased the surveillance of the area and is monitoring the volcano closely in collaboration with scientists from the University of Iceland and the Icelandic Civil Protection Authorities.
The Icelandic Meteorological Office has in light of this elevated activity raised the aviation color code for Öræfajökull to yellow.
Source : Vedur
Kanlaon , Philippines :
KANLAON VOLCANO BULLETIN 18 November 2017 08:00 A.M.
Kanlaon Volcano’s seismic monitoring network recorded twenty four (24) volcanic earthquakes during the past 24 hours. No degassing activity was observed during times when the summit crater was visible. Ground deformation data from continuous GPS measurements indicate slight inflation of the edifice since December 2015. Alert Level 2 status prevails over Kanlaon Volcano, which means that the volcano is undergoing a moderate level of unrest. There is probable intrusion of magma at depth which may or may not lead to a magmatic eruption.
The local government units and the public are strictly reminded that entry into the 4-kilometer radius Permanent Danger Zone (PDZ) is strictly prohibited due to the further possibilities of sudden and hazardous steam-driven or phreatic eruptions. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ejecta from any sudden phreatic eruption can be hazardous to aircraft. DOST-PHIVOLCS is closely monitoring Kanlaon Volcano’s activity and any new development will be relayed to all concerned.
Source : Phivolcs
Nevados of Chillan , Chile :
Volcanic Complex Nevados of Chillan:
During this period, 1172 seismic events, of which ninety-four were classified as volcano-tectonic events (VT), processes related to the fracturing of a rigid material, with local amplitudes (ML) maximum of 2, 3 have been registered. The strongest earthquake was located 3.2 km east-southeast (ESE) of the active crater, 2.6 km deep.
Similarly, one thousand seventy-eight earthquakes associated with fluid dynamics within the volcano, of which 1069 were classified as long-period type (LP) events, with a reduced displacement value (DRC) recorded maximum of 25.5 cm2 for an event located 1.7 km south-southwest (SSO) of the active crater at a depth of 0.7 km. In addition, nine Tornillo (TO) long period events have been recorded in connection with the transport of magmatic and / or hydrothermal fluids in volcanic conduits. Their reduced displacement value is less than 1.7 cm2.
The images obtained by the cameras installed near the volcanic complex showed mainly vapor emissions associated with the fumaroles of the currently active craters with column heights of less than 100 m from the crater level.
According to the data provided by the GNSS stations operating on the volcano, no deformation is attributable to the observed changes in the morphology of the volcano. The data provided by the inclinometer stations show stable positions over time.
No emissions of sulfur dioxide (SO2) in the volcanic complex sector have been reported, according to data published by the Ozone Monitoring Instrument, Sulfur Dioxide Group (IMO) (http: // so2 .gsfc.nasa.gov /) and the National Environmental Satellite Data and Information Service (NESDIS) (http://satepsanoine.nesdis.noaa.gov).
No thermal warnings were reported on the volcanic complex based on data processed by Middle Infrared Observation of Volcanic Activity (Mirova) (http://www.mirovaweb.it/).
During the first half of November, no explosive activity was recorded in the area of the active crater, however, it continues to be recorded a recurrent seismic activity localized preferentially to shallow levels, dominating the dynamics of the related fluids in volcanic ducts, suggesting the action of a hydrothermal system driven by heat transfer from a small apparent volume of magma. The reappearance of new explosion cycles is not ruled out, as has been the case in previous months.
Due to the above, the Volcanic Technical Alert is maintained at:
YELLOW LEVEL: changes in the behavior of volcanic activity – likely time for an Eruption: weeks / months.
Note: It is recommended to apply preventive restrictions on access to an area close to the crater with a radius of 3 kilometers.
Source : Sernageomin