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| View of the ash plumes from the explosion and pyroclastic flow from the west (Image: Bomberos Retalhuleu / CONRED) |
February 7, 2016 - EARTH - The following constitutes the new activity, unrest and ongoing reports of volcanoes across the globe.
Santiaguito (Guatemala): A strong explosion occurred from the active Caliente lava dome this morning around 10:30 local time. It genereated a pyroclastic flow that traveled down the southeast flank of the dome complex reaching a length of approx. 2-3 km. No damage or injuries were reported.
Ash plumes from both the explosion and the pyroclastic flow rose to an elevation of 17,000 ft (5.5 km) and produced moderate ash falls in the southern sectors of the volcano, in particular in the village and coffee farm of El Palmar. Authorities ordered preventive evacuations in areas to the S and SE closest to the volcano.
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| Santiaguito's pyroclastic flow this morning seen from NE near Santa Maria de Jesus (Image: Silverio Zum via Erick Colop/Twitter) |
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| El Palmar under ash fall after the explosion (Image: Stereo100Noticias @stereo100xela / twitter) |
At the moment, it is unclear what exactly triggered the pyroclastic flow - collapse of ejected material or partial collapse of the upper parts of the dome itself, or, most likely, a combination of both. Whether the event was (as often) an isolated one or might be a first in a series of stronger explosions and collapses with more pyroclastic flows is impossible to know at the moment.
According to CONRED, this morning's eruption was preceded by 34 small to moderate explosions within 24 hours, a quite unusually high rate, suggesting that magma and/or gas supply into the dome has been elevated at the moment.
Soputan (North-Sulawesi, Indonesia): A larger explosive eruption was reported to have occurred about two hours ago (10:15 UTC). At 11:45 UTC, Darwin VAAC issued alerts to aviation about an ash plume that had risen to estimated 23,000 ft (7 km) altitude and has been drifting NW. Aviation color code was immediately raised to RED.
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| Picture allegedly showing an ash plume from Soputan today (from the first, smaller eruption; Source: Istimewa/Tribun Regional) |
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| Forecast of ash plume from Soputan's eruption this morning (VAAC Darwin) |
According to a local newspaper article, there were two eruptions today: a presumably smaller one (which did not cause any alerts) in the morning at 10:00, and a "terrific" eruption at 18:15 local time (or 10:15 GMT), which sent a large ash plume into the sky. Ash fall was reported from the areas at the feet of the volcano, but there seems not to have been any damage reported.
Alaid (Kuriles Islands, Russia): The most recent eruption of the volcano, which began in October last year, can be regarded as over and the aviation color code was lowered back to green.
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| Comparison of satellite images from July 2015 and January this year,
showing that large parts of the summit crater have been filled by new
lava (Images: Nasa, annotations: Culture Volcan) |
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| MODIS thermal signal from Alaid (MIROVA) |
Satellite data compiled by Culture Volcan show no more heat emission from the volcano since January and visible satellite imagery now show that the crater has been partially filled with fresh lava from the eruption.
Pagan (Mariana Islands): Satellite data and ground-based observations from a field crew and local residents near Pagan indicated that steam-and-gas emissions have significantly decreased since March 2015. The Aviation Color Code and Volcano Alert Level were lowered to Unassigned on January 30.
Cotopaxi (Ecuador): On January 29, IG reported that in recent weeks superficial activity at Cotopaxi was characterized by minor steam emissions from the crater and sporadic gas emissions with minor amounts of ash.
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| The volcano's last eruption in November, 2015. |
Sulfur dioxide emissions were less than 1,000 tons per day (pre-eruptive levels) and seismicity had almost returned to baseline levels. At 1843 on 24 January a plume with low-to-moderate levels of ash rose 700 m above the crater and drifted W. The emission coincided with a hybrid earthquake.
Chirpoi (Kurile Islands, Russia): Satellite images detected a thermal anomaly over Snow, a volcano of Chirpoi, during 25, 27-28, and 30-31 January. The Aviation Color Code remained at Yellow.
Macdonald (Austral Islands): Scientists and crew aboard CSIRO’s (Commonwealth Scientific and Industrial Research Organisation) Marine National Facility research vessel Investigator observed a plume rising from McDonald Island (the largest island) during the last week of January. Visual observations of the McDonald Islands are very rare due to its remote location.
Egon (Flores Island, Indonesia): Volcanic unrest has decreased at the volcano, making the likelihood of an impending eruption smaller. The volcano's alert level was lowered from 3 to 2 (on a scale of 1-4).
"During 20 January-1 February seismicity at Egon was dominated by signals indicating emissions; shallow volcanic events had decreased.
RSAM values increased on 25 January but did not exceed values detected during the previous peak on 12 January; overall seismicity had declined. The Alert Level was lowered to 2 (on a scale of 1-4) and residents were advised to stay at least 1.5 km away from the crater."
Bardarbunga (Central Iceland): Over the past few months, seismic activity at the volcano, mainly under the volcano's large, ice-covered caldera has been increasing again, suggesting that magma might be filling the volcano's reservoir underneath the caldera.
Since the beginning of the year, more than 300 shallow earthquakes of magnitudes up to 3.8 on the Richter scale were recorded, clustered in areas near the southern and northeastern caldera rim.
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| Earthquakes under and near Bardarbunga volcano since January 2016 (yellow circles = older than 2 days, red = past 48 hours) |
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| Time vs depth of earthquakes since January 1, 2016 |
Another cluster of small earthquakes concentrates along the 2014-15 eruptive dyke 20 km to the NE of the volcano.
Whether or not, and if so, when the observed earthquake activity under the caldera could lead to another eruption of the volcano, now considered one of, if not even THE most active in Iceland, is impossible to predict.
Sakurajima (Kyushu, Japan): After several months of unusual calm, the volcano had a moderately strong vulcanian explosion from the Showa crater this morning. An ash plume rose to approx. 10,000 ft (3 km) altitude.
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| Eruption of Sakurajima volcano this morning (NHK) |
Until the end of Sep 2015, Sakurajima had been producing such explosions, of varying intensity, at rates of typically 3-5 or more per day. This activity ceased around 28 Sep 2015 and until now, the volcano had only manifested surface activity in the form of minor ash emissions, degassing, as well as, very rarely, minor explosions. Whether the volcano is back to its previously typical behavior with more frequent and stronger explosions, as it had been during most of the recent years, remains to be seen.
Sinabung (Sumatra, Indonesia): Recently, explosions from the active summit lava dome have become more frequent, producing ash plumes that rose 1-2 km above the summit.
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| Explosion at Sinabung volcano yesterday (Image: Endro Lewa / Facebook) |
Extrusion of viscous lava also continues at slow pace, generating small to moderate pyroclastic flows from time to time.
Fuego (Guatemala): Activity at the volcano is again increasing and seems to be heading towards another (the 3rd in 2016) paroxysm.
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| Glowing avalanches after an explosion of Fuego. |
Explosions have become stronger, and possibly, one or several short lava flows are active on the upper flanks. The thermal output of the volcano, measured by NASA's satellite-based MODIS spectroradiometer, also shows a clear increasing trend.
- Volcano Discovery.
