Friday, 1 November 2019

Volcanos

Global Volcanic Activity - Ongoing Activity for the week of 23 October - 29 October 2019

Aira | Kyushu (Japan) : JMA reported that two eruptive events at Minamidake crater (at Aira Caldera’s Sakurajima volcano) recorded during 25-28 October generated plumes that rose 1.2 km. The Alert Level remained at 3 (on a 5-level scale).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 23-29 October ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 18, 20-21, and 23 October that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted N, E, and SE. A weak thermal anomaly was identified in satellite images on 20 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kanlaon | Philippines : On 25 October PHIVOLCS lowered the Alert Level for Kanlaon to 0 (on a scale of 0-5) noting that volcanic activity had declined to baseline levels in June and had continued to be low.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 21-27 October lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.8 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Incandescence from both summit craters was visible at night. Sometimes dense white plumes rose to 500 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Krakatau | Indonesia : PVMBG reported that during 21-27 October diffuse white plumes rose as high as 100 m above Anak Krakatau’s active vent. As many as three eruptive events per day during 25-27 October generated ash plumes that rose as high as 200 m above the vent. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Nevados de Chillan | Chile : ONEMI and SERNAGEOMIN reported that during 22-24 October white-to-gray plumes from Nevados de Chillán’s Nicanor Crater rose as high as 1.3 km above the rim and drifted SE. Explosions ejecting incandescent material onto the flank were visible at night. A new lava flow from the crater had begun to effuse on 16 October and continued to very slowly advance on the NE flank. Diffuse white plumes rose from the crater on 25 and 29 October; cloudy weather obscured views in between those dates. The volcano Alert Level remained at Orange, the second highest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.

Piton de la Fournaise | Reunion Island (France) : OVPF reported that inflation began to be detected at Piton de la Fournaise on 11 October and a seismic crisis was recorded on 21 October. A second seismic crisis began at 0415 on 25 October accompanied by rapid deformation. Volcanic tremor began at 1440, signaling the arrival of magma to the surface; the eruption area was not visible in webcam views. Field observers first saw two active fissures at the S part of l’Enclos Fouqué at an elevation of 1,400 m. Several lava flows were identified, with the front of the longest flow reaching an area 2 km upstream from National Road RN2 by 1700. Tremor intensity began to decline around three hours after the start of the eruption and continued to decline through the morning of 26 October. That same morning there was one active vent producing 10-20-m-high lava fountains. Downstream of piton Tremblet the flow forked and by 1700 on 26 October the leading toe was about 250 m from RN2. On 27 October tremor intensity fluctuated concurrently with the variable intensity of cone formation. The cone had grown to 10 m high and lava was ejected 20 m above the cone rim. Only one lava flow was active and was 200 m long; the flow near RN2 had not progressed. The eruption ceased at 1630.

Sabancaya | Peru : Instituto Geofísico del Perú (IGP) reported that an average of 48 low-to-medium intensity explosions per day occurred at Sabancaya during 21-27 October. Gas-and-ash plumes rose as high as 2.5 km above the summit and drifted W, SW, and S. There were 15 thermal anomalies identified in satellite data. The report noted that the lava dome in the summit crater had been slowing extruding since February and filling in the N part of the crater, though the rate of the extrusion had increased in recent months. On 26 October Observatorio Vulcanológico del INGEMMET (OVI) conducted a drone overflight and captured video of the lava dome. The estimated volume of the lava dome was 4.6 million cubic meters based on the footage. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Sangeang Api | Indonesia : The Darwin VAAC reported that during 26-28 October multiple discrete ash emissions from Sangeang Api rose to 2.1-2.7 km (7,000-9,000 ft) a.s.l. and dissipated rapidly to the NW, WNW, and W. A thermal anomaly was visible in satellite images on 26 October. The Alert Level remained at 2 (on a scale of 1-4).

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 18-25 October. Resuspended ash drifted 110 km SE during 19-20 October. Explosions recorded on 21 October generated ash plume that rose to 10-11 km (32,800-36,100 ft) a.s.l. and drifted 1,300 km SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

White Island | North Island (New Zealand) : GeoNet reported that sulfur dioxide emissions and the level of volcanic tremor both increased at White Island over the past several months, and were at the highest levels since 2016. The report noted that the changes could be related to a variety of processes, including an increased level of unrest, though the level of hazards on the island remained unchanged; the Volcanic Alert Level remained at 1 (the second lowest level on a 0-5 scale) and the Aviation colour Code remained at Green. The crater lake level continued to rise and impact surface activity around vents, creating small-scale geysering, on the W side of the crater floor.

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