Thursday, 27 June 2019

Volcanos

Global Volcanic Activity - New Activity for the week of 19 June - 25 June 2019

Colima | Mexico : Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima reported that intermittent steam-and-gas emissions, mainly from the NE side of the crater, and small explosions continued to be recorded during 14-21 June. Weather conditions often prevented visual observations of the crater.

Raikoke | Kuril Islands (Russia) : A powerful eruption at Raikoke that began on 22 June (after 95 years of dormancy) was identified based on satellite observations, prompting KVERT and SVERT to raise the Aviation Color Code to Red. A series of at least nine explosions (six within the first 25 minutes) beginning at 0505 and continuing to about 1900 produced ash plumes, with a significant sulfur dioxide component, that rose 10-13 km (32,800-42,700 ft) a.s.l. and drifted E and NE. Lightning was detected in the eruption plumes. Strong explosions at 1640 on 22 June generated ash plumes that rose to 10-11 km (32,800-36,100 ft) a.s.l. The ash and gas was entrained by jet streams and by a cyclone around the Komandorskiye Islands, causing parts of the material to spiral counterclockwise as it drifted farther NE. By 23 June the leading edge of the plume had drifted 2,000 km ENE. According to a news article, at least 40 flights in that region were diverted. On 23 June ash plumes continued to be visible, rising to 4.5 km and drifting NE. The Aviation Color Code was lowered to Orange. Gas-and-steam plumes possibly with some ash rose to 4.5 km (14,800 ft) a.s.l. and drifted 60 km NW. That same day observers on a passing ship approached the island from the W side; they photographed the island and sent out a drone. An expedition member noted that the entire island was mantled with light-colored ash deposits up to several dozen centimeters thick. In some of the drainages and at the base of some drainages deposits were several meters thick. In some areas along the shoreline waves interacted with the deposits, causing steam explosions and dark brown steam emissions. Gas-and-ash plumes rose 1.5 km above the summit crater rim and drifted W. Minor ashfall was reported in Severo-Kurilsk (340 km NE) during 1830-1920. On 25 June ash plumes continued to be produced, rising as high as 2 km (6,600 ft) a.s.l. and drifting NW.

Ubinas | Peru : Instituto GeofĂ­sico del PerĂș (IGP) reported that seismic activity at Ubinas increased suddenly on 18 June with signals indicting rock fracturing. During 21-24 June signals indicating fluid movement emerged and, beginning at 0700 on 24 June, webcams recorded ash, gas, and water vapor plumes rising from the crater. The plumes were visible in satellite images rising to 6.1 km (20,000 ft) a.s.l. and drifting N, NE, and E. IGP recommended that the authorities raise the Alert Level to Yellow (on a 4 level scale).

Ulawun | New Britain (Papua New Guinea) : RVO reported that RSAM values at Ulawun steadily increased during 24-25 June, and then sharply increased at around 0330 on 26 June. The RSAM values reflect an increase in seismicity dominated by volcanic tremor. An eruption began in the morning hours of 26 June with emissions of gray ash that over time became darker and more energetic. The plumes rose 1 km and drifted NW, causing minor ashfall in NW and SW areas. Locals heard roaring and rumbling during 0600-0800. The Darwin VAAC issued several notices about ash plumes visible in satellite data. These stated that during 1130-1155 ash plumes rose to 6.7-8.5 km (22,000-28,000 ft) a.s.l. and drifted W, while ash plumes that rose to 12.8-13.4 km (42,000-44,000 ft) a.s.l. drifted S and SW. A new pulse of activity generated ash plumes that by 1512 rose to 16.8 km (55,000 ft) a.s.l. and drifted S and SE. By 1730 the ash plume had risen to 19.2 km (63,000 ft) a.s.l. and spread over 90 km in all directions. Ash from earlier ejections continued to drift S at 13.4 km a.s.l. and W at 8.5 km a.s.l. RVO stated that RSAM values peaked at about 2,500 units during 1330-1600, and then dropped to 1,600 units as the eruption subsided. RVO stated that parts of the ash plume at lower altitudes drifted W, causing variable amounts of ashfall in areas to the NW and SW. A pyroclastic flow descended the N flank. Residents evacuated to areas to the NE and W; a news article noted that around 3,000 people had gathered at a local church. According to another news source an observer in a helicopter reported a column of incandescent material rising from the crater, residents noted that the sky had turned black, and a main road in the N part of the island was blocked by volcanic material. Residents also reported a lava flow near Noau village and Eana Valley. RVO reported that the eruption ceased between 1800 and 1900. Incandescence visible on the N flank was either from a lava flow or pyroclastic flow deposits.

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