Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the Week 7 July – 13 July 2021

Aira – Kyushu (Japan) : JMA reported that very small eruptive events were occasionally recorded at Minamidake Crater (at Aira Caldera’s Sakurajima volcano). Crater incandescence was visible at night during 9-12 July. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Dukono – Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 8 and 11-13 July ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted N, NW, W, and SW. 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) : According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 2, 4, and 6-8 July produced ash plumes that rose as high as 3 km (10,000 ft) a.s.l. and drifted E and SE. A thermal anomaly was identified in satellite images during 5-7 July. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna – Sicily (Italy) : INGV reported continuing Strombolian activity and two episodes of lava fountaining Etna’s Southeast Crater (SEC) during 5-11 July. The first episode began at 1130 on 6 July with Strombolian activity at SEC. The intensity and frequency of explosions progressively intensified and formed lava fountains. Ash plumes rose to 1.5 km (5,000 ft) a.s.l. and drifted S, causing ashfall in areas downwind. A small lava flow originated from the S side of the cone and traveled SW, stopping at 2,800 m elevation. During fieldwork on 7 July scientist observed deposits of bombs, 1 m in diameter, on the N flank and smaller bombs scattered farther away. A second episode began at 2100 on 8 July with Strombolian activity which again intensified and formed lava fountains. Ash plumes rose to 3.4 km (11,000 ft) a.s.l. and drifted SE, causing ashfall in downwind areas. Lava flowed SW to 2,350 m elevation.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was idenitifed in satellite images during 5-8 July and ash plumes were visible drifting 60 km W and E during 6-8 July. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krysuvik-Trolladyngja – Iceland : The fissure eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 7-13 July. Lava fountaining and overflows from the fifth vent were sometimes visible, and lava from the crater flowed in tubes as well as on the surface. Visible activity at the vent occasionally paused for various lengths of time, though sub-surface lava likely continued flowing through the tube system. Weather conditions prevented views of the crater on some days and also created hazardous conditions. The Aviation colour Code remained at Orange due to the lack of ash and tephra emissions, though IMO warned of the potential for lapilli and scoria fallout within a 650 m radius of the active vent. Authorities warned of increased gas emissions hazards.

Lewotolok – Lembata Island (Indonesia) : PVMBG reported that daily white-and-gray plumes from Lewotolok rose as high as 1.1 km and drifted SW, W, and NW during 6-12 July. Incandescent material was ejected from the summit vent on 6, 8, and 10 July; on 6 July material landed as far as 300 m away. The Darwin VAAC noted that on 7 July an ash plume rose 2.7 km (9,000 ft) a.s.l. and drifted E, based on satellite data and information from PVMBG. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater.

Merapi – Central Java (Indonesia) : BPPTKG reported that the lava dome just below Merapi’s SW rim and the lava dome in the summit crater both remained active during 2-8 July. The SW rim lava-dome volume was an estimated 1.815 million cubic meters by 8 July and continued to shed material down the flank. The volume of the summit lava dome was 2,741 million cubic meters. A total of 17 pyroclastic flows traveled a maximum of 2 km down the SW flank and as far as 1.5 km SE. As many as 125 incandescent avalanches traveled a maximum of 2 km down the SW flank and 1.8 km down the SE flank. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 5 km away from the summit.

Nevados de Chillan – Chile : SERNAGEOMIN reported continuing explosive and effusive activity at Nevados de Chillán’s Nicanor Crater during 16-30 June, alomg with increased sulfur dioxide emissions and thermal anomalies. Explosions generated ash plumes that rose as high as 1.4 km above the crater rim and crater incandescence at night; incandescent material was ejected as far as 500 m onto the N, E, and S flanks. The L5 and L6 lava flows continued to be active, with increased effusion rates during 17-19 and 27-28 June. During the periods of increased effusion rates the flow temperatures were higher, nighttime incandescence was more intense, emissions rose higher, and more pyroclastic flows were recorded. The pyroclastic flows traveled less than 500 m down the NE flank and were sourced from collapses at the sides of L6 and the front of L5. The average temperature was 131 degrees Celsius with a maximum of 174 degrees for L5 and an average of 163 degrees Celsius with a maximum of 181 degrees for L6. Temperatures at the vents at Nicanor Crater were as high as 360 degrees Celsius during explosive phases. Satellite images indicated that the L5 lava flow was 1,033 m long and L6 was 894 m long, and that the distal end of L6 had thickened. The average sulfur dioxide emission rate was 694 (± 43) tons/day, reaching a high value of 903 on 19 June. There was a total of 35 thermal anomalies. The Alert Level remained at Yellow, the second lowest level on a four-colour scale. ONEMI stated that Alert Level Yellow (the middle level on a three-colour scale) remained in place for the communities of Pinto and Coihueco, noting that the public should stay at least 2 km away from the crater.

Popocatepetl – Mexico : CENAPRED reported that each day during 6-13 July there were 47-112 steam-and-gas emissions from Popocatépetl. Some emissions contained ash during 8-13 July. Almost daily periods of low-amplitude tremor lasted from 10 minutes to five hours. A few volcano-tectonic earthquakes were recorded. Crater incandescence was visible at night during 12-13 July. The Alert Level remained at Yellow, Phase Two (middle level on a three-colour scale).

Semeru – Eastern Java (Indonesia) : Semeru continued to erupt during 7-13 July. Inclement weather often prevented visual observations, though a gray-and-white ash plume was seen rising 500 m above the summit and drifting SW on 6 July. The Alert Level remained at 2 (on a scale of 1-4), with a general exclusion zone of 1 km and extensions to 5 km in the SSE sector.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that continuous volcanic tremor at Semisopochnoi began at 1200 on 12 July and explosive activity was recorded by the infrasound network. Emissions began at 1300 and lasted tens of minutes; a sulfur dioxide gas plume possibly containing ash was identified in satellite images drifting S at an altitude less than 1.5 km (5,000 ft) a.s.l. The Aviation colour Code was raised to Orange and the Volcano Alert Level was raised to Watch. Volcanic tremor decreased to low levels after several hours.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 2-9 July. A plume of re-suspended ash drifted 90 km E during 6-7 July. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Sinabung – Indonesia : PVMBG reported that on most days during 6-13 July white gas-and-steam plumes from Sinabung rose as high as 500 m above the summit. At 0925 on 13 July an eruptive or collapse event produced an ash plume that rose 500 m and drifted ESE. 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.

Veniaminof – United States : AVO changed both the Aviation colour Code and Volcano Alert Level for Veniaminof to Green and Normal, respectively, on 8 July, noting that seismic stations were back online. The monitoring network consists of local and regional seismic stations, regional infrasound networks, lightning detection, and satellite image monitoring.

from WordPress https://ift.tt/3eJdU75