Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 13 October – 19 October 2021

Asosan – Kyushu (Japan) : According to JMA the number of volcanic tremor signals at Asosan began on 12 October. Tremor amplitude began increasing at 1530 on 13 October, prompting JMA to raise the Alert Level to 2 (on a scale of 1-5) almost two hours later. White plumes rose 1.4 km above Nakadake Crater. An eruption was detected at 0443 on 14 October; weather clouds prevented visual confirmation of an eruption plume, though ejected incandescent material was visible in thermal camera images. During a field visit to the volcano later that day, scientists confirmed ashfall in several areas, including parts of Takamori Town (Kumamoto Prefecture), Taketa City (Oita Prefecture), and Takachiho Town (Miyazaki Prefecture). Small eruptive events occurred at 1057 and 1325 on 15 October. Volcanic tremor amplitude increased at 1400 on 18 October. During an overflight scientists observed ash deposits extending SE from Nakadake Crater. Volcanic tremor amplitude continued to fluctuate at high levels on 19 October. At 1143 on 20 October a notable eruption ejected blocks 900 m S and produced an ash plume that rose 3.5 km above the crater rim and drifted E. Pyroclastic flows descended 1.3 km W.

Kilauea – Hawaiian Islands (USA) : HVO reported that the summit eruption at Kilauea continued in Halema`uma`u Crater during 12-19 October. A 10-m-wide, horseshoe-shaped spatter rampart had formed around the W vent and was open to the E where lava was feeding the lake. For about 10 hours on 12 October a new vent N of the W vent produced 10-15-m-high lava fountains. Lava fountains from the W vent rose as high as 20 m and fed the lava lake which was 46 m deep by 18 October. The lava lake was not level with the deepest parts measured around the W vent; the W end was 4-5 m higher than the N and S parts of the lake and 12 m higher than the E end. Cooled and crusted parts of the lake’s surface overturned, or “foundered,” in all parts of the lake except the E part. The sulfur dioxide emission rate was high at 1,600-6,800 tonnes per day during 12-14 and 16-17 October.

Manam – Papua New Guinea : RVO reported that sporadic small ash emissions from Manam’s Southern Crater were observed starting at the end of September. Nighttime incandescence began on 8 October and incandescent material was occasionally ejected from the crater. The activity was characterized as moderately Strombolian with incandescent material rolling down SW Valley, visibly appearing as short lava flows. The Darwin VAAC noted that on 18 October an ash plume rose to 2.4 km (8,000 ft) a.s.l. and drifted NW. A thermal anomaly was visible in satellite images. RVO stated that at around 0800 on 20 October a large explosion at Southern Crater produced ash plumes that rose at least 1 km above the summit and drifted N and NW. According to the Darwin VAAC ash plumes rose as high as 15.2 km (50,000 ft) a.s.l. between 0840-0950, expanded radially, and then drifted E. Lower-level plumes rose 4.6-5.5 km (15,000-18,000 ft) a.s.l. and drifted NW. Later that day a collapse of newly erupted material, as well deposits from the previous few weeks, produced a debris flow that originated at the head of the valley and descended the SW Valley.

Pagan – Mariana Islands (USA) : The U.S. Geological Survey reported that ash and sulfur dioxide emissions from Pagan were last detected on 6 September. The Aviation Color Code and the Volcano Alert Level were both lowered to Unassigned on 24 September; Pagan is monitored with satellite imagery, distal geophysical data, and mariner reports and not ground-based instruments.

Rabaul – New Britain (Papua New Guinea) : On 6 October RVO raised the Alert Level for Rabaul to Stage 1 (the lowest level on a four-stage scale) due to ongoing deformation and recent increases in seismicity. During the month of September, the seismic network detected a total of 22 high-frequency volcano-tectonic earthquakes, which was more than the 12 recorded in August. The earthquakes were distributed in the Beehives, Vulcan, Greet Harbour, and Namanula areas. Deformation data from a GPS station located at the S part of Matupit Island showed a continuing trend of uplift, with 39 mm/month in August and 35-39 mm/month in September. Diffuse white fumarolic plumes rose from the crater floor and inner walls.

Vulcano – Aeolian Islands (Italy) : INGV continued to monitor elevated activity at Vulcano during 12-19 October. Scientists collected temperature, water chemistry, and gas-emissions data from four fumarolic vents located inside La Fossa Crater near the rim and from one vent near the beach. According to news articles, elevated levels of carbon dioxide impacted nearby residents in Porto Levante causing a few families to leave their homes on 13 October. Several residents had reported inexplicable illnesses and some deaths of domestic animals the previous week. On 14 October authorities restricted public access to the crater.

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