Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 18 April - 24 April 2018

Ibu | Halmahera (Indonesia) : PVMBG reported that at 0637 on 20 April an eruption at Ibu generated a gray-white ash plume that rose at least 600 m above the crater rim and drifted S. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Kanlaon | Philippines : PHIVOLCS reported that during 17-19 April dirty-white steam plumes from Kanlaon rose as high as 1.2 km above the crater rim and drifted SW, NW, and NE. White steam plumes rose 300-600 m and drifted SW and NW during 20-24 April. The Alert Level remained at 2 (on a scale of 0-5).

Kilauea | Hawaiian Islands (USA) : During 18-24 April HVO reported that the lava lake continued to rise, fall, and spatter in Kilauea’s Overlook crater. The lake level was high, and by late on 21 April had overflowed the S crater rim. As of midday on 23 April the new flows has covered about 16 ha of the floor, or about 30%. Overflows of the crater rim continued through 24 April, flowing as far as 375 m onto the N, SW, and S parts of the crater floor. HVO noted that the overflows were the first significant ones since May 2015. Surface lava flows were active above Pulama pali. On 18 April geologists observed the pit crater on the W side of Pu'u 'O'o Crater, noting that overflows had built up the crater rim to several meters above the crater floor and 7 m higher compared to late March.

Kirishimayama | Kyushu (Japan) : An explosive eruption at Iwo-yama (also called Ioyama, NW flank of Karakuni-dake), a stratovolcano of the Kirishimayama volcano group, occurred at 1555 on 19 April prompting JMA to raise the Alert Level to 3 (on a scale of 1-5). This was the first eruption in that area since 1768; frequent and recent activity has occurred from Shinmoedake (Shinmoe peak). Ash plumes rose as high as 500 m above new vents in the SE part of the crater, and a large amount of ejected tephra including boulders were deposited around the crater area. Webcams showed expansion of vents by 2100. A new fumarole was observed at 1630 on 20 April in the vicinity of the highway, on the W side of Iwo-yama. During overflights on 20 and 21 April scientists observed multiple vents with fumarolic emissions, and intermittent ejections of black-gray muddy water. The activity continued through 23 April.

Langila | New Britain (Papua New Guinea) : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that on 24 April an ash plume from Langila rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted SW. An image acquired around six hours later indicated that the ash from the event had dissipated.

Maly Semyachik | Eastern Kamchatka (Russia) : KVERT reported that activity at Maly Semyachik increased during the second half of March; the ice covering the crater lake melted within a 5-6-day period, and a weak thermal anomaly was visible in satellite images. The Aviation colour Code was raised to Yellow (the second lowest level on a four-colour scale) on 22 March. A weak thermal anomaly continued to be detected through 20 April, though no further activity prompted KVERT to lower the Aviation colour Code to Green.

Nevados de Chillan | Chile : Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported continuing activity during 17-18 April associated with growth of the Gil-Cruz lava dome in Nevados de Chillán’s Nicanor Crater. Seismicity consisted of long-period events and tremor associated with explosions. The webcam recorded pulsating white gas emissions with possible ash, nighttime incandescence, and an intermittent ejection of ballistics from explosions. The 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.

Sinabung | Indonesia : PVMBG reported that during 18-22 April gray-to-white plumes from Sinabung rose as high as 500 m above the crater rim and drifted in multiple directions. At 1604 on 20 April an event produced an ash plume that rose 3 km and pyroclastic flows that traveled 1 km down the E, SE, W, and NW flanks. The Alert Level remained at 4 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions of 7 km on the SSE sector, 6 km in the ESE sector, and 4 km in the NNE sector.