Volcanos

Roundup of Global Volcanic Activity - Ongoing Activity for the week of 16 August - 22 August 2017

Aira | Kyushu (Japan) : JMA reported 26 events at Showa Crater (at Aira Caldera’s Sakurajima volcano) during 18-21 August, one of which was explosive. Material was ejected as high and as far as 500 m. Ash plumes rose as high as 1.7 km above the crater rim. The Alert Level remained at 3 (on a 5-level scale).

Bezymianny | Central Kamchatka (Russia) : KVERT reported that during 11-18 August a daily thermal anomaly over Bezymianny was identified in satellite images. A lava flow continued to flow down the W flank of the dome; incandescence from the dome was visible at night. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Bogoslof | Fox Islands (USA) : AVO reported that photographs of Bogoslof taken during an overflight on 15 August showed that the vent area (which had dried out during the 7 August eruption) had refilled with water. Seismicity decreased on 16 August and remained low at least through 18 August. Weakly elevated surface temperatures consistent with a warm lake were identified in satellite data during 19-20 August. Satellite data acquired on 21 August showed an approximately 125-m-diameter lava dome within the intra-island lake, just W of the 1992 lava dome. A cold volcanic plume, likely from the lava dome, drifted about 55 km S of the island. Some minor explosions were detected in infrasound data at about 0410 on 22 August. The lava dome had grown to 160 m in diameter. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Cleveland | Chuginadak Island (USA) : AVO reported that elevated surface temperatures at Cleveland were identified in satellite data during 17-21 August. Minor degassing from the summit was observed in satellite and webcam images during 20-21 August. A 1-minute-long moderate explosion was detected at 1043 on 22 August in infrasound and seismic data. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 16-22 August ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted E, NE, NW, and W. Ash plumes drifted as far as 150 km on 17 August.

Fuego | Guatemala : INSIVUMEH reported that the eighth effusive episode at Fuego in 2017 began on 20 August. Constant explosions generated ash plumes that rose 2.3 km above the crater and drifted more than 50 km W and SW. Ashfall was reported in areas downwind including Panimaché I (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), and Yepocapa (8 km WNW). Two lava fountains, each 300 m high, fed lava flows that traveled 1.4 km SSW down the Ceniza ravine and 1.2 km W down the Seca (Santa Teresa) ravine. Incandescent block avalanches occurred throughout the crater. Some explosions generated shock waves that rattled nearby structures. Seismicity decreased on 21 August. Weak explosions generated ash plumes that rose 1 km and drifted 20 km. Suspended ash from explosions and pyroclastic flows was visible. The lava flows had lengthened 200 m in the Ceniza ravine and 100 m in the Santa Teresa ravine. The report warned that pyroclastic flows were concentrated in the Santa Teresa ravine, possibly filling the drainage with deposits (similar to activity from 5 May) and increasing the chances for lahars. Ash fell in San Pedro Yepocapa (8 km N) and Chimaltenango (21 km NNE). On 22 August INSIVUMEH noted that after 48 hours the effusive episode was over. Explosions produced ash plumes that rose 1.2 km and drifted SW, and continued to vibrate nearby structures. Incandescent material was ejected as high as 200 m above the crater rim.

Karymsky | Eastern Kamchatka (Russia) : A thermal anomaly over Karymsky was identified in satellite images on 11 August, as well as ash plumes drifting about 400 km SE during 12-13 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kilauea | Hawaiian Islands (USA) : During 16-22 August HVO reported that the lava lake continued to rise, fall, and spatter in Kilauea’s Overlook crater. Webcams recorded incandescence from long-active sources within Pu'u 'O'o Crater. The 61G lava flow, originating from a vent on Pu'u 'O'o Crater's E flank, continued to enter the ocean at Kamokuna. A breakout 120 m up-slope of the ocean entry began at 0410 on 19 August and lasted about 9.5 hours; it produced a lava fall over the sea cliff W of the ramp and a small ‘a’a flow on the W portion of the delta. At 2135 a large littoral explosion occurred near the front of the delta, producing spatter that was ejected higher than the sea cliff (about 28 m high). Another smaller explosion was observed five minutes later. HVO scientists documented ongoing littoral explosions on 21 August, as well as continued widening of the cracks running parallel to the coastline.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that ash plumes from Klyuchevskoy were identified in satellite images drifting 315 km E and NW during 11-12 and 15-17 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Langila | New Britain (Papua New Guinea) : Based on analyses of satellite imagery, the Darwin VAAC reported that on 16 August an ash plume from Langila rose 2.1 km (7,000 ft) a.s.l. and drifted NW.

Manam | Papua New Guinea : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that on 21 August an ash plume from Manam rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted NNW.

Piton de la Fournaise | Reunion Island (France) : Mainly based on seismicity, OVPF reported that the eruption at Piton de la Fournaise that began on 14 July continued during 16-22 August; weather clouds prevented visual and satellite observations most of the week. Volcanic tremor rapidly increased in the early evening on 15 August, concurrent with the presence of ephemeral lava fountains, at the cone and another area, visible in webcam images. The signal fluctuated at high levels until the evening of 19 August, when it began to stabilize at low levels. Satellite data from 19 August indicated a decreased lava-flow rate.

Poas | Costa Rica : OVSICORI-UNA reported that an event at Poás at 1517 on 22 August generated a plume that rose 300 m above the crater rim.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that explosive activity at Sabancaya was similar to the previous week; there was an average of 41 explosions recorded per day during 14-20 August. The earthquakes were dominated by long-period signals, with fewer numbers of hybrid events recorded. Gas-and-ash plumes rose 3.4 km above the crater rim and drifted no more than 30 km SE. The report warned the public not to approach the crater within a 12-km radius.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly was identified daily in satellite images over Sheveluch during 11-18 August. Ash plumes drifted about 180 km E, NW, and NE during 12 and 15-16 August. The Aviation colour Code remained at Orange.

Sinabung | Indonesia : PVMBG reported that the lava dome in Sinabung’s crater that had been growing since April was destroyed during the 2-3 August events. The dome had grown to an estimated volume of 2.3 million cubic meters. Measurements on 6 August indicated that a new dome had a volume of 23,700 cubic meters. Based on PVMBG ground observations, the Darwin VAAC reported that on 16 August an ash plume from Sinabung rose to 2.7 km (9,000 ft) a.s.l. and drifted ESE.

Suwanosejima | Ryukyu Islands (Japan) : Based on JMA notices, the Tokyo VAAC reported explosions at Suwanosejima during 19-20 August.

Turrialba | Costa Rica : OVSICORI-UNA reported that an event at Turrialba at 1012 on 21 August generated a plume that rose 200 m above the crater rim and drifted NW.