Roundup of Global Volcanic Activity – Ongoing Activity for the week of 29 August -2 September 2018

Aira | Kyushu (Japan) : JMA reported that there were 14 events and 15 explosions at Minamidake crater (at Aira Caldera’s Sakurajima volcano) during 27 August-3 September, with ash plumes rising as high as 2.8 km above the crater rim and material ejected as far as 1.3 km. Crater incandescence was occasionally visible at night. The sulfur dioxide emission rate was 1,500 tons/day on 27 August. The Alert Level remained at 3 (on a 5-level scale).

Ambae | Vanuatu : The Vanuatu Meteorology and Geo-hazards Department reported that at 2015 on 1 September explosions at Ambae’s Lake Voui generated ash plumes that rose 4-11 km above the crater rim. According to the Wellington VAAC the ash plumes were visible in satellite images rising as high as 10.7 km (35,000 ft) a.s.l. and drifting E; the ash quickly dissipated. Moderate ashfall was likely produced in areas NE and E. The Alert Level remained at 3 (on a scale of 0-5).

Dukono | Halmahera (Indonesia) : Based on satellite data, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 29 August-4 September ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted N, NE, and E.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 24-31 August that sent ash plumes to 3-6 km (17,100 ft) a.s.l. A thermal anomaly was visible in satellite data during 24-25 and 30 August. Ash plumes drifted about 135 km SE, S, and SW during 24-25 and 27-30 August, producing ashfall on 29 and 30 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Fuego | Guatemala : INSIVUMEH reported that heavy rain generated lahars during 29 August-1 September that descended Fuego’s El Jute (SE), Las Lajas (SE), Cenizas (SSW), Taniluyá (SW), Seca (W), Mineral, Honda, and Pantaleón (W) drainages. The lahars were hot, had a sulfur odor, and carried tree branches and blocks (2-3 m in diameter). On 1 September lahars disrupted roads between San Pedro Yepocapa (8 km NW) and Sangre de Cristo (8 km WSW), and from Finca Palo Verde and El Porvenir (8 km ENE). During 2-4 September explosions produced ash plumes that rose as high as 950 m above the crater rim and drifted 10-15 km W and SW. Avalanches of incandescent material were confined to the crater. Ashfall was reported in areas downwind including San Pedro Yepocapa, Sangre de Cristo, Panimaché I and II (8 km SW), Morelia (9 km SW), and Finca Palo Verde.

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that an ash plume from Karymsky was identified in satellite images drifting about 40 km S on 25 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kilauea | Hawaiian Islands (USA) : HVO reported a break in visible lava activity at Kilauea’s Fissure 8 during 26-31 August. On 1 September incandescence at Fissure 8 was evident in the afternoon; spattering from a small area produced lava flows that slowly covered the 15 x 65 m crater floor by the evening. Lava continued to fill the Fissure 8 crater on 3 September. The Volcano Alert Level remained at Watch and the Aviation colour Code remained at Orange.

Mayon | Luzon (Philippines) : PHIVOLCS reported that at 0653 on 27 August a short-lived degassing event at Mayon produced a light-brown ash plume that rose 200 m above the summit rim and drifted NE. During 28 August-3 September white steam plumes rose as high as 1 km and drifted in multiple directions. Crater incandescence was visible nightly. The Alert Level remained at 2 (on a 0-5 scale) and PHIVOLCS reminded residents to stay away from the 6-km-radius Permanent Danger Zone and the 7-km Extended Danger Zone on the SSW and ENE flanks.

Reventador | Ecuador : During 29 August-3 September IG reported a high level of seismic activity at Reventador, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Steam, gas, and ash plumes rose as high as 600 m above the crater rim and drifted NE, NW, and W. Crater incandescence was visible.

Rincon de la Vieja | Costa Rica : OVSICORI-UNA reported two distinct, two-minute-long eruptions at Rincón de la Vieja beginning at 0434 and 1305 on 31 August. Weather conditions prevented webcam views and estimates of plume heights.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that explosions at Sabancaya averaged 25 per day during 27 August-2 September. Hybrid earthquakes were infrequent and of low magnitude. Gas-and-ash plumes rose as high as 3 km above the crater rim and drifted 50 km SE, E, and NE. The MIROVA system detected six thermal anomalies, and on 2 September the sulfur dioxide gas flux was high at 3,970 tons/day. The report noted that the public should not approach the crater within a 12-km radius.

Sangay | Ecuador : Based on satellite images and wind model data, the Washington VAAC reported that during 28 August-3 September ash emissions from Sangay rose to 5.8-6.7 km (19,000-22,000 ft) a.s.l. and drifted over 45 km in multiple directions. A thermal anomaly was sometimes visible.

Santa Maria | Guatemala : INSIVUMEH reported that during 1-4 September weak explosions at Santa María’s Santiaguito lava-dome complex generated ash plumes that rose 600-700 m and drifted SW. Avalanches of material descended the SE flanks of the lava dome. Ashfall was reported to the south in Monte Claro.

Semeru | Eastern Java (Indonesia) : Based on analysis of satellite images and wind model data, the Darwin VAAC reported that on 4 September a discrete eruption at Semeru generated an ash plume that rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted W.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite data during 25 and 28-30 August; cloudy weather prevented views of the volcano on the other days during 24-31 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Sierra Negra | Isla Isabela (Ecuador) : IG reported that the eruption at Sierra Negra that began on 26 June was divided into two main phases. The first and most energetic phase lasted one day (26 June) and was characterized by the opening of five fissures and lava flows traveling as far as 7 km from the vents. Lava was only produced from fissure 4 during the 57-day-long second phase (27 June-23 August), with lava reaching the sea on 6 July and expanding the coastline. By 25 August the lava flows in total covered an area of 30.6 square kilometers. Activity continued to decline the last week of August with decreased seismicity, gas emission, and no surficial activity visible.

Turrialba | Costa Rica : OVSICORI-UNA reported that at 1340 on 30 August an event at Turrialba produced an ash plume that passively rose 200 m above the crater rim and drifted SW. Gas-and-ash emissions became continuous during 31 August-1 September, with plumes rising 200 m and drifting SW and W.

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