Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 11 July – 17 July 2018

Agung | Bali (Indonesia) : PVMBG reported that an event at 1409 on 13 July generated an ash plume that rose 1.5 km above Agung’s crater rim and drifted W. An event was detected at 0452 on 15 July, though no ash was visible. An ash plume from an event at 0905 rose 1.5 km and drifted W and SE. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone was unchanged at a 4-km radius.

Aira | Kyushu (Japan) : JMA reported that there were nine events at Minamidake crater (at Aira Caldera’s Sakurajima volcano) during 9-17 July generating plumes that rose as high as 2.3 km above the crater rim. At 1538 on 16 July an explosion produced an ash plume that rose 4.6 km, and ejected material as far as 1.7 km E. Crater incandescence was visible at night during 16-17 July. The Alert Level remained at 3 (on a 5-level scale).

Ambae | Vanuatu : Based on satellite data, webcam and pilot observations, and wind model data, the Wellington VAAC reported that during 16-17 July ash plumes from the vent at Ambae’s Lake Voui rose to altitudes of 2.3-9.1 km (8,000-30,000 ft) a.s.l. and drifted NE.

Cleveland | Chuginadak Island (USA) : AVO reported that unrest at Cleveland continued during 11-17 July, though nothing significant was detected in seismic or infrasound data. Weakly elevated surface temperatures were identified in satellite images on 11 July; meteorological cloud cover prevented views of the crater on the other days. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Dukono | Halmahera (Indonesia) : Based on PVMBG observations and satellite data, the Darwin VAAC reported that during 11-12 and 14-17 July ash plumes from Dukono rose to altitudes of 1.8 km (6,000 ft) a.s.l. and drifted NW, NNE, NE, and E.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 8-12 July that sent ash plumes as high as 4 km (13,100 ft) a.s.l. Satellite data showed ash plumes drifting 37 km W during 10-11 July. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that during 9-15 July gas emissions continued to rise from Etna’s summit craters. Visibility of the fairly continuous, low-energy, Strombolian activity deep within the Northeast Crater (NEC) and Bocca Nuova was sometimes hindered by gas emissions. Ejected incandescent material fell back into the crater. Strong and prolonged roars (up to several tens of seconds) from NEC were sometimes accompanied by gray-brown and reddish ash emissions. Collapses of the crater’s inner walls widened the crater. Gas emissions from New Southeast Crater (NSEC) were weak and sometimes pulsating.

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that during 8 and 10-12 July a thermal anomaly over Karymsky was identified in satellite images, as well as diffuse gas-and-steam plumes with some ash on 10 July. An explosion at 0550 on 17 July generated an ash plume that rose as high as 5 km (16,400 ft) a.s.l. and drifted 11 km WSW. The Aviation colour Code was raised to Orange (the second highest level on a four-colour scale).

Kilauea | Hawaiian Islands (USA) : HVO reported that the eruption at Kilauea’s Lower East Rift Zone (LERZ) and within Halema`uma`u Crater continued during 11-17 July. Lava fountaining and spatter was concentrated at Fissure 8, feeding lava flows that spread through Leilani Estates and Lanipuna Gardens subdivisions, and built out the coastline at multiple ocean entries.

Inward slumping of the crater rim and walls of Halema`uma`u continued, adjusting from the withdrawal of magma and subsidence of the summit area. Explosions from collapse events occurred almost daily, producing gas-and-ash-poor plumes. Sulfur dioxide emissions from the summit were very low.

Fountaining at Fissure 8 continued, producing Pele's hair and other volcanic glass that fell within Leilani Estates. The fountains continued to feed the lava flow that traveled NE, and then SSE, W of Kapoho Crater. A few channel overflows occurred. The channelized ‘a’a flow reached the ocean on 12 July, producing a large plume of laze (a corrosive steam plume mixed with hydrochloric acid and fine volcanic glass particles), and covering the Kua O Ka La Charter School and Ahalanui Beach Park. Lava entered the ocean at several points along a broad 6-km-wide flow front, though the main entry area was at Ahalanui (750 m NE of Isaac Hale Park) by 17 July. On 13 July a new island, 6-9 m in diameter, formed a few meters offshore, possibly fed by a submarine tumulus. On 16 July explosions were noted at the main ocean entry, some were strong. Hawaii County Civil Defense Agency noted that an explosion early in the morning ejected tephra that injured 23 people on a nearby tour boat. That same day volcanologists using a RADAR gun measured an average flow velocity of 29 km/hr of lava exiting Fissure 8.

Mayon | Luzon (Philippines) : PHIVOLCS reported that at 1509 on 13 July a minor rockfall descended the Mi-isi drainage on Mayon’s S flank, generating a brownish ash cloud. The event was preceded by heavy rainfall on the upper flanks. Sulfur dioxide emissions were 2,398 tonnes/day. Precise leveling data obtained during 2-14 April indicated inflation relative to data collected in late March; electronic tilt data showed pronounced inflation on the mid-flank beginning on 25 June possibly due to a deep aseismic magma intrusion. 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.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that explosions at Sabancaya averaged 23 per day during 9-17 July. Hybrid earthquakes were infrequent and low magnitude. Gas-and-ash plumes rose as high as 2.5 km above the crater rim and drifted 30 km S, SE, and E. The MIROVA system detected two thermal anomalies. The report noted that the public should not approach the crater within a 12-km radius.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 6-13 July. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Stromboli | Aeolian Islands (Italy) : INGV reported that activity at Stromboli during 9-15 July was characterized by ongoing Strombolian activity and degassing from multiple vents. Explosions mainly from two vents in Area N (north crater area) and three vents in Area C-S (South Central crater area) occurred at a rate of 14-19 per hour, except four per hour were recorded on 15 July. Low-intensity explosions from the N1 vent (NCA) ejected lapilli and bombs as high as 80 m. Explosions at the N2 vent (NCA) ejected tephra 120 m high. Vent C (Area C-S) produced gas emissions and sporadic spattering. Low-intensity explosions at S2 (Area C-S) ejected tephra less than 80 m high.