Roundup of Global Volcanic Activity – Ongoing Activity for the week of 17 May – 23 May 2017
Aira | Kyushu (Japan) : JMA reported that 10 events at Showa Crater (at Aira Caldera’s Sakurajima volcano) were detected during 15-18 May. One of the events, an explosion at 2302 on 17 May, generated a large ash plume that rose 3 km above the crater rim and ejected material 500-800 m from the crater. That same day at 1526 an explosion at Minamidake summit crater produced an ash plume that rose 1.1 km above the crater. At 0058 on 19 May a plume rose 1.4 km above Showa Crater’s rim. Very small events occasionally occurred at Minamidake summit crater during 19-22 May. The Alert Level remained at 3 (on a 5-level scale).
Bagana | Bougainville (Papua New Guinea) : Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 20-22 May ash plumes from Bagana rose 2.4 km (8,000 ft) a.s.l. and drifted W.
Bezymianny | Central Kamchatka (Russia) : KVERT reported gas-and-steam activity at Bezymianny during 12-19 May, and a thermal anomaly identified in satellite images daily. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).
Bogoslof | Fox Islands (USA) : AVO reported that the eruption at Bogoslof which began at 2232 on 16 May lasted about 73 minutes. Trace amounts of ash fell in the community of Nikolski on Umnak Island. Later that day the Aviation colour Code (ACC) was lowered to Orange and the Volcano Alert Level (VAL) was lowered to Watch; no further ash emissions were detected and seismicity was low. Satellite data showed that the event altered the N coastline of the island. The crater lake was breached with a 550-m-wide gap along the N shore, and the NE shore had been extended 300 m from new tephra deposits.
Cleveland | Chuginadak Island (USA) : AVO reported that a short-lived explosion at Cleveland was detected in both seismic and infrasound data at 1938 on 16 May; the seismic signal lasted about 11 minutes. An ash cloud observed in satellite images rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted SW for about five hours. The explosions completely destroyed the lava dome that was emplaced in the summit crater during April-May. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.
Colima | Mexico : On 19 May the Centro Universitario de Estudios e Investigaciones de Vulcanologia – Universidad de Colima reported that during the previous week seismic data revealed 25 high-frequency events, 15 long-period events, 2.2 hours of tremor, 12 landslides, and three low-intensity explosions. During 15-16 May sulfur dioxide emissions were below detectable limits (8.6 t/d).
Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 18-23 May ash plumes from Dukono rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted in multiple directions.
Ebeko | Paramushir Island (Russia) : KVERT reported that on 15 May explosions at Ebeko were observed by residents of Severo-Kurilsk (Paramushir Island) about 7 km E. Ash plumes rose as high as 2 km (6,600 ft) a.s.l. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).
Ibu | Halmahera (Indonesia) : Based on analyses of satellite imagery and information from PVMBG, the Darwin VAAC reported that during 19-20 and 23 May ash plumes from Ibu rose 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted NE, E, and S.
Kambalny | Southern Kamchatka (Russia) : On 19 May KVERT reported that the eruption at Kambalny likely had ended, with only gas-and-steam activity observed during the previous month. The explosive phase began on 24 March and ended on 10 April. The Aviation colour Code was lowered to Green.
Kilauea | Hawaiian Islands (USA) : During 17-23 May HVO reported that the lava lake continued to rise, fall, and spatter in Kilauea’s Overlook crater; the lake rose as high as 15 m below the crater rim and was visible from Hawaii Volcanoes National Park’s Jaggar overlook. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater, from a vent high on the NE flank of the cone, and from a small lava pond in a pit on the W side of the 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 adding to a growing delta. Surface lava flows were active above and on the upper slopes of the pali.
Klyuchevskoy | Central Kamchatka (Russia) : Based on video and satellite data, KVERT reported that explosions at Klyuchevskoy on 17 May generated ash plumes that rose to 6 km (19,700 ft) a.s.l. and drifted about 180 km N and NE. A weak thermal anomaly was identified daily. 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 and wind model data, the Darwin VAAC reported that on 19 May an ash plume from Langila rose 4.6 km (15,000 ft) a.s.l. and drifted almost 170 km WSW and dissipated. During 19-20 May ash plumes drifted N and NNW at 1.8 km (6,000 ft) a.s.l. On 23 May ash plumes rose 2.1 and 3 km (7,000 and 10,000 ft) a.s.l. and drifted NW and SW, respectively.
Piton de la Fournaise : OVPF reported that a seismic crisis at Piton de la Fournaise began at 1340 on 17 May and was accompanied by rapid deformation that suggested rising magma; volcanic tremor was recorded at 2010. The seismic and deformation activity was located in the NE part of l’Enclos Fouqué caldera. During an overflight at 1100 on 18 May scientists observed no surface activity at the base of the Nez Coupé de Sainte Rose rampart (on the N side of the volcano) nor outside of l’Enclos Fouqué caldera, and suggested that fractures opened but did not emit lava. Seismicity increased at 0400 on 18 May. The number of shallow (2 km depth) volcano-tectonic earthquakes progressively decreased over the next three days: 40 shallow and 22 deep on 18 May, 18 shallow and 22 deep on 19 May, 7 shallow and 9 deep on 20 May, 8 shallow and 1 deep on 21 May. Carbon dioxide concentrations in soils measured at remote stations were high. During a field visit on 22 May scientists mapped the deformation associated with the 17 May event and measured displacements that did not exceed 35 cm. On 23 May OVPF reported that the 17-18 May activity resulted in two new zones of fumaroles that followed the trends seen in seismic and deformation data.
Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that during 15-21 May explosive activity at Sabancaya was similar to the previous week, with an average of 39 explosions detected per day. The number and magnitude of long-period and hybrid events was low. Gas-and-ash plumes rose as high as 4.2 km above the crater rim and drifted more than 40 km NE, E, and SE. The MIROVA system detected six thermal anomalies.
San Miguel | El Salvador : On 19 May SNET reported that during the previous 24 hours RSAM values at San Miguel continued to decrease, fluctuating between 69 and 80 units (typical background levels average 50 units). Sulfur dioxide flux was also lower, though changing winds may have affected readings.
Sinabung | Indonesia : Based on PVMBG observations, webcam and satellite images, and wind data, the Darwin VAAC reported that during 17-20 and 24 May ash plumes from Sinabung rose 4.3-8.8 km (14,000-29,000 ft) a.s.l. and drifted in multiple directions. BNPB reported a high-intensity eruption at the volcano on 20 May. An ash plume rose 4 km and drifted SE. There were 2,038 families (7,214 people) displaced to eight shelters, and an additional 2,863 people living in refugee camps. The Alert Level remained at 4 (on a scale of 1-4), with an exclusion zone of 7 km from the volcano on the SSE sector, and 6 km in the ESE sector, and 4 km in the NNE sector.
Turrialba | Costa Rica : OVSICORI-UNA reported that low-to-moderate amplitude tremor was recorded at Turrialba during 17-23 May. Small numbers of volcano-tectonic and long-period events were recorded during 18-19 May, and low-frequency and volcano-tectonic events were detected during 21-22 May. Ash emission were observed during 17-23 May, rising as high as 1 km above the vent. Ashfall was reported in El Tapojo and Juan Viñas (15 km SSE) during 17-18 May, and in Capellades (along with a strong sulfur odor) during 19-20 May.