Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 26 April-2 May 2017

Bagana | Bougainville (Papua New Guinea) : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 26-28 April ash plumes from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted N and NE.

Bezymianny | Central Kamchatka (Russia) : KVERT reported gas-and-steam activity at Bezymianny during 21-28 April, and a daily thermal anomaly identified in satellite images. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Cleveland | Chuginadak Island (USA) : AVO reported that satellite images of Cleveland acquired during 28 April-2 May showed that the lava dome in the summit crater had widened and grown taller. AVO further noted that dome extrusion had occurred with little to no detectable seismicity. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Colima | Mexico : On 28 April the Centro Universitario de Estudios e Investigaciones de Vulcanologia – Universidad de Colima reported that during the previous week seismic data revealed 34 high-frequency events, 26 long-period events, 2.5 hours of tremor, 8 landslides, and one low-intensity explosion. During fieldwork on the N part of the volcano, scientists found deposits of ballistics within 1.9 km of the crater. A higher density of deposits was found to the NNE, and deposits from pyroclastic flows were noted as far as 1.5 and 1.7 km N of the crater.

Dukono | Halmahera (Indonesia) | 1.693°N, 127.894°E | Elevation 1229 m

Based on analyses of satellite imagery, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 26 April-2 May ash plumes from Dukono rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted W and 280 km E.

Ebeko | Paramushir Island (Russia) : KVERT reported that during 23-26 April several explosions at Ebeko were observed by residents of Severo-Kurilsk (Paramushir Island) about 7 km E. Ash plumes rose as high as 2.1 km (6,900 ft) a.s.l. Minor amounts of ash fell in Severo-Kurilsk on 25 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that at 1820 on 26 April lava began effusing from a vent on the S side of Etna’s New Southeast Crater (NSEC), traveling to the base of the cone. Around 2220 Strombolian activity ejected material from the vent and the lava flow headed towards the Valle del Bove. A lava flow on the N side of the cone began at 0220 on 27 April and traveled NE towards the Valle del Leone. Ash emissions were visible at 0320. Strombolian activity began to diminish around 1230 and eventually ceased. The lava flows advanced until around 1600; phreato-magmatic explosions occurred in areas where the NE flow interacted with snow.

Fuego | Guatemala | 14.473°N, 90.88°W | Elevation 3763 m

INSIVUMEH reported that beginning at 1700 on 24 April a hot lahar descended Fuego’s Río Ceniza (SSW) drainage, carrying blocks 2 m in diameter, branches, and tree trunks. The lahar was heard up to 1 km away. During 29 April-2 May explosions generated ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as15 km W and SW. Some of the explosions produced shock waves felt within a 10-km radius. Ash fell in Sangre de Cristo (8 km WSW) and possibly other areas. Incandescent material was ejected as high as 200 m above the crater rim.

Kick ’em Jenny | North of Grenada : The University of the West Indies (UWI) Seismic Research Centre (SRC) reported that seismic activity at Kick ’em Jenny increased on 29 April. A high-amplitude signal lasting 25 seconds was recorded by stations on Grenada and Montserrat. This signal followed an increase in the number of background events associated with the volcano. The report reminded the public of the 5-km maritime exclusion zone.

Kilauea | Hawaiian Islands (USA) : During 26 April-2 May 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, 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. A growing lava delta is building where the lava enters the water; a small collapse of the delta on 27 April was indicated by the presence of a large dark plume. Surface lava flows were active above the pali.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly was identified in satellite images over Klyuchevskoy daily during 21-28 April. Ash plumes drifted about 125 km SW during 22-23 and 25 April. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Nevado del Ruiz | Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 25 April-2 May seismicity at Nevado del Ruiz continued to indicate unrest; the number and magnitude of events were higher compared to the previous week. Significant amounts of water vapor and gas continued to be emitted. Gas, steam, and ash plumes rose 1.2 km above the crater rim on 26 April and drifted NW and SW. A low-energy thermal anomaly was identified on 28 April. The Alert Level remained at III (Yellow; the second lowest level on a four-colour scale).

Nevados de Chillan | Chile : The Buenos Aires VAAC reported that on 29 April a webcam recorded a puff rising from Nevados de Chillán and dissipating rapidly

Popocatepetl | Mexico : Each day during 25 April-2 May CENAPRED reported 26-109 steam and gas emissions from Popocatépetl, sometimes containing ash, and crater incandescence at night or in the early morning. Around seven explosions were detected almost each day, with as many as 15 counted during 26-27 April (from mid-morning to mid-morning). Explosions generated plumes that consisted of water vapor and gas, with low ash content, and during 26-27 April they ejected tephra as far as 100 m NE of the crater. The Alert Level remained at Yellow, Phase Two.

Reventador | Ecuador : During 25 April-2 May IG reported a high level of seismic activity including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador. Steam, gas, and ash plumes rose around 500 m above the crater rim and drifted W and SW on most days. On 25 April incandescent blocks were observed rolling 800 m down the SW and SE flanks. Crater glow was noted through 28 April. Weather clouds prevented visual observations during 29 April-1 May.

Rinjani | Lombok Island (Indonesia) : PVMBG reported an increase of volcanic tremor at Rinjani on 28 April, with a pattern similar to the one recorded just prior to the 27 September 2016 eruption. The Alert Level remained at 2 (on a scale of 1-4); the public was warned not to approach the crater within a 1.5-km radius.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that during 24-30 April seismicity at Sabancaya slightly declined compared to the previous week, with an average of 33 explosions recorded per day. Ash plumes rose as high as 3.2 km above the crater rim and drifted more than 40 km SE. Based on webcam images, satellite views, and seismic data the Buenos Aires VAAC reported sporadic gas-and-ash puffs during 25 April-2 May. Strong ash plumes rose to an altitude of 7.9 km (26,000 ft) a.s.l. (or 2.4 km above the crater rim) and drifted SE on 26 and 28 April.

San Miguel | El Salvador : SNET reported that during 27-28 April RSAM values at San Miguel fluctuated between 106 and 176 units (typical background levels average 50 units). At 1532 on 27 April a strong gas plume rose 1.2 km above the crater rim.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 21-28 April lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. A thermal anomaly over the dome was identified in satellite images daily. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Sinabung | Indonesia : Based on PVMBG observations, satellite images, and wind data, the Darwin VAAC reported that during 26-30 April and 2 May ash plumes from Sinabung rose to altitudes of 3.3-4.6 km (11,000-15,000 ft) a.s.l. and drifted in multiple directions.

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