Volcano World

AVO lowered the Volcano Alert Level for the Atka volcanic complex to Normal (the lowest level on a four-level scale) and the Aviation Color Code to Green (the lowest color on a four-color scale) at 0734 on 9 April. The report noted that activity at the volcano had decreased following the small explosion at the summit crater of Korovin on 27 March, one of the volcanoes at the complex. Though occasional small earthquakes and weak volcanic tremor continued to be recorded, the activity was at background levels.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Eruptive activity at Barren Island continued according to notices from the Darwin VAAC. Ash plumes identified in satellite images during 2-3 April rose 0.9-1.5 km (3,000-5,000 ft) a.s.l. and drifted SW and W. Weather conditions prevented views on 4 April. A thermal anomaly over the summit was identified in Sentinel data on 30 March and 4 April.

Sources: Copernicus,Darwin Volcanic Ash Advisory Centre (VAAC)

A small vent at Etna?s Southeast Crater began emitting unprecedented quantities of volcanic gas puffs that formed vortex rings during the evening of 2 April. INGV issued a Volcano Observatory Notice for Aviation (VONA) at 2016 on 2 April raising the Aviation Color Code to Yellow (the second highest color on a four-color scale) due to increased signs of unrest. The Aviation Color Code was raised to Orange at 2030 because explosive activity at the summit craters was visible in webcam images; ash emissions were not produced. A series of six explosive events were recorded by the seismic network during 1501-1510 on 7 April. Coincident with the seismic signals a four-minute-long, dense ash emission from Bocca Nuova Crater rose to 5 km a.s.l., or about 1.6 km above the summit, and quickly dispersed to the S. A VONA issued at 1018 on 9 April noted sporadic activity at the summit craters.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

Instituto Geofsico-Escuela Politcnica Nacional (IG-EPN) reported that during 2 March-1 April an estimated 44 million cubic meters of lava had erupted at Fernandina, making the current eruption the largest in the last 15 years, surpassed only by the 2009 eruption. Fissure 13, located just below the crater rim on the upper SE flank, continued to be active during 2-9 April; the rate of lava effusion was about five cubic meters per second at least through 4 April, though the advancement rate of the distal end of the lava flow was variable. Sulfur dioxide emissions were generally at moderate levels, fluctuating between about 100 and 1,000 tons per day, though emissions were as high as around 1,650 tons per day on 4 April. Daily thermal anomalies over the lava flow continued to be detected and were variable in both number and intensity. The lava flows continued to advance down the flank and by 4 April were about 13.2 km long and about 1.3 km from the coastline. Based on observations from the Direccin del Parque Nacional Galpagos, the Ministerio del Ambiente, and Agua y Transicin Ecolgica the flows reached the ocean on 7 April. An 8 April satellite image showed plumes of gas and steam rising from the ocean entry.

Source: Instituto Geofsico-Escuela Politcnica Nacional (IG-EPN)

OVSICORI-UNA reported continuing emissions at Pos during 3-9 April. Vents on the nearly dry crater floor vigorously emitted plumes of gas and steam; ash was present in the plumes during 3-5 April and absent on the rest of the days. The plumes rose a few hundred meters above the crater rim and mainly drifted W, SW, and S and were often detected downwind in residential areas of Heredia and El Valle Central. Incandescence was visible from Boca A and Boca C during 3-4 April, and at Boca A during 4-5 April. A sulfur odor was reported in Heredia and El Valle Central during 3-4 April and in Sarch on 9 April. Weather conditions sometimes prevented visual observations.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

IMO reported that the eruption along the fissure within the Reykanes volcanic system continued during 3-9 April. Two cones produced lava flows during the beginning of the week, but by 8 April only the larger, main cone was active. Lava flowed mostly S and the flows thickened near the crater and slightly to the S where the flows were most active. On 7 April lava filled the main crater, overflowed the crater rim, and cascaded down the cone?s flank. Part of N crater rim collapsed at 2130 causing lava to flow N; the lava built up a mound, blocking the path, and by the next day most of the lava again flowed S. The average lava effusion rate decreased from about 6.6 cubic meters per second during 27 March-3 April to about 3.6 cubic meters per second during 3-8 April. During an overflight on 8 April observers confirmed that there had been a gradual decrease in the intensity of the eruption. The lava-flow field was an estimated 6.14 square kilometers with an approximate volume of 31.1 million cubic meters. Concurrent with a decrease in eruption intensity, inflation had accelerated. Seismicity continued to be at low levels and was concentrated between Sylingarfell and Stra-Skgfell, and in the W part of Grindavk. Sulfur dioxide emissions continued to be high around the eruption site and were detected in residential areas downwind. On 3 April the Civil Protection Emergency Level was lowered to the middle level on a three-level scale. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Sources: Almannavarnadeild rkislgreglustjra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management),Icelandic Meteorological Office (IMO)

Signs of unrest at Ahyi Seamount had not been observed in satellite images since 27 March when an area of discolored water was present near the seamount. Both the Aviation Color Code and the Volcano Alert Level were lowered to Unassigned at 0346 on 10 April due to the absence of activity and the lack of local monitoring stations.

Source: US Geological Survey

PVMBG reported that the eruption at Dukono was ongoing during 3-9 April. Gray-and-white ash plumes rose as high as 1 km above the summit and drifted SW, S, and SE during 3 and 7-9 April. According to the Darwin VAAC an ash plume rose to 2.4 km (8,000 ft) a.s.l., or about 1.6 km above the summit, and drifted SW on 4 April. Plumes were either absent or not observed due to weather conditions on the other days. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

KVERT reported that moderate explosive activity was ongoing at Ebeko during 28 March-4 April. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 28-29 March and 1 and 3-4 April generated ash plumes that rose as high as 4.5 km (14,800 ft) a.s.l. and drifted S and SE. A thermal anomaly was identified in satellite images on 29 March and 4 April; on other days there was no activity or weather conditions prevented views. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

INSIVUMEH reported that eruptive activity continued at Fuego during 1-9 April. Explosions were recorded daily, averaging 2-10 per hour on most days, when counts were reported. The explosions generated gas-and-ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as 30 km NW, W, and SW. Explosions caused frequent, daily block avalanches that descended various drainages including the Ceniza (SSW), Seca (W), Taniluy (SW), and Las Lajas (SE), and sometimes reached vegetated areas. Weak rumbling sounds and shock waves were reported on most days. Ashfall was reported in areas downwind during 4-7 April including El Porvenir (11 km SW), El Rodeo, Finca Palo Verde, Sangre de Cristo (8 km WSW), Yepocapa (8 km NW), Santa Sofa (12 km SW), Los Yucales (12 km SW), Panimach I and II (8 km WSW), and Morelia (9 km SW); ash possibly fell in La Soledad (11 km N), Acatenango (8 km E), Parramos (18 km NNE), and other nearby communities during 4-5 April. The explosions also ejected incandescent material up to 300 m above the summit during 5-6 April. In the afternoon of 8 April lahars descended the Las Lajas and Ceniza drainages, carrying tree branches, trunks, and blocks as large as 1.5 m in diameter.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)