Report for Etna
INGV reported continuing episodes of lava fountaining, intra-crater explosive activity, and discontinuous ash emissions at Etna’s Southeast Crater (SEC) during the week of 29 March-4 April, though weather conditions often prevented visual observations. Gas emissions rose from the other summit craters and occasional explosive activity was visible; puffs of ash sometimes rose from Voragine Crater during 31 March-2 April.

At 0707 on 31 March a loud explosion was followed by several ash puffs, marking the beginning of the 17th lava-fountaining episode since they began on 16 February. At around 1100 a thermal anomaly at the S base of SEC was visible during an overflight and in thermal camera images. Explosive activity increased by late afternoon and several lava flows effused from the S-base vent. The main part of the flow traveled towards the Valle del Bove with other smaller flows traveled S and SW. Two other vents at the S base had opened by evening and one ejected spatter a few tens of meters high. Periods of lava fountaining began through the night, and the main lava flow descended the W wall of the Valle del Bove. Strombolian activity intensified at 1950, with an eruption plume that rose to 1.2 km (4,000 ft) a.s.l. and drifted SSW. Lava fountaining began at around 0100 on 1 April. At 0218 lava overflowed the E rim of SEC and headed towards the Valle del Bove, running parallel to the flows from the S base.

Lava fountains continued to be visible during the morning of 1 April and intense Strombolian activity produced dense ash plumes that drifted S. By 0940 the eruption plume had risen to 9 km (29,500 ft) a.s.l. and drifted SSW. Lava fountaining ceased around 1000 and the eruption plume rose to 5.5 km (18,000 ft) a.s.l. and drifted S. Ash fell in Milia, Nicolosi, and Catania and lapilli (1 cm in diameter) fell in Rifugio Sapienza. Lava effusion and flow advancement continued; lava from the S base of SEC spread out like a fan. A series of loud bangs were audible in the late morning and ash emissions continued until the afternoon. Lava overflowed the E rim of SEC at 1040, and a SSE flow entered the Valle del Bove at the SW wall. Explosive activity began to decline at 1320, and effusive activity waned overnight during 1-2 April.

Report for Langila
Based on analyses of satellite imagery and wind model data, the Darwin VAAC reported that on 5 April an ash plume from Langila rose to 1.5 km (5,000 ft) a.s.l. and drifted SW.

Report for Sinabung
PVMBG reported that the eruption at Sinabung continued during 31 March-6 April. Weather conditions sometimes prevented visual observations of the volcano, though daily white fumarolic plumes were visible rising as high as 500 m above the summit. Avalanches were detected daily by the seismic network and observed traveling 500-1,500 m down the E and SE flanks. An eruptive event produced a gray ash plume that rose 500 m above them summit on 1 April. Pyroclastic flows went as far as 1.5 km down the E and SE flanks. Ash plumes rose 0.7-2 km during 2-5 April and mainly drifted E and SE. The Alert Level remained at 3 (on a scale of 1-4), with a general exclusion zone of 3 km and extensions to 5 km in the SE sector and 4 km in the NE sector.

Report for Merapi
BPPTKG reported that the lava dome just below Merapi’s SW rim and the lava dome in the summit crater both continued to grow during 26 March-1 April. The SW rim lava-dome volume was an estimated 1,060,000 cubic meters on 1 April, with a growth rate of about 13,400 cubic meters per day, and continued to shed material down the flank. A total of 14 pyroclastic flows traveled a maximum of 1.8 km down the SW flank. Incandescent avalanches, recorded 158 times, traveled as far as 1.1 km down the SW flank. The summit lava dome had grown to 70 m tall and produced one incandescent avalanche. Minor ashfall was reported in Ngadirojo, Stabelan (4 km NW), Takeran, Tlogolele (5 km NW), Selo (3 km NNW), Pos Babadan (4 km NW), and Pasar Talun (12 km W). The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 5 km away from the summit.

Report for Tengger Caldera
PVMBG reported that during 30 March-5 April white steam-and-gas plumes rose 50-700 m above the summit of Tengger Caldera’s Bromo cone. The plumes were white to gray during 1-2 April. The Alert Level remained at 2 (on a scale of 1-4), and visitors were warned to stay outside of a 1-km radius of the crater.

Report for Raung
PVMBG reported that daily gray-and-white ash plumes rose 50-500 m above Raung's summit during 31 March-5 April and drifted N and S. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Report for Lewotolok
PVMBG reported that the Strombolian eruption at Lewotolok continued during 30 March-6 April. Gray-and-white ash plumes rose as high as 700 m above the summit and drifted in multiple directions, though rainy weather conditions prevented visual observations during 2-3 and 5 April. Incandescent material was ejected 300-500 m above the summit and 500 m SE during 30-31 March; eruptive events were recorded by the seismic network on the other days but not visually confirmed. Rumbling was occasionally noted. According to news articles secondary lahars from Cyclone Seroja destroyed homes, and impacted as many as 300, in several villages to the SW; mud-and-debris flows and flooding severely impacted other parts of Indonesia and killed at least 70 people. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 4 km away from the summit crater.

Report for Dukono
Based on satellite and wind model data, the Darwin VAAC reported that during 31 March-6 April ash plumes from Dukono rose to 2.4 km (8,000 ft) a.s.l. and drifted E, SE, and SSE. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Report for Suwanosejima
JMA reported that during 30-31 March large volcanic bombs were ejected at least 41 times from Suwanosejima's Ontake Crater as high as 800 m above the crater rim and to distances as far as 1 km. The Alert Level was raised to 3 (on a 5-level scale) at 0330 on 31 March and the public was warned to stay outside a 2 km radius of the crater. The increased activity prompted an overflight that same day where scientists confirmed several hundred high-temperature bomb deposits with a thermal camera within a 1 km radius. Explosions at 2205 on 30 March and 0257 on 31 March ejected bombs onto the S and SE flanks, respectively. Grayish-white emissions rose from the crater. After 1500 eruption plumes rose as high as 1.4 km above the crater rim. The number of explosions decreased; two per day were recorded during 1-2 April and one was recorded on 3 April. The Alert Level was lowered to 2 on 5 April and the public was warned to stay 1 km away from the crater.

Report for Aira
JMA reported that during 29-30 March explosions at Minamidake Crater (at Aira Caldera's Sakurajima volcano) produced ash plumes that rose as high as 2.7 km above the crater rim and ejected bombs 600-900 m away. An explosion was recorded on 4 April. An explosion at 0641 on 5 April ejected bombs 800-1,100 m away from the crater and generated an ash plume that rose up to 3 km above the crater rim. The Alert Level remained at 3 (on a 5-level scale).

Report for Ebeko
Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 25 and 28-29 March that sent ash plumes up to 2.5 km a.s.l. (8,200 ft) and drifted in different directions. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Report for Karymsky
KVERT reported that explosions at 1130 on 3 April likely caused ash plumes to rise to 8.5 km (27,900 ft) a.s.l. above Karymsky and drift NE, based on satellite data. The Aviation Color Code was raised to Orange (the second highest level on a four-color scale).

Report for Sheveluch
KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 28 March-2 April. On 3 April a plume of re-suspended ash rose to 2.5 km (8,200 ft) a.sl. and drifted 250 km ESE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Report for Semisopochnoi
AVO reported that a small plume from Semisopochnoi’s North Cerberus crater was visible in a satellite image on 31 March. Steam obscured the crater during the first part of 1 April. Later that day an ash plume was visible, and was followed by a sulfur dioxide plume an hour later. At 2200 a plume rose to an altitude below 3 km (10,000 ft) a.s.l. No activity was identified in partly cloudy images during 2-6 April. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Report for Gareloi
AVO reported that a loss of operation and communication with all seismic stations on Gareloi was likely due to snow cover. Both the Aviation Color Code and the Volcano Alert Level were changed to Unassigned, reflecting the lack of this data to detect unrest. The observatory noted that regional infrasound networks, lightning detection, and satellite images will be used to monitor and detected unrest.

Report for Tanaga
AVO reported a loss of operation and communication with all but two seismic stations on Tanaga, likely caused by snow cover. Both the Aviation Color Code and the Volcano Alert Level were changed to Unassigned, reflecting the inability to locate earthquakes to detect unrest. Monitoring will continue with the remaining seismic stations, regional infrasound networks, lightning detection, and satellite images.

Report for Shishaldin
AVO reinstated the Green Aviation Color Code and the Normal Volcano Alert Level for Shishaldin on 2 April, after several seismic stations again became operational following a months-long outage, thus improving the observatory’s monitoring capability.

Report for Veniaminof
AVO reported that during 31 March-1 April clear satellite and web camera images of Veniaminof showed no signs of emissions. On 2 April the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. Satellite data showed elevated surface temperatures, especially over the flank-vent lava flows through 4 April. Low-level ash emissions were recorded by the webcam on 5 April, prompting AVO to raise the Volcano Alert Level and Aviation Color Code to Watch and Orange, respectively. Tephra deposits were visible to the SE.

Report for Kilauea
HVO reported that the W vent on the inner NW wall of Kilauea's Halema`uma`u Crater continued to supply the lava lake during 31 March-6 April. Lava flowed at a low rate from the main vent into the lake through crusted-over channels and submerged inlets. The total depth of the lake measured about 225 m and lava continued to circulate in the W part; the E half of the lake remained solidified and expanded toward the W. The sulfur dioxide emission rate was 1,200 tons/day on 1 April. HVO field crews observed weak spattering from two areas at the W vent during 1-2 April. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Report for Pacaya
INSIVUMEH reported that explosions at Pacaya’s Mackenney Crater during 30-31 March produced gas-and-ash plumes that rose 1.8 km above the summit and drifted up to 50 km S, SW, W, and NW. Explosions ejected blocks as high as 150 m above the summit. Lava flows on the W flank advanced to 3 km long and were near La Breña; the flows overtook an unoccupied building on the Campo Alegre farm that was used for monitoring and visitor services. The flow front was about 500 m from the town of El Patrocinio. Incandescent blocks detached from the end of the lava flow and set fire to vegetation. During 31 March-2 April explosions ejected incandescent blocks as high as 225 m above the summit. Ash plumes rose 500 m and drifted 20 km S and SW. The SW-flank lava flows remained active. Explosions continued during 3-6 April, with ash plumes rising as high as 1 km and drifting 6-20 km W, SW, and S. The lava flow continued to be active on the SW flank, setting fire to local vegetation. Strombolian activity ejected material 300 m high during 5-6 April.

Report for Ubinas
Instituto Geofísico del Perú (IGP) reported that during 29 March-4 April there were 11 volcano-tectonic earthquakes at Ubinas with magnitudes less than 1.8, and a few seismic signals indicated emissions. Sporadic steam-and-gas plumes rose as high as 200 m above the crater rim. On 5 April the Alert Level was lowered to Green (the lowest level on a four-color scale).

Report for Soufriere St. Vincent
University of the West Indies Seismic Research Centre (UWI-SRC) and National Emergency Management Organisation (NEMO) reported that the lava dome in Soufrière St. Vincent’s main crater continued to slowly grow during 31 March-6 April, expanding to the N and S. Gas-and-steam continued to rise from the top of the dome, as well as along the contact with the pre-existing 1979 dome. A swarm of volcano-tectonic (VT) earthquakes began at 0638 on 5 April. The number and frequency of the VTs increased until about 0830 and then stabilized. The rate declined at around 1400 and then significantly dropped at 1600, though small VT events continued to be detected through 1800. The events were located at depths of 6 km, slightly deeper than the swarm events recorded during 22-25 March, located at revised depths of 3-5 km. Several reports of felt events came from nearby communities, including Fancy and Chateaubelair. The largest event, a M 3.5, was recorded at 0920 and felt by local residents. The swarm was more intense than the previous one, with an average rate of about 50 earthquakes per hour compared with 1.5 per hour during 22-25 March. The Alert Level remained at Orange (the second highest level on a four-color scale).

Report for Krysuvik-Trolladyngja
IMO reported that the small eruption in the W part of the Krýsuvík-Trölladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 31 March-6 April. Video and visitor photographs showed spattering and lava fountaining from the two cones, and lava flows from both cones moved W and S within the Geldingadalur valley. A new fissure, 100-200 m long, opened about 700 m NE of the Geldingadalur cones around noon on 5 April. During a helicopter overflight, scientists observed a gas plume rising from the new fissure and a fast-moving lava flow descending into the Meradalir valley to the SE. On 6 April lava from the second fissure was advancing at a rate of 7 cubic meters per second; lava-flow rates at the Geldingadalir site averaged 5.5 cubic meters per second. Around midnight during 6-7 April a third fissure opened in between the first two; all three were oriented NE-SW. Earlier on 6 April field teams had observed a landslide in same area. Lava from the third fissure mostly flowed SW into Geldingadalur. The Aviation Color Code remained Orange due to the lack of ash and tephra emissions.