At 0622 on 5 May an eruption at Ibu generated an ash plume that rose at least 600 m above the crater rim and drifted N and NE, based on information from the Darwin VAAC and PVMBG. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Based on satellite data, KVERT reported that during 28 April and 2-3 May explosions at Karymsky generated ash plumes that rose as high as 5.5 km (18,000 ft) and drifted 150 km NE and SE. A weak thermal anomaly over the volcano was visible on 3 May. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

On 2 May HVO noted that the intrusion of magma into Kīlauea's lower East Rift Zone (ERZ) continued, with deformation and frequent earthquakes (many felt by residents). Small cracks formed on some of the roads in and adjacent to Leilani Estates. Seismicity at Puʻu ʻŌʻō Crater remained elevated after floor collapses which began on 30 April. Short-lived ash plumes periodically rose from the crater. The lava flows on the pali near the Royal Gardens subdivision were sluggish. Deflation at the summit accelerated around midday, accompanied by a drop in the level of the lava lake.

On 3 May the intensity of the ERZ seismicity decreased slightly, and the eastward migration of hypocenters slowed or ceased; deformation continued. The lava level in Overlook crater dropped over 30 m, though spattering in the lake continued. At 1030 ground shaking from a M 5 earthquake S of Puʻu ʻŌʻō caused rockfalls and possibly a collapse in the crater; an ash plume rose from the crater and drifted SW. More ground cracks in the E part of Leilani Estates formed that afternoon; hot white and blue fumes rose from the cracks. Lava spatter and gas bursts began erupting from 150-m-long fissures just after 1700 and ended around 1830. Lava flows spread less than 10 m, and strong sulfur dioxide odors were noted. The lava lake in the Overlook Crater dropped an additional 37 m.

By the morning of 4 May three fissures were active; fissure 2 opened at 0100 and fissure 3 opened around 0600. Spatter was ejected as high as 30 m and lava flows were traveling short distances. Large, loud bubble bursts occurred at fissure 3. Ash plumes from intermittent collapses at Puʻu ʻŌʻō continued to rise above the crater, and the 61 G lava flow was no longer being fed. A M 6.9 earthquake occurred at 1233, centered on the S flank. Fissures 4 and 5 opened at 1039 and 1200, respectively, and by 1600 there were six, each several hundred meters long. The sixth fissure was on the E edge of the subdivision. The Hawaii Emergency Management Agency stated that multiple agencies were assisting with the mandatory evacuation of residents (about 1,700) in the Leilani Estates and Lanipuna Gardens subdivisions. A temporary flight restriction was declared for most of lower Puna. The report noted dangerously high concentrations of sulfur dioxide.

Based on satellite InSAR data, the summit caldera floor subsided about 10 cm during 23 April-5 May. Corresponding to this deflationary trend, the summit lava lake in Overlook crater had dropped to about 128 m below the crater rim since 30 April. Summit seismicity increased during 4-5 May coincident with the M 6.9 earthquake; about 152 events (M 2-3) were recorded. Rockfalls from the inner crater walls produced ash plumes that rose above the Halemaʻumaʻu crater rim on 5 May. New ground cracks on Highway 130 opened on 5 May, and at dawn fissure 7 formed. By mid-afternoon fissure 7 stopped erupting, and the 8th fissure opened at 2044 near fissures 2 and 7. Lava fountains from fissure 8 rose as high as 70 m, and in other areas were as high as 100 m. A lava flow from fissure 7 traveled 260 m NE. The lava lake in Overlook Crater continued to drop.

The eruption from one or two fissures was continuous during 5-7 May, and ‘a’a lava flows from fissure 8 advanced 0.9 km NNE by 1000 on 6 May. HVO warned that poor air quality from sulfur dioxide gas emissions, and smoke plumes from burning asphalt and houses was a health concern. Strong gas emissions rose from the fissures during 6-7 May, though lava effusion was minimal overnight. New cracks crossed Highway 130 west of the eruption site, and some others widened. The level of the summit lava lake continued to drop, and by 7 May was 220 m below the crater rim. Two new fissures emerged on 7 May. The first (fissure 11) opened at about 0930 in a forested area SW of Leilani Estates, and was active for about three hours. The second (fissure 12) opened at about 1220 between fissures 10 and 11. By 1515 both new fissures were active, and the W end of fissure 10 was robustly steaming. According to a news article, lava had covered an area about 36,000 square meters.

Lava effusion at night during 7-8 May was minimal, and by around 0700 on 8 May the ERZ eruption had paused. The fissure system was about 4 km long and continued to strongly emit gas. Ash plumes generated by falling rocks in Overlook crater continued to produced ash plumes. On 8 May the Office of the Mayor stated that 35 structures had been destroyed, and lava covered. HVO maps show the locations and numbers of the fissures.

Sources: US Geological Survey Hawaiian Volcano Observatory (HVO), Hawaii Emergency Management Agency, Hawaii County Civil Defense Agency

On 2 May at 0703 an eruption at Marapi produced a dense, gray ash plume that rose 4 km above the crater rim and drifted SE. The Alert Level remained at 2 (on a scale of 1-4). Residents and visitors were advised not to enter an area within 3 km of the summit.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Badan Nacional Penanggulangan Bencana (BNPB)

Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) raised the Alert Level for Osorno to Yellow (the second lowest level on a four-color scale) on 8 May, due to a gradual increase in the number and magnitude of seismic events recorded during 1-30 April. Earthquakes were concentrated on the NNW flank. The largest of the 294 total events was a M 3, located 2 km NW of the crater at a depth of 3.3 km.

Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI), Servicio Nacional de Geología y Minería (SERNAGEOMIN)

OVPF reported that the eruption at Piton de la Fournaise which began on 27 April from fissures at Rivals Crater continued through 8 May. Spattering was weak at the highest-elevation vent of the three. During fieldwork on 3 May scientists observed spattering from the central vent. Lava breakouts frequently occurred from a well-developed lava tube originating at the central vent. During 5-7 May activity was mainly confined to the lava tube, though the lava-flow front had not significantly advanced. The central vent had completely closed over by 6 May. Fires on and at the foot of the rampart were reported on 7 May. Tremor intensity had decreased during the previous few days but stabilized on 8 May.

Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)

JMA reported that there were seven events and 15 explosions at Minamidake crater (at Aira Caldera’s Sakurajima volcano) during 1-7 May. Tephra was ejected as far as 1.3 km from the crater, and ash plumes rose as high as 2.8 km above the crater rim. The Alert Level remained at 3 (on a 5-level scale).

Source: Japan Meteorological Agency (JMA)

Based on analyses of satellite imagery and model data, the Darwin VAAC reported that on 8 May a possible ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

AVO reported that a small explosion at Cleveland was detected in seismic and infrasound data at 2149 on 4 May. The event produced a small ash cloud that rose as high as 6.7 km (22,000 ft) a.s.l. and drifted SE. The Aviation Color Code and the Volcano Alert Level were raised to Orange/Watch. No additional significant activity led AVO to the lower the levels back to Yellow/Advisory on 6 May.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Based on analyses of satellite imagery, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 2-8 May ash plumes from Dukono rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted NE and E.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 1-3 May that sent ash plumes as high as 2.8 km (9,200 ft) a.s.l. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Based on webcam and satellite observations KVERT reported that at 1150 on 8 May an ash plume from Klyuchevskoy rose to altitudes of 5-5.5 km (16,400-18,000 ft) a.s.l. and drifted 105 km SSE. The Aviation Color Code was raised to Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

INSIVUMEH reported that during 1-2 May Strombolian explosions at Pacaya’s Mackenney Crater ejected material as high as 50 m above the crater rim. A 500-m-long lava flow advanced NW towards Cerro Chino. Nighttime crater incandescence was visible, and rumbling was heard in areas within 2-3 km. Activity increased on 4 May, with explosions ejecting tephra as high as 80 m. The lava flow continued to advance and by 6 May was 600 m long. Strombolian explosions ejected material 15 m above the crater rim, and nighttime incandescence continued to be present.

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

Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that explosive activity at Sabancaya increased compared to the previous week; explosions averaged 25 per day during 30 April-6 May. The number of long-period events and signals indicating emissions increased. Gas-and-ash plumes rose as high as 2 km above the crater rim and drifted 40 km N, NE, and E. The MIROVA system detected four thermal anomalies, and on 6 May the sulfur dioxide gas flux was high at 2,662 tons/day. The report noted that the public should not approach the crater within a 12-km radius.

Sources: Instituto Geológico Minero y Metalúrgico (INGEMMET), Instituto Geofísico del Perú (IGP)

INSIVUMEH reported that explosions at Santa María's Santiaguito lava-dome complex, detected by the seismic network during 1-2 and 5-6 May, generated ash plumes that rose 600-700 m and drifted SW. Avalanches of material descended the SE flank of the lava dome.

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

KVERT reported that a weak thermal anomaly over Sheveluch was identified in satellite images on 28 and 30 April and 2 May. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

The Tokyo VAAC reported explosions at Suwanosejima on 2 and 4 May, based on JMA notices and satellite data.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)