A helicorder plot from a station on Pagan showed that seismic signals from a source at or near the Ahyi seamount stopped at 1610 on 8 May. An additional isolated event was reported at 1810.

Source: Matthew Haney, Alaska Volcano Observatory via Bill Chadwick, Oregon State University's Marine Science Center and NOAA/PMEL EOI Program, personal communication

PVMBG reported that during 2-8 May white plumes rose as high as 650 m above Merapi. Thumping noises continued to be reported from multiple observation posts. Seismicity fluctuated but remained above background levels. The Alert Level remained at 2 (on a scale of 1-4) on 29 April.

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

CONRED and INSIVUMEH reported that activity at the Santa María's Santiaguito lava-dome complex increased on 9 May. Pyroclastic flows descended the E and SE flanks, and a dense ash plume rose to an altitude of 7.6 km (25,000 ft) a.s.l. Ashfall was reported in areas at least 20 km away, including Las Marías, San Marcos (10 km SW), Palajunoj (18 km SSW), El Faro (SW flank), La Florida (5 km S), Patzulín, and Quetzaltenango (18 km WNW); about 130 people were evacuated from these areas due to persistent airborne ash. A deep notch left in the crater between the E and NE flanks channeled a pyroclastic flow which traveled 7 km into the Nima I drainage (S flank). Deposits in the drainage were estimated to be a million cubic meters; secondary explosions in the drainage were caused by the interaction of water and these hot deposits.

INSIVUMEH noted that activity returned to a normal range on 10 May, with 2-3 explosions per hour generating ash plumes that rose 800 m and drifted W. On 11 May explosions produced ash plumes that rose 800 m, drifted SW, and caused ashfall in San Marcos and the El Rosario Palajunoj finca.

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

PVMBG reported that during 1-30 April diffuse white plumes from Tengger Caldera's Bromo cone rose 50 m above the crater. Seismicity increased during 15-30 April. From 1 to 4 May seismicity again increased and denser white plumes rose as high as 250 m. On 4 May the Alert Level was raised to 2 (on a scale of 1-4). Residents and visitors were warned not to approach the crater within a radius of 1 km.

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

JMA reported that a small non-explosive eruption from Showa Crater at Aira Caldera’s Sakurajima volcano occurred during 7-9 May. Incandescence from the crater was detected at night. A very small eruption at Minamidake Crater at 1151 on 8 May produced a plume that rose 400 m above the crater rim. The Alert Level remained at 3 (on a scale of 1-5). The Tokyo VAAC reported that during 10 and 12 May plumes rose to altitudes of 2.4-5.5 km (8,000-18,000 ft) a.s.l. and drifted W, SE, and E. On 13 May a pilot observed an ash plume that rose to an altitude of 1.2 km (4,000 ft) a.s.l.

Sources: Japan Meteorological Agency (JMA), Tokyo Volcanic Ash Advisory Center (VAAC)

SVERT reported that satellite images of Chirinkotan showed gas-and-steam emissions on 7 May. Cloud cover obscured views on the other days during 5-12 May. The Aviation Color Code remained at Yellow.

Source: Sakhalin Volcanic Eruption Response Team (SVERT)

SVERT reported that satellite images over Snow, a volcano of Chirpoi, detected a thermal anomaly on 7 and 9 May. Cloud cover obscured views on other days during 5-12 May. The Aviation Color Code remained at Yellow.

Source: Sakhalin Volcanic Eruption Response Team (SVERT)

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 8-9 and 12 May ash plumes from Dukono rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75-110 km WNW, W, and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

INGV reported that weak Strombolian activity at Etna's New Southeast Crater (NSEC) continued through 9 May. Some explosions ejected incandescent pyroclastic material a few tens of meters above the crater rim that rarely fell onto the outer flanks.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

KVERT reported that Vulcanian and Strombolian activity continued at Karymsky during 2-8 May. Satellite images detected a thermal anomaly on the volcano every day except during 3-4 May, days cloud cover obscure views. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

During 7-13 May HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kīlauea's Halemaʻumaʻu Crater. Gas emissions remained elevated. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas; smaller particles may have been dropped several kilometers away.

At Puʻu ʻŌʻō Crater, glow emanated from spatter cones on the N and S portions of the crater floor, and from the lava pond in the NE spatter cone. The S spatter cone periodically erupted lava flows that overflowed on the N flanks and extended from the S base of the cone. The N cone ejected spatter. The Kahauale’a 2 lava flow continued to advance, with breakouts from the main stalled lobe, and burn adjoining forest. On 5 May geologists mapped the farthest point of activity, 8.6 km NE of Pu’u 'O'o.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

PVMBG reported that during January-8 May diffuse white plumes rose 25-50 m above Anak Krakatau. Seismicity continued to be dominated by shallow and deep volcanic earthquakes, as well as signals indicating emissions. The Alert Level remained at 2 (on a scale of 1-4). Residents and visitors were warned not to approach the volcano within 1 km of the crater.

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

According to SNET, the Ministerio de Medio Ambiente y Recursos Naturales (MARN) reported that on 10 May San Miguel emitted small amounts of ash. Ashfall, less than 1 mm thick, was observed in areas between the Parque de las Placitas and Placitas.

Source: Servicio Nacional de Estudios Territoriales (SNET)

KVERT reported that during 2-8 May lava-dome extrusion onto Shiveluch’s SE flank was accompanied by ash explosions, incandescence, hot avalanches, and fumarolic activity. Satellite images showed a bright thermal anomaly daily. Video images showed ash plumes rising to altitudes of 7-9.5 km (23,000-31,000 ft) a.s.l. and drifting 60 km NW at 1150 on 13 May. Later that day, at 1300, satellite images detected an ash plume that rose to altitudes of 5-8 km (16,400-26,000 ft) a.s.l. and drifted 90 km NW. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

AVO reported that although cloud cover occasionally prevented web-cam and satellite observations of Shishaldin's summit area during 7-13 May, periods of elevated surface temperatures and minor steaming were observed. A report from 9 May noted that dark ash-covered snow near the summit was visible on an unspecified day during the past week. A continuous “tremor-like” signal detected during 0430-0630 on 13 May coincided with a distinct increase in surface temperatures, possibly indicating a Strombolian eruption. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

IGP's Observatorio Volcanologico de Arequipa (IGP-OVA) and Observatorio Vulcanológico del INGEMMET (OVI) reported that during 7-12 May gas-and-ash plumes, sometimes with only minor amounts of ash, rose 0.6-3 km above the crater. Ash fell in various towns downwind of the plumes including Querapi (4 km S), Ubinas (6.5 km SSE), Escacha, Anascapa, San Miguel, and Tonohaya. Significant ashfall was reported in Santa Rosa de Phara on 8 May.

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