Volcano World

PHIVOLCS stated that unrest at Bulusan had increased, noting that 62 volcanic earthquakes were recorded during 7-10 May and 124 were recorded during 10-11 May. Inflation of the upper flanks first recorded on 6 March in tilt data was sustained. GPS data indicated short-term inflation starting in late February, though the long-term pattern since July 2019 showed deflation. The data suggested shallow hydrothermal processes. The Alert Level for Bulusan was raised to 1 on 11 May, reflecting abnormal conditions, and the public was reminded not to enter the 4-km-radius Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

SERNAGEOMIN noted that sulfur dioxide emissions and thermal anomalies at Nevados de Chilln?s Nicanor Crater had both increased in March, and inflation began on 27 March. During the second half of April the dome grew at a higher rate, with growth concentrated on the W part. The dome was 66 m high at the center. The L5 lava flow advanced and was about 940 m long, and 50 m thick near the flow front. The effusion rate increased on 28 April. During 2-5 May activity was characterized by increased crater incandescence and a series of intense explosions that destroyed part of the summit lava dome. Dense ash plumes rose above the crater. Block-and-ash flows traveled less than 400 m down the NE flank and pyroclastic flows traveled short distances SW. During 4-5 May the effusion rate increased and the L5 lava flow advanced. A new lava flow (L6) emerged on 5 May from the summit crater and descended 100 m down the NE flank. A high-temperature elongated deposit in between the L5 and L6 flows was visible in infrared images. The Alert Level remained at Yellow, the second lowest level on a four-color scale. ONEMI stated that Alert Level Yellow (the middle level on a three-color scale) remained in place for the communities of Pinto and Coihueco, noting that the public should stay at least 2 km away from the crater.

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

OVPF reported that the eruption at Piton de la Fournaise continued during 4-11 May. Both craters were active, producing lava flows that mainly traveled though lava tubes. Lava emerged from the end of the flow field, advancing E to 1,200 m elevation by 8 May, and setting fire to local vegetation. Minor inflation of the summit area was recorded. Lava fountaining was weak at the smaller vent to the SE and a small lava pond continued to occupy the crater of the larger cone, just NW a higher elevation. Gas plumes rose from both craters, though the plumes from the smaller crater were denser. An 11 May report stated that the larger cone was 35 m tall and 226 m in diameter at its base. The Alert Level remained at 2-2.

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

JMA reported that during 3-10 May incandescence from Minamidake Crater (at Aira Caldera?s Sakurajima volcano) was visible nightly. There were four explosions and four non-explosive events during 3-7 May, producing ash plumes that rose as high has 2.5 km above the summit and ejecting bombs 0.8-1.1 km away from the crater. Very small eruptive events were recorded during 7-10 May. The sulfur dioxide emission rate was 1,300 tons per day on 19 May. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Source: Japan Meteorological Agency (JMA)

Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 4-6 May that sent ash plumes to 2.5 km (8,200 ft) a.s.l. and drifted N and SE. A thermal anomaly was identified in satellite data on 5 May. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

INSIVUMEH reported that 5-12 explosions per hour were recorded during 4-11 May at Fuego, generating ash plumes as high as 1.1 km above the crater rim. Shock waves sometimes rattled buildings around the volcano. Ashfall was reported daily in several areas downwind, including Morelia (9 km SW), Panimach I and II (8 km SW), Santa Sofa (12 km SW), El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), and San Pedro Yepocapa (8 km NW). Block avalanches descended the Ceniza (SSW), Seca (W), Trinidad (S), Taniluy (SW), Las Lajas (SE), and Honda drainages, often reaching vegetated areas. Explosions ejected incandescent material 100-450 m above the summit during 4-8 May.

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

KVERT reported that a weak thermal anomaly over Karymsky was visible in satellite images during 29-30 April and 1 May; weather clouds prevented observations during 2-7 May. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

HVO reported that the W vent on the inner NW wall of Kilauea's Halema`uma`u Crater continued to supply the lava lake at a low rate during 5-11 May through a submerged inlet. The depth of the lake was 229 m by 11 May. Lava continued to circulate in the W part, though the active area continued to shrink. The E half of the lake remained solidified and comprised about 93 percent of the total area, based on thermal measurements acquired on 16 April. The sulfur dioxide emission rate was 200-300 tons per day during 5-7 May, and 150 tons per day on 10 May, continuing a downward trend that began in mid-April. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

IMO reported that the fissure eruption in the W part of the Krsuvk-Trlladyngja volcanic system, close to Fagradalsfjall on the Reykjanes Peninsula, continued during 5-11 May. On 2 May pulsating high jets of lava from crater 5 prompted authorities to widen the restricted zone because; ash and lava could be deposited several hundred of meters away. Cycles of lava jetting and effusion periodically continued during 3-7 May, with lava steadily enlarging the flow field. By 4 May the area of the flow field had grown to 1.41 square kilometers, and the total volume erupted was 23 million cubic meters. Activity was quiet for a period of time during 8-9 May, though IMO noted that fountaining quickly resumed during the morning of 9 May. High jets of lava occurred every 10 minutes, sometimes with jets rising as high as 300 m. Tephra (a few centimeters in diameter) was deposited as far as 1 km from the vent and small amounts of tephra were reported in Grndavk. Hot deposits have caused small vegetation fires within a few hundreds of meters around the eruption site. On 10 May gas plumes rose higher than 2 km a.s.l. The eruption area was closed due to local wildfires and unfavorable wind conditions. Very high fountains were visible in Reykjavik. On 11 May lava fountains again rose up to 300 m tall and were seen from the capital. The cone had grown to about 50 m high. The Aviation Color Code remained at Orange due to the lack of ash and tephra emissions.

Sources: Icelandic Meteorological Office (IMO),Icelandic National Broadcasting Service (RUV),Institute of Earth Sciences

PVMBG reported that mostly white plumes from Lewotolok rose as high as 600 m and drifted SE, W, and NW during 4-11 May. Gray-and-white plumes rose 500 m and drifted W, NW, and SE on 6 and 8 May. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit crater.

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