Volcano World

The Sezione di Catania - Osservatorio Etneo (INGV) reported continuing activity at Etna during 14-20 April with two episodes of Strombolian activity at SE Crater. The first episode began at 0900 on 15 April and progressively intensified until about 1130, when lava overflowed the crater and descended the SE flank; activity ceased at 1150. The lava flow was about 1.2 km long and reached 2,620 m elevation based on 17 and 18 April satellite images. The second episode began at 1905 on 18 April and progressively intensified until about 2330, with two lava flows overflowing the crater; one descended the SE flank along the same path as the 15 April flow, and the other descended the SW flank. Activity ceased at 0055 on 19 April.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that Strombolian activity at Klyuchevskoy began on 20 April. Incandescence at the summit was first observed at 1004 and continued to intensify through the day. The Aviation Color Code was raised to Yellow (the second lowest level on a four-color scale) at 2232.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

The Japan Meteorological Agency (JMA) reported that the number of shallow volcanic earthquakes increased beneath an area near Kuchinoerabujima?s Furudake Crater with 100 earthquakes recorded during 7-16 April. No changes to geothermal areas located in and around both Shindake and Furudake craters were observed during a field survey conducted on 11 April. Sulfur dioxide emissions were low, averaging 20 tons per day on 11 April, and no ground deformation had been detected since November 2023. The Alert Level was raised to 2 (on a scale of 1-5) at 2325 on 16 April; the public was warned that ejected blocks may land within 1 km of both craters, and pyroclastic flows may affect areas within 2 km of the W flank of Shindake Crater.

Source: Japan Meteorological Agency (JMA)

The Observatorio Vulcanolgico y Sismolgico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported frequent explosions and ash-and-gas plumes at Pos during 16-22 April. Weather clouds often prevented visual observations, though during daily periods of clearer weather the plumes were confirmed to have contained ash. Both seismic and acoustic data indicated that frequent small eruptions at varying intensities occurred through the week, a change from the continuous activity of the previous week; activity generally began decreasing on 11 April. Ash emissions rose around 200 m above the crater rim and drifted SW and WSW, primary from Boca C during the first part of the week, then from Boca A starting on 20 or 21 April. Incandescence at Boca A was sometimes visible during dark hours. Energetic explosions ejected blocks as high as the crater rim. Sulfur dioxide emissions measured by a Differential Optical Absorption Spectroscopy (DOAS) station averaged 230-439 tons per day (t/d), though the average was 1,217 t/d on 17 April. Notably, a strong explosive phase began at 1414 on 21 April and lasted for five minutes. A dense ash plume from Boca A rose 4.5 km above the crater rim and drifted SW, and hot ballistics (around 250 degrees Celsius) were ejected to the W. Weather clouds prevented clear views of the plume. According to a news article ash, gas, and incandescent material were ejected. Ash fell across the Valle Central to the SW, including in Zarcero (18 km W), Grecia (16 km SW), Alajuela (20 km S), Heredia (28 km SE), and San Jos (33 km SE), and on social media residents posted photos of ashfall on the streets, cars, and homes. Lower-energy ash emissions continued through the rest of the day, generating brown ash plumes at 1554, 1628, and 1721. Small eruptive events were recorded on 22 April. That same day field measurements of the gas emissions using a DOAS instrument yielded an average that exceeded 1,000 t/d. The volcano?s Alert Level remained at 3 (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest color on a four-color scale).

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) ,Tico Times

The Darwin Volcanic Ash Advisory Centre (VAAC) reported that a possible ash plume at Ulawun was observed by a pilot at 0730 on 21 April and rose to 3.7 km (12,000 ft) a.s.l. and drifted S. Weather clouds obscured satellite views.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

On 17 April GeoNet reported that during the previous few months gas-and-steam emissions at Whakaari/White Island more frequently contained ash. The webcams located at Whakatane and Te Kaha recorded an increase in ash content in the emissions during the last few weeks and minor amounts of ash were identified in satellite data as reported by the Wellington Volcanic Ash Advisory Center (VAAC). A hazy plume drifting downwind was visible from the mainland coast. Impact craters visible on the main crater floor during recent observation flights indicated that explosive activity had ejected rocks several hundreds of meters from the vent. Additionally, there were increases in temperatures (based on thermal infrared data) and sulfur dioxide emissions (detected by satellite and overflights). Recent activity was consistent with a low level of eruptive activity; the Volcanic Alert Level was raised to 3 (on a scale of 0-5) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale). GeoNet stated that the Alert Levels were reflective of the current level of activity, but there was uncertainty due to the current lack of consistent, usable, real-time monitoring data; GeoNet relies on remote cameras, satellite images, and periodic overflights to monitor Whakaari.

Source: GeoNet

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 14-21 April. Nightly crater incandescence was visible at Minamidake Crater in webcam images, and very small eruptive events were recorded during 14-18 April. On 17 April sulfur dioxide emissions averaged 900 tons per day. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both the Minimadake and Showa craters.

Source: Japan Meteorological Agency (JMA)

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that a thermal anomaly over Bezymianny was identified in satellite images during 10-17 April and that there were occasional avalanches of hot material. According to the Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS), incandescent debris avalanches descended mainly the E flank, and crater incandescence was often visible during dark hours. Ash plumes generated from these avalanches on most days rose as high as 3.1 km above the summit and drifted NNW, NW, W, and E. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are reported in UTC; specific events are in local time where noted.

Sources: Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS),Kamchatkan Volcanic Eruption Response Team (KVERT)

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported increased seismicity at Bulusan. Seismicity recorded from 0300 on 12 April until 2200 on 21 April consisted of 94 weak volcano-tectonic earthquakes indicating rock fracturing, another four low-frequency volcanic earthquakes indicating fluid movement. The earthquake locations were within 20 km depth, with about half characterized as shallow. Weak-to-moderate gas emissions rose from the summit crater and active vents. The Alert Level remained at 0 (the lowest level on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono continued during 16-22 April. White-and-gray ash plumes that were sometimes dense rose 600-1,500 m above the crater rim and drifted in multiple directions. Occasional rumbling and banging sounds were heard during 19-20 April. The Alert Level remained at Level 2 (on a scale of 1-4) and the public was warned to stay 4 km away from the Malupang Warirang Crater.

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