Report for Etna
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.

Report for Whakaari/White Island
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.

Report for Ulawun
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.

Report for Marapi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity from Verbeek Crater at Marapi (on Sumatra) continued during 16-22 April. Ash plumes rose 200-1,000 m above the summit and drifted NE, E, SE, and S on 16, 19, and 21 April. An explosion was recorded at 2141 on 21 April but was not visually confirmed due to weather cloud cover. According to a news report a resident Padang Panjang City (11 km SW) said that the explosion was so loud that it shook the windows. A webcam image at 2212 on 21 April showed incandescent material being ejected above the summit. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 3 km away from the active crater.

Report for Merapi
The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 11-17 April. Seismicity remained at high levels. The SW lava dome produced 46 lava avalanches that traveled as far as 2 km SW down the Bebeng drainage, 30 that traveled as far as 2 km SW down the Krasak drainage, and 46 that traveled as far as 2 km W down the Sat/Putih drainage. Small morphological changes to the SW lava dome resulted from continuing effusion and minor collapses of material. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit, based on location.

Report for Semeru
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 16-22 April, with multiple daily eruptive events recorded by the seismic network. White-and-gray ash plumes rose 500-1,300 m above the summit and drifted in multiple directions; ash plumes were not visible on 18 April. Incandescence at the summit was visible in a 17 April webcam image. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 17 km from the summit, and to avoid other drainages including the Bang, Kembar, and Sat, due to lahar, avalanche, and pyroclastic flow hazards.

Report for Lewotobi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Lewotobi Laki-laki continued during 16-22 April. Dense gray ash plumes rose 2.5-3.5 km above the summit on 16 April and drifted multiple directions. Ash plumes during 17-18 April rose 500-700 m above the summit and drifted mainly N and NE; weather clouds sometimes obscured views. Multiple ash plumes per day were recorded during 19-22 April. Ash plumes rose as high as 3 km and drifted in multiple directions. An eruptive event that was recorded at 2359 on 20 April ejected incandescent material onto the upper flanks. According to a news report, the event was accompanied by a loud banging sound heard at the Lewotobi Laki-laki observation post, 4.9 km WSW. On 22 April ash-and-gas plumes were continuously emitted from approximately 1000 at least through 1554; dense gray ash plumes rose 1.3-1.5 km above the summit and drifted W and NW, though weather clouds sometimes obscured views. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 6 km away from the center of Laki-laki.

Report for Lewotolok
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 16-22 April. White steam-and-gas plumes rose as high as 100 m above the summit of the cone and drifted E and SE. Ash plumes rose 400 m above the summit and drifted SE on 17 April. Nighttime webcam images showed either incandescence at the summit or incandescent material being ejected above the summit. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the vent and 2.5 km away on the S, SE, and W flanks.

Report for Dukono
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.

Report for Ibu
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 16-22 April. Daily dense gray ash plumes rose 300-600 m above the summit and drifted in multiple directions. Nighttime crater incandescence was visible in a webcam images on 16, 18, and 21 April. The Alert Level remained at 3 (the second highest level on a four-level scale) and the public was advised to stay 4 km away from the active crater and 5 km away from the N crater wall opening.

Report for Kanlaon
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 16-22 April. The seismic network recorded 1-16 daily volcanic earthquakes and two periods of volcanic tremor (34 and 42 minutes long) on 15 April. Daily sulfur dioxide emissions ranged from 1,170 to 3,078 tonnes per day. Gas-and-steam emissions that occasionally contained ash generally rose as high as 200 m above the crater rim and drifted SW, W, and WNW. There were two ash emissions on 15 April (20 and 70 minutes long), and another on 20 April (31 minutes long); voluminous gas-and-ash plumes rose 600 m above the rim and drifted SW on 20 April. The Alert Level remained at 3 (on a scale of 0-5); the public was warned to stay 6 km away from the summit and pilots were warned not to fly close to the volcano.

Report for Bulusan
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).

Report for Suwanosejima
The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 14-21 April. Incandescence was observed nightly in webcam images. Eruptive activity generated emissions that rose 400 m above the crater rim. Ashfall was reported by the Suwanosejima Branch of the Toshima Village Office (3.5 km SSW). The Alert Level remained at 2 (the second level on a five-level scale) and the public was warned to be cautious within 1.5 km of the crater.

Report for Kuchinoerabujima
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.

Report for Aira
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.

Report for Yakedake
The Japan Meteorological Agency (JMA) lowered the Alert Level for Yakedake to 1 (on a scale of 1-5) at 1100 on 18 April, noting that seismicity has remind at low levels after a period of elevated seismicity was recorded during 3-9 March. JMA warned climbers to be alert to any changes at the volcano and to wear a helmet.

Report for Bezymianny
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.

Report for Klyuchevskoy
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.

Report for Sheveluch
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that lava extrusion may have continued at Sheveluch’s “300 years of RAS” dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 10-17 April. Daily thermal anomalies over the domes were identified in satellite images. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Report for Great Sitkin
The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 16-22 April. Small daily earthquakes were detected by the seismic network. Inflation of the lava flow and minor advancement at the E and SE margins were visible in radar data from 17 April. Minor steaming at the lava flow was visible on 21 April. Weather clouds often obscured views of the volcano. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale).

Report for Kilauea
The Hawaiian Volcano Observatory (HVO) reported that the eruption within Kilauea’s Kaluapele summit caldera, from two vents along the SW margin of Halema’uma’u Crater, continued at variable levels during 16-22 April. Both the N and S vents were strongly incandescent and produced gas emissions on 16 April. Later that evening at around 2110 incandescence at the N vent intensified and began to eject spatter at intervals of 10-20 seconds. Spatter bursts increased in size and frequency, and at around 2130 dome fountains 3-5 m high had formed. A lava pond in the crater rose and was visible at 2145, and by 2201 lava overflowed the crater and traveled short distances (up to 100 m) on the crater floor. Sulfur dioxide emissions were elevated. The activity ceased at 2321. Incandescence from the S vent disappeared when the N vent overflowed but returned once the flows ceased. Both the N and S vents were strongly incandescent and produced gas emissions during 17-20 April.

At around 0745 on 20 April a narrow lava flow was produced from the S vent. Lava fountaining to 2-3 m began soon after, and by 0915 lava flows had traveled about 1 km across the crater floor. After brief pauses during 0930-0943 and 1030-1050, followed by lava flows being fed by 5-m-high dome fountains. Lava flows and dome fountaining resumed after another break during 1110-1222, and then again ceased at 1244. Small gas-pistoning events occurred every 3-5 minutes and were superimposed upon the longer cycles of activity. Intermittent spattering at the N vent began at around 0130 on 22 April and increased in frequency. Lava overflowed the S vent at 0320, and by 0330 lava fountaining was occurring at both vents. Lava overflowed the N vent at 0347. By 0436 the fountain at the S vent was over 200 m high and the N vent fountain was more than 50 m high, feeding lava flows that cascaded down the vent flanks and onto the crater floor. Lava fountains at the N vent slightly grew through the day, rising as high as 60 m. The activity abruptly ceased at 1328, after lava had covered about 30 percent of the crater floor. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale).

Report for Poas
The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported frequent explosions and ash-and-gas plumes at Poás 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 José (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).