PHIVOLCS reported that a phreatic explosion occurred at 0458 on 19 October from the vents on Bulusan's upper SE flank. The seismic network recorded the event as an explosion-type earthquake that lasted nine minutes. Dense weather clouds obscured views although limited observations indicated that the plume rose 1 km. A 20-minute-long phreatic explosion occurred from the summit crater at 1234 on 21 October. A thin layer of ash was reported in Casiguran and Gubat, and trace amounts of ash fell in barangays in Barcelona, Casiguran, and Gubat. At 1531 on 23 October a 15-minute-long phreatic explosion from the summit vent produced an ash plume that rose 2.5 km and drifted WSW. Small pyroclastic flows traveled about 2 km down the flank. Trace ashfall was reported in multiple barangays in Irosin Town, ashfall 0.5 mm thick was reported in the municipality of Juban, and the most ash, 1 mm thick deposits, were found in barangay Puting Sapa, Juban. A second and much smaller explosion was recorded at 1539 from the SE vent and generated an ash plume that rose 500 m. Rumbling and a sulfur odor was noted in several nearby areas. The Alert Level remained at 1, indicating abnormal conditions and a 4-km-radius Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

AVO reported that an explosion at Cleveland was detected at 1310 on 24 October by both infrasound (air pressure) sensors and seismometers. Residents in Nikolski (75 km E) reported hearing the explosion. Weather clouds obscured satellite views although no eruption plume was detected above the cloud deck at 8.5 km (30,000 ft) a.s.l. AVO raised the Level of Concern Color Code to Orange and the Volcano Alert Level to Watch. Clear webcam views on 25 October showed intermittent, minor steam emissions possibly containing slight amounts of ash rising just above the crater rim.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

KVERT reported that, according to observers in Severo-Kurilsk (Paramushir Island) about 7 km E, a gas-and-steam plume continuing ash rose from Ebeko to an altitude of 1.5 km (4,900 ft) a.s.l. and drifted 15 km ENE on 20 October. The Aviation Color Code was raised to Yellow (the second lowest on a four-color scale). Later that day observers noted gas, steam, and ash plumes rising 1.3-1.4 km (4,300-4,600 ft) a.s.l. and drifting 10 km NE. Ground-based and satellite observations during 21-23 October indicated quiet conditions; the Aviation Color Code was lowered to Green on 24 October.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

On 19 October KVERT stated that moderate steam-and-gas emissions and an occasional weak thermal anomaly at Karymsky continued to be detected in satellite images. The Aviation Color Code was lowered to Yellow.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Based on analyses of satellite imagery, the Darwin VAAC reported that during 19-21 and 23-25 October ash plumes from Ulawun rose to altitudes of 2.7-3 km (9,000-10,000 ft) a.s.l. and drifted 25-110 km NW, W, and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 19 and 24-25 October ash plumes from Bagana rose to altitudes of 2.1-3 km (7,000-10,000 ft) a.s.l. and drifted NW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Based on multiple sources including webcam and satellite images, the Mexico City MWO, and Jalisco Civil Protection agency, the Washington VAAC reported that ash plumes from Colima rose to altitudes of 4.7-6.7 km (15,400-22,000 ft) a.s.l. and drifted N, NE, and SW during 18-20, 22, and 24 October.

On 21 October the Unidad Estatal de Protección Civil de Colima reported that lava continued to flow down the S flank. The lava flow was 2.3 km long, 320 m wide, and had an estimated volume of 21 million m³. Low-to-moderate explosions continued. The exclusion zone was maintained at 12 km in the Montegrande canyon (SSE) and 8 km on the other flanks.

Sources: Washington Volcanic Ash Advisory Center (VAAC), Unidad Estatal de Protección Civil de Colima

Based on analyses of satellite imagery, information from PVMBG, and model data, the Darwin VAAC reported that during 18-19 and 21-25 October ash plumes from Dukono rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted as far as 215 km E, NW, W, SW, and S.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

During 19-25 October HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kīlauea's Overlook vent; the lava lake rose as high as 6 m below the Halemaʻumaʻu floor. A small explosion from the lake on 19 October was triggered by a rockslide, and a slightly larger explosion on 20 October was caused by a collapse of a slice of the crater rim.

Webcams recorded incandescence from long-active sources within Puʻu ʻŌʻō Crater. The 61G lava flow, originating from a vent on Puʻu ʻŌʻō Crater's E flank, continued to enter the ocean near Kamokuna.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

KVERT reported that a Strombolian eruption at Klyuchevskoy continued during 14-21 October. Gas-and-steam emissions with variable amounts of ash rose from the summit crater and from the cinder cone in the Apakhonchich drainage on the E flank. A lava flow traveled down the Apakhonchich drainage. Satellite images showed a large and bright daily thermal anomaly at the volcano, and ash plumes from explosions that rose to altitudes of 5-6 km (16,400-19,700 ft) a.s.l. and drifted 300 km NW, E, and SE during 14 and 18-19 October. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 18-24 October seismicity at Nevado del Ruiz was characterized by a slight decrease in the number and magnitude of earthquakes compared to the previous week. Some seismic signals were associated with gas-and-ash emissions which were confirmed by webcam images, and Parque Nacional Natural los Nevados (PNNN) and SGC officials. A steam, gas, and ash plume rose 2 km above the crater and drifted W on 18 October. Two low-energy thermal anomalies were detected on 18 and 20 October. The Washington VAAC reported that on 19 and 20 October ash plumes rose to altitudes of 7.3 and 6.1 km (24,000 and 20,000 ft) a.s.l. and drifted NW and SW, respectively. The Alert Level remained at III (Yellow; the second lowest level on a four-color scale).

Sources: Servicio Geológico Colombiano (SGC), Washington Volcanic Ash Advisory Center (VAAC)

PVMBG reported that during 1 August-17 October seismicity at Papandayan fluctuated but decreased overall. Visual monitoring occurred from the Pakuwon Village post where observers noted white plumes rising at most 35 m above the crater. The Alert Level was lowered to 1 (on a scale of 1-4) on 19 October; residents and tourists were reminded not to approach the craters within a 500-m radius.

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

PVMBG reported that, although inclement weather conditions often prevented visual observations of Raung during 1 June-19 October, white plumes were occasionally seen rising as high as 300 m above the crater. Seismicity fluctuated but continued to decrease, and then was stable. The Alert Level remained was lowered to 1 (on a scale of 1-4) on 20 October, and the public was reminded not to approach the crater.

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

KVERT reported that during 14-21 October lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome. According to video and satellite data, explosions generated ash plumes that rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. and drifted 210 km NW, E, and SE during 14-16, 18, and 20 October. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

PVMBG reported that during 1-20 October brownish, reddish, and grayish gray plumes from Tengger Caldera's Bromo cone rose as high as 900 m above the crater and drifted E, NW, W, and SW. Seismic activity was dominated by constant tremor although the amplitude decreased. On 20 October the Alert Level was lowered to 2 (on a scale of 1-4); residents and visitors were reminded not to approach the crater within a radius of 1 km.

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

OVSICORI-UNA reported that during 18-22 October continuous passive ash emissions rose from Turrialba as high as 1 km above the vent and drifted NE and W. The activity was accompanied by stable, low-to-moderate amplitude tremor with a few brief intervals of rest. Ash fell in Siquirres (30 ENE), Guacimo (23 km NNE), Guapiles (21 km N), and Moravia (27 km W). During 23-25 October emissions were discontinuous and ash content was low; plumes drifted NW and W. Ashfall was reported in San José (36 km WSW), Tibás (35 km WSW), Guadalupe (32 km WSW), Curridabat (32 km WSW), Tres Ríos (27 km SW), Moravia, San Pedro (32 km WSW), and various areas of the Valle Central.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)