The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, these notices are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of eruptions during the week, but rather a summary of activity that meet selected criteria. Carefully reviewed, detailed reports are published in the Bulletin of the Global Volcanism Network.

The Servicio Nacional de Geología y Minería (SERNAGEOMIN) reported that during 15-24 October surficial activity at Copahue increased based on analysis by Observatorio Volcánico de los Andes del Sur (OVDAS). Tremor signals slightly intensified on 15 October. Sulfur dioxide emissions increased on 15 October and averaged 2,900-3,000 tons per day (t/d) during 17-19 October, higher than the average of 2,400 t/d more typically observed. Sulfur dioxide emissions were detected with both satellite images and Differential Optical Absorption Spectroscopy (DOAS) instruments. Beginning on 16 October episodic intensifications of a thermal anomaly in El Agrio Crater were identified in satellite data with the most intense anomaly recorded on 19 October. Gas-and-steam emissions rose no higher than 300 m above the crater rim and contained ash starting on 17 October; the ash content was denser on 19 October. Gas-and-ash plumes on 19 October deposited ash in an area extending 2.9 km SE of the vent. By 24 October activity had decreased; sulfur dioxide emissions, a thermal anomaly, and ash emissions were no longer being detected. SERNAGEOMIN noted that an increase may occur again and raised the Alert Level to Yellow (the second lowest level on a four-color scale). SENAPRED declared a Yellow Alert (the middle level on a three-color scale) for residents of the Alto Biobío municipality and access to an area within 500 m of El Agrio Crater was restricted to the public. The Servicio Geológico Minero Argentino (SEGEMAR) maintained an Alert Level of Green (the lowest level on a four-color scale) for Argentina, based on Argentine Volcano Monitoring Observatory (OAVV) analysis. SEGEMAR noted that the crater lake had dried up during the previous few weeks due to seasonal changes in rainfall. Weekly averages of sulfur dioxide emissions were less than 2,000 t/d with a peak of 6,270 t/d on 16 October based on TROPOMI satellite data. Gas-and-steam plumes were visible during 20-24 October when weather conditions allowed for visual observations. Tremor levels decreased after 19 October; an increase recorded on 24 October may have been due to weather. SEGEMAR noted that a possible phreatic eruption could impact an area within 1 km of the crater.

Sources: Servicio Geológico Minero Argentino (SEGEMAR),Servicio Nacional de Geología y Minería (SERNAGEOMIN),Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that daily white emissions at Iya rose as high as 308 m above the cater rim and drifted in multiple directions during 23-29 October. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the active crater area.

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

The Darwin VAAC reported that an ash plume from Langila was identified in satellite images on 28 October rising to 2.1 km (7,000 ft) a.s.l. and drifting WSW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

The Alaska Volcano Observatory (AVO) reported that low-level unrest at Spurr was ongoing during 23-29 October. Several daily small earthquakes were recorded by the seismic network. No unusual activity was observed in mostly clear satellite or web camera data. Scientists visited Spurr on 24 October to perform pre-winter work including hardening the network and ensuring all systems were operational. During an overflight they observed vigorous steaming from the fumaroles in the summit crater and snow covering the vent at Crater Peak, a vent 3.5 km S of the summit. The Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest level on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that unrest at Taal continued during 22-29 October. Two phreatic events lasting 5-9 minutes long were recorded on 22 October. Hot fluids upwelling in the lake were observed and steam-and-gas plumes rose 1.5 km above the crater rim and drifted SE. Upwelling of hot fluids was again observed on 23 October; weather conditions often obscured views during 23-25 October. Four-minute-long tremor signals were recorded on 24 and 27 October. Steam-and-gas plumes rose 300-900 m and drifted NNE and NE during 26-27 October. The Alert Level remained at 1 (on a scale of 0-5), and PHIVOLCS reminded the public that the entire Taal Volcano Island was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 21-28 October. Nightly crater incandescence was visible in webcam images. Very small eruptive events were recorded during the first half of the week. On 21 October sulfur dioxide emissions were very high, averaging 4,000 tons per day. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 1 km away from both 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 18, 20, and 22-24 October. The volcano was obscured by weather clouds on the other days of the week. The Aviation Color Code remained at Yellow (the second level on a four-color scale). Dates are reported in UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Dukono was ongoing during 23-29 October. Daily gray-and-white ash plumes that were sometimes dense rose 100-700 m above the summit and drifted NE and E. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.

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

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate explosive activity was ongoing at Ebeko during 17-24 October. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions on 20 October generated ash plumes that rose as high as 2.5 km (8,200 ft) a.s.l. and drifted E. Satellite data indicated that either no activity was observed, or weather conditions prevented views. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick lava flow in Great Sitkin?s summit crater during 23-29 October. The lava flow had filled most of the summit crater with minor advancement in the N part of the E lobe. The local seismic network continued to detect small earthquakes associated with the ongoing eruption. Minor steaming from the lava flow was visible in webcam images on 28 October. Weather clouds often obscured webcam and satellite views of the summit. 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).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 23-29 October. Daily gray or white-and-gray ash plumes that were often dense rose 0.3-2 km above the summit and drifted W, NW, and NE. Some of the webcam images posted with the reports showed incandescence visible above the crater rim. 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.

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

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing unrest at Kanlaon during 22-29 October. The seismic network recorded 1-6 daily volcanic earthquakes. The summit was obscured by weather conditions daily. Sulfur dioxide emissions continued to be high, averaging 4,853-5,188 tonnes/day (t/d) during 26-27 October. A special notice issued on 28 October noted that summit emissions of sulfur dioxide measured with a Flyspec instrument averaged 10,074 tonnes/day (t/d), the fifth highest ever recorded at the volcano. Sulfur odors were reported in Masulog and Canlaon City (8 km ESE) proper and, to a lesser degree, in the neighborhoods of Panubigan and Binalbagan, Canlaon City. The Alert Level remained at 2 (on a scale of 0-5) and PHIVOLCS reminded the public to remain outside of the 4-km-radius Permanent Danger Zone and warned pilots not to fly close to the volcano.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)