Report for Sheveluch
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing eruptive activity at Sheveluch’s “300 years of RAS” dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 11-18 December. A thermal anomaly was identified in satellite images during 14-15 and 17-18 December; the volcano was obscured by weather clouds on the other days. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC; specific events are in local time where noted.

Report for Kanlaon
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 16-23 December. The seismic network recorded 1-7 daily volcanic earthquakes. Gas-and-steam emissions of variable densities rose as high as 100 m above the crater rim and drifted NW, W, and SW; weather clouds obscured views on 18 December. Daily sulfur dioxide emissions ranged from 1,787 to 2,763 tonnes per day. Diffuse ash emissions rose 300 m above the summit and drifted NW during 0901-0929 and 1029-1107. Later that day a period of ash emissions began at 1605 and persisted for about two hours, sending plumes as high as 900 m above the summit that drifted NW. By the end of the day there had been four periods of ash emissions. The Alert Level remained at 2 (on a scale of 0-5); the public was warned to stay out of the 4-km-radius Permanent Danger Zone (PDZ) and pilots were advised to avoid flying close to the summit.

Report for Home Reef
Satellite images of Home Reef showed that between 17-22 December new lobes of lava advanced in multiple directions from a crater the center of the island. Flows to the E and SE each entered the ocean and extended the coastline by about 100 m. Near infrared data on 17 and 22 December showed thermal anomalies over the summit; the 22 December image showed brighter areas over the at least six lava flows in all sectors except the SW.

Report for Semeru
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 17-23 December, with daily eruptive events recorded by the seismic network. White-and-gray or gray ash plumes were observed daily rising 300-1,200 m above the summit and drifting in multiple directions; some eruptive events were not observed due to weather conditions. Minor incandescence at the summit on the upper SE flank was visible in several nighttime webcam images. According to a news article lahars were detected for three hours on 21 December. There were no reports of damage to villages caused by the lahars but a photo showed a truck that got stuck in the deposits as it crossed the Bondeli River. The Alert Level remained at 3 (the second lowest level on a scale of 1-4) and the public was warned to stay at least 5 km away from the summit in all directions, 13 km from the summit on the SE flank along the Kobokan drainage, and 500 m from the banks of the Kobokan drainage as far as 17 km SE of the summit.

Report for Whakaari/White Island
According to the Wellington Volcanic Ash Advisory Center (VAAC) a low-level ash plume at Whakaari/White Island was observed by a pilot and identified in satellite and webcam images rising more than 900 m above the summit. The Volcanic Alert Level remained at 2 (on a scale of 0-5) and the Aviation Color Code remained at Yellow (the second lowest level on a four-color scale).

Report for Popocatepetl
The Centro Nacional de Prevención de Desastres (CENAPRED) reported that eruptive activity continued at Popocatépetl during 16-23 December. The seismic network recorded 4-32 long-period events per day, accompanied by steam-and-gas emissions with occasional minor ash content that drifted NNE, NE, and E. In addition, the seismic network recorded 0-76 minutes of low-amplitude tremor daily; during 18-19 December there was a 70-minute sequence of low-amplitude signals indicting emissions. According to the Washington Volcanic Ash Advisory Center (VAAC) ash plumes visible in webcam and satellite images during 17-18 and 21 December rose 5.8-7 km (19,000-23,000 ft) a.s.l. (as high as 1.6 km above the summit) and drifted NE and NNE. The 21 December ash plume was characterized as large. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale) and the public was warned to stay 12 km away from the crater.

Report for Merapi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Merapi continued during 10-16 December. The SW lava dome produced 3-36 daily lava avalanches that traveled as far as 1.5 km SW down the Bebeng drainage, 1.8 km down the Sat/Putih drainage, and as far as 1.8 km SW down the Krasak drainage. A pyroclastic flow traveled 1.5 km down the flanks on 20 December. 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 Suwanosejima
The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 12-19 December. Incandescence was observed nightly in webcam images, and eruption plumes rose as high as 800 m above the crater rim. Ashfall was reported in Toshima Village (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 Aira
The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 15-22 December. Nightly crater incandescence was visible in webcam images and small eruptive events were occasionally detected. Sulfur dioxide emissions were characterized as high, averaging 2,800 tons per day on 19 December. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to be cautious within 2 km of both the Minimadake and Showa craters.

Report for Katmai
The Anchorage Volcanic Ash Advisory Center (VAAC) reported that during 16-17 and 20 December plumes of unconsolidated ash in the vicinity of Katmai and the Valley of Ten Thousand Smokes were visible in satellite images rising to 1.8 km (6,000 ft) a.s.l. Plumes drifted SE on 20 December. The ash was originally deposited during the Novarupta-Katmai eruption in 1912. The Volcano Alert Level remained at Normal (the lowest level on a four-level scale) and the Aviation Color Code remained at Green (the lowest level on a four-color scale).

Report for Kilauea
The Hawaiian Volcano Observatory (HVO) reported that the eruption within Kilauea’s Kaluapele summit caldera, characterized by episodic fountaining, incandescence, and intermittent spatter from craters along the SW margin of Halema’uma’u Crater, continued at variable levels during 16-22 December. Incandescence at both the S and N vents was visible during dark hours on most nights, though sometimes weather conditions prevented clear views. Seismic signals showed pronounced tremor bursts every 3-12 minutes during 16-17 December, possibly related to gas pistoning. Continuous, low level volcanic tremor signals were recorded during the rest of the week. Sulfur dioxide emission rates averaged 3,400 tonnes per day (t/d) on 17 December; the rate was somewhat elevated relative to emission rates of 1,200-1,500 t/d typically observed during non-fountaining periods. Incandescence was continuous at both vents during 21-22 December; nearly-continuous spattering occurred at one side of the N vent and the S vent produced intermittent spatter. 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 Dukono
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 17-23 December. Daily white-and-gray gas-and-ash plumes rose as high as 800 m above the summit and drifted E. 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 17-23 December. Daily white-to-gray or gray ash plumes rose 200-900 m above the summit and drifted in multiple directions; weather conditions occasionally prevented visual confirmation. Incandescence at the summit was visible in several nighttime webcam images. The Alert Level remained at 2 (the second lowest level on a four-level scale) and the public was advised to stay 2 km away from the active crater and 3.5 km away from the N crater wall opening.

Report for Ahyi
On 19 December the US Geological Survey reported that there were no definitive signs of unrest at Ahyi Seamount during the previous week. One low-confidence detection from Ahyi's direction was observed in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi) on 17 December. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Report for Yellowstone
The Yellowstone Volcano Observatory (YVO) reported that a small hydrothermal explosion occurred at Black Diamond Pool, in Yellowstone’s Biscuit Basin thermal area, at 0923 on 20 December based on webcam images. The Volcano Alert Level remained at Normal (the lowest level on a four-level scale) and the Aviation Color Code remained at Green (the lowest color on a four-color scale).

Report for Marapi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 17-23 December. White emissions rose as high as 150 m above the summit and drifted E and SE during 17 and 20-21 December; weather conditions sometimes prevented visual observations. Eruptive events were recorded at 2115 on 18 December and at 1247 on 19 December though weather conditions prevented visual confirmation. 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 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 December. The dome continued to slowly inflate and there was minor advancement at the margins of the flow. Seismicity was low, though a data outage that began on 20 December degraded seismic monitoring. Elevated surface temperatures consistent with lava effusion were identified in satellite data daily or almost daily. 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 Sabancaya
The Instituto Geofísico del Perú’s (IGP) Centro Vulcanológico Nacional (CENVUL) reported eruptive activity at Sabancaya during 15-22 December. The seismic network detected 8-14 daily earthquakes indicating the movement of magma and gases. An explosion on 16 December generated a gas, steam, and ash plume that rose 1.3 km above the crater rim. Six thermal anomalies at the bottom of the crater were identified in satellite images. The next day, on 17 December, an explosion produced a gas, steam, and ash plume that rose 1.2 km above the crater rim. Three thermal anomalies at the bottom of the crater were identified in satellite images. Daily gas-and-steam plumes rose as high as 1.3 km above the crater rim during the rest of the week and drifted in various directions within 10 km. There were 1-2 thermal anomalies identified in satellite images each day during 20-22 December. The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay outside of a 12 km radius from the summit.

Report for Purace
The Servicio Geologico Colombiano (SGC) reported continuing eruptive activity at Puracé during 17-23 December. Seismicity was characterized by pulses of tremor, long-period signals indicating fluid movement, and periods of continuous tremor. The seismicity was located at depths of less than 2 km and was related to internal movement of gases as well as emissions. Low-magnitude earthquakes indicating rock fracturing were located beneath Puracé and Piocollo volcanoes, within 3 km of the craters, at depths of 1-3 km. Gas-and-ash emissions, 2-7 per day, were associated with some seismic signals and visible in webcam images rising 600-1,700 m above the summit and drifting NW, W, and SW. Significant sulfur dioxide emissions detected in satellite data dispersed within 250 m of the crater. Elevated temperatures in the crater area continued to be detected and were possibly associated with the emissions of hot gases. White gas-and-steam emissions, first observed on 18 November, continued to rise from the fissure on the inner N wall. Ashfall was reported in Cristales (NW) and in the area of the Puracé Indigenous Reserve Cabildo (NW) during 16-17 December and in Coconuco (12 km WNW) and in Chapa (28 km SW) of the municipality of Sotará (23 km W) during 17-18 December. A gas odor was reported in Chapa and ashfall was noted in the Río Negro sector and at the Paletará Indigenous Council House (16 km SW) during 18-19 December. The Alert Level remained at Orange (the second highest level on a four-color scale) and the public was warned to stay away from the crater.

Report for Reventador
The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that eruptive activity continued at Reventador during 16-23 December. Seismic data was not available due to transmission problems. Ash-and-gas plumes visible in webcam and/or satellite images were reported daily rising as high as 1.3 km above the crater rim and drifting in multiple directions. Minor amounts of ash fell in Santa Rosa (30 km SSW), Linares, and El Chaco (35 km SSW) during 19-20 December. Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Orange (the second highest level on a four-color scale).

Report for Sangay
The Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN) reported that the eruption continued at Sangay during 16-23 December. The seismic network recorded 110-328 daily explosions. Ash-and-gas plumes were observed in satellite images on a few days during the beginning of the week rising 800-900 m above the summit and drifting mainly S, SW, and W. Weather clouds often obscured views, especially during the second part of the week. The Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale).

Report for Krasheninnikov
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that eruptive activity at Krasheninnikov continued during 11-18 December. A large thermal anomaly over the volcano was identified in satellite images during 12, 15, and 17-18 December; weather clouds obscured views on the other days. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified.

Report for Fuego
The Instituto Nacional de Sismología, Vulcanologia, Meteorologia e Hidrología (INSIVUMEH) reported that eruptive activity at Fuego continued during 16-23 December. Daily Strombolian explosions recorded by the seismic network, at rates of 4-12 per hour, generated gas-and-ash plumes that rose as high as 1.1 km above the summit and drifted as far as 30 km in multiple directions. Occasional rumbling sounds, shock waves, and/or sounds associated with gas emissions were reported. Explosions occasionally ejected incandescent material as high as 300 m above the summit and showered the upper flanks with incandescent material. Incandescent block avalanches descended the Las Lajas (SE), Santa Teresa (W), Taniluya (SSW), and Ceniza (SSW) drainages, sometimes reaching vegetated areas. Ashfall was reported in areas downwind including Panimaché I and II (8 km SW), Morelia (10 km SW), and Yepocapa (8 km NW) during 16-17 December, in Panimaché I and II and Finca Paloverde (10 km SW) during 17-18 December, and in San Pedro Yepocapa and other areas on the SW flank during 20-21 December. During the early afternoon on 18 December lahars descended the Ceniza, Zarco, and Mazate drainages, carrying tree branches, trunks, volcanic material, and blocks as large as 3 m in diameter.