Report for Gaua
The Vanuatu Meteorology and Geohazards (VMGD) reported that unrest continued at Gaua during September. Sulfur dioxide emissions were identified in satellite images during 7, 9-10, and 20 September and steam and/or gas emissions were visible in satellite images rising from the vent during 7, 9, 11, and 17-18 September. A very low thermal anomaly was detected on 14 September. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay away from the main cone.

Report for Ambae
The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambae during the month of September based on seismic and satellite data, webcam images, and field observations. Sulfur dioxide emissions were identified in satellite images during 1-10, 12-14, and 16-21 September. A very low-level thermal anomaly was also detected in satellite images during 11 and 20-22 September. Steam and/or gas emissions were visible in satellite and webcam observations on 12 September. The Alert Level remained at 2 (on a scale of 0-5), and the public was warned to stay outside of Danger Zone A, defined as a 2-km radius around the active vents in Lake Voui, and to stay away from drainages during heavy rains.

Report for Ambrym
The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambrym during September. A weak thermal anomaly was detected in satellite images on 4 and 12 September. Seismic data confirmed ongoing unrest. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside of Permanent Danger Zone A, defined as a 1-km radius around Benbow Crater and a 2-km radius around Marum Crater, and to stay 500 m away from the ground cracks created by the December 2018 eruption.

Report for Lopevi
The Vanuatu Meteorology and Geohazards Department (VMGD) reported that seismic data confirmed continuing unrest at Lopevi during September. Low-level thermal anomalies were identified in satellite images during 12-13 and 17 September. Small fumarolic steam plumes were continuously emitted from the summit crater on 22 September based on webcam images. The Alert Level remained at 2 (on a scale of 0-4).

Report for Yasur
The Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a level of “major unrest,” as defined by the Alert Level 2 status (on a scale of 0-5) during September. Sulfur dioxide gas emissions were identified in satellite images during 2-17 and 19-21 September, and low-level thermal anomalies were identified during 6-7, 9-12, 16-17, and 19 September. Field photos and webcam images indicated that explosions continued periodically, producing emissions of gas, steam, and/or ash during 3, 9-10, 12, 14, 16-19, 21, and 23-25 September. Seismic data confirmed continuing volcanic activity with explosions that were occasionally strong. The report warned that ejected material from explosions could fall in and around the crater. The public was reminded to not enter the restricted area within 600 m around the boundaries of the Permanent Exclusion Zone, defined by Danger Zone A on the hazard map.

Report for Marapi
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 24-30 September. Eruptive events at 1959 on 24 September and at 2116 on 26 September were recorded but weather conditions prevented visual confirmation. An eruptive event at 1831 on 26 September produced a dense white-and-gray ash plume that rose 1 km above the summit and drifted E. 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 19-25 September. The SW lava dome produced 5 lava avalanches that traveled as far as 2 km SW down the Bebeng drainage, 37 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 lava effusion and minor collapses. 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 24-30 September, with daily eruptive events recorded by the seismic network. Daily white-and-gray or gray ash plumes rose 400-900 m above the summit and drifted in multiple directions. The Alert Level remained at 2 (the second lowest level on a scale of 1-4). The public was warned to stay at least 3 km away from the summit in all directions, 8 km from the summit to the SE, 500 m from the banks of the Kobokan drainage as far as 13 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 daily white-and-gray or gray ash plumes with variable densities rose as high as 2 km above the summit of Lewotobi Laki-laki and drifted N, NW, W, and SW during 23-29 September. According to a news article the Fransiskus Xaverius Seda Airport (60 km W) was closed on 26 September through early 27 September; volcanic ash caused six flights to be canceled. PVMBG noted that seismic activity during the week was dominated by low-frequency earthquakes, non-harmonic tremor, and signals indicating eruptive events and emissions. The number of explosions fluctuated at moderate levels and the number of deep volcanic earthquakes declined. Tilt data indicated inflation at shallow depths and GNSS (Global Navigation Satellite System) data showed continuing deformation. At 1500 on 29 September the Alert Level was lowered to 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 24-30 September. On most days white-and-gray ash plumes rose 100-600 m above the summit of the cone and drifted W and NW; only white plumes rising to 100 m above the summit were observed on 27 September. Several nighttime webcam images showed Strombolian ejections of incandescent material above the cone and onto the flanks. The Alert Level remained at 3 (on a scale of 1-4) and the public was warned to stay 3 km away from the summit.

Report for Dukono
The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 24-30 September. White-and-gray gas-and-ash plumes rose as high as 700 m above the summit on most days and drifted E, NW, and W. White plumes rose as high as 200 m above the summit and drifted E and SW on 26 and 29 September. 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 24-30 September. Dense gray or white-and-gray ash plumes rose 300-700 m above the summit and drifted in multiple directions. Incandescence at the summit was visible in a few 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 Suwanosejima
The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 22-29 September. Incandescence was observed nightly in webcam images. Eruptive events during 23-28 September generated ash plumes that rose 1-1.6 km above the crater rim and drifted mainly N, NW, and E. Small amounts of ashfall were reported in Toshima Village (3.5 km SSW) on 27 September. Ash emissions were continuous from 2238 on 27 September to 0100 on 28 September. 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 22-29 September. Nightly crater incandescence was visible in webcam images. A very small eruptive event was recorded on 27 September. 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 Karymsky
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that explosions at Karymsky were last observed in August. In September activity was at moderate levels characterized by steam-and-gas emissions and a weak thermal anomaly identified in satellite images; weather clouds sometimes obscured views. On 25 September the Aviation Color Code was lowered to Yellow (the second 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 Krasheninnikov
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that the eruption at Krasheninnikov continued during 18-25 September. A daily large thermal anomaly over the volcano was identified in satellite images. Explosions at Northern Cone produced ash plumes that rose 2.4 km a.s.l., or nearly 600 m above the summit, and drifted 260 km SE and E during 23-25 September. A commercial satellite image on 25 September showed that lava flows had traveled 2.9 km NW, 2.8 km NE, and 3 km ENE. The upper half of the ENE flows were incandescent along with the main vent of Northern Cone. 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 Klyuchevskoy
The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that wind was no longer resuspending ash previously deposited on the N flank of Klyuchevskoy. Only fumarolic emissions were observed. The Aviation Color Code was lowered to Green (the lowest level on a four-color scale) on 25 September. Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified.

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 18-25 September. Daily thermal anomalies over the domes were identified in satellite images. Ash plumes were identified in satellite and webcam images rising to 5 km a.s.l. and drifting more than 150 km SE and NW during 18-19 September. Plumes of resuspended ash drifted 1,700 km E and SE during 23-25 September. 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 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 24-29 September. Satellite data indicated that the SE part of the flow slightly inflated. Advancement was detected around the SW, S, and SE margins of the flow; the fastest moving part of the flow advanced at a rate of about 5 m per day. Small daily earthquakes were detected by the seismic network daily along with rockfall signals. Weather clouds often obscured satellite and webcam views, though elevated surface temperatures were identified in 29 September satellite views. 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 Katmai
The Alaska Volcano Observatory (AVO) reported that on 27 September strong winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes dispersed unconsolidated ash up to 1.8 km (6,000 ft) a.s.l. to the SE. 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 23-29 September. Incandescence at both the N and S vents was visible overnight during the week and gas plumes continued to be emitted from them. Scientists did not see lava in the vents during an overflight on 24 September. Weak spattering and occasional flames at the N vent were visible during 27-28 September. Persistent glow from N vent overnight during 28-29 September was punctuated by nine gas-piston cycles of lava overflowing the cone and draining back into the cone. They were recorded at 2147 on 28 September and at 0215, at 0426, at 0512, at 0618, at 0632, at 0700, at 0740, and at 0814 on 29 September, and each lasted 5-10 minutes. There was intermittent but strong incandescence at the S vent. 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 Fuego
The Instituto Nacional de Sismología, Vulcanologia, Meteorologia e Hidrología (INSIVUMEH) reported that eruptive activity at Fuego continued during 23-30 September. Daily Strombolian explosions were recorded by the seismic network at rates of 5-10 per hour. The explosions generated daily gas-and-ash plumes that rose as high as 1.1 km above the summit and drifted as far as 40 km NW, W, and SW. Occasional rumbling sounds, shock waves, and/or sound associated with gas emissions were reported; the shock waves rattled buildings and structures in communities on the SW and W flanks during 23-24 September. Explosions ejected incandescent material 100-200 m above the summit during 27-30 September, sometimes showering the upper flanks with incandescent material. Daily block avalanches descended the flanks, including the Las Lajas (SE), Seca (W), Taniluya (SSW), Trinidad (SSW), Santa Teresa (W), and Ceniza (SSW) drainages, occasionally reaching vegetated areas. Ashfall was reported in areas downwind including Finca Palo Verde (10 km WSW), Yepocapa (12 km SW), Sangre de Cristo (8 km W), El Porvenir (11 km SW), Quisaché (8 km NW), and Soledad (11 km N) during 23-24 September, in Yepocapa during 24-25 September, in areas on the SW flank during 25-26 September, and in Panimache (8 km SW), Sangre de Cristo, Finca Palo Verde, and Yepocapa during 28-29 September.

Heavy rain generated lahars in multiple drainages during 22-23, 25, and 28 September. Special reports issued at 1655, at 1707, at 1736, and 1813 on 22 September noted that lahars descended the El Jute (ESE), Las Lajas, Ceniza, Zarco, Mazate, Seca, and Mineral (W) drainages. The lahars that descended the El Jute and Las Lajas drainages were hot and had a sulfur odor. On 23 September lahars descended the Santa Teresa, El Jute, Ceniza, and possibly the Las Lajas based on reports from 1410, 1440, and 1500. Reports issued at 1530 and 1601 on 25 September noted that lahars traveled down the Seca, Mineral, Ceniza, Zarco, and Mazate drainages. Lahars descended the Ceniza, Zarco, and Mazate drainages the next day based on a report from 1940 on 28 September. All of the lahars were characterized as a mixture of water and sediment that carried tree branches, trunks, and blocks as large as 3 m in diameter.

Report for Sabancaya
The Instituto Geofísico del Perú’s (IGP) Centro Vulcanológico Nacional (CENVUL) reported that daily gas-and-steam plumes at Sabancaya rose 300-1,300 m above the crater rim and drifted less than 10 km in multiple directions during 23-29 September. Thermal anomalies on the summit crater floor were detected almost daily. 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 Reykjanes
The Icelandic Meteorological Office (IMO) reported that by 23 September around 10 million cubic meters of magma had accumulated beneath Svartsengi since the last eruption within the Reykjanes volcanic system ended on 5 August. Data showed that magma was accumulating at around 4 km depth. The rate of magma accumulation was steady; model calculations based on deformation measurements indicated that by 27 September the volume may reach 11 million cubic meters, a volume that in some previous cases was followed by eruptions. Since the likelihood of an eruption had increased, IMO raised the Volcanic Alert Level System (VAL) to 2 (on a scale of 0-3) on 25 September and concurrently a risk assessment map of the area was also updated.