Report for Stromboli
INGV reported that Stromboli’s crater terrace activity was analyzed during 5-11 August through webcam views, and field inspections during 7-8 August. At least nine vents in Area N (north crater area, NCA) were active on 7 August, three of which had well-formed spatter cones, with Strombolian activity ejecting material 150 m high. A large scoria cone in Area C-S (South Central crater area) jetted material 200 m high. Lava from Area C-S vents continued to travel down the upper part of the Sciara del Fuoco, reaching 500-600 m elevation.
Report for Piton de la Fournaise
OVPF reported that a seismic crisis at Piton de la Fournaise began at 0700 on 11 August and was accompanied by rapid deformation. The locations of the earthquakes and area of deformation indicated that magma rose from deep under the SE edge of Dolomieu Crater to beneath the E and SE flanks. Tremor began around 1620, indicating the likely start of this year’s fourth eruption, though inclement weather conditions prevented visual confirmation. The Alert Level was raised to 2-2. On 12 August OVPF confirmed that fissures had opened in the E part of l’Enclos Fouqué, SE of the upper Grandes Pentes. Scientists saw two fissures, about 1.4 km apart, at 1,700 and 1,500 m elevation during an overflight on 13 August. Only the lowest elevation fissure was active. Three distinct cones along the fissure fed lava flows that merged into one which traveled to 665 m elevation and caused small fires as it burned local vegetation.
Report for Ulawun
RVO reported that during 7-8 August minor emissions of white vapor rose from Ulawun’s summit crater. Seismicity was dominated by low-level volcanic tremor and remained at low-to-moderate levels. RSAM values fluctuated between 400 and 550 units; peaks did not go above 700.
Report for Tangkubanparahu
PVMBG reported that during 5-11 August phreatic events at Tangkubanparahu's Ratu Crater continued to produced sometimes dense, gray-to-white plumes that rose as high as 200 m above the vent and ash plumes rose as high as 100 m. The emissions were accompanied by roaring. Ashfall was localized around Ratu Crater. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.
Report for Slamet
PVMBG reported that seismicity at Slamet significantly increased beginning in June, with 51,511 signals indicating emissions and 22 tectonic earthquakes recorded through 8 August. White plumes with variable density rose as high as 300 m above the crater rim.Tremor began to be recorded at the end of July with gradually increasing amplitude. In addition, notable inflation was detected at the end of July and long-term temperatures of hot springs showed an upward trend. The Alert Level was raised to 2 (on a scale of 1-4) and the public was warned to stay outside a radius of 2 km.
Report for Merapi
PVMBG reported that during 5-11 August the lava-dome volume at Merapi had decreased compared to the week before and was an estimated 461,000 cubic meters, based on analyses of drone images. Extruded lava fell into the upper parts of the SE-flank, generating a total of two block-and-ash flows that traveled as far as 1.2 km down the Gendol drainage on 4 and 6 August. Diffuse white plumes rose as high as 50 m above the summit on some days. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.
Report for Sangeang Api
The Darwin VAAC reported that during 7-13 August ash plumes from Sangeang Api were identified in satellite images rising to 2.4-3 km (8,000-10,000 ft) a.s.l. and drifting in multiple directions. The Alert Level remained at 2 (on a scale of 1-4).
Report for Karangetang
PVMBG reported that during 5-11 August lava continued to effuse from Karangetang’s Main Crater and travel down drainages on the W and SW flanks, producing incandescent avalanches that descended those same drainages. White plumes rose from the summit craters rose 50-100 m above the peak. The Alert Level remained at 2 (on a scale of 1-4).
Report for Dukono
Based on satellite and wind model data, and statements from ground-based observers, the Darwin VAAC reported that during 7-13 August ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted in multiple directions. Ashfall was reported on 8 August at the Galela Airport, Maluku Utara, 17 km NW. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Report for Ibu
PVMBG reported that during 7-12 August white-to-gray plumes rose 200-800 m above Ibu’s crater rim. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.
Report for Suwanosejima
JMA reported that volcanic earthquakes began to be detected at Suwanosejima on 4 August and volcanic tremors were occasionally recorded during 4-9 August. Four eruptive events occurred at Ontake Crater on 5 August and one on 6 August. Large blocks were ejected as far as 400 m and ash plumes rose as high as 1.5 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Report for Aira
JMA reported that during 5-13 August very small eruptive events were detected at Minamidake crater (at Aira Caldera’s Sakurajima volcano), though none of them were explosive. Crater incandescence was occasionally visible in webcams at night. The Alert Level remained at 3 (on a 5-level scale).
Report for Asosan
JMA reported that increased eruptive activity at Asosan that began on 28 July continued at least through 13 August. Ash plumes drifted N and NW, and crater incandescence was visible at night. Sulfur dioxide gas emissions were very high at 2,000-5,000 tons per day. The Alert Level remained at 2 (on a scale of 1-5).
Report for Asamayama
JMA reported that at 2208 on 7 August a small phreatic eruption at Asamayama produced an ash plume that rose higher than 1.8 km above the crater rim and drifted N. Blocks were ejected 200 m from the crater. The eruption lasted about 20 minutes and was the first since 19 June 2015. The Alert Level was raised to 3 (on a scale of 1-5). Ash fell in Tsumagoi Village and Naganohara Town, in the Gunma Prefecture. White plumes rose as high as 700 m above the crater rim during 8-13 August, and the amount of sulfur dioxide released was 90-200 tons per day.
Report for Sarychev Peak
SVERT reported that an ash plume from Sarychev Peak rose to 2.7 km (9,000 ft) a.s.l. and drifted 50 km SE on 11 August, based on Tokyo VAAC notices. The Aviation Color Code was raised to Yellow.
Report for Ebeko
Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions on 2 and 4 August that sent ash plumes up to 3 km (10,000 ft) a.s.l. and drifted SE. A thermal anomaly was identified in satellite images on those same two days. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Report for Karymsky
KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 2 and 4-6 August. Ash plumes drifted 180 km SE and NW during 3-5 August. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Report for Klyuchevskoy
KVERT reported that a weak thermal anomaly over Klyuchevskoy was visible in satellite images during 5-6 August. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Report for Sheveluch
KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 2-9 August. A diffuse ash plume rose to 2.5 km (8,200 ft) a.s.l. and drifted 40 km NW on 5 August. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Report for Semisopochnoi
AVO reported that during 7-13 August seismicity at Semisopochnoi remained elevated and was characterized by periods of continuous tremor and discrete low-frequency earthquakes. No unusual activity was observed in satellite images, though views were often cloudy. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.
Report for Shishaldin
AVO reported that during 7-13 August continuous, low-level tremor at Shishaldin was recorded by the seismic network and elevated surface temperatures were visible in satellite images. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Report for Veniaminof
AVO reported that seismic unrest at Veniaminof continued during 7-13 August with low-frequency earthquakes being common. Satellite and webcam views showed nothing unusual. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.
Report for Popocatepetl
CENAPRED reported that each day during 7-13 August there were 125-209 steam-and-gas emissions from Popocatépetl, some of which contained ash. As many as seven explosions were recorded daily, with the exceptions of 7 August (no explosion were detected) and 11 August (16 were documented). Two explosions on 13 August were characterized as major (at 0427 and 0453) and ejected incandescent material onto the flanks. The Alert Level remained at Yellow, Phase Two (middle level on a three-color scale).
Report for Nevados de Chillan
ONEMI and SERNAGEOMIN reported that during 8-13 August multiple explosions at Nevados de Chillán’s Nicanor Crater generated gas-and-ash plumes and ejected incandescent material around the crater. These explosions were recorded at 0438 on 8 August, at 2223 on 10 August, at 1831 and 1952 on 12 August, and at 0427, 1058, and 1116 on 13 August. Eruption plumes rose as high as 765 m above the summit. The Alert Level remained at Orange, the second highest level on a four-color scale, and residents were reminded not to approach the crater within 3 km. ONEMI maintained an Alert Level Yellow (the middle level on a three-color scale) for the communities of Pinto, Coihueco, and San Fabián; on 13 August they stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.
Report for Villarrica
POVI reported that a portion of the E edge of Villarrica’s summit crater rim collapsed between 9 and 12 August.