KVERT reported that activity at Bezymianny increased on 21 July and then escalated on 24 July. Lava-dome extrusion significantly increased on 21 July, causing collapses of the E part of the lava dome and subsequent hot avalanches of material. Activity continued and on 22 July the Aviation Color Code was raised to Orange (the third level on a four-color scale). Extrusion and collapses continued through 24 July with ash plumes continuing to rise 2-3 km a.s.l. and drift at least 70 km SW. A strong explosive eruption began at 1510 on 24 July, prompting KVERT to raise the Aviation Color Code to Red at 2002. The explosions produced a large ash plume that initially rose to 9.6 km (31,500 ft) a.s.l. and then to 12 km (39,400 ft) a.s.l.; the plume drifted 300 km ESE. Pyroclastic flows descended the flanks. By 0035 on 25 July the explosive phase had ended so the Aviation Color Code was lowered to Orange. Effusion at the lava dome continued and viscous lava extruded onto the dome’s flanks. The activity was accompanied by notable steam-and-gas emissions and the descent of hot avalanches. Ash clouds generated on 24 July were visible in satellite images drifting 2,500 km SE until 25 July and 1,800 km SW until 27 July. The Aviation Color Code was lowered to Yellow at 2317 on 28 July. Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

INGV reported that activity at Etna’s summit craters continued during 24-28 July. Volcanologists conducted a field inspection of the summit area on 24 July, the day after intense activity that included Strombolian explosions and lava fountaining at Voragine Crater, and lava overflows at Bocca Nuova Crater. Explosive activity at Voragine Crater occurred at intervals of 35-40 minutes during the inspection and ejected material beyond the crater rim. Lava flows originated from three breaches along Bocca Nuova Crater’s WNW, W, and SW rim and continued to advance. The WNW flow traveled the farthest, reaching 2,905 m elevation, followed by the W and SW flows that reached 2,950 and 3,026 m elevations, respectively. The total volume of the lava flows that breached the crater rim, the flows that pooled within the crater, and ejected pyroclastic deposits, were estimated to be 2.4 x 10^6 cubic meters. Activity at Voragine Crater on 25 July was characterized by intermittent explosive activity and a period of Strombolian activity.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

KVERT reported moderate levels of activity at Karymsky during 18-25 July. A thermal anomaly over the volcano was identified in satellite images during 19, 21-23, 25 July; weather clouds obscured views on the other days during the week. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Iceland Met Office (IMO) reported that electrical conductivity levels in the Skálmur River, which drains from the Sandfellsjökull glacier on the E part of the Mýrdalsjökull ice cap that covers Katla, began to increase late on 26 July. Increased seismicity within the Katla caldera began to be detected around 0600 on 27 July. Unrest significantly increased at around 1100 and a jökulhlaup (a glacier-outburst flood) began in the river at around 1320. Reports indicated increased sulfur odors originating from Mýrdalsjökull, specifically in Hólaskjól. As a precaution, and to account for the possibility of volcanic unrest, at 1554 IMO raised the Aviation Color Code to Yellow, the second lowest level on a four-color scale. The flood water flowed over a 1-km-long section of Highway 1 (also known as the Ring Road), damaging the road in several places, and washing away part of the road located next to the Skálmur River bridge. According to a news article local authorities closed the road between Víkur and Kirkjubæjarklausturs and evacuated Sólheimajökull, an area near the glacier, and a service area the end of the Sólheimajökull road. The peak flow rate may have been as high as 1,000 cubic meters per second, making the jökulhlaup significantly larger than previous events in 2011 and 1950. Electrical conductivity levels indicated that the flooding had significantly decreased later that night, though the report noted that it may be days before the rivers return to seasonally normal levels. At 1031 on 29 July IMO lowered the Aviation Color Code to Green, noting that activity at Mýrdalsjökull had returned to normal levels, and water levels and electrical conductivity in the Skálmur River had decreased.

Sources: Icelandic Meteorological Office (IMO), Icelandic National Broadcasting Service (RUV), Icelandic National Broadcasting Service (RUV)

PVMBG reported temperature increases at all three of Kelimutu’s crater lakes and water-color changes at two of them based on 14 and 28 July field observations and webcam images. The variations were most significant at Crater I (Tiwu Ata Polo). The color of the water changed from brown on 14 July to blackish brown on 28 July and the temperature increased from 19 to 22 degrees Celsius. Water bubbles and/or upwelling in the NE part of the lake were observed on both days. At Crater II (Tiwu Koofai Nuwamuri) the water color was turquois green on 14 July. Light-yellow to golden-yellow sulfur deposits were floating on the water in the central part on the lake and along the S edge of the water on 14 July. There was a minor sulfur odor and the water temperature was 25 degrees Celsius. By 28 July the water color had changed to light blue and light-yellow sulfur deposits were scattered on the surface in the central part of the lake and along the margins. A sulfur odor was present and gas plumes rose as high as 100 m above the water’s surface. The water temperature had increased to 33 degrees Celsius. The color of the lake water at Crater III (Tiwu Ata Bupu) remained at dark green during 14-28 July, but the temperature increased from 16 to 19 degrees Celsius. Though the activity indicated increased activity within the hydrothermal system, the Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 250 m from the crater rims.

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

HVO reported that localized earthquake and ground deformation rates in around Kīlauea's upper East Rift Zone significantly increased twice during 22-23 July. The Volcano Alert Level was raised to Watch (the third level on a four-level scale) and the Aviation Color Code was raised to Orange (the third color on a four-color scale) at 0406 in response to the increases, and then lowered back to Advisory and Yellow, respectively, at 0904 because of a significant decrease in the activity; seismicity and ground deformation rates remain elevated but at a lower intensity. Pulses of increased seismicity were detected during 24-25 July; over 500 earthquakes were recorded, including 12 events with magnitudes greater than 3. Seismicity rapidly decreased to normal levels by midday on 25 July and remained at low levels through 30 July. Minor deformation was detected.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

A 30 July satellite image showed lava flows extending over 5 km NNW of Nyamuragira’s N crater rim and a new flow extending almost 2 km W of the NW crater rim, based on thermal anomalies. Weather clouds obscured parts of the NNW flow, possibly including the furthest extent of the flow. A thermally anomalous area about 800 m E-W and more than 1.1 km N-S was centered over the vent area in the crater.

Source: Copernicus

GeoNet reported that a vigorous gas-and-steam plume containing ash was visible in Whakatane and Te Kaha webcam images rising from Whakaari/White Island during 0630-0730 on 26 July. The plume rose about 1 km and contained a minor amount of ash at lower heights; ash fell on the W part of the island. The Volcanic Alert Level remained at 2 (on a scale of 0-5) and the Aviation Color Code remained at Yellow (the second level on a four-color scale).

Source: GeoNet

The Yellowstone Volcano Observatory (YVO) reported that on 23 July a hydrothermal explosion occurred at Yellowstone’s Black Diamond Pool in the Biscuit Basin thermal area. The explosion ejected a plume of water, mud, and rock fragments 120-180 m high and NE towards Firehole River. Some ejected boulders were more than a meter in diameter. A section of the boardwalk to the S of the pool was notably damaged. The area, including the parking lot and boardwalks, was closed to visitors after the explosion. Hydrothermal explosions are relatively common in Yellowstone; on average, there are a few of varying sizes somewhere in the park each year, often in the backcountry where they may go unnoticed. 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).

Source: Yellowstone Volcano Observatory (YVO)

JMA reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 22-29 July. Nighttime crater incandescence was visible in webcam images. An eruptive event at 0249 on 23 July produced an ash plume that rose 1.1 km above the crater rim and drifted N. Sulfur dioxide emissions were relatively low, averaging 800 tons per day (t/d) on 24 July, and lower than the average of 2,400 t/d on 5 July. Eruptive events at 1155 on 27 July and at 0208, 0514, and 1439 on 28 July produced ash plumes that rose 1-1.8 km above the crater rim and drifted mainly N. An explosion at 1646 on 29 July generated a large ash plume that rose 4.4 km above the crater rim and drifted SE and ejected large blocks 1.3-1.7 km from the crater rim. An ash plume from an eruptive event at 1856 on 29 July rose 1.1 km above the crater rim and drifted S. 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)

PVMBG reported that the eruption at Dukono was ongoing during 24-30 July. Gray-and-white ash plumes rose 100-900 m above the summit and drifted E and NW during 24-26 and 30 July. White steam-and-gas plumes rose 100-700 m and drifted E and NW on 27 and 29 July; emissions were not observed on 28 July. 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)

KVERT reported that moderate explosive activity was ongoing at Ebeko during 18-25 July. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 19-20 July generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted NW, E, and SE. Thermal anomalies were identified in satellite images those same days; on other days 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)

AVO reported that slow lava effusion in Great Sitkin’s summit crater continued during 24-30 July; a 30 July radar image showed flow advancement to the E and S. Seismicity was low with few small daily earthquakes. Weakly elevated surface temperatures and steam emissions from the growing dome were visible in satellite images during 28-30 July. Weather clouds often obscured or partially obscured satellite and webcam 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).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

PVMBG reported that activity at Ibu continued during 24-30 July. Daily white-and-gray ash plumes rose as high as 2.1 km above the summit and drifted in multiple directions. Eruptive events were occasionally not observable. Daily webcam images posted with the reports showed incandescence emanating above the crater rim, possibly reflected in the emissions. 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)

PVMBG reported that eruptive activity at Lewotobi’s Laki-laki volcano continued during 24-30 July. Gray or white-and-gray ash plumes that were sometimes dense rose as high as 1 km above the summit and drifted mainly SW, W, and NW on almost all days; an eruptive event was recorded on 28 July, though no emissions were observed. The Alert Level remained at 3 (the second highest level on a scale of 1-4) and the public was warned to stay outside of the exclusion zone, defined as a 3-km radius around both Laki-laki and Perempuan craters, 4 km to the NNW and SSE of Laki-laki.

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

BPPTKG reported that the eruption at Merapi (on Java) continued during 19-25 July. Earthquakes were less intense compared to the previous week. The SW lava dome produced 126 lava avalanches that traveled as far as 1.9 km down the upper part of the Bebeng drainage. Five pyroclastic flows traveled as far as 1.2 km down the Bebeng drainage. Morphological changes to the SW lava dome were due to continuing effusion and collapses of material and slight changes were detected at the dome in the main crater. The volume of the SW dome was an estimated 2,538,700 cubic meters and the dome in the main crater was stable at an estimated 2,360,700 cubic meters based on webcam images and a 23 July drone survey. The hottest temperature at the SW dome was around 219 degrees Celsius, similar to the previous measurement. 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.

Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)

IG-EPN reported that an eruption at Reventador was ongoing during 23-30 July. Seismicity was characterized by 61-90 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Weather conditions prevented visual observations during 23-25 July. Several ash-and-gas plumes observed during 26-30 July rose as high as 1.1 km above the crater rim and drifted N. NW, W, and SW. Avalanches of incandescent material traveled 800-900 m down the flanks during 27-29 July. On 28 July a pyroclastic flow descended the flanks as far as 600 m and on 29 July pyroclastic flows descended the SE flank 600-800 m. During 29-30 July ejected incandescent material fell onto the flanks as far as 400 m below the crater rim. Secretaría de Gestión de Riesgos maintained the Alert Level at Orange (the second highest level on a four-color scale).

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

Instituto Geofísico del Perú (IGP) reported that the eruption at Sabancaya continued at moderate levels during 22-29 July with a daily average of 56 explosions. Gas-and-ash plumes rose as high as 3.1 km above the summit and drifted less than 10 km S and SE. Thermal anomalies over the lava dome in the summit crater were identified in satellite data. Slight inflation was detected N of Hualca Hualca (7 km N). Sulfur dioxide emissions were at moderate levels, averaging 608 tons per day. 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.

Source: Instituto Geofísico del Perú (IGP)

IG-EPN reported that high levels of eruptive activity continued at Sangay during 23-30 July. The seismic network recorded 1,175-1,840 daily explosions. Daily gas-and-ash plumes were visible in webcam and/or satellite images and rose 500-2,500 m above the summit and drifted mainly NW, W, and SW. Incandescent material at the summit crater was periodically visible during dark hours, and several episodes of incandescent material were visible descending the SE drainage as far as 2 km during 23-28 July; weather conditions often obscured views. On 24 July a pyroclastic flow traveled 2 km down the SE drainage. Minor ashfall was reported in towns in the Chimborazo province including Alausí (60 km SW) and Guarguallá (25 km WNW) during 24-25 July, Alausí during 27-29 July, and Chunchi (73 km SW) on 30 July. Secretaría de Gestión de Riesgos (SGR) maintained the Alert Level at Yellow (the second highest level on a four-color scale).

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Secretaría de Gestión de Riesgos (SGR)

KVERT reported that thermal anomalies over both the “300 years of RAS” dome on the SW flank of Old Sheveluch and the lava dome in the crater of Young Sheveluch were identified in satellite images during 18-25 July. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

JMA reported that eruptive activity at Suwanosejima's Ontake Crater continued during 22-29 July. Crater incandescence was observed nightly in webcam images. An explosion at 1527 on 24 July produced an ash plume that rose 700 m above the crater rim and drifted W. Another explosion was detected at 1231 on 25 July, though details about possible emissions were unknown. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay at least 1.5 km away from the crater.

Source: Japan Meteorological Agency (JMA)

Instituto Geofísico del Perú (IGP) reported that during 24-30 July daily seismicity at Ubinas was characterized by 55-116 events associated with rock fracturing and 49-129 events associated with fluid movement. Gas-and-steam emissions were sometimes visible rising 200-600 m above the crater rim. Daily thermal anomalies were identified in satellite images. The Alert Level remained at Yellow (the second level on a four-color scale) and the public was warned to stay 2 km away from the crater.

Source: Instituto Geofísico del Perú (IGP)

Servicio Nacional de Geología y Minería (SERNAGEOMIN) reported that an explosion at Villarrica ejected incandescent material around 190 m above the crater rim on 24 July. Some of the incandescent material landed on the flanks and rolled short distances based on the webcam view posted with the report. According to POVI a series of phreatomagmatic pulses on 29 July produced ash plumes and ashfall on the upper E flank. The Volcanic Alert level remained at Yellow (the third level on a four-level scale) and the public was warned to stay 1.5 km away from the crater. SENAPRED maintained the Alert Level at Yellow (the middle level on a three-color scale) for the communities of Villarrica, Pucón (16 km N), Curarrehue, and Panguipulli.

Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Sistema y Servicio Nacional de Prevención y Repuesta Ante Desastres (SENAPRED), Proyecto Observación Villarrica Internet (POVI)