An explosive eruption at Bagana on 15 July was similar to one that occurred on 7 July. According to the Darwin VAAC an eruption at around 0830 on 15 July produced an ash plume that rose to 16.5 km (54,000 ft) a.s.l. by 1000 and drifted N based on satellite images. The plume was visible continuing to drift N in an image from 1900 but had dissipated by 2150. Ground-based reports indicated that pyroclastic flows had occurred in the vicinity of the volcano; small deposits confined to one drainage were inspected by RVO during an overflight on 17 July, and were confirmed to be from the 7 July event. The Autonomous Bougainville Government (ABG) issued a statement on 17 July noting significant impacts of ashfall in local communities. According to the National Disaster Centre, ashfall from the first event lasted until 10 July; an eruption was also reported by RVO on 14 July. Ashfall (presumably from events on 7 and 15 July) impacted about 8,111 people in Torokina, South Bougainville, including Tsito/Vuakovi, Gotana (9 km SW), Koromaketo, Kenaia, Longkogari, Kenbaki, Piva (13 km SW), and Atsinima (27km WNW) and in the Tsitovi district according to ABG. Significant ashfall was also reported in Ruruvu (22 km N) in the Wakunai District of Central Bougainville. The Alert Level was at Stage 3 (the third level on a four-level scale), confirmed by RVO the evening before. An evacuation was called for the villages in Wakunai, where heavy ashfall had contaminated water sources; the communities of Ruruvu, Togarau, Kakarapaia, Karauturi, Atao, and Kuritaturi were asked to evacuate to a disaster center at the Wakunai District Station within 24 hours. Communities in Torokina, nearest to Bagana, were to immediately evacuate to the Piva District station.

Sources: Autonomous Bougainville Government, Rabaul Volcano Observatory (RVO), Darwin Volcanic Ash Advisory Centre (VAAC), Papua New Guinea National Disaster Centre

According to the Institute of Earth Sciences lava continues to eruption from main vent at Fagradalsfjall and travel S and SW. On 14 July the advancing edge of the flow connected with the 2021 lava field in the NE part of Meradalir . The main vent was elongated and about 22 m tall on 15 July. During 13-17 July the lava flow rate was an estimated 12.7 cubic meters per second, and by 18 July the total erupted volume was about 8.4 million cubic meters. The flow advanced an average of 300-400 m per day, though the distance was highly variable. Flow thicknesses averaged 10 m, though some areas reached 20 m. At about 2330 on 18 July lava filled the main cone and occasionally spilled over onto the flanks. A breach high on the NW rim occurred at around 0251 on 19 July and lava flowed down the NW flank. Spatter was ejected beyond the crater rim. At around 0259 lava fountaining increased and lava flowed short distances E. At around 0412 sections of the NW wall of the cone collapsed, draining the crater, and sending lava flows N and W. According to Almannavarnadeild ríkislögreglustjóra and news sources the police closed the pathway to see the eruption on 13 July, then reopened the path to tourists on 17 July. Firefighters were working to control the burning vegetation set on fire by the lava.

Sources: Almannavarnadeild ríkislögreglustjóra (National Commissioner of the Icelandic Police and Department of Civil Protection and Emergency Management), Institute of Earth Sciences

JMA reported that during 10-17 July data from the Global Navigation Satellite System (GNSS) indicated continuing minor inflation at shallow depths beneath Ioyama, located on the NW flank of the Karakuni-dake stratovolcano in the Kirishimayama volcano group. A few shallow volcanic earthquakes were recorded. Vigorous fumarolic activity was visible at the fumarolic are on the S side of Ioyama. The Alert Level remained at 2 (on a 5-level scale) and the public was warned to stay 1 km away from Ioyama.

Source: Japan Meteorological Agency (JMA)

JMA reported that shallow volcanic earthquakes at Kuchinoerabujima had been frequent since starting in late June, with most epicenters located near Furudake Crater, and some near Shindake Crater (just N of Furudake). Both the number and magnitude of the volcanic earthquakes increased on 9 June and remained elevated through 19 July; there were 285 events on 13 July, 241 on 14 July, 200 on 15 July, 104 on 16 July, 85 on 17 July, and 72 by 1500 on 18 July. The public was warned to stay 2 km away from Furudake. The Alert Level remained at 3 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)

The Darwin VAAC reported that diffuse ash plumes at Langila were visible in satellite images at 1440 on 14 July rising to 1.8 km (6,000 ft) a.s.l. and drifting N. A thermal anomaly was also identified. Diffuse ash emissions continued to be identified in images through most of the next day. The ash emissions had dissipated by 1700 on 15 July; steam-and-gas emissions continued.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

PVMBG reported continuing daily steam-and-gas emissions at Lokon-Empung during 12-18 July. White plumes with variable densities rose as high as 400 m above the crater rim and drifted S and N. The Alert Level was raised to 3 (on a scale of 1-4) at 1800 on 17 July and the public was reminded not to approach Tompaluan Crater within a radius of 2.5 km.

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

PHIVOLCS reported that the eruption at Mayon continued during 11-18 July, with slow lava effusion from the summit crater feeding lava flows on the S and SE flanks. The length of the lava flow in the Mi-Isi (S) drainage remained at 2.8 km and the flow in the Bonga (SE) drainage advanced to 2.4 km by 18 July. The lava flow in the Basud drainage on the E flank was 600 m long. Collapses at the lava dome and from the lava flows produced incandescent rockfalls and pyroclastic density currents (PDCs, or pyroclastic flows) that descended the Mi-Isi and Bonga drainages; material also traveled as far as 4 km down the Basud drainage. Steam-and-gas plumes rose 200-750 m above the summit and drifted WSW, W, and ESE during 11-14 July; emissions were not reported on the other days of the week. Sulfur dioxide emissions were reported on most days and showed an increasing trend, averaging between 1,128 and 2,989 tonnes per day, with the highest value recorded on 15 July. Each day seismic stations recorded 150-423 rockfall events and 3-10 PDC events (from dome and lava-front collapses). There were 3-39 volcanic earthquakes recorded on most days, though 184 and 267 were recorded during 16-17 July and 17-18 July, respectively. At 2300 on 16 July the seismic network began recording a continuous series of weak low-frequency volcanic earthquakes (LFVQs). Some of the events were detected by infrasound sensors and produced audible rumbling sounds during the evening of 17 July and the morning of 18 July. By 1530 on 18 July a total of 573 LFVQs had been detected. Most of the events originated from a shallow source and were associated with a rapid release of volcanic gases, though visually there were no changes in effusive activity. The Disaster Response Operations Monitoring and Information Center (DROMIC) reported that as of 1800 on 17 July there were 5,801 families, or 20,257 individuals, that were either in evacuation shelters or staying in other types of alternative housing. The Alert Level remained at 3 (on a 0-5 scale) and residents were reminded to stay away from the 6-km-radius Permanent Danger Zone (PDZ). PHIVOLCS recommended that civil aviation authorities advise pilots to avoid flying close to the summit.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Disaster Response Operations Monitoring and Information Center (DROMIC)

OVPF reported that the eruption that began on 2 July at Piton de la Fournaise was ongoing during 12-19 July. Though there were multiple active fissures at the start of the eruption, since 3 July only the SE flank fissure was active, located on the upper part of Grandes Pentes at approximately 1,720 m a.s.l. Volcano-tectonic earthquake events (VTs) fluctuated throughout the week but remained low relative to the onset of the eruption. Lava ejections continued to build a cone over the active vent throughout the week, and on 12 July the top of the cone became partially closed. The flow front did not extend any further to the E and remained stalled 1.8 km from the road. Active flows traveled through lava tubes above 1,500 m elevation and continued to widen (increasing about 180 m since 7 July) and thicken. Although clouds often prevented measurements, satellite analysis showed that lava flow rates fluctuated between less than 1 and 13.5 cubic m/s. The total volume of lava effused since the beginning of the eruption was an estimated 6 +/- 3 million cubic meters. There was slight deflation at the summit during 13-16 July, followed by slight inflation during 17-19 July.

Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)

AVO reported that a new eruption at Shishaldin began after increasing activity. Intermittent tremor and low-frequency earthquakes had gradually become more regular and consistent during 10-11 July, and strongly elevated surface temperatures at the summit were identified in satellite images those same days. The Volcano Alert Level was raised to Advisory (the second level on a four-level scale) and the Aviation Color Code was raised to Yellow (the second color on a four-color scale). Late on 11 July incandescence at the summit was observed in web camera images. Strongly elevated surface temperatures continued to be observed in satellite data and seismic tremor amplitudes increased during 11-12 July; sulfur dioxide emissions were also detected. The observations suggested that lava was likely present at the summit crater, so AVO raised the Volcano Alert Level to Watch and the Aviation Color Code to Orange. The US Coast Guard conducted an overflight on 12 July and confirmed that lava was erupting at the summit.

A significant explosion at 0109 on 14 July produced an ash plume that rose 9-12 km (30,000-40,000 ft) a.s.l. and drifted S. Webcam images and photos taken at around 0700 from a ship SW of Unimak Island showed small lahar deposits (from the interaction of hot pyroclastic material and snow and ice) on the flanks as well as ashfall on the SW and N flanks. A smaller explosion at 0710 generated an ash plume that rose 4.5 km (14,800 ft) a.s.l. Low-level ash emissions continued during the morning based on webcam images and pilot reports.

Seismic tremor amplitude began increasing at around 1700 and remained elevated. An ash plume at an altitude of 4.6 km (15,000 ft) a.s.l. and drifting SSE was visible in a satellite image at 2100. AVO stated that activity had intensified. At 2357 AVO raised the Aviation Color Code to Red and noted that seismicity had remained elevated for over six hours and explosion signals were frequently detected by regional infrasound (pressure sensor) networks. A continuous ash plume extended more than 125 km SSE at an altitude of 4.9 km (16,100 ft) a.s.l., though some of the explosions sent ash plumes as high as 6 km (19,700 ft) a.s.l. Strongly elevated surface temperatures were observed in satellite data during 15-16 July. By 0734 on 16 July explosive activity had declined and seismicity had significantly declined. The Aviation Color Code was lowered to Orange. A remnant ash cloud drifted about 500 km SE before dissipating. Lava continued to erupt at the summit during 16-17 July and produced strongly elevated surface temperatures visible in satellite images. Lava effusion increased at 0100 on 18 July, shown by elevated surface temperatures identified satellite data, increasing seismic tremor, and activity detected on regional infrasound arrays. Activity again intensified and at 0700 a rapidly expanding ash cloud was visible drifting SSE, eventually reaching 9.1 km (30,000 ft) a.s.l. The Aviation Color Code was raised to Red and the Volcano Alert Level was raised to Warning. A Volcano Observatory Notice to Aviation (VONA) issued at 0837 noted that the plume was rising to 7.3 km (24,000 ft) a.s.l. based on recent pilot observations. By 0930 the main ash plume had detached. The eruption gradually declined, so at 1208 the Volcano Alert Level was lowered to Watch and the Aviation Color Code was lowered to Orange. Continuing ash emissions generated plumes that drifted S at altitudes below 3 km (10,000 ft) a.s.l.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Instituto Geofísico del Perú (IGP) reported that the eruption at Ubinas continued at low-to-moderate levels during 10-16 July. During the week there were 80 volcano-tectonic earthquakes indicating rock fracturing and 93 long-period earthquakes signifying the movement of gas and magma. On 16 July there were two seismic signals associated with major explosive events, and 3.6 hours of seismic signals related to ash emissions. Emissions of gas and ash rose to 1.5 km above the summit and drifted as far as 15 km to the E, SE, and S. The Alert Level remained at Orange (the third level on a four-color scale) and the public was warned to stay 4 km away from the crater.

Source: Instituto Geofísico del Perú (IGP)

RVO reported that variable amounts of white steam plumes were visible rising from Ulawun during 1-18 July. Seismicity was low during 1-16 July and consisted of small, discrete, low-frequency earthquakes and occasional small high-frequency volcano-tectonic events. RSAM values generally fluctuated around 50, but during 1800-2300 on 16 July the values increased to 500. The values continued to climb at a slow irregular rate to 610 through 0500 on 18 July, but then dropped to 400-500 during the next two hours (0500-0700), though peaks as high as 1,600 were recorded. By 0700 the values had decreased to 300 and remained steady afterwards. Minor ash emissions began on 18 July and during the morning of 19 July brown-to-gray emissions with low ash content were rising a few hundred meters above the crater rim and drifting SE.

Source: Rabaul Volcano Observatory (RVO)