The Weekly Volcanic Activity Report: July 16-22, 2026

New activity/unrest: Ahyi, United States | Atka Volcanic Complex, United States | Etna, Italy | Krakatau, Indonesia | Kuchinoerabujima, Japan.

New activity/unrest

Ahyi, United States

20.437°N, 145.03°E; Elev. -55 m

The US Geological Survey reported that small plumes of discolored water around the Ahyi Seamount had been intermittently identified in satellite images over the last few months, though recent ones had more discrete plume shapes suggesting more vigorous activity. Plumes on 1, 7, and 11 July drifted less than 500 m from the vent area. No signals were detected in data from underwater pressure sensors near Wake Island (about 2,270 km E of Ahyi). The plumes were likely the result of gas released into the water column and could reflect either vigorous hydrothermal degassing or be associated with an ongoing effusive eruption. At 1013 on 16 July the Aviation Color Code was raised to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level was raised to Advisory (the second lowest level on a four-level scale).

Geological summary: Ahyi seamount is a large conical submarine volcano ~18 km SE of the island of Farallon de Pajaros in the northern Marianas. Water discoloration has been observed there, and in 1979 the crew of a fishing boat felt shocks over the summit area, followed by upwelling of sulfur-bearing water. On 24-25 April 2001 an explosive eruption was detected seismically by a station on Rangiroa Atoll, Tuamotu Archipelago. The event was well constrained (+/- 15 km) at a location near the southern base of Ahyi. An eruption in April-May 2014 was detected by NOAA divers, hydroacoustic sensors, and seismic stations.

Atka Volcanic Complex, United States

52.331°N, 174.139°W; Elev. 1,518 m

The Alaska Volcano Observatory (AVO) reported that a small phreatic explosion originating at Korovin’s summit crater lake within the Atka Volcanic Complex was detected in seismic and infrasound data at 0355 on 16 July. No emissions were identified in satellite images, but regional weather clouds obscured views below 3 km (10,000 ft) a.s.l.; an ash plume generated by a small explosion would be expected to be small and dissipate quickly. Elevated seismicity declined immediately after the event. The Volcano Alert Level was raised to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code was raised to Yellow (the second lowest color on a four-color scale) at 0503. Typical elevated temperatures at the crater lake were seen in clear overnight satellite images during 18-19 July. Unrest declined; at 1208 on 21 July the Volcano Alert Level was lowered to Normal and the Aviation Color Code was lowered to Green.

Geological summary: The Atka Volcanic Complex consists of a central shield and Pleistocene caldera and four notable volcanic cones. A major explosive dacitic eruption accompanied formation of the caldera about 500,000 to 300,000 years ago; approximately half of the caldera rime remains, open towards the NW. The Sarichef cone, ~5 km ESE of the caldera rim, retains a symmetrical profile, unlike most other heavily eroded features outside the caldera to the S and W. The Kliuchef stratovolcano grew within the caldera and exhibits five eruptive vents striking NE, including two at the summit, that have been active in the Holocene. A 700-m-diameter crater 1 km NE of the summit may have been the source vent for a large 1812 CE eruption. Hot springs and fumaroles are located on the flanks of Kliuchef and in a glacial valley to the SW. The most frequently active volcano of the complex is Korovin, at the NE tip of Atka Island about 5 km N of Kliuchef. An 800-m-diameter crater on the SE side of the summit contains a deep circular pit that sometimes contains a crater lake thought to be the source of phreatic ash explosions. The smaller Konia cone, slightly offset to the E, lies between Kliuchef and Korovin. Most of the lava flows in the complex are basaltic, though some dacitic flows are also present.

Etna, Italy

37.748°N, 14.999°E; Elev. 3,357 m

The Sezione di Catania – Osservatorio Etneo (INGV) reported eruptive activity at Etna’s summit craters during 13-19 July characterized by gas emissions rising along the fissure between Voragine Crater (VOR) and Northeast Crater (NEC), gas emissions rising from Southeast Crater, and explosive activity at both NEC and Bocca Nuova Crater (BN). INGV staff conducted field surveys on 16 and 18 July and observed sporadic explosions at NEC and yellowish-brown ash emissions rising from the W vent in BN. Ash emissions at BN became nearly continuous during 18-19 July with grayish-brown plumes rising several hundred meters above the summit. A notably energetic event at 1807 on 19 July produced a gray ash cloud that rose 300 m above the vent. The Alert Level remained at Yellow (the second lowest level on a four-level scale) according to the Dipartimento della Protezione Civile.

Geological summary: Mount Etna, towering above Catania on the island of Sicily, has one of the world’s longest documented records of volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.

Krakatau, Indonesia

6.1009°S, 105.4233°E; Elev. 285 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Krakatau continued during 16-22 July. White, gray, and/or black ash plumes rose as high as 200 m above the summit and drifted in multiple directions during 16 and 19-20 July. Incandescence was visible at night on 11 July. White plumes rose up to 100 m above the summit on the other days. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3 km away from the active crater.

Geological summary: The renowned Krakatau (frequently misnamed as Krakatoa) volcano lies in the Sunda Strait between Java and Sumatra. Collapse of an older edifice, perhaps in 416 or 535 CE, formed a 7-km-wide caldera. Remnants of that volcano are preserved in Verlaten and Lang Islands; subsequently the Rakata, Danan, and Perbuwatan cones were formed, coalescing to create the pre-1883 Krakatau Island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan, and left only a remnant of Rakata. This eruption caused more than 36,000 fatalities, most as a result of tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatau (Child of Krakatau) was constructed within the 1883 caldera at a point between the former Danan and Perbuwatan cones. Anak Krakatau has been the site of frequent eruptions since 1927.

Kuchinoerabujima, Japan

30.443°N, 130.217°E; Elev. 657 m

The Japan Meteorological Agency (JMA) reported that further analysis of seismic data at Kuchinoerabujima from 9 July and results from field visits indicated that there likely was no increase in volcanic unrest. At 1550 on 17 July the Alert Level was lowered to 1 (on a scale of 1-5).

Geological summary: A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km W of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. All historical eruptions have occurred from Shindake, although a lava flow from the S flank of Furudake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shindake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions.

Ongoing activity

Aira, Japan

31.5772°N, 130.6589°E; Elev. 1,117 m

The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 13-20 July. Volcanologists conducted a field survey on 13 July and measured high sulfur dioxide emissions, averaging 2,200 tons per day. That same day ash plumes rose as high as 1.7 km above the summit and drifted N and NE. Crater incandescence was visible in webcam images during 13-17 July. Very small eruptive events were recorded during 17-20 July. 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.

Geological summary: The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan’s most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim and built an island that was joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4,850 years ago, after which eruptions took place at Minamidake. Frequent eruptions since the 8th century have deposited ash on the city of Kagoshima, located across Kagoshima Bay only 8 km from the summit. The largest recorded eruption took place during 1471-76.

Ambae, Vanuatu

15.389°S, 167.835°E; Elev. 1,496 m

The Wellington Volcanic Ash Advisory Center (VAAC) reported that ash-and-gas plumes at Ambae were identified in satellite and webcam views during 15 and 18-20 July rising 2.7-4.3 km (9,000-14,000 ft) a.s.l. and drifting SE, S, and SW. The plumes were brown on 19 July. The same day some flights were disrupted or canceled according to a government source. The Alert Level remained at 3 (on a scale of 0-5), and the public was warned to stay outside of Danger Zone B, defined as a 3-km radius around the active vents in Lake Voui, and to stay away from drainages during heavy rains.

Geological summary: The island of Ambae, also known as Aoba, is a massive 2,500 km3 basaltic shield that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW-trending rift zone with numerous scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and Manaro Lakua) is located at the summit within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. That large central edifice is also called Manaro Voui or Lombenben volcano. Post-caldera explosive eruptions formed the summit craters about 360 years ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast.

Dukono, Indonesia

1.6992°N, 127.8783°E; Elev. 1,273 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 16-22 July. Daily white plumes rose as high as 200 m above the summit and drifted in multiple directions. At 0650 on 16 July a white-and-gray ash plume rose 2.1 km above the summit and drifted N. White-and-gray ash plumes rose 100-500 m above the summit and drifted NE and E during 17 and 20-22 July. 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.

Geological summary: The Dukono complex in northern Halmahera is on an edifice with a broad, low profile containing multiple peaks and overlapping craters. Almost continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the Gunung Mamuya cone, 10 km NE. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also had reported eruptions.

Great Sitkin, United States

52.076°N, 176.13°W; Elev. 1,740 m

The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkin’s summit crater during 15-22 July. The flow advanced ESE based on radar satellite data. Seismicity was minor and likely associated with rockfalls on the growing dome. Elevated surface temperatures were identified on most days and webcam and satellite images showed minor steaming from the dome during 18-19 July. 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).

Geological summary: The Great Sitkin volcano forms much of the northern side of Great Sitkin Island. A younger volcano capped by a small, 0.8 x 1.2 km ice-filled summit caldera was constructed within a large late-Pleistocene or early Holocene scarp formed by massive edifice failure that truncated an older edifice and produced a submarine debris avalanche. Deposits from this and an even older debris avalanche from a source to the south cover a broad area of the ocean floor north of the volcano. The summit lies along the eastern rim of the younger collapse scarp. Deposits from an earlier caldera-forming eruption of unknown age cover the flanks of the island to a depth up to 6 m. The small younger caldera was partially filled by lava domes emplaced in 1945 and 1974, and five small older flank lava domes, two of which lie on the coastline, were constructed along northwest- and NNW-trending lines. Hot springs, mud pots, and fumaroles occur near the head of Big Fox Creek, south of the volcano. Eruptions have been recorded since the late-19th century.

Ibu, Indonesia

1.4941°N, 127.6324°E; Elev. 1,357 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity at Ibu continued during 16-22 July, with daily eruptive events recorded by the seismic network. Daily gray or white-to-gray ash plumes rose 200-800 m above the summit and drifted E, NE, and NW. Incandescence at the summit was visible in some 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.

Geological summary: The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.

Kanlaon, Philippines

10.4096°N, 123.13°E; Elev. 2,422 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported continuing eruptive activity at Kanlaon during 16-22 July. The seismic network recorded 8-36 daily volcanic earthquakes; the counts included 1-3 daily periods of tremor on most days, lasting 28 minutes to four hours and 43 minutes. Sulfur dioxide emissions ranged from 625 to 1,914 tonnes per day. Volcanic emissions rose 300-900 m above the summit and drifted in multiple directions. 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.

Geological summary: Kanlaon volcano (also spelled Canlaon) forms the highest point on the Philippine island of Negros. The massive andesitic stratovolcano is covered with fissure-controlled pyroclastic cones and craters, many of which are filled by lakes. The largest debris avalanche known in the Philippines traveled 33 km SW from Kanlaon. The summit contains a 2-km-wide, elongated northern caldera with a crater lake and a smaller but higher active vent, Lugud crater, to the south. Eruptions recorded since 1866 have typically consisted of phreatic explosions of small-to-moderate size that produce minor local ashfall.

Kilauea, United States

19.421°N, 155.287°W; Elev. 1,222 m

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 15-22 July. Gas plumes rose from both the N and S vents and drifted SW though the week. Nighttime incandescence was persistent at both vents, though it was stronger at the S vent and intermittent at the N vent. Flames, likely caused by the ignition of volcanic gases, were visible at both vents during 15-18 July and only at the S vent during the rest of the week. The Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest color on a four-color scale).

Geological summary: Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Lewotobi, Indonesia

8.542°S, 122.775°E; Elev. 1,703 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity continued at Lewotobi Laki-Laki during 16-22 July. Multiple daily gray ash plumes rose 200-1,600 m above the summit and drifted in various directions. Incandescence in the plume was visible in a webcam image at 0042 on 18 July. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 5 km away from the center of Laki-Laki.

Geological summary: The Lewotobi edifice in eastern Flores Island is composed of the two adjacent Lewotobi Laki-laki and Lewotobi Perempuan stratovolcanoes (the “husband and wife”). Their summits are less than 2 km apart along a NW-SE line. The conical Laki-laki to the NW has been frequently active during the 19th and 20th centuries, while the taller and broader Perempuan has had observed eruptions in 1921 and 1935. Small lava domes have grown during the 20th century in both of the summit craters, which are open to the north. A prominent cone, Iliwokar, occurs on the E flank of Perampuan.

Lewotolok, Indonesia

8.274°S, 123.508°E; Elev. 1,431 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported ongoing eruptive activity at Lewotolok during 16-22 July. Daily white plumes rose as high as 200 m above the summit. Gray ash plumes rose 500-600 m above the summit and drifted W, SW, and SE during 16-17 July. A nighttime webcam image showed incandescent material being ejected above the summit and onto the flanks at 2103 on 17 July. The Alert Level remained at 2 (on a scale of 1-4) and the public was warned to stay 2 km away from the summit.

Geological summary: The Lewotolok (or Lewotolo) stratovolcano occupies the eastern end of an elongated peninsula extending north into the Flores Sea, connected to Lembata (formerly Lomblen) Island by a narrow isthmus. It is symmetrical when viewed from the north and east. A small cone with a 130-m-wide crater constructed at the SE side of a larger crater forms the volcano’s high point. Many lava flows have reached the coastline. Eruptions recorded since 1660 have consisted of explosive activity from the summit crater.

Mayon, Philippines

13.257°N, 123.685°E; Elev. 2,462 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported that the eruption at Mayon continued during 16-22 July, characterized by lava effusion, periodic pyroclastic density currents (PDCs), incandescent rockfalls, and occasional ash-and-gas plumes. Emissions were visible daily rising as high as 2 km above the summit and drifting SSE, SSW, and W. Each day the seismic network recorded 18-314 rockfalls, and a decreasing number of daily volcanic earthquakes from as many as 196 on 16 July to as few as 4 on 22 and 23 July. The earthquake counts included 3-51 daily periods of volcanic tremor lasting 1-54 minutes during 16-19 July. A total of 16 PDCs occurred on 16 July, one occurred on 18 July, and four were recorded on 19 July. Daily measurements of sulfur dioxide emissions averaged 912-4,814 tonnes per day. The lava flows did not advance in the Mi-isi (S), Bonga (SE), and Basud (E) drainages, remaining 1.8, 3.2, and 3.8 km long, respectively.

Geological summary: Symmetrical Mayon, which rises above the Albay Gulf NW of Legazpi City, is the most active volcano of the Philippines. The steep upper slopes are capped by a small summit crater. Recorded eruptions since 1616 CE range from Strombolian to basaltic Plinian, with cyclical activity beginning with basaltic eruptions, followed by longer periods of andesitic lava flows. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic density currents and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often damaged populated lowland areas. A violent eruption in 1814 killed more than 1,200 people and devastated several towns.

Merapi, Indonesia

7.54°S, 110.446°E; Elev. 2,910 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Merapi (on Java) continued during 16-22 July with daily lava avalanches produced by the active lava dome on the upper SW flank. There were 8-14 daily lava avalanches that traveled as far as 2 km down the Sat/Putih drainage on the W flank during 17-19 and 22 July. As many as 14 lava avalanches descended the Boyong drainage (S flank) as far as 2 km on 20 July. One pyroclastic flow was detected on 22 July. 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.

Geological summary: Merapi, one of Indonesia’s most active volcanoes, lies in one of the world’s most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities.

Purace, Colombia

2.3095°N, 76.3948°W; Elev. 4,650 m

The Servicio Geologico Colombiano (SGC) reported ongoing low-level eruptive activity at Puracé during 14-20 July. Seismic activity associated with rock fracturing processes continued at similar levels compared to the previous week with signals mainly located between Piocollo and Puracé volcanoes at depths of 1-3 km and magnitudes below 1.6. A thermal anomaly continued to be detected in satellite images within the crater of Puracé and Curiquinga and in the fumarolic field along the outer rim of Puracé. Sulfur dioxide emissions persisted and slow deformation continued between Puracé, Piocollo, and Curiquinga volcanoes. Signals associated with fluid movement and emissions were ongoing from beneath Puracé at depths less than 3 km. Gas-and-ash emissions occurred at around the same frequency as the previous week, though they rose higher; the tallest plume rose 2.8 km above the crater rim. Ashfall was reported in the rural communities of Hato Viejo (12 km WNW), Cristales, Río Negro (20 km SW), 20 de Julio, Alto Anambío (7 km NNW), and Popayán (28 km NW) during 18-20 July. The Alert Level remained at Yellow (the second lowest level on a four-color scale).

Geological summary: Puracé is an active andesitic volcano with a 600-m-diameter summit crater at the NW end of the Los Coconucos Volcanic Chain. This volcanic complex includes nine composite and five monogenetic volcanoes, extending from the Puracé crater more than 6 km SE to the summit of Pan de Azúcar stratovolcano. The dacitic massif which the complex is built on extends about 13 km NW-SE and 10 km NE-SW. Frequent small to moderate explosive eruptions reported since 1816 CE have modified the morphology of the summit crater, with the largest eruptions in 1849, 1869, and 1885.

Rincon de la Vieja, Costa Rica

10.8314°N, 85.3364°W; Elev. 1,729 m

The Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported minor eruptive events at Rincón de la Vieja during 16-22 July. At around 2103 on 19 July a phreatic eruption lasting 30 seconds generated lahars on the N flank. At 0115 on 23 July seismic and acoustic signals were recorded for about 30 seconds, with the acoustic data showing two pulses, a smaller one followed by a larger one. Webcams could not be checked to verify any eruptive activity. The Alert Level remained at Level 2, Yellow, the second lowest level on a four-level scale.

Geological summary: Rincón de la Vieja is a volcanic complex in the Guanacaste Range of NW Costa Rica. Sometimes referred to as the Rincon de la Vieja-Santa María Volcanic Complex, it consists of a slightly arcuate 20-km-long ridge of 12 craters and pyroclastic cones constructed within the 15-km-wide early Pleistocene Guachipelín caldera, whose rim is exposed on the south side. Sometimes known as the “Colossus of Guanacaste,” it has an estimated volume of 130 km3 and contains at least nine major eruptive centers. The Santa María cone, the highest peak of the complex, is located on the E side of the ridge and has a lake within the 400-m-diameter crater. A Plinian eruption producing the 0.25 km3 Río Blanca tephra about 3,500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous reported eruptions possibly dating back to the 16th century, have been from the active crater, near the center of the complex, with an acidic 300-m-diameter lake.

Sabancaya, Peru

15.787°S, 71.857°W; Elev. 5,960 m

The Instituto Geofísico del Perú’s (IGP) Centro Vulcanológico Nacional (CENVUL) reported continuing eruptive activity at Sabancaya during 13-19 July. The seismic network detected 47 seismic events related to the movement of magmatic fluids, along with additional earthquakes indicating rock fracturing. Gas, steam, and ash plumes periodically rose as high as 1 km above the crater rim and drifted less than 10 km E and SE. Thermal anomalies on the crater floor were identified in satellite images and moderate sulfur dioxide emissions averaged 732 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 from the summit.

Geological summary: Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning “tongue of fire” in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of observed eruptions date back to 1750 CE.

Semeru, Indonesia

8.108°S, 112.922°E; Elev. 3,657 m

The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 16-22 July, with daily eruptive events recorded by the seismic network. White-to-gray or gray ash plumes rose 500-1,100 m above the summit and drifted N, NE, SE, and S on most days. Two pyroclastic flows descended the SE flank during 1-17 July based on instrumental data and visual observations. An eruption at 0621 on 18 July was followed by a pyroclastic flow that descended the SE flank as far as 3.5 km. Weather clouds obscured views during 21-22 July. 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 Jonggring Saloko Crater 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.

Geological summary: Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano.

Sheveluch, Russia

56.653°N, 161.36°E; Elev. 3,283 m

The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing lava effusion and explosive activity at the lava domes along the N crater floor of Young Sheveluch (on the SW flank of Old Sheveluch) during 16-22 July. A thermal anomaly was identified in satellite images on all or most days. Explosions at 0045 on 16 July produced ash plumes that rose 6.5 km (21,300 ft) a.s.l. and drifted 1,300 km SE. Ash plumes from explosions the next day rose 8.8 km (28,900 ft) a.s.l. and drifted 200 km E at 2040 on 17 July. Explosions at 0915 on 20 July generated ash plumes that rose 10.5 km (34,500 ft) a.s.l. and drifted 750 km E. 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.

Geological summary: The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka’s largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.

Taal, Philippines

14.0106°N, 120.9975°E; Elev. 311 m

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported eruptive activity at Taal during 16-22 July. The seismic network recorded 0-10 daily volcanic earthquakes during 16-21 July, including daily periods of volcanic tremor that lasted as short as one minute to as long as eight hours. Daily gas-and-steam emissions generally rose as high as 900 m above the crater rim and drifted NE and E. Minor phreatomagmatic eruptions lasted for 2.5 minutes on 16 July and one minute on 17 July. Sulfur dioxide emissions averaged 129 tonnes per day (t/d) on 20 July. Two minor phreatomagmatic eruptions occurred on 21 July. One of them, recorded during 2009-2013, ejected jets of ash and steam-rich plumes that rose 2.8 km above the crater rim and drifted SE. On 22 July there were 61 volcanic earthquakes and three periods of volcanic tremor lasting 1-31 minutes. Sulfur dioxide emissions averaged 741 t/d and steam-and-gas plumes rose as high as 800 m above the crater rim and drifted SW. The Alert Level remained at 1 (on a scale of 0-5); PHIVOLCS reminded the public that the entire Taal Volcano Island (TVI) was a Permanent Danger Zone (PDZ) and recommended that the Main Crater and areas along the Daang Kastila fissure should remain prohibited. Pilots were warned to avoid flying over TVI.

Geological summary: Taal is one of the most active volcanoes in the Philippines and has produced some powerful eruptions. The 15 x 20 km Talisay (Taal) caldera is largely filled by Lake Taal, whose 267 km2 surface lies only 3 m above sea level. The maximum depth of the lake is 160 m, with several submerged eruptive centers. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all observed eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones. Powerful pyroclastic flows and surges have caused many fatalities.

References:

¹ Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report – GVP – July 16-22, 2026 – Managing Editor: Sally Sennert

Teo Blašković

I'm a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.

Earth

Space

Space weather

Monitoring tools

watchers.LIVE

SWX

SAM

StormWall

Support, updates, and contact

Subscribe

Newsletter

Report an event

Feeds and contact