4-4-4-4-4-4-4-4-4-4-4-4-4 From: "Venzke, Ed" <VENZKEE@xxxxxx> Smithsonian / USGS Weekly Volcanic Activity Report 30 July-5 August 2025 Sally Sennert - Weekly Report Editor (kuhns@xxxxxx) Volcano Disaster Assistance Program Staff URL: https://volcano.si.edu/reports_weekly.cfm New Activity/Unrest: Barren Island, India | Bur ni Telong, Indonesia | Kilauea, United States | Klyuchevskoy, Russia | Krasheninnikov, Russia | Kusatsu-Shiranesan, Japan | Lewotobi, Indonesia | Nyamulagira, DR Congo | Reykjanes, Iceland Ongoing Activity: Aira, Japan | Ambae, Vanuatu | Ambrym, Vanuatu | Dukono, Indonesia | Etna, Italy | Fuego, Guatemala | Gaua, Vanuatu | Great Sitkin, United States | Home Reef, Tonga | Ibu, Indonesia | Karymsky, Russia | Kirishimayama, Japan | Lewotolok, Indonesia | Marapi, Indonesia | Merapi, Indonesia | Poas, Costa Rica | Santa Maria, Guatemala | Semeru, Indonesia | Sheveluch, Russia | Suwanosejima, Japan | Telica, Nicaragua | Yasur, Vanuatu The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, these reports are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports about recent activity are published in issues of the Bulletin of the Global Volcanism Network. Note that many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source. *New Activity/Unrest* *Barren Island* | India | 12.278°N, 93.858°E | Summit elev. 354 m Eruptive activity was identified at Barren Island on 30 July by the Darwin VAAC. An ash plumes was seen in partially obscured Himawari-9 satellite imagery (0410 on 31 July UTC) at 2.1 km (7,000 ft) a.s.l. drifting NE. Geologic Summary. Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S volcanic arc extending between Sumatra and Burma (Myanmar). It is the emergent summit of a volcano that rises from a depth of about 2250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast. Source: Darwin Volcanic Ash Advisory Centre (VAAC) http://www.bom.gov.au/aviation/volcanic-ash/darwin-va-advisory.shtml *Bur ni Telong* | Indonesia | 4.769°N, 96.821°E | Summit elev. 2617 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi reported increased volcanic activity at Bur ni Telong, noting a significant increase in deep volcanic earthquakes in July, especially during 22-24 July. This was subsequently followed by an increase in shallow volcanic earthquakes observed during 1-2 August, prompting PVMBG to raise the Alert Level to Level II (on a scale from 1 to 4) at 0600 on 2 August. The public was advised to maintain a minimum distance of 1.5 km from the crater area and to avoid the fumarole and solfatara regions, especially during cloudy or rainy weather. Geologic Summary. The conical Bur ni Telong volcano was constructed at the southern base of the massive Bur ni Geureudong volcanic complex, one of the largest in northern Sumatra. The historically active volcano lies 4.5 km from the summit of Geureudong,and its summit crater has migrated to the ESE, leaving arcuate crater rims. Lava flows are exposed on the southern flank. Explosive eruptions were recorded during the 19th and 20th centuries. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ *Kilauea* | United States | 19.421°N, 155.287°W | Summit elev. 1222 m The Hawaiian Volcano Observatory (HVO) reported that episodic eruptive activity within Halemaâ??umaâ??u crater and the SW area of Kaluapele (Kilauea summit caldera), continued at variable levels during 30 July-5 August. Incandescence was observed at the northern vent on the morning of 31 July and continued to be visible in webcam images overnight. Other areas within the crater showed very low levels of incandescence, with only faint, intermittent glow from two locations higher on the eruptive cone in overnight webcam images. Summit tilt varied more than usual during the reporting period, with deflationary activity recorded during the night of 1 August through the morning of 3 August before briefly switching back to inflation. Then, around 0400 on 4 August, ground deformation data (tiltmeter) showed that minor summit deflation had resumed. During 0514-0518 on 4 August, a gas-pistoning event occurred at the north vent, with lava briefly appearing before draining back without any overflow or significant spattering activity. A second gas-pistoning event followed at 0551, during which there was minor spattering and lava overflowed the vent, which drained back by 0559. Ground deformation stalled around 0600, with no net inflation recorded since the night of 1 August. Strong incandescence was observed from the north vent early in the morning on 5 August, with occasional spattering observed in webcam images. A helicopter overflight later in the morning confirmed that lava was 5-10 m from the top of the vent. The degassed lava was observed feeding a low-volume flow into a lava tube within older lava flows on the crater floor. No new surface lava flows or incandescent breakouts were observed on the Halemaâ??umaâ??u crater floor in connection with this activity. 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). Geologic 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. Source: US Geological Survey Hawaiian Volcano Observatory (HVO) https://volcanoes.usgs.gov/observatories/hvo/ *Klyuchevskoy* | Russia | 56.056°N, 160.642°E | Summit elev. 4754 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that eruptive activity at Klyuchevskoyâ??s summit crater continued during 30 July-5 August. Satellite data showed a strong thermal anomaly at the volcano all week. Since 30 July a lava flow has been moving down the WSW flank, accompanied by phreatic explosions. Satellite data at 2315 on 1 August showed an ash plume extending for 150 km to the SE. Ash seen in satellite imagery at 0613 on 2 August was rising up to 7-8 km (23,000-26,200 ft) a.s.l. and drifting 50 km E. Additional satellite data from 4 August at 0432 showed ash reaching up to 7.5 km (24,600 ft) a.s.l. and extending for 50 km to the NE. Two lava flows were reported on 4 August effusing down the W and SE flanks, with ash rising up to 7 km (23,000 ft) a.s.l. and drifting for 600 km to the SE. 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. Geologic Summary. Klyuchevskoy is the highest and most active volcano on the Kamchatka Peninsula. Since its origin about 6,000 years ago, this symmetrical, basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during approximately the past 3,000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 and 3,600 m elevation. Eruptions recorded since the late 17th century have resulted in frequent changes to the morphology of the 700-m-wide summit crater. These eruptions over the past 400 years have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ *Krasheninnikov* | Russia | 54.596°N, 160.27°E | Summit elev. 1816 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that an explosive eruption at Krasheninnikov began at 1650 on 2 August. Initial ash explosions rose to 3-4 km (10,000-13,100 ft) a.s.l. from the summit crater of the northern cone; the rim is at about 1,600 m elevation. A fissure also opened on the NW flank and was effusing viscous lava. According to reports from Kronotsky nature park staff, explosions generated ash plumes that rose to 5-6 km (16,400-19,700 ft) a.s.l. by 2150, causing ashfall in part of the park. Satellite imagery showed an ash plume drifting 72-75 km E. The Aviation Color Code (ACC) was raised from Green to Orange (the second highest level on a four-color scale) at 2157. Ash explosions continued throughout the night, rising as high as 8-10 km (32,800 ft) a.s.l. and drifting 185 km E by 0150 on 3 August. The ACC was raised to Red (the highest level) at 0223 on 3 August. By 0711 activity had decreased, with possible moderate explosive activity continuing, but satellite views were obscured by clouds; the ACC was lowered back to Orange. The edge of the diffuse detached ash plume, about 20 km wide and 115 km long, was at 4 km (13,100 ft) a.s.l. and 290 km ESE. On 4 August at 0410 satellite data showed an ash plume rising to 3.5-4 km (11,500-13,100 ft) a.s.l. and drifting 580 km SE and ESE; by 0750 the ash plume had extended to 750 km. Additional explosions produced ash plumes that rose to 5-6 km (16,400-19,700 ft) a.s.l. and had drifted 840 km SE and ESE by 2220. On 5 August explosions generated ash plumes that again rose to 5-6 km (16,400-19,700 ft) a.s.l. and extended 160 km SE and ESE at 0530. Lava effusion on the NW flank was accompanied by ash emissions from the crater through 5 August. The volcanic system includes a 9 x 10 km caldera containing two overlapping stratovolcanoes, distinguished as northern and southern cones, each with a summit crater. This is the first observed activity at this volcano, and the first known since eruptions during about 1350-1550 CE (400-600 years before present, using a 1950 CE baseline) that built the Pauk lava cone in the northern summit crater, produced the Yuzhny lava flow on SW flank outside the caldera, and the Molodoy flow from the upper SW flank of the southern cone. Explosive activity around 850 CE created the northern cone summit crater. Dates and times are provided in Coordinated Universal Time (UTC); specific events are indicated in local time where specified. Geologic Summary. The late-Pleistocene to Holocene Krasheninnikov volcano is comprised of two overlapping stratovolcanoes within a 9 x 10 km Pleistocene caldera. Young lava flows from summit and flank vents descend both into the caldera and down its outer flanks, and older flows that covered much of the SE caldera rim extended downslope at least 7 km. Tephra deposits from the caldera-forming eruption directly overlie a 39,000 years before present (BP) tephra thought to be associated with the formation of Uzon caldera (Florenskii, 1988). The intra-caldera stratovolcanoes are situated along a NE-SW-trending fissure that has also produced zones of Holocene cinder cones extending 15-20 km beyond the caldera. Construction of the southern edifice began about 11,000 years BP and lasted for about 4,500 years; it has a summit crater about 800-900 m wide. The northern edifice was constructed during a cycle of similar length that began about 6,500 years ago; it has a summit crater about 1.5 km wide, within which is low cone with an 800-m-wide crater containing another small cone. An eruptive cycle during about 600-400 years BP (1350-1550 CE) produced the Pauk lava cone in the crater of the northern cone and the Yuzhny lava flow on SW flank outside the caldera, followed by the Molodoy flow from the upper SW flank (Ponomareva, 1987; Ponomareva and Tsyurupa, 1985; Ponomareva and Braitseva, 1990). Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/; Tokyo Volcanic Ash Advisory Center (VAAC) http://ds.data.jma.go.jp/svd/vaac/data/vaac_list.html *Kusatsu-Shiranesan* | Japan | 36.618°N, 138.528°E | Summit elev. 2165 m The Japan Meteorological Agency (JMA) reported increased unrest near Kusatsu-Shiranesanâ??s Yugama crater starting around 1500 on 3 August, characterized by an increase in volcanic earthquakes with epicenters near the Yugama crater. Additionally, ground deformation data since June 2024 indicated minor uplift of the NW Yugama crater area. Low-amplitude, short-duration seismic tremor recorded on 2 August was the first since 12 November 2020. Volcanic earthquakes continued to be recorded, prompting the JMA to raise the alert level at 0550 on 4 August to Level 2 (on a 5-level scale). The public was advised to maintain a minimum distance of 1 km from Yugama Crater. Geologic Summary. The Kusatsu-Shiranesan complex, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes. The andesitic-to-dacitic volcano was formed in three eruptive stages beginning in the early to mid-Pleistocene. The Pleistocene Oshi pyroclastic flow produced extensive welded tuffs and non-welded pumice that covers much of the E, S, and SW flanks. The latest eruptive stage began about 14,000 years ago. Historical eruptions have consisted of phreatic explosions from the acidic crater lakes or their margins. Fumaroles and hot springs that dot the flanks have strongly acidified many rivers draining from the volcano. The crater was the site of active sulfur mining for many years during the 19th and 20th centuries. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ *Lewotobi* | Indonesia | 8.542°S, 122.775°E | Summit elev. 1703 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Lewotobi Laki-laki continued during 30 July-5 August, with two significant explosive eruptions occurring during 1-2 August. After 18 days without an eruption, activity began to intensify, marked by a notable increase in deep volcanic earthquakes from 1800-2000 on 1 August. A significant explosive eruption during 2048-2051 generated a dense gray ash column that reached 10 km above the summit (based on initial ground observer estimates) and ejected incandescent ballistic fragments 3-4 km in multiple directions. Volcanic lightning was also observed within the ash column. At 0105 on 2 August, a larger eruption began that lasting 14 minutes, sending a dense gray-to-black ash column to 18 km above the summit (based on initial ground observer estimates). The plume drifted toward the SW, W, and NW. The eruption was accompanied by a rumbling sound and a loud bang that was heard at the Lewotobi Laki-laki Volcano Observation Post (6 km WNW). Ash from the eruptions caused widespread impacts, including the disruption of flights on multiple routes to and from East Nusa Tenggara and Bali, as well as affecting school operations in Talibura district (27 km W), Waigete district (39 km WSW), and parts of Maumere city (61 km W). Fransiskus Xaverius Seda Airport (59 km west) remained closed until 0600 on 3 August. Villages considered at risk for lahars included Dulipali (4 km NNW), Padangpasir (6 km W), Nobo (6 km N), Nurabelen (7 km ENE), Klatanlo (3 km NW), Hokeng Jaya (5 km WNW), Boru (8 km WNW), and Nawokote (7km NW). Seismic activity and degassing decreased after the 2 August event, returning to levels comparable to the previous week; dense white plumes rose about 300-500 m above the summit. The Alert Level remained at 4 (on a scale of 1-4) and the public was advised to maintain a minimum distance of at least 6 km from Lewotobi Laki-laki, except in the southwestâ??northeast sector, where the distance is 7 km. Geologic 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. Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/; Badan Nacional Penanggulangan Bencana (BNPB) http://www.bnpb.go.id/; Antara News http://www.antaranews.com/; Radio Republik Indonesia https://www.rri.co.id/ *Nyamulagira* | DR Congo | 1.408°S, 29.2°E | Summit elev. 3058 m Satellite images acquired on 30 July showed continued eruptive activity at Nyamulagira. Thermal anomalies associated with active lava flows were detected on the WNW flank. Additionally, strong thermal anomalies were observed within the summit crater area, partially obscured by rising gas and/or steam plumes. Geologic Summary. Africa's most active volcano, Nyamulagira (also known as Nyamuragira), is a massive high-potassium basaltic shield about 25 km N of Lake Kivu and 13 km NNW of the steep-sided Nyiragongo volcano. The summit is truncated by a small 2 x 2.3 km caldera that has walls up to about 100 m high. Documented eruptions have occurred within the summit caldera, as well as from the numerous flank fissures and cinder cones. A lava lake in the summit crater, active since at least 1921, drained in 1938, at the time of a major flank eruption. Recent lava flows extend down the flanks more than 30 km from the summit as far as Lake Kivu; extensive lava flows from this volcano have covered 1,500 km2 of the western branch of the East African Rift. Sources: Copernicus https://www.copernicus.eu/en; MIROVA http://www.mirovaweb.it/ *Reykjanes* | Iceland | 63.817°N, 22.717°W | Summit elev. 140 m The Icelandic Meteorological Office (IMO) reported that a fissure within the Reykjanes volcanic system that began erupting on 16 July in an area NE of Stóra Skógfell, along the Sundhnúkur crater row, continued to erupt during 30 July-4 August. Fountaining activity decreased during this time, but flows continued to spread across the lava field. On 5 August the eruption ended with no activity observed in the crater and volcanic tremor decreasing to pre-eruptive levels. The Aviation Color Code was reduced from Orange to Yellow, reflecting continuing hazards from cooling flows and gas near the lava field. Uplift is continuing at the rate of 2-3 cm beneath Svartsengi as determined by satellite and GNSS measurements. Geologic Summary. The Reykjanes volcanic system at the SW tip of the Reykjanes Peninsula, where the Mid-Atlantic Ridge rises above sea level, comprises a broad area of postglacial basaltic crater rows and small shield volcanoes. The submarine Reykjaneshryggur volcanic system is contiguous with and is considered part of the Reykjanes volcanic system, which is the westernmost of a series of four closely-spaced en-echelon fissure systems that extend diagonally across the Reykjanes Peninsula. Most of the subaerial part of the system (also known as the Reykjanes/Svartsengi volcanic system) is covered by Holocene lavas. Subaerial eruptions have occurred in historical time during the 13th century at several locations on the NE-SW-trending fissure system, and numerous submarine eruptions dating back to the 12th century have been observed during historical time, some of which have formed ephemeral islands. Basaltic rocks of probable Holocene age have been recovered during dredging operations, and tephra deposits from earlier Holocene eruptions are preserved on the nearby Reykjanes Peninsula. Source: Icelandic Meteorological Office (IMO) http://en.vedur.is/ *Ongoing Activity* *Aira* | Japan | 31.5772°N, 130.6589°E | Summit elev. 1117 m The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Calderaâ??s Sakurajima volcano) during 28 July-4 August. Three explosions occurred at the Minamidake crater 28-30 July, with ash plumes rising up to 1 km (3,300 ft) above the crater rim. On 2 August at 2006, an explosion produced an ash plume that rose 1.1 km (3,600 ft) above the rim. Very small eruptive events occasionally occurred during 3-4 August. 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. Geologic 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. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ *Ambae* | Vanuatu | 15.389°S, 167.835°E | Summit elev. 1496 m The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambae during the month of July based on seismic and satellite data. Satellite imagery and webcam observations from 13, 17, 26, and 28-29 July showed continuous steam and/or gas emissions. Sulfur dioxide emissions were recorded in satellite images acquired on 1-3, 5-7, 9-16, 18-19, 22-24, 27-28, and 30 July. A low-level thermal anomaly was also detected in satellite images from 10, 23, and 28 July. 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. Geologic 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. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ *Ambrym* | Vanuatu | 16.25°S, 168.12°E | Summit elev. 1334 m The Vanuatu Meteorology and Geohazards Department (VMGD) reported ongoing unrest at Ambrym during the month of July. Field observations and webcam images from 11 and 14 July confirmed continuous degassing at Marum crater. Low-level thermal anomalies were detected in satellite imagery from 14 and 27 July. Seismic data further confirmed ongoing unrest. The Alert Level remained at 2 (on a scale of 0-5). VMGD warned the public to stay outside the Permanent Exclusion Zone, which includes a 1-km radius around Benbow Crater, and Danger Zone A, a 2-km radius around Marum Crater (including Maben-Mbwelesu, Niri-Mbwelesu, and Mbwelesu), and to stay 500 m away from the ground cracks created by the December 2018 eruption. Geologic Summary. Ambrym is a large basaltic volcano with a 12-km-wide caldera formed during a major Plinian eruption with dacitic pyroclastic flows about 1,900 years ago. A thick, almost exclusively pyroclastic sequence, initially dacitic then basaltic, overlies lava flows of a pre-caldera shield volcano. Post-caldera eruptions, primarily from Marum and Benbow cones, have partially filled the caldera floor and produced lava flows that ponded on the floor or overflowed through gaps in the caldera rim. Post-caldera eruptions have also formed a series of scoria cones and maars along a fissure system oriented ENE-WSW. Eruptions have been frequently reported since 1774, though mostly limited to extra-caldera eruptions that would have affected local populations. Since 1950 observations of eruptive activity from cones within the caldera or from flank vents have occurred almost yearly. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ *Dukono* | Indonesia | 1.6992°N, 127.8783°E | Summit elev. 1273 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Dukono continued during 30 July-5 August. White-and-gray gas-and-ash plumes rose 100-700 m above the summit and drifted in multiple directions on most days. The number of seismically recorded explosions varied from 9 to 174 per day, with the highest value recorded on 2 August. 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. Geologic 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. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ *Etna* | Italy | 37.748°N, 14.999°E | Summit elev. 3357 m The Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo (INGV-OE), reported that eruptive activity continued at Etnaâ??s summit craters during 28 July-3 August. The activity primarily involved variable-rate degassing, except at the SE crater, where low-level explosive activity generated ash emissions that were deposited throughout the summit area. Geologic 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. Source: Sezione di Catania - Osservatorio Etneo (INGV) http://www.ct.ingv.it/ *Fuego* | Guatemala | 14.4748°N, 90.8806°W | Summit elev. 3799 m The Instituto Nacional de SismologÃa, Vulcanologia, MeteorologÃa e HidrologÃa (INSIVUMEH) reported that eruptive activity at Fuego continued during 30 July-5 August. A fumarole was visible on those days with white emissions rising 100 m above the crater and drifting W. Pulses of gas and ash were visible during 30 July and 1-2 August. Weak incandescence at the summit was occasionally observed in overnight webcam images. Geologic Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ *Gaua* | Vanuatu | 14.281°S, 167.514°E | Summit elev. 729 m The Vanuatu Meteorology and Geohazards Department (VMGD) reported that unrest continued at Gaua during the month of July. Satellite images taken on 2-4, 7, and 9 July showed continuous steam and/or gas emissions from the vent. Sulfur dioxide emissions were detected in satellite images from 28 July. Additionally, a low-level thermal anomaly was recorded in satellite images from 7 and 11 July. The alert level remained at 2 (on a scale of 0-5), and the public was warned to stay away from the main cone. Geologic Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km summit caldera. Small vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; littoral cones were formed where these lava flows reached the ocean. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. The active Mount Garet (or Garat) cone in the SW part of the caldera has three pit craters across the summit area. Construction of Garet and other small cinder cones has left a crescent-shaped lake. The onset of eruptive activity from a vent high on the SE flank in 1962 ended a long period of dormancy. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ *Great Sitkin* | United States | 52.076°N, 176.13°W | Summit elev. 1740 m The Alaska Volcano Observatory (AVO) reported that slow lava effusion continued to feed a thick flow in Great Sitkinâ??s summit crater during 30 July-5 August. Low-level seismicity continued with occasional small earthquakes and rockfall signals detected. On 1 August elevated surface temperatures were observed in satellite data, with occasional steam emissions seen in clear views. High-resolution satellite views showed minor advancement of the SW lava lobe over the past week, as well as ongoing minor inflation of the S portion of the lava dome. Clouds obscured all satellite and webcam views on 2-5 August. 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). Geologic 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. Source: US Geological Survey Alaska Volcano Observatory (AVO) https://avo.alaska.edu/ *Home Reef* | Tonga | 18.992°S, 174.775°W | Summit elev. -10 m The Tonga Geological Services reported no signs of activity at Home Reef during 19 July-2 August. A thermal anomaly was last detected on 11 July, and both discolored water and sulfur deposits around the crater were last seen on 16 July. The Aviation Color Code remained at Yellow (the second lowest level on a four-level scale, the Maritime Alert Level remained at Orange (the third level on a four-level scale) with advice to stay at least 2 nautical miles (3.7 km) from the island, and the Alert Level for residents of Vavaâ??u and Haâ??apai remained at Green (the first level on a four-level scale). Geologic Summary. Home Reef, a submarine volcano midway between Metis Shoal and Late Island in the central Tonga islands, was first reported active in the mid-19th century, when an ephemeral island formed. An eruption in 1984 produced a 12-km-high eruption plume, large amounts of floating pumice, and an ephemeral 500 x 1,500 m island, with cliffs 30-50 m high that enclosed a water-filled crater. In 2006 an island-forming eruption produced widespread dacitic pumice rafts that drifted as far as Australia. Another island was built during a September-October 2022 eruption. Source: Tonga Geological Services, Government of Tonga https://www.facebook.com/tongageologicalservice *Ibu* | Indonesia | 1.488°N, 127.63°E | Summit elev. 1325 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that the eruption at Ibu continued during 30 July-5 August. Daily dense gray or white-to-gray ash plumes rose 300-900 m above the summit and drifted N, NW, and W. Between 109 and 137 daily explosions were noted. Crater incandescence was visible in nighttime webcam images. The Alert Level remained at 2 (the second highest 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. Geologic 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. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ *Karymsky* | Russia | 54.049°N, 159.443°E | Summit elev. 1513 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that moderate steam-and-gas activity continued at Karymsky during 31 July-6 August. A weak thermal anomaly over the volcano was observed in satellite images during 2-5 August. The volcano was quiet or obscured by clouds on the other days of the week. The Aviation Color Code remained at 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. Geologic Summary. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater. Source: *Kirishimayama* | Japan | 31.934°N, 130.862°E | Summit elev. 1700 m The Japan Meteorological Agency (JMA) reported that eruptive activity continued at Shinmoedake (Shinmoe peak, a stratovolcano of the Kirishimayama volcano group) during 28 July-4 August. The number of volcanic earthquakes with epicenters directly beneath Shinmoedake had been fluctuating since late October 2024; volcanic tremor was occasionally detected. Eruptive activity occurred intermittently with grayish white plumes rising as high as 1.2 km above the crater rim. A field survey conducted at the foot of the mountain on 28 July found sulfur dioxide emissions of 600 tons per day, compared to 1,600 tons per day on 15 July. The Alert Level remained at 3 (on a 5-level scale) and the public was warned to exercise caution within 3 km from Shinmoedake Crater. Geologic Summary. Kirishimayama is a large group of more than 20 Quaternary volcanoes located north of Kagoshima Bay. The late-Pleistocene to Holocene dominantly andesitic group consists of stratovolcanoes, pyroclastic cones, maars, and underlying shield volcanoes located over an area of 20 x 30 km. The larger stratovolcanoes are scattered throughout the field, with the centrally located Karakunidake being the highest. Onamiike and Miike, the two largest maars, are located SW of Karakunidake and at its far eastern end, respectively. Holocene eruptions have been concentrated along an E-W line of vents from Miike to Ohachi, and at Shinmoedake to the NE. Frequent small-to-moderate explosive eruptions have been recorded since the 8th century. Source: *Lewotolok* | Indonesia | 8.274°S, 123.508°E | Summit elev. 1431 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that an eruption at Lewotolok was ongoing during 30 July-5 August. White-to-gray or gray ash plumes typically rose 200-400 m above the summit of the cone and drifted in multiple directions. Clear nighttime webcam images showed incandescent material being ejected above the cone. Between 50 and 181 daily explosions were recorded over the week-long period. 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. Geologic 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. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ *Marapi* | Indonesia | 0.38°S, 100.474°E | Summit elev. 2885 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that eruptive activity at Marapi (on Sumatra) continued during 30 July-5 August. There were two explosions on 31 July, at 0100 and 0741. Only the 0741 event was observed, with a plume that rose 400 m above the summit and dispersed to the N. Another eruption was detected seismically on 2 August at 1233 but was not witnessed due to cloudy weather. 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. Geologic Summary. Gunung Marapi, not to be confused with the better-known Merapi volcano on Java, is Sumatra's most active volcano. This massive complex stratovolcano rises 2,000 m above the Bukittinggi Plain in the Padang Highlands. A broad summit contains multiple partially overlapping summit craters constructed within the small 1.4-km-wide Bancah caldera. The summit craters are located along an ENE-WSW line, with volcanism migrating to the west. More than 50 eruptions, typically consisting of small-to-moderate explosive activity, have been recorded since the end of the 18th century; no lava flows outside the summit craters have been reported in historical time. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ *Merapi* | Indonesia | 7.54°S, 110.446°E | Summit elev. 2910 m The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 25-31 July. During that 19 avalanches were observed descending into the upper reaches of the Krasak River and reaching as far as 2 km from the summit. There were six avalanches in the upper reaches of the Bebeng River that traveled as far as 1.9 km. Fifty avalanches descended into the upper Sat/Putih River, extending a maximum of 2 km. Based on analysis of aerial photos from 17 July, the volume of the SW lava dome and the central dome were 4,011,000 cubic meters and 2,368,900 cubic meters, respectively. Small morphological changes to the SW lava dome resulted from continuing 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. Geologic 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. Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) http://www.merapi.bgl.esdm.go.id/ *Poas* | Costa Rica | 10.2°N, 84.233°W | Summit elev. 2697 m The Observatorio Vulcanológico y Sismológico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported continuing gas-and-steam emissions with occasional minor amounts of ash at Poás during 30 July-5 August. Strong incandescence at Boca A vent was observed. Sulfur dioxide emissions remained high and were between 250 and 1,000 tons per day during the week. The volcanic Alert Level remained at 2 (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). Geologic Summary. The broad vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the complex stratovolcano extends to the lower N flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since an eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water. Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) http://www.ovsicori.una.ac.cr/; Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE) http://www.cne.go.cr/ *Santa Maria* | Guatemala | 14.757°N, 91.552°W | Summit elev. 3745 m The Instituto Nacional de SismologÃa, VulcanologÃa, MeteorologÃa e HidrologÃa (INSIVUMEH) reported strong eruptive activity continuing at Santa Mariaâ??s Santiaguito dome complex during 30 July-5 August, including lava extrusion at Caliente dome. Daily explosions, 1-2 per hour when reported, generated gas-and-ash plumes that rose as high as 1 km above the dome and drifted W. Effusion of blocky lava and collapses of previous deposits produced block avalanches that descended multiple flanks; the collapsed material sometimes produced pyroclastic flows that reached the base of the volcano. Incandescence was visible at Caliente dome mostly during dark hours. Minor ashfall was reported in communities to the S and SW during 1 and 3-5 August. Geologic Summary. Symmetrical, forest-covered Santa MarÃa volcano is part of a chain of large stratovolcanoes that rise above the Pacific coastal plain of Guatemala. The sharp-topped, conical profile is cut on the SW flank by a 1.5-km-wide crater. The oval-shaped crater extends from just below the summit to the lower flank, and was formed during a catastrophic eruption in 1902. The renowned Plinian eruption of 1902 that devastated much of SW Guatemala followed a long repose period after construction of the large basaltic andesite stratovolcano. The massive dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four vents, with activity progressing E towards the most recent, Caliente. Dome growth has been accompanied by almost continuous minor explosions, with periodic lava extrusion, larger explosions, pyroclastic flows, and lahars. Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH) http://www.insivumeh.gob.gt/ *Semeru* | Indonesia | 8.108°S, 112.922°E | Summit elev. 3657 m The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) reported that activity continued at Semeru during 30 July-5 August, with between 39 and 51 daily eruptive events recorded by the seismic network. Eruptive plumes rose between 400 and 900 m above the summit and generally traveled to the S and SW. 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. Geologic 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. Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM) http://vsi.esdm.go.id/ *Sheveluch* | Russia | 56.653°N, 161.36°E | Summit elev. 3283 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported continuing eruptive activity at Sheveluchâ??s â??300 years of RASâ?? dome on the SW flank of Old Sheveluch and at the Young Sheveluch dome during 31 July-6 August. Thermal anomalies were identified over the domes in satellite images from 30-31 July and 2 August. The volcano was obscured by clouds during the other days of the week. 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. Geologic 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. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://kvert.febras.net/ *Suwanosejima* | Japan | 29.638°N, 129.714°E | Summit elev. 796 m The Japan Meteorological Agency (JMA) reported that eruptive activity at Suwanosejima's Ontake Crater continued during 28 July-4 August. Eruption plumes rose up to 500 m above the crater rim and no explosions were detected. 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. Geologic Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island. Source: Japan Meteorological Agency (JMA) http://www.jma.go.jp/jma/ *Telica* | Nicaragua | 12.606°N, 86.84°W | Summit elev. 1036 m The Washington Volcanic Ash Advisory Center (VAAC) reported that during 3-4 August ash plumes from Telica were identified in satellite and/or webcam images at 1.5 km (5,000 ft) a.s.l. drifting SW. A plume with possible ash was visible in webcam images drifting SW on 3 August. Geologic Summary. Telica, one of Nicaragua's most active volcanoes, has erupted frequently since the beginning of the Spanish era. This volcano group consists of several interlocking cones and vents with a general NW alignment. Sixteenth-century eruptions were reported at symmetrical Santa Clara volcano at the SW end of the group. However, its eroded and breached crater has been covered by forests throughout historical time, and these eruptions may have originated from Telica, whose upper slopes in contrast are unvegetated. The steep-sided cone of Telica is truncated by a 700-m-wide double crater; the southern crater, the source of recent eruptions, is 120 m deep. El Liston, immediately E, has several nested craters. The fumaroles and boiling mudpots of Hervideros de San Jacinto, SE of Telica, form a prominent geothermal area frequented by tourists, and geothermal exploration has occurred nearby. Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html *Yasur* | Vanuatu | 19.532°S, 169.447°E | Summit elev. 361 m The Vanuatu Meteorology and Geohazards Department (VMGD) reported that activity at Yasur continued at a level of â??major unrest,â?? as defined by the Alert Level 2 status (on a scale of 0-5) during July. Satellite and webcam images from 1, 3-17, 20-23, 25-26, and 28-31 July showed that explosive activity continued, producing gas, steam, and/or ash emissions. Sulfur dioxide emissions were detected in satellite images from 2-14 and 17-30 July. Low-to-moderate thermal anomalies were observed in satellite images on 5, 11-13, 15, 21, 24-25, and 27-29 July. Seismic data confirmed ongoing volcanic activity, with explosions that were occasionally strong. The public was advised to maintain a minimum distance of 600 m from the eruptive vents, designated as Danger Zone A on the Yasur Caldera Safety Map. Geologic Summary. Yasur has exhibited essentially continuous Strombolian and Vulcanian activity at least since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island in Vanuatu, this pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide open feature associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century. Source: Vanuatu Meteorology and Geohazards Department (VMGD) http://www.geohazards.gov.vu/ 4-4-4-4-4-4-4-4-4-4-4-4-4 ============================================================== Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI). 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