New activity/unrest was reported for just 2 volcanoes from March 11 to 17, 2020. During the same period, ongoing activity was reported for 19 volcanoes.
New activity/unrest: Antillanca Volcanic Complex, Chile | Kanlaon, Philippines.
Ongoing activity: Aira, Kyushu (Japan) | Asosan, Kyushu (Japan) | Dukono, Halmahera (Indonesia) | Ebeko, Paramushir Island (Russia) | Ibu, Halmahera (Indonesia) | Kadovar, Papua New Guinea | Kerinci, Indonesia | Klyuchevskoy, Central Kamchatka (Russia) | Nevado del Ruiz, Colombia | Nevados de Chillan, Chile | Nishinoshima, Japan | Reykjanes, Iceland | Rincon de la Vieja, Costa Rica | Semisopochnoi, United States | Sheveluch, Central Kamchatka (Russia) | Shishaldin, Fox Islands (USA) | Suwanosejima, Ryukyu Islands (Japan) | Taal, Luzon (Philippines) | Yasur, Vanuatu.
Antillanca Volcanic Complex, Chile
40.783°S, 72.15°W, Summit elev. 1979 m
On 11 March SERNAGEOMIN raised the Alert Level for the Antillanca Volcanic Complex to Yellow because of increased seismicity near Casablanca stratovolcano. Volcano-tectonic (VT) earthquakes began to be recorded in August 2019 and were located about 6.3 km NE of the stratovolcano. During 31 January-1 February a total of 131 VT events were located to the W and NW; the two largest events were M 3.1 and 3.2. A swarm of 73 VT events were detected on 9 March with epicenters located 2.4 km NNW and a maximum local magnitude of 1.8.
Geological summary: The Antillanca Volcanic Complex is a cluster of late-Pleistocene to Holocene basaltic-to-andesitic scoria cones, maars, and small stratovolcanoes covering an area of 380 km2 SE of Lago Puyehue and NE of Lago Rupanco. The most prominent edifice is the Holocene Casablanca stratovolcano, which has a truncated conical profile and produced major explosive eruptions about 2,910 and 2,260 radiocarbon years ago. Older late-Pleistocene stratovolcanoes, such as Sarnoso to the SW and Fiuchá to the NW, are extensively dissected by glaciers. Fissures oriented in four major directions influence the orientation of the cones. Thermal areas are found in scattered locations on the NW side of the complex.
10.412°N, 123.132°E, Summit elev. 2435 m
PHIVOLCS reported that ground-deformation data at Kanlaon indicated long-term slow inflation of the volcano since 2017, slow inflation of the lower flanks since May 2019, and notable inflation of the upper flanks beginning near the end of January 2020. The seismic network recorded a total of 80 volcanic earthquakes since 9 March; 77 of them were low-frequency events associated with magmatic fluids. The deformation and seismic data both indicated unrest; PHIVOLCS raised the Alert Level to 1 (on a scale of 0-5) on 11 March and reminded the public to remain outside of the 4-km-radius Permanent Danger Zone. During 12-17 March there were between two and eight volcanic earthquakes recorded daily.
Geological summary: Kanlaon volcano (also spelled Canlaon), the most active of the central Philippines, forms the highest point on the island of Negros. The massive andesitic stratovolcano is dotted 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, historically active vent, Lugud crater, to the south. Historical eruptions, recorded since 1866, have typically consisted of phreatic explosions of small-to-moderate size that produce minor ashfalls near the volcano.
Aira, Kyushu (Japan)
31.593°N, 130.657°E, Summit elev. 1117 m
JMA reported that during 9-16 March incandescence from Minamidake Crater (at Aira Caldera’s Sakurajima volcano) was visible nightly. Occasional eruptive events were recorded. An eruption at 1433 on 12 March generated an ash plume that rose 2.1 km above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
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 Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
Asosan, Kyushu (Japan)
32.884°N, 131.104°E, Summit elev. 1592 m
JMA reported that eruptive activity at Asosan was recorded during 9-16 March. Gray-to-white ash plumes rose 600-800 m above the crater rim and caused ashfall in areas downwind. The sulfur dioxide emission rate was high at 1,600-1,700 tons per day on 11 and 16 March. The Alert Level remained at 2 (on a scale of 1-5).
Geological summary: The 24-km-wide Asosan caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 km3 of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Nakadake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 CE. The Nakadake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 CE. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Nakadake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.
Dukono, Halmahera (Indonesia)
1.693°N, 127.894°E, Summit elev. 1229 m
Based on satellite and wind model data, the Darwin VAAC reported that during 11-17 March ash plumes from Dukono rose to 2.1 km (7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Geological summary: Reports from this remote volcano in northernmost Halmahera are rare, but Dukono has been one of Indonesia's most active volcanoes. More-or-less continuous explosive eruptions, sometimes accompanied by lava flows, occurred from 1933 until at least the mid-1990s, when routine observations were curtailed. During a major eruption in 1550, a lava flow filled in the strait between Halmahera and the north-flank cone of Gunung Mamuya. This complex volcano presents a broad, low profile with multiple summit peaks and overlapping craters. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also been active during historical time.
Ebeko, Paramushir Island (Russia)
50.686°N, 156.014°E, Summit elev. 1103 m
Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions on 8 March that sent ash plumes up to 2.5 km (8,200 ft) a.s.l. Ash plumes drifted NE. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Geological summary: The flat-topped summit of the central cone of Ebeko volcano, one of the most active in the Kuril Islands, occupies the northern end of Paramushir Island. Three summit craters located along a SSW-NNE line form Ebeko volcano proper, at the northern end of a complex of five volcanic cones. Blocky lava flows extend west from Ebeko and SE from the neighboring Nezametnyi cone. The eastern part of the southern crater contains strong solfataras and a large boiling spring. The central crater is filled by a lake about 20 m deep whose shores are lined with steaming solfataras; the northern crater lies across a narrow, low barrier from the central crater and contains a small, cold crescentic lake. Historical activity, recorded since the late-18th century, has been restricted to small-to-moderate explosive eruptions from the summit craters. Intense fumarolic activity occurs in the summit craters, on the outer flanks of the cone, and in lateral explosion craters.
Ibu, Halmahera (Indonesia)
1.488°N, 127.63°E, Summit elev. 1325 m
The Darwin VAAC reported that on 17 March multiple discrete ash plumes from Ibu rose to 2.1 km (7,000 ft) a.s.l. and drifted SW based on satellite images and weather models. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.
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, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley. A large parasitic cone is located ENE of the summit. 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. Only a few eruptions have been recorded in historical time, the first a small explosive eruption from the summit crater in 1911. An eruption producing a lava dome that eventually covered much of the floor of the inner summit crater began in December 1998.
Kadovar, Papua New Guinea
3.608°S, 144.588°E, Summit elev. 365 m
Based on satellite and wind model data, the Darwin VAAC reported that during 13-15 March ash plumes from Kadovar rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE.
Geological summary: The 2-km-wide island of Kadovar is the emergent summit of a Bismarck Sea stratovolcano of Holocene age. It is part of the Schouten Islands, and lies off the coast of New Guinea, about 25 km N of the mouth of the Sepik River. Prior to an eruption that began in 2018, a lava dome formed the high point of the andesitic volcano, filling an arcuate landslide scarp open to the south; submarine debris-avalanche deposits occur in that direction. Thick lava flows with columnar jointing forms low cliffs along the coast. The youthful island lacks fringing or offshore reefs. A period of heightened thermal phenomena took place in 1976. An eruption began in January 2018 that included lava effusion from vents at the summit and at the E coast.
1.697°S, 101.264°E, Summit elev. 3800 m
PVMBG reported that at 1633 on 14 March a brown ash emission rose 500 m above Kerinci’s summit and drifted WNW. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.
Geological summary: Gunung Kerinci in central Sumatra forms Indonesia's highest volcano and is one of the most active in Sumatra. It is capped by an unvegetated young summit cone that was constructed NE of an older crater remnant. There is a deep 600-m-wide summit crater often partially filled by a small crater lake that lies on the NE crater floor, opposite the SW-rim summit. The massive 13 x 25 km wide volcano towers 2400-3300 m above surrounding plains and is elongated in a N-S direction. Frequently active, Kerinci has been the source of numerous moderate explosive eruptions since its first recorded eruption in 1838.
Klyuchevskoy, Central Kamchatka (Russia)
56.056°N, 160.642°E, Summit elev. 4754 m
KVERT reported that Strombolian activity at Klyuchevskoy was visible during 6-13 March, and the number of hot avalanches descending the flanks in all directions significantly increased. A bright thermal anomaly was identified daily in satellite images, and gas-and-steam plume containing some ash drifted 135 km E, NE, and N during 8-9 and 12 March. The Aviation Color Code remained at Orange.
Geological summary: Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.
Nevado del Ruiz, Colombia
4.892°N, 75.324°W, Summit elev. 5279 m
Servicio Geológico Colombiano (SGC) reported that three gas-and-ash emissions from Nevado del Ruiz recorded on 10 March (at 0742, 1029, and 1055) rose 345-700 m above the summit and drifted SW, S, and SE. Minor ashfall was reported around the volcano and in towns downwind. The Alert Level remained at 3 (Yellow; the second lowest level on a four-color scale).
Geological summary: Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.
Nevados de Chillan, Chile
36.868°S, 71.378°W, Summit elev. 3180 m
SERNAGEOMIN lowered the Alert Level for Nevados de Chillán to Yellow, the second lowest level on a four-color scale, on 5 March. ONEMI maintained an Alert Level Yellow (the middle level on a three-color scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.
Geological summary: The compound volcano of Nevados de Chillán is one of the most active of the Central Andes. Three late-Pleistocene to Holocene stratovolcanoes were constructed along a NNW-SSE line within three nested Pleistocene calderas, which produced ignimbrite sheets extending more than 100 km into the Central Depression of Chile. The largest stratovolcano, dominantly andesitic, Cerro Blanco (Volcán Nevado), is located at the NW end of the group. Volcán Viejo (Volcán Chillán), which was the main active vent during the 17th-19th centuries, occupies the SE end. The new Volcán Nuevo lava-dome complex formed between 1906 and 1945 between the two volcanoes and grew to exceed Volcán Viejo in elevation. The Volcán Arrau dome complex was constructed SE of Volcán Nuevo between 1973 and 1986 and eventually exceeded its height.
27.247°N, 140.874°E, Summit elev. 25 m
During an overflight on 9 March the Japan Coast Guard (JCG) noted continuous activity from the central vent at Nishinoshima, including an ash plume rising as high as 1 km. Ejected material landed near the cone’s base. Lava from the NE side of the central vent flowed 1 km N and into the sea. Steam plumes rose along the E coast where lava entered the sea. Lava also effused from a vent on the SW flank of the cone. Discolored yellow-green water was visible offshore to the W, N, and E. Sulfur dioxide emissions had increased since 17 February measurements. The marine exclusion zone was defined as a radius of about 2.6 km from the island.
Geological summary: The small island of Nishinoshima was enlarged when several new islands coalesced during an eruption in 1973-74. Another eruption that began offshore in 2013 completely covered the previous exposed surface and enlarged the island again. Water discoloration has been observed on several occasions since. The island is the summit of a massive submarine volcano that has prominent satellitic peaks to the S, W, and NE. The summit of the southern cone rises to within 214 m of the sea surface 9 km SSE.
63.85°N, 22.566°W, Summit elev. 140 m
On 18 March IMO raised the Aviation Color Code for Reykjanes to Yellow noting that recent InSAR and GPS data indicated that during the second week of March deformation had restarted. The uplift was concentrated in the same place as that recorded in January-February, though at a slower rate. The cause of the deformation was likely an intrusion of magma at 4.5 km depth.
A large (M 4.6) earthquake was recorded on 12 March and located 3.5 km NE of Thorbjorn, possibly connected to the inflation. A sequence of aftershocks lasted for a few days and was characterized by eight earthquakes over M 3 and about 80 events with magnitudes between 2 and 3. Since the large event a total of 850 earthquakes were recorded in the area.
Geological 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.
Rincon de la Vieja, Costa Rica
10.83°N, 85.324°W, Summit elev. 1916 m
OVSICORI-UNA reported a minor increase in tremor amplitude at Rincón de la Vieja beginning at 0200 on 12 March. At 1845 on 14 March an eruption was recorded by the seismic network, but weather conditions prevented visual confirmation; strong tremor was recorded during 1845-2030. Tremor levels increased at around 0300 on 15 March and stopped around 0100 on 17 March, possibly indicating a small eruption.
Geological summary: Rincón de la Vieja, the largest volcano in NW Costa Rica, is a remote volcanic complex in the Guanacaste Range. The volcano consists of an elongated, arcuate NW-SE-trending ridge that was 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. Activity has migrated to the SE, where the youngest-looking craters are located. The twin cone of 1916-m-high Santa María volcano, the highest peak of the complex, is located at the eastern end of a smaller, 5-km-wide caldera and has a 500-m-wide crater. A plinian eruption producing the 0.25 km3 Río Blanca tephra about 3500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous historical eruptions possibly dating back to the 16th century, have been from the prominent active crater containing a 500-m-wide acid lake located ENE of Von Seebach crater.
Semisopochnoi, United States
51.93°N, 179.58°E, Summit elev. 1221 m
Seismicity at Semisopochnoi increased over a period of a few days and by 15 March was characterized by nearly continuous tremor and frequent signals indicating small explosions. The unrest prompted AVO to raise the Aviation Color Code to Orange and the Volcano Alert Level to Watch on 15 March. A robust steam plume rising from the N cone of Mount Cerberus and minor ash deposits around the crater rim were visible in a clear satellite image acquired on 16 March.
Geological summary: Semisopochnoi, the largest subaerial volcano of the western Aleutians, is 20 km wide at sea level and contains an 8-km-wide caldera. It formed as a result of collapse of a low-angle, dominantly basaltic volcano following the eruption of a large volume of dacitic pumice. The high point of the island is 1221-m-high Anvil Peak, a double-peaked late-Pleistocene cone that forms much of the island's northern part. The three-peaked 774-m-high Mount Cerberus volcano was constructed during the Holocene within the caldera. Each of the peaks contains a summit crater; lava flows on the northern flank of Cerberus appear younger than those on the southern side. Other post-caldera volcanoes include the symmetrical 855-m-high Sugarloaf Peak SSE of the caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake in the NE part of the caldera. Most documented historical eruptions have originated from Cerberus, although Coats (1950) considered that both Sugarloaf and Lakeshore Cone within the caldera could have been active during historical time.
Sheveluch, Central Kamchatka (Russia)
56.653°N, 161.36°E, Summit elev. 3283 m
KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 6-13 March. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Geological summary: The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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.
Shishaldin, Fox Islands (USA)
54.756°N, 163.97°W, Summit elev. 2857 m
Lava and a possible new cone in Shishaldin’s summit crater were visible in a satellite image on 14 March prompting AVO to raise the Volcano Alert Level to Watch and the Aviation Color Code to Orange. Weak but elevated seismicity was also recorded along with small explosion signals during 14-17 March. Elevated surface temperatures, consistent with lava in the summit crater, were identified in satellite images during 15-17 March. A small steam plume rising from the summit crater was visible in a webcam image on 17 March.
Geological summary: The beautifully symmetrical Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steam plume often rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the W and NE sides at 1,500-1,800 m elevation. There are over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of Strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.
Suwanosejima, Ryukyu Islands (Japan)
29.638°N, 129.714°E, Summit elev. 796 m
JMA reported that during 28 February-6 March incandescence from Suwanosejima’s Ontake Crater was visible nightly. Occasional eruptive events generated ash plumes that rose as high as 900 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).
Geological summary: The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed 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 the horseshoe-shaped Sakuchi caldera, which extends 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.
Taal, Luzon (Philippines)
14.002°N, 120.993°E, Summit elev. 311 m
PHIVOLCS reported that during 11-17 March weak steam plumes at Taal rose 50-100 m above Volcano Island lake and drifted SW and NE. According to the Disaster Response Operations Monitoring and Information Center (DROMIC) there were a total of 4,131 people in 11 evacuation centers, and an additional 17,563 displaced people were staying at other locations as of 11 March. The Alert Level remained at 2 (on a scale of 0-5) and PHIVOLCS recommended no entry onto Volcano Island, the area defined as the Permanent Danger Zone.
Geological summary: Taal is one of the most active volcanoes in the Philippines and has produced some of its most powerful historical eruptions. Though not topographically prominent, its prehistorical eruptions have greatly changed the landscape of SW Luzon. 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, and several eruptive centers lie submerged beneath the lake. The 5-km-wide Volcano Island in north-central Lake Taal is the location of all historical eruptions. The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones that have grown about 25% in area during historical time. Powerful pyroclastic flows and surges from historical eruptions have caused many fatalities.
19.532°S, 169.447°E, Summit elev. 361 m
Based on webcam images and satellite data the Wellington VAAC reported that during on 13 and 17 March low-level ash plumes from Yasur rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted N and SE.
Geological summary: Yasur, the best-known and most frequently visited of the Vanuatu volcanoes, has been in more-or-less continuous Strombolian and Vulcanian activity 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, this mostly unvegetated 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, horseshoe-shaped caldera 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.