********************************************************* GVP/USGS Weekly Volcanic Activity Report 5-11 July 2006 ********************************************************* From: "Kuhn, Sally" <KUHNS@xxxxxx> GVP/USGS Weekly Volcanic Activity Report 5-11 July 2006 New Activity/Unrest: | Bamus, Papua New Guinea | Karangetang, Indonesia | Mayon, Philippines | Merapi, Indonesia | Sulu Range, Papua New Guinea | Tungurahua, Ecuador Ongoing Activity: | Galeras, Colombia | Karymsky, Russia | Kilauea, USA | Manam, Papua New Guinea | Semeru, Indonesia | Soufriere Hills, Montserrat | St. Helens, USA Suwanose-jima, Japan | Tengger Caldera, Indonesia | Ubinas, Perú New Activity/Unrest BAMUS New Britain Island, Papua New Guinea 5.20°S, 151.23°E; summit elev. 2248 m; All times are local (= UTC + 10 hours) RVO reported that white vapor emissions from Bamus were observed during 1000-1130 on 12 July. The emissions were forceful and slightly gray in color at 1110. The vapor plume drifted SSE. Geologic Summary. Symmetrical 2248-m-high Bamus volcano, also referred to locally as South Son, is located SW of Ulawun volcano, known as the North Son. These two volcanoes are the highest in the 1000-km-long Bismarck volcanic arc. The andesitic Bamus stratovolcano is draped by rainforest and contains a breached summit crater filled with a lava dome. A satellitic cone is located on the southern flank, and a prominent 1.5-km-wide crater with two small adjacent cones is situated halfway up the SE flank. Young pyroclastic-flow deposits are found on the volcano's flanks, and villagers describe an eruption that took place during the late-19th century. Source: Herman Patia, Rabaul Volcanological Observatory Bamus Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-11= KARANGETANG [Api Siau] Siau Island, Indonesia 2.47°N, 125.29°E; summit elev. 1,784 m The Alert Status of Karangetang was raised on 13 July from 2 to 3 (on a scale of 1-4) due to increased eruptive activity. On 12 July, lava flows were observed moving E toward the Kahetang and Batu Awang rivers at a maximum distance of 2 km from the vent. White emissions reached a height of 600 m above the crater (7,800 ft a.s.l.). Geologic Summary. Karangetang (also known as Api Siau) lies at the northern end of the island of Siau, N of Sulawesi. The 1,784-m-high stratovolcano contains five summit craters along a N-S line. One of Indonesia's most active volcanoes, Karangetang has had more than 40 recorded eruptions since 1675. Twentieth-century eruptions have included frequent explosions, sometimes accompanied by pyroclastic flows and lahars. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://portal.vsi.esdm.go.id/joomla/index.php?option=com_frontpage&Itemid=1 Karangetang Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0607-02= MAYON southeastern Luzon, Philippines 13.257°N, 123.685°E; summit elev. 2,462 m Phreatic eruptions at Mayon on 13 July produced ash that fell up to approximately 5.3 km NE in Calbayog, Malilipot. The Alert Level was raised from 1 to 3 (scale is 0-5, 0 referring to No Alert status) after observers reported lava flows on the SE slopes, the predominant direction for lava flows and rockfalls. On 16 July, a danger zone 6 km from the summit was extended to 7 km in the SE area. Incandescent material was shed from an 800 m long lava flow moving SSE towards Bonga gully on 16 and 17 July. On 18 July, PHIVOLCS reported that the lava flow reached 1 km in length and incandescent boulders rolled 3 km towards the Bonga gully. Geologic Summary. The beautifully symmetrical Mayon volcano, which rises to 2,462 m above the Albay Gulf, is the Philippines' most active volcano. The structurally simple volcano has steep upper slopes that average 35-40° and is capped by a small summit crater. The historical eruptions of this basaltic-andesitic volcano date back to 1616 and range from Strombolian to basaltic Plinian. Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often devastated populated lowland areas. Mayon's most violent eruption, in 1814, killed more than 1,200 people and devastated several towns. Eruptions that began in February 2000 led PHIVOLCS to recommend on 23 February the evacuation of people within a radius of 7 km from the summit in the SE and within a 6 km radius for the rest of the volcano. Sources: PHIVOLCS http://www.phivolcs.dost.gov.ph/news/mayon71706.html, Manila Standard Today http://www.manilastandardtoday.com/?page=regions02_july14_2006, AP http://www.forbes.com/home/feeds/ap/2006/07/14/ap2880283.html, AP/Sunnex http://www.sunstar.com.ph/static/net/2006/07/16/mayon.volcano.erupts..html Mayon Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0703-03= MERAPI central Java, Indonesia 7.542°S, 110.442°E; summit elev. 2,947 m During 12-18 July, active lava flows at Merapi reached a maximum distance of 2 km SE along the Gendol River. Gas plumes were also observed daily and reached heights of 1 km above the crater (13,000 ft a.s.l.). On 17 July, CVGHM reported that the Alert Level was lowered to 3 (on a scale of 1-4) in all remaining areas previously at Alert Level 4 (S slopes). Pyroclastic flows were not observed during the reporting period. 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 N of the major city of Yogyakarta. The steep-sided modern Merapi edifice, its upper part unvegetated due to frequent eruptive activity, was constructed to the SW of an arcuate scarp cutting the eroded older Batulawang volcano. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated and inhabited lands on the volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory. Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) http://www.vsi.esdm.go.id/portal/html/index.php Merapi Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0603-25= SULU RANGE New Britain Island, Papua New Guinea 5.50°S, 150.942°E The RVO reported that seismic activity from the Sulu Range continued at a high level during 13-15 July. No emissions were reported during this period. According to news reports, on 16 July disaster officials in Papua New Guinea evacuated three villages and moved 1,400 people to camps outside of the hazard zone. Geologic Summary. The Sulu Range consists of a group of partially overlapping small stratovolcanoes in west-central New Britain off Bangula Bay. The 610-m Mount Malopu forms the high point of the basaltic-to-rhyolitic complex at its SW end. Lava Point forms a peninsula extending about 1 km into Bangula Bay at the NW side of the Sulu Range. The Walo hydrothermal area, consisting of solfataras and mud pots, lies on the coastal plain west of the SW base of the Sulu Range. Prior to 2006, no historical eruptions had occurred from the Sulu Range, although some of the cones display a relatively undissected morphology. Sources: Herman Patia and Steve Saunders, Rabaul Volcano Observatory, Association of American Publishers http://www9.sbs.com.au/theworldnews/region.php?id=130254®ion=2 TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m During 12-18 July, eruptive activity at Tungurahua increased. Incandescent blocks rolled 500 m down the flanks and steam emissions with moderate ash content reached heights of 300 m above the crater (17,500 ft a.s.l.) during 11-13 July. On 14 July, a large eruption generated ash clouds that reached heights of 15 km above the summit (66,000 ft a.s.l.). The plume expanded in multiple directions and then drifted predominantly W, SW, and E. Ash accumulated to a maximum thickness of 15 mm in Pillate, about 7 km to the W. At least five pyroclastic flows, the first since 1999, traveled N and NW. The resulting deposits were up to 8 m thick and 20 m wide. At least four lava flows were also observed. Over 3,700 people from seven small villages near the volcano evacuated to nearby towns. On 15 and 16 July, multiple pyroclastic flows reached the area of Cusúa, approximately 7 km NW of the summit. Explosions and pyroclastic flows generated ash clouds that reached heights of 6 km above the volcano (36,200 ft a.s.l.). On 17 July, eruption columns with high ash content reached heights of 5 km above the summit (32,900 ft a.s.l.). On 18 July, moderate explosions produced steam columns that reached maximum heights of 3 km above the crater (26,300 ft a.s.l.). A child died after ash inhalation complicated a heart illness. Geologic Summary. The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have been restricted to the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano. Sources: Instituto Geofísico-Escuela Poltécnica Nacional http://www.igepn.edu.ec/vulcanologia/tungurahua/actividad/informet.htm, Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/ARCHIVE/ANAT/2006E291935.html, Reuters http://today.reuters.co.uk/news/newsArticle.aspx?type=worldNews&storyID=2006-07-16T004057Z_01_N15207928_RTRUKOC_0_UK-ECUADOR-VOLCANO.xml&archived=False, Prensa Latina http://www.plenglish.com/article.asp?ID=%7B353B9A38-F013-4878-9EC8-6E1D7F5F5F5B%7D&language=EN Tungurahua Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08= Ongoing Activity GALERAS Colombia 1.22°N, 77.37°W; summit elev. 4,276 m According to a news article, on 12 July the Colombian government ordered the evacuation of ~10,000 people living near Galeras due to an increase in volcanic activity. INGEOMINAS reported an increase in seismic activity and at least two explosive eruptions. Ash accumulated about 10 km N and NE in the towns of La Florida and Nariño and 5 km NE in the town of Genoy. The Alert Level was increased from 2 (probable eruption in days to weeks) to 1 (eruption imminent or occurring). On 13 July, due to a decrease in activity, the Alert Level was lowered from 1 to 3 (changes in the behavior of volcanic activity have been noted). Approximately 2,000 people had been taken to shelters. Geologic Summary. Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Long-term extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors. Sources: Instituto Colombiano de Geología y Minería http://www.ingeominas.gov.co/tmsingeominas/ModuloPublicacionPortal/PublicacionPortal.asp, Reuters http://today.reuters.com/News/CrisesArticle.aspx?storyId=N12302107, Sapa-AP http://www.iol.co.za/index.php?set_id=1&click_id=122&art_id=qw1152824943911R131, BBC News http://news.bbc.co.uk/2/hi/americas/5176234.stm Galeras Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-08= KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m Activity at Karymsky continued during 8-14 July, with 250-1000 shallow earthquakes occurring daily. Based on interpretations of seismic data, ash plumes reached altitudes of 5 km (16,400 ft) a.s.l. A thermal anomaly in the crater was observed on 9 July. Karymsky remained at Concern Color Code Orange <http://www.avo.alaska.edu/color_codes.php>. 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 about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-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. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996. Source: Kamchatkan Volcanic Eruption Response Team http://www.kscnet.ru/ivs/kvert/updates.shtml Karymsky Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-13= KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m During 14-18 July, small areas of incandescence were observed from Kilauea's Campout flow on Pulama pali. Lava continued to flow off of a lava delta into the ocean at the East Lae`apuki entry. Seismicity levels were low at the summit and moderate at Pu`u `O`o. Geologic Summary. Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed by lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. The latest Kilauea eruption began in January 1983 along the E rift zone. This long-term ongoing eruption from Pu`u `O`o-Kupaianaha has produced lava flows that have traveled 11-12 km from the vents to the sea, paving about 104 km2 of land on the S flank of Kilauea and building more than 200 hectares of new land. Source: US Geological Survey Hawaiian Volcano Observatory http://volcanoes.usgs.gov/update.html Kilauea information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1302-01- MANAM offshore New Guinea, Papua New Guinea 4.10°S, 145.06°E; summit elev. 1,807 m According to the Darwin VAAC, a pilot reported that an ash cloud from Manam reached altitudes of 4.6 km (15,000 ft) a.s.l. on 17 July and drifted N. Ash was not visible on satellite imagery due to local cloud cover. Geologic Summary. The 10-km-wide island of Manam is one of Papua New Guinea's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1,807-m-high stratovolcano to its lower flanks. These "avalanche valleys," regularly spaced 90 degrees apart, channel lava flows and pyroclastic avalanches that have sometimes reached the coast. Five satellitic centers are located near the island's shoreline. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during the past century into the SE avalanche valley. Frequent historical eruptions have been recorded since 1616. Source: Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/products/IDD41300.shtml Manam Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0501-02= SEMERU Java, Indonesia 8.11°S, 112.92°E; summit elev. 3,676 m Eruption plumes from Semeru were visible on satellite imagery on 14 July drifting SE at unknown altitudes. On 17 July plumes reached altitudes of 4.3 km (14,000 ft) a.s.l. Geologic Summary. Semeru is the highest volcano on Java and one of its most active. The symmetrical stratovolcano rises abruptly to 3,676 m above coastal plains to the S and lies at the southern end of a volcanic massif extending N to the Tengger caldera. Semeru has been in almost continuous eruption since 1967. Frequent small-to-moderate Vulcanian eruptions have accompanied intermittent lava dome extrusion, and periodic pyroclastic flows and lahars have damaged villages below the volcano. A major secondary lahar on 14 May 1981 caused more than 250 deaths and damaged 16 villages. Source: Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Semeru Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0603-30= SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev. 1,052 m According to the Washington VAAC, the Montserrat Volcano Observatory reported a pyroclastic flow from Soufrière Hills on 13 July that reached the sea and produced an ash plume to an altitude of 2.4 km (8,000 ft) a.s.l. Geologic Summary. The complex dominantly andesitic Soufrière Hills volcano occupies the southern half of the island of Montserrat. The summit area consists primarily of a series of lava domes emplaced along an ESE-trending zone. English's Crater, a 1-km-wide crater breached widely to the east, was formed during an eruption about 4000 years ago in which the summit collapsed, producing a large submarine debris avalanche. Block-and-ash flow and surge deposits associated with dome growth predominate in flank deposits at Soufrière Hills. Non-eruptive seismic swarms occurred at 30-year intervals in the 20th century, but with the exception of a 17th-century eruption that produced the Castle Peak lava dome, no historical eruptions were recorded on Montserrat until 1995. Long-term small-to-moderate ash eruptions beginning in that year were later accompanied by lava-dome growth and pyroclastic flows that forced evacuation of the southern half of the island and ultimately destroyed the capital city of Plymouth, causing major social and economic disruption. Source: Washington Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/ARCHIVE/ANAT/2006E291935.html Soufrière Hills Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1600-05= ST. HELENS Washington, USA 46.20°N, 122.18°W; summit elev. 2,549 m; All times are local (= UTC - 8 hours [or 7 hours early April- late October]) During 12-18 July, the lava dome at Mount St. Helens continued to grow and produce small rockfalls. On 18 July at 0956, a M 3.6 earthquake (one of the largest earthquakes during the ongoing eruption) triggered rockfalls from the spine and crater walls. Dust plumes rose above the crater rim and quickly dissipated. The hazard status remained at Volcano Advisory (Alert Level 2); aviation color code Orange. Geologic Summary. Prior to 1980, Mount St. Helens formed a conical, youthful volcano sometimes known as the Fuji-san of America. During the 1980 eruption the upper 400 m of the summit was removed by slope failure, leaving a 2 x 3.5 km horseshoe-shaped crater now partially filled by a lava dome. Mount St. Helens was formed during nine eruptive periods beginning about 40-50,000 years ago, and has been the most active volcano in the Cascade Range during the Holocene. The modern edifice was constructed during the last 2,200 years, when the volcano produced basaltic as well as andesitic and dacitic products from summit and flank vents. Historical eruptions in the 19th century originated from the Goat Rocks area on the N flank, and were witnessed by early settlers. Source: US Geological Survey Cascades Volcano Observatory http://vulcan.wr.usgs.gov/Volcanoes/MSH/CurrentActivity/framework.html St. Helens Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1201-05- SUWANOSE-JIMA Ryukyu Islands, Japan 29.53°N, 129.72°E; summit elev. 799 m A pilot observed an ash plume from Suwanose-jima on 16 July that reached an altitude of 1.8 km (6,000 ft) a.s.l. and drifted N. Ash was not visible on satellite imagery. Geologic Summary. The 8-km-long, spindle-shaped island of Suwanose-jima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. Only about 50 persons live on the sparsely populated island. The summit of the volcano is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. Suwanose-jima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from On-take, the NE summit crater, that began in 1949 and lasted nearly a half century. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, after which the island was uninhabited for around 70 years. The SW crater produced lava flows that reached the western coast in 1813, and lava flows reached the eastern coast of the island in 1884. Source: Tokyo Volcanic Ash Advisory Center http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Suwanose-jima Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0802-03= TENGGER CALDERA Java, Indonesia 7.942°S, 112.950°E; summit elev. 2,329 m A small plume from Tengger Caldera was visible on a satellite image on 14 July. No ash was detected. Geologic Summary. The 16-km-wide Tengger caldera in eastern Java occupies the northern end of a volcanic massif extending from Semeru volcano. The massive Tengger volcanic complex consists of five overlapping stratovolcanoes, each truncated by a caldera. The most recent is the 9 x 10 km wide Sandsea caldera, which formed incrementally during the late Pleistocene and early Holocene. An overlapping cluster of post-caldera cones was constructed on the floor of the Sandsea caldera within the past several thousand years. The youngest of these is Bromo, one of Java's most frequently visited and most active volcanoes. More than 50 mild-to-moderate explosive eruptions have occurred there since 1804. Source: Darwin Volcanic Ash Advisory Center http://www.bom.gov.au/info/vaac/advisories.shtml Tengger Caldera Information from the Global Volcanism Program http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=0603-31= UBINAS Perú 16.355°S, 70.903°W; summit elev. 5,672 m According to the Buenos Aires VAAC, ash clouds from Ubinas were visible on satellite imagery during 14-15 July and reached altitudes of 5.5 km (18,000 ft) a.s.l. On 17 July, a pilot reported ash clouds that also reached altitudes of 5.5 km (18,000 ft) a.s.l. and drifted NE. Geologic Summary. A small, 1.2-km-wide caldera that cuts the top of Ubinas, Peru's most active volcano, gives it a truncated appearance. Ubinas is the northernmost of three young volcanoes located along a regional structural lineament about 50 km behind the main volcanic front of Peru. The upper slopes of the stratovolcano, composed primarily of Pleistocene andesitic lava flows, steepen to nearly 45 degrees. The steep-walled, 150-m-deep summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank of Ubinas extend 10 km from the volcano. Widespread plinian pumice-fall deposits from Ubinas include some of Holocene age. Holocene lava flows are visible on the volcano's flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor explosive eruptions. Source: Buenos Aires Volcanic Ash Advisory Center http://www.bom.gov.au/products/Volc_ash_recent.shtml Ubinas Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1504-02 +++++++++++++++++++++++++++++++++++++ Sally S. Kuhn Global Volcanism Program Smithsonian Institution National Museum of Natural History MRC-119 Department of Mineral Sciences Washington, D.C., 20560 http://www.volcano.si.edu/ <http://www.volcano.si.edu/> Phone: 202.633.1805 Fax: 202.357.2476 <http://www.volcano.si.edu/reports/usgs/> ++++++++++++++++++++++++++++++++++++++++++ ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
