*************************************************** GVP/USGS Weekly Volcanic Activity Report 13-19 June 2007 http://www.volcano.si.edu/reports/usgs/ *************************************************** New Activity/Unrest: | Kilauea, USA | Kliuchevskoi, Russia Ongoing Activity: | Fourpeaked, USA | Karymsky, Russia | Masaya, Nicaragua | Rabaul, Papua New Guinea | Reventador, Ecuador | Sakura-jima, Japan | Shiveluch, Russia | Soufrière Hills, Montserrat | St. Helens, USA | Tungurahua, Ecuador | Ubinas, Perú New Activity/Unrest KILAUEA Hawaii, USA 19.43°N, 155.29°W; summit elev. 1,222 m; All times are local (=UTC -10 hours) During 13-19 June, lava from Kilauea flowed SE across a growing lava delta into the ocean at the Poupou entry. On 14 June, the Petunia flow went over the top of the Pulama pali. On 16 June, the front of the Petunia flow advanced down the Pulama pali and was about 90-180 m wide. On 17 June, a swarm of earthquakes and rapid deflation began at 0215 in the upper E rift zone. The earthquakes were centered about 1 km SW of Mauna Ulu and about 1.5-3 km deep. About 70 earthquakes were recorded in the first 2 hours; at least 10 of those earthquakes were M 3 or greater. NPS crews evacuated visitors and closed the Chain of Craters road and the Crater Rim Drive between Jaggar museum and the Thurston lava tube parking lot. Fresh cracks about 2 cm wide opened in the Chain of Craters road near the Mauna Ulu turnoff. GPS receivers in the area of most intense seismic activity documented an approximate 10 cm of widening across the rift zone, near Makaopuhi crater. HVO observers noted rockfalls from the S wall of Pu'u 'O'o cone and collapse of the crater floor around the vents. On 18 June, the earthquake swarm continued at a lower rate; about 10 to 15 small earthquakes per hour were recorded compared to more than about 100 per hour the morning of 17 June. Strong tremor beneath the summit was recorded and deflation continued. GPS receivers continued to show widening across the rift zone to more than 40 cm. According to a news article, Crater Rim drive and a few trails were re-opened to the public. HVO reported on 19 June that a magma intrusion was thought to have started in the Mauna Ulu area early on 17 June and subsequently moved slowly 6 km E along the rift zone. A large area of Pu'u 'O'o's crater floor had subsided about 20 m since 17 June. GPS receivers continued to show extension across the rift zone to about 100 cm. HVO scientists confirmed a new 50-m-long lava flow from a 200-m-long fissure in the forest NE of Kane Nui o Hamo, approximately 6 km W of Pu'u 'O'o and 13 km SE of Kilauea summit. Steam plumes were spotted on the N flank of Kane Nui o Hamo. Steam and gas issued from the fissure. Seismicity decreased on 20 June and GPS receivers no longer showed extension on the rift zone. Aerial views of the crater floor and SW flank indicated more subsidence since 18 June. 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 broad areas on the S flank of Kilauea and adding new land beyond the former coastline. Sources: US Geological Survey Hawaiian Volcano Observatory http://volcano.wr.usgs.gov/hvostatus.php, Associated Press http://www.khnl.com/Global/story.asp?S=6674767 Kilauea information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1302-01- KLIUCHEVSKOI Kamchatka Peninsula, Russia 56.06°N, 160.64°E; summit elev. 4,835 m; All times are local (= UTC + 12 [or 13 late March-late October]) KVERT reported that during 8-15 June, seismic activity at Kliuchevskoi continued above background levels and a thermal anomaly in the crater was detected on satellite imagery. Strombolian and Vulcanian activity at the summit crater, lava flows, and phreatic bursts at the SE flank of the volcano were observed on 8 and 13 June. Based on video and visual observations, ash plumes rose to altitudes of 7 km (23,000 ft) a.s.l. during 8-10 and 13 June and drifted E, SE, and NW. Ash plumes were visible on satellite imagery drifting multiple directions during 8-15 June. KVERT reported that seismicity increased on 19 June at 1010. Beginning at 0400 on 20 June, ash plumes were visible on satellite imagery, drifting W. Based on atmospheric profiles, plume altitudes rose to an altitude of 6.5-7.5 km (21,300-24,600 ft) a.s.l. Ashfall was reported from Kozyrevsk village. The Level of Concern Color Code was raised to Red. Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions have occurred during the past 3,000 years, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation. The morphology of its 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 major explosive and effusive eruptions from flank craters. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml Kliuchevskoi Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-26= Ongoing Activity FOURPEAKED Alaska Peninsula, USA 58.770°N, 153.672°W; summit elev. 2,105 m AVO reported that on 6 June the Volcanic Activity Alert Level <http://www.avo.alaska.edu/color_codes.php > for Fourpeaked was lowered from Advisory to Normal and the Aviation Color Code was lowered from Yellow to Green based on declining rates of seismicity and gas emission. Geologic Summary. Poorly known Fourpeaked volcano in NE Katmai National Park consists of isolated outcrops surrounded by the Fourpeaked Glacier, which descends eastward almost to the Shelikof Strait. The orientation of lava flows and extensive hydrothermal alteration of rocks near the present summit suggest that it probably marks the vent of Fourpeaked volcano. Eruptive activity during the Holocene had not been confirmed prior to the first historical eruption of Fourpeaked in September 2006. A N-trending fissure extending 1 km from the summit produced minor ashfall. Source: Alaska Volcano Observatory (AVO) http://www.avo.alaska.edu/ Fourpeaked Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1102-26- KARYMSKY Kamchatka Peninsula, Russia 54.05°N, 159.43°E; summit elev. 1,536 m Seismic activity at Karymsky indicated that ash plumes possibly rose to an altitude of 6.8 km (22,300 ft) a.s.l. during 8-13 June. Seismicity was above background levels during 8-15 June. On 11 June, ash plumes were visible on satellite imagery drifting S and SW. A thermal anomaly was visible in the crater during 9-10 and 12-13 June. The Level of Concern Color Code remained at Orange. Based on information from KEMSD, the Tokyo VAAC reported that eruption plumes rose to 3-6.1 km (10,000-20,000 ft) a.s.l. during 13-14 and 17 June. Ash was not identified on satellite imagery. 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. Sources: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml, Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Karymsky Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1000-13= MASAYA Nicaragua 11.984°N, 86.161°W; summit elev. 635 m The Washington VAAC reported that a plume from Masaya composed of little to no ash was visible on satellite imagery on 12 June. Geologic Summary. Masaya is one of Nicaragua's most unusual and most active volcanoes. It is a broad, 6 x 11 km basaltic caldera with steep-sided walls up to 300 m high that is filled on its NW end by more than a dozen vents erupted along a circular fracture system 4 km in diameter. The twin volcanoes of Nindiri and Masaya, the source of historical eruptions, were constructed at the southern end of the fracture system and contain multiple summit craters. A major basaltic plinian tephra was erupted from Masaya about 6,500 years ago. Historical lava flows cover much of the caldera floor and have confined a lake to the far eastern end of the caldera. A lava flow from the 1670 eruption overtopped the N caldera rim. Masaya has been frequently active since the time of the Spanish Conquistadors, when an active lava lake prompted several attempts to extract the volcano's molten "gold." Source: Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html Masaya Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1404-10= RABAUL New Britain Island, Papua New Guinea 4.271°S, 152.203°E; summit elev. 688 m RVO reported that during 19-20 June, four explosions from Rabaul caldera's Tavurvur cone produced shockwaves that rattled windows of houses in Rabaul Town and surrounding areas. The explosions showered the flanks of the volcano with lava fragments. Ash plumes rose to an altitude of 2.7 km (8,900 ft) a.s.l. and drifted NW. Ashfall was reported from Rabaul Town and surrounding areas. Geologic Summary. The low-lying Rabaul caldera on the tip of the Gazelle Peninsula at the NE end of New Britain forms a broad sheltered harbor. The outer flanks of the 688-m-high asymmetrical pyroclastic shield volcano are formed by thick pyroclastic-flow deposits. The 8 x 14 km caldera is widely breached on the E, where its floor is flooded by Blanche Bay. Two major Holocene caldera-forming eruptions at Rabaul took place as recently as 3,500 and 1,400 years ago. Three small stratovolcanoes lie outside the northern and NE caldera rims. Post-caldera eruptions built basaltic-to-dacitic pyroclastic cones on the caldera floor near the NE and western caldera walls. Several of these, including Vulcan cone, which was formed during a large eruption in 1878, have produced major explosive activity during historical time. A powerful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city. Source: Herman Patia, Rabaul Volcano Observatory Rabaul Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=0502-14= REVENTADOR Ecuador 0.078°S, 77.656°W, summit elev. 3,562 m Based on seismic interpretation, IG reported that lahars occurred on the flanks of Reventador on 15 and 19 June. According to the Washington VAAC, the IG reported that activity on 18 June possibly produced ash plumes that drifted NW. Ash was not visible on satellite imagery. Geologic Summary. Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well E of the principal volcanic axis. It is a forested stratovolcano that rises above the remote jungles of the western Amazon basin. A 3-km-wide caldera breached to the E was formed by edifice collapse and is partially filled by a young, unvegetated stratovolcano that rises about 1,300 m above the caldera floor. Reventador has been the source of numerous lava flows as well as explosive eruptions that were visible from Quito in historical time. Frequent lahars in this region of heavy rainfall have constructed a debris plain on the eastern floor of the caldera. Sources: Instituto Geofísico-Escuela Poltécnica Nacional http://www.igepn.edu.ec/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html Reventador Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-01= SAKURA-JIMA Kyushu, Japan 31.58°N, 130.67°E; summit elev. 1,117 m Based on information from JMA, the Tokyo VAAC reported an explosion from Sakura-jima on 16 June. Ash was not detected on satellite imagery. Geologic Summary. Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira caldera at the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. 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. Source: Tokyo Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/JP/messages.html Sakura-jima Information from the Global Volcanism Program http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=0802-08= SHIVELUCH Kamchatka Peninsula, Russia 56.653°N, 161.360°E; summit elev. 3,283 m KVERT reported that seismic activity at Shiveluch continued above background levels during 8-15 June and a thermal anomaly in the crater was detected on satellite imagery. Gas-and-steam plumes rose to altitudes of 4 km (13,100 ft) a.s.l. during 8-10 and 13 June. Ash plumes rose to altitudes of 4.5 km (14,800 ft) a.s.l. on 8 and 10 June and were seen on satellite imagery drifting NW on 12 June. Based on seismic interpretation, multiple ash plumes rose to 6.3 km (20,700 ft) a.s.l. during 8-15. The Level of Concern Color Code remained at Orange. Geologic Summary. The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large horseshoe-shaped caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. During the 1990s, intermittent explosive eruptions took place from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964. Source: Kamchatkan Volcanic Eruption Response Team (KVERT) http://www.kscnet.ru/ivs/kvert/updates.shtml Shiveluch Information from the Global Volcanism Program http://www.volcano.si.edu/gvp/world/volcano.cfm?vnum=1000-27= SOUFRIÈRE HILLS Montserrat, West Indies 16.72°N, 62.18°W; summit elev. 1,052 m MVO reported that during 8-18 June the lava dome at Soufrière Hills changed very little based on visual observations, and seismic activity was very low. Low-level rockfall and pyroclastic flow activity continued. The Alert Level remained at 4 (on a scale of 0-5). 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: Montserrat Volcano Observatory http://www.mvo.ms/ 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 Data from deformation-monitoring instruments indicated that during 13-19 June lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. In some instances, clouds inhibited visual observations. 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- TUNGURAHUA Ecuador 1.47°S, 78.44°W; summit elev. 5,023 m The IG reported that heavy and occasionally continuous rains resulted in mudflows and lahars on the flanks of Tungurahua during 12 and 14-16 June. On 12 June, lahars in the Pampas sector disrupted traffic on the route between Ambato and Baños for several hours. Traffic was again disrupted on 14 June and lahars occurred in W and SW drainages. A potable water system in a locality to the SW was affected by one of the lahars. Slight ashfall was reported from Bilbao, about 8 km to the W. On 15 June, lahars traveled in NW, W, and SW drainages. Mudflows interrupted traffic on the route between Ambato and Baños and dragged blocks 1 m in diameter in the W-flank Mandur drainage. According to the Washington VAAC, IG reported that an ash plume rose to an altitude of 5 km (16,500 ft) a.s.l. and drifted WSW. Ash was not visible on satellite imagery. During 15-16 June, heavy rains led to a landslide in the Peras Pamba sector near Cusúa (8 km NW) that blocked the flow of the Chambo river for about 20 minutes. Mudflows continued to affect the Pampas sector on 16 June. On 18 June, an ash plume rose to an altitude of 7 km (23,000 ft) a.s.l. and drifted W. 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/, Washington Volcanic Ash Advisory Center (VAAC) http://www.ssd.noaa.gov/VAAC/messages.html Tungurahua Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1502-08= UBINAS Perú 16.355°S, 70.903°W; summit elev. 5,672 m Based on observations from satellite imagery and Significant Meteorological Information (SIGMET) advisories, the Buenos Aires VAAC reported that during 13-17 June continuous emissions from Ubinas produced ash plumes to altitudes of 5.8-6.7 km (19,000-22,000 ft) a.s.l. Plumes drifted NNE, E, SE, SW, and W. 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 (VAAC) http://www.ssd.noaa.gov/VAAC/OTH/AG/messages.html Ubinas Information from the Global Volcanism Program http://www.volcano.si.edu/world/volcano.cfm?vnum=1504-02= +++++++++++++++++++++++++++++++++++++ Sally Kuhn Sennert SI/USGS Weekly Volcanic Activity Report Editor Global Volcanism Program http://www.volcano.si.edu/reports/usgs/ Smithsonian Institution, National Museum of Natural History Department of Mineral Sciences, MRC-119 Washington, D.C., 20560 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. ==============================================================
