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Bulletin of the Global Volcanism Network, February 2010
From: "Ed Venzke" <VENZKEE@xxxxxx>
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Bulletin of the Global Volcanism Network
Volume 35, Number 2, February 2010
Turrialba (Costa Rica) Phreatic eruption of 5-6 January 2010 opens SW crater's upper wall
Kizimen (Russia) Seismic crisis starting in July 2009 (up to 120 earthquakes per day)
Fukutoku-Okanoba (Japan) Airborne ash and cloudy water during 3 February 2010 eruption
Manam (Papua New Guinea) Intermittent ash plumes continue; ~ 14,000 people still displaced
Langila (Papua New Guinea) Weak ash plumes in February 2010
Ulawun (Papua New Guinea) Steam plumes (with some possible ash) in February 2010
Rabaul (Papua New Guinea) Quiet during early 2010 with few emissions or earthquakes; 2008 summary
Bagana (Papua New Guinea) Occasional thermal alerts from possible lava flows during early 2010
Yellowstone (USA) Second largest recorded earthquake swarm during January-February 2010
Editors: Rick Wunderman, Edward Venzke, and Sally Kuhn Sennert
Volunteer Staff: Paul S. Berger, Robert Andrews, Catie Carter, Jacquelyn Gluck, Hugh Replogle, Russell Ross, Stephen Bentley, and Ludmilla Eichelberger
Turrialba
Costa Rica
10.025°N, 83.767°W; summit elev. 3,340 m
All times are local (= UTC - 6 hours)
Since 2002, elongate cracks have opened at Turrialba, and new points began degassing, emitting high levels of sulfurous gas and helium, but no eruptions had occurred (BGVN 32:08, 33:01, and 34:09). Ongoing fumarolic activity through August 2009 caused significant damage to local vegetation (BGVN 34:09). This report continues through February 2010. Phreatic eruptions on 5 and 6 January 2010 resulted in ashfall ten's of kilometers from the active W crater. New vents formed on the crater wall, ultimately merging into an elongate fissure.
On 25 September 2009, scientists from the Observatorio Vulcanologico y Sismologico de Costa Rica, Universidad Nacional (OVSICORI-UNA) reported results from three trips to inspect new fissures and to assess the impact of gases. Gases blown 10 km SW mildly burned trees to a greater degree than the previous year. Vegetation within a 4-km radius on the W, NW, and E flanks was also burned more severely that previously noted. Several elongated fissures were documented on the rim S of the W crater, as well as 1 km downslope to the NW. One E-W-trending crack that was first seen several months before had opened as much as 12 cm, and emitted gas and vapor at 90°C. On the lower NW flanks, at least three radial fissures emitted high gas-and-steam plumes. Some fissures near the summit were 5-10 cm wide. The last of the remaining residents in the affected areas had moved away due to the intensification and impact of the gases.
Report from the Red Sismologica Nacional, January 2010. Gerardo J. Soto sent a report by the Red Sismologica Nacional (National Seismological Network; RSN: UCR-ICE) summarizing events during early January. The seismic signals recorded during 2009 consisted mostly of B-type earthquakes, tremor, and some A-type earthquakes. The seismic records through the afternoon of 3 January remained typical, but after 1000 on 4 January signals underwent a sudden change. Tremor became common and was of long duration (~ 4 events/hour with typical durations of 10-20 minutes), but signals did not suggesting internal fracturing. Abundant low-frequency signals (B-type earthquakes) corresponded with substantial gas plumes. After 1400 on 5 January tremor occurred almost constantly. Two strong earthquakes occurred, at 1429 and 1445.
These two earthquakes coincided with the first reports of ash, which fell mainly over the farms adjacent to La Central and La Silvia, Capellades town. Finer ash was reported at Tierra Blanca, Llano Grande and Tres Rios, ~ 25 km SW, and in eastern San Jose, ~ 30 km away. The ash was expelled for over 22 hours, in a continuing sequence of pulses.
The RSN report further stated that field and aerial trips inspected the two small pits that opened on the upper SE wall of the SW crater. These pits later joined and formed a fracture-like structure (aligned N40ºE, the same trend as the tectonic depression and faults on the summit). The ash emitted from the pits was devoid of new (juvenile) magma material and most clasts were hydrothermally altered. Fumaroles expelled gas and ash at high pressure with a jet-type noise heard several kilometers away. Observers approaching the pits on the 6th watched pulsating emissions coming from both new vents on the upper wall.
Report from OVSICORI-UNA, January-February 2010. An OVSICORI-UNA report written on 6 January also noted that the phreatic eruption began at 1400 on 5 January, followed by reports of ashfall as far away as 30 km, particularly in areas to the SW. Residents of the village La Central located ~ 4 km SW of the crater heard nothing but received fine ash (figure 1) accompanied by rain. In contrast, in the village of La Silvia located roughly the same distance W of the crater, people heard noises attributed to eruptions. Erupted material was generally fine-grained (sub-millimeter in diameter) and dark.
Figure 1. Sketch map of Turrialba emphasizing the fresh deposits mapped on 6 January 2010 (shaded area). The town of La Central (~ 4 km from the W crater) lies on the approximate dispersal axis and received 1-1.5 mm of ash fall. Courtesy of OVSICORI-UNA.
Mapping by OVSICORI-UNA on 6 January traced the deposit WSW (figure 3); the deposit had a thickness of 1-1.5 mm between La Central and La Silvia. At 8 km from the vent on the road near Oreamuno the deposit was ~ 0.5 mm thick. Some fine ashfall was seen 15 km from the vent (at Llanos Grande) and reached ~ 30 km away to neighborhoods of SE San Jose. The delicacy of the deposit and the associated rain meant that some of the best samples came from roof tops and plant leaves. On corrugated roofs the uppermost portions of the ridges still preserved considerable ash. Some of the near-source ejecta were on the order of a meter in diameter.
Field observations on 6 January revealed that two small vents had opened and joined together on the SE inner wall of the SW crater. Gas emission temperatures were more than 350°C. On 8 January seismic activity and gas emissions decreased. Observations on 9 January revealed that the combined vent was about 20-25 m wide and 65-80 m long (figures 2 and 3).
Figure 2. An aerial view on 9 January 2010 of Turrialba's W crater and one or more new cavities developed in the upslope area (see enlarged view in next figure). Courtesy OVSICORI-UNA.
Figure 3. Close-up of the area affected by Turrialba's phreatic eruption as seen from the air on 9 January 2010. The vent on the far wall began as two small separate ones. The cover of fresh fine-grained deposits appears as a smooth area around the new vent. Some of the larger near source ejecta reached on the order of a meter or so across. Courtesy OVSICORI-UNA.
A plume on 15 February that reached 1.5-2 km in height was photographed by OVSICORI-UNA (figure 4). The noise from the emission was heard 4 km to the SW.
Figure 4. Photograph of a weak, inclined steam-and-gas plume from Turrialba taken on 15 February 2010. Courtesy OVSICORI-UNA.
Aviation notices, January 2010. Washington Volcanic Ash Advisory Center (VAAC) reports started on 7 January, and began with pilot reports of ash to the E of the summit, but analysts lacked clear evidence of ash based on satellite imagery. METAR reports (routine, in most cases hourly, aviation weather reports from places such as airports) continued to mention the plume on the 7th, but weather clouds prevented detection of possible ash clouds. Later on the 7th, analysts began to rely on a wider array of data, and although still unable to see the plume in imagery, they began to put out numerous regular reports through the 9th. On 16 January the VAAC reported that the "Observatory has confirmed that there are no ash emissions at this time. Gas and steam emissions are possible."
Geologic Summary. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazu volcano overlooking the city of Cartago. The massive 3,340-m-high Turrialba is exceeded in height only by Irazu, covers an area of 500 sq km, and is one of Costa Rica's most voluminous volcanoes. Three well-defined craters occur at the upper SW end of a broad 800 x 2,200 m wide summit depression that is breached to the NE. Most activity at Turrialba originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred at Turrialba during the past 3,500 years. Except for the eruption discussed here (5-6 January 2010), Turrialba has been quiescent since a series of explosive eruptions during the 19th century that were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.
Information Contacts: E. Duarte, E. Fernandez, J. Brenes, R. Van der Laat, and T. Marino, Observatorio Vulcanologico Sismologica de Costa Rica-Universidad Nacional (OVSICORI-UNA), Apartado 86-3000, Heredia, Costa Rica (URL: http://www.ovsicori.una.ac.cr/); Gerardo J. Soto, Red Sismologica Nacional, Escuela Centroamericana de Geologia (UCR). Apdo. Postal 214-2060, San Jose, Costa Rica (URL: http://www.rsn.geologia.ucr.ac.cr/); Washington Volcanic Ash Advisory Center, Satellite Analysis Branch (SAB), NOAA/NESDIS E/SP23, NOAA Science Center Room 401, 5200 Auth Rd, Camp Springs, MD 20746, USA (URL: http://www.ssd.noaa.gov/VAAC/).
Kizimen
Kamchatka Peninsula, Russia
55.130°N, 160.32°E; summit elev. 2,376 m
Earthquakes at Kizimen appeared in July 2009 and increased substantially in the middle of that month (figures 5 and 6). During 11 July 2009 to 6 April 2010 instruments recorded 1,940 earthquakes. The largest number of seismic events took place during July and reached up to 120 a day. On 20 August instruments also recorded weak, faltering, and spasmodic volcanic tremor. Witnesses near the volcano felt shaking from many earthquakes, sometimes accompanied by an underground rumble.
Figure 5. Sketch map showing location of Kizimen on the Kamchatkan Peninsula.
Figure 6. A plot of seismic events at Kizimen during July 2009 to April 2010. A new station was installed around the beginning of 2010, accounting for the increased number of recorded events then. Plotted data taken from online reporting by the Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS).
In August 2009 scientists from Institute of Volcanology and Seismology researched the fumarolic field on the NW slope (figures 7 and 8). The temperature on the NW part of the field had risen from 181°C to 235°C. On the SW part of the volcano it changed from 171°C to 340°C. On the central part it was 340°C.
Figure 7. Fumarolic gases escaping at Kizimen, August 2009. Scientists are sampling the gases and condensate (left center). Photo by Alexandr Ovsyannikov.
Figure 8. View from the NE looking at Kizimen with a cloud-covered summit and patches of snow. Photo by Igor Tembrel (Tembrel and Ovsyannikov, 2009).
The volcano sits in an area that is structurally complex, the scene of intense tectonism and extensive modern deformation. According to Melekestsev and others (1995), Kizimen is "located on the SE flank of the Shchapinsky graben and is confined to a system of large amplitude NE-striking faults that includes the junction of the graben with the horst of the Tumrok ridge."
Geologic Summary. Kizimen is an isolated, conical stratovolcano that is morphologically similar to Mount St. Helens prior to its 1980 eruption. The summit of Kizimen consists of overlapping lava domes, and blocky lava flows descend the flanks of the volcano, which is the westernmost of a volcanic chain north of Kronotsky volcano. The 2,376-m-high Kizimen was formed during four eruptive cycles beginning about 12,000 years ago and lasting 2,000-3,500 years. The largest eruptions took place about 10,000 and 8,300-8,400 years ago, and three periods of long-term lava dome growth have occurred. The latest eruptive cycle began about 3,000 years ago with a large explosion and was followed by lava dome growth lasting intermittently ~ 1,000 years. An explosive eruption ~ 1,100 years ago produced a lateral blast and created a 1.0 x 0.7 km wide crater breached to the NE, inside which a small lava dome (the fourth at Kizimen) has grown. A single explosive eruption, during 1927-28, has be!
en recorded in historical time.
References. Tembrel, I., and Ovsyannikov, A., 2009, The condition Kizimen volcano on summer 2009: Kamchatka, Vestnik KRAUNC, Earth Science Series; Petropavlovsk-Kamchatsky, v. 14, p. 7-9 [ISSN 1816-5524]. (in Russian)
Melekestsev, I., Ponomareva, V., and Volynets, O., 1995, Kizimen volcano (Kamchatka)-a future Mount St. Helens?: Journal of Volcanology and Geothermal Research, v. 65, p. 205-226.
Information Contacts Kamchatka Volcanic Eruptions Response Team (KVERT), Institute of Volcanology and Seismology (IV&S) Far East Division, Russian Academy of Sciences (FED RAS), Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences (KB GS RAS), Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia (Email: kvert@xxxxxxxxx, URL: http://www.kscnet.ru/ivs; http://emsd.iks.ru/~ssl/monitoring/main.htm); Alexandr Ovsyannikov and Igor Tembrel, IV&S FED RAS.
Fukutoku-Okanoba
Volcano Islands, Japan
24.28°N, 141.485°E; summit elev. -14 m (submarine)
All times are local (= UTC + 10 hours)
The submarine volcano Fukutoku-Okanoba, frequently the source of discolored water (e.g., BGVN 32:01 and 30:11), erupted on the morning of 3 February 2010, sending a plume of ash and steam 100 m into the air (figure 9) and turning the surrounding ocean a yellow-green color (figure 10). Additional observations of discolored water have been frequently documented in JMA reports since November 2006 (BGVN 32:01). More details of that activity, from January 2007 through December 2009, will be provided in a following Bulletin.
Figure 9. Aerial photograph of an ash plume rising from the ocean over Fukutoku-Okanoba on 3 February 2010. Photograph courtesy Japan Coast Guard.
Figure 10. During a lull in the 3 February 2010 eruption of Fukutoku-Okanoba, some water above the summit bubbled and took on yellowish-green colors. Aerial photograph courtesy Japan Coast Guard.
The February 2010 eruption was discovered at about 0745 by the Japan Coast Guard patrol boat Yashima on a routine survey. The crew first noticed "smoke" coming from the surface of the ocean ~ 5 km NNE of the island of Minami-Iwo-jima. The crew also heard a blast and felt its pressure wave. The Yashima continued to monitor the site from a safe distance.
Satellite imagery provided evidence that the activity persisted for at least several days. On 9 February the underwater plume appears as a complex shape N of the volcano (figure 11). Two days later, on 11 February, the plume was spread W of the volcano (figure 12).
Figure 11. On 9 February 2010, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this false-color image of the ocean around Fukutoku-Okanoba volcano. Water colored by the underwater plume appears lighter in contrast to the surrounding water. The discolored water initially formed a rough V-shape N of the summit. Courtesy of NASA Earth Observatory.
Figure 12. Satellite image taken 11 February 2010 of the ocean around Fukutoku-Okanoba volcano. The water colored by the plume forms a V-shape W of the volcano summit. This true-color image (enhanced for publication) was taken by the Advanced Land Imager (ALI) on NASA's EO-1 satellite. Courtesy of NASA Earth Observatory.
JMA isssued eruption alerts for 9 March and 8 April 2010. This suggests that the eruption continued into April.
Geologic Summary. Fukutoku-Okanoba is a submarine volcano located 5 km NE of the pyramidal island of Minami-Iwo-jima. Water discoloration is frequently observed from the volcano, and several ephemeral islands have formed in the 20th century. The first of these formed Shin-Iwo-jima ("New Sulfur Island") in 1904, and the most recent island was formed in 1986. Fukutoku-Okanoba is part of an elongated edifice with two major topographic highs trending NNW-SSE and is a trachyandesitic volcano geochemically similar to Iwo-jima.
Information Contacts: Japan Meteorological Agency, 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/indexe.html); NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/).
Manam
Northeast of New Guinea, Papua New Guinea
4.080°S, 145.037°E; summit elev. 1,807 m
Intermittent ash plumes and steam emissions at Manam have been reported between 2 April 2008 and 2 November 2009, but the volcano has been relatively quiet (BGVN 34:01 and 34:11). Based on analyses of satellite imagery, the Darwin Volcanic Ash Advisory Centre reported that on 12 December 2009 an eruption produced a plume that rose to an altitude of 3 km and drifted 75 km N. According to a report by the Rabaul Volcano Observatory, the volcano was quiet again throughout February 2010. However, steam emissions were reported, and a dull glow from the Main Crater was visible on the night of 16 February. There were no MODVOLC thermal alerts between 3 October 2009 and mid-April 2010.
A January 2010 report by the United Nations Office for the Coordination of Humanitarian Affairs discussed refugees originally evacuated from Manam Island in November 2004 after several deadly eruptions (BGVN 29:11). In early 2010 there remained ~ 14,000 people living in camps on the nearby mainland unable to return home because of ongoing volcanic hazards. In addition, "a government plan to permanently resettle the [evacuees] inland was never realized and local and international assistance has all but disappeared."
Geologic Summary. The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1,807-m-high basaltic-andesitic 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 small satellitic centers are located near the island's shoreline on the northern, southern and western sides. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE avalanche valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded at Manam since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-l!
ying coastal areas and entered the sea, sometimes impacting populated areas.
Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea (Email: hguria@xxxxxxxxxxxxx); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/); ReliefWeb, UN Office for the Coordination of Humanitarian Affairs (OCHA) (URL: http://www.reliefweb.int/).
Langila
New Britain, Papua New Guinea
5.525°S, 148.42°E; summit elev. 1,330 m
In September 2009 eruptions occurred at Langila's Crater 2, sending aloft dense ash plumes seen for hundreds of kilometers. Activity subsided but continued as late as the end of October 2009 (BGVN 34:11). Later reports from the Rabaul Volcano Observatory noted activity at Langila in December 2009 and February 2010. No MODVOC thermal alerts were recorded after 5-6 October 2009, through February 2010.
Vulcanian eruptive activity continued at Crater 2 throughout December 2009. The eruptive activity consisted of variable gray ash clouds on most days of the month that rose ~ 1 km above the summit before being blown NE, causing fine ashfall downwind.
During 11-15 February 2010 observers saw weak ash plumes from Crater 2. During the latter part of the month the plumes were stronger, rising 700-900 m above the crater and drifting SE and SW. During 15-19 February observers heard occasional weak booming noises.
Geologic Summary. Langila, one of the most active volcanoes of New Britain, consists of a group of four small overlapping composite basaltic-andesitic cones on the lower eastern flank of the extinct Talawe volcano. Talawe is the highest volcano in the Cape Gloucester area of NW New Britain. A rectangular, 2.5-km-long crater is breached widely to the SE; Langila volcano was constructed NE of the breached crater of Talawe. An extensive lava field reaches the coast on the north and NE sides of Langila. Frequent mild-to-moderate explosive eruptions, sometimes accompanied by lava flows, have been recorded since the 19th century from three active craters at the summit of Langila. The youngest and smallest crater (no. 3 crater) was formed in 1960 and has a diameter of 150 m.
Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea (Email: hguria@xxxxxxxxxxxxx); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).
Ulawun
New Britain, Papua New Guinea
5.05°S, 151.33°E; summit elev. 2,334 m
A Rabaul Volcano Observatory (RVO) report noted steam plumes (figure 13) and increased seismicity at Ulawun during February 2010. Some of the mid-February plumes may have contained ash. As late as October 2009, Ulawun was generally quiet except for modest seismicity (BGVN 34:10).
Figure 13. Ulawun issuing passive steaming as seen from the SE side in this undated photo. RVO described this as "moderate volumes of white vapor from the summit crater." From Arumba (2009).
A government report written in October 2009 mentioning Ulawun (Arumba, 2009) summarized activity during 2008 as generally quiet, but noted it had changed "with the commencement and continuation of high frequency volcano-tectonic earthquakes from about March [2008] onwards."
The increase in the seismicity was slight and took place during the second half of February 2010. RVO noted that during 12-27 February, Ulawun emitted steam, sometimes forcefully. There was no audible noise and no glow visible from the crater at night. According to the Darwin Volcanic Ash Advisory Centre, the plumes seen during 14-15 February 2010 may have contained ash. They reached 2.4-3.7 km altitude and drifted 45-95 km NNE.
RVO noted a further increase in the seismicity during 19-24 February, with overlapping tremor events and an increase in RSAM (Real-time Seismic-Amplitude Measurement). Volcano-tectonic earthquakes were recorded on 1, 3, 7, 8, 17, and 24 February, with daily totals ranging between 1 and 5. Low-frequency earthquakes were recorded almost every day, with daily totals between 201 and 646.
A check of MODVOLC thermal alerts in mid-April 2010 found no anomalies for Ulawun as far back as May 2001. Those 2001 alerts corresponded with new vents and large plumes in early 2001 (BGVN 26:05, 26:06). A few months earlier, observers had seen Strombolian eruptions (BGVN 25:11).
Geologic Summary. The symmetrical basaltic-to-andesitic Ulawun stratovolcano is the highest volcano of the Bismarck arc, and one of Papua New Guinea's most frequently active. Ulawun volcano, also known as the Father, rises above the N coast of the island of New Britain across a low saddle NE of Bamus volcano, the South Son. The upper 1,000 m of the 2,334-m-high Ulawun volcano is unvegetated. A prominent E-W-trending escarpment on the S may be the result of large-scale slumping. Satellitic cones occupy the NW and eastern flanks. A steep-walled valley cuts the NW side of Ulawun volcano, and a flank lava-flow complex lies to the S of this valley. Historical eruptions date back to the beginning of the 18th century. Twentieth-century eruptions were mildly explosive until 1967, but after 1970 several larger eruptions produced lava flows and basaltic pyroclastic flows, greatly modifying the summit crater.
Reference. Arumba, J., 2009, Agenda Item 3, Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP), 46th CCOP Annual Session, 18-23 October 2009, Vungtau, Vietnam; Member Country Report of Papua New Guinea, October 2009, Annual member country report, 16 p.
Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea (Email: hguria@xxxxxxxxxxxxx); Darwin Volcanic Ash Advisory Centre (VAAC), Commonwealth Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/; Email: darwin.vaac@xxxxxxxxxx); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).
Rabaul
New Britain, Papua New Guinea
4.271°S, 152.203°E; summit elev. 688 m
This report discusses quiet at Tavurvur cone during the first quarter of 2010. Reports only covered parts of the reporting interval, 1 January to 8 April 2010. A report discussed in a subsection below provides an overview for 2008, including ashfall, mudflow, aviation, stress on inhabitants, and monitoring instruments. Our previous report noted intermittent ash plumes and incandescent ejections during 2009 (BGVN 34:11).
According to the Rabaul Volcano Observatory (RVO), ash emissions were absent on most days at Tavurvur cone during 1-25 January 2010, but steam plumes, white to blue in color were occasionally seen. Approximately three brown-gray ash clouds were produced on 3 January. Minor ash emissions on 8 January rose less than 200 m above the cone. A few small low-frequency earthquakes took place during 1-10 January, but they then remained absent through at least 25 January. Volcano-tectonic earthquakes were noted on 8 and 14 January. One ash cloud was noted on 31 January. GPS measurements and tide gauge data continued to show minor uplift--rates of ~ 1 cm every 1 to 2 weeks during January 2010.
Based on information from the United Kingdom's National Weather Service office in Port Moresby, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that on 18 January, an ash plume from Tavurvur cone rose to 2.4 km altitude.
RVO reported that during 21-27 February and 2-8 April, the volcano was quiet with small-to-moderate volumes of white vapor emissions and small low-frequency earthquakes. During the later interval the cone was not emitting ash and sulfur dioxide (SO2) fluxes remained at the lowest levels since measurements on the gas began in June 2009. After intervals of rainfall, steam emissions became voluminous.
RVO advised people to avoid entering the crater because of slope instability and gas accumulation in low lying areas. As of early 2010, the last posted MODVOLC thermal alerts at Rabaul took place 24 November 2009.
Summary of 2008 activity. Although Bulletin reports covered the year 2008 (BGVN 33:03, 33:11, 34:08), a recent report (Arumba, 2009) provides an authoritative summary touching on a broader range of topics.
Arumba (2009) stated that "Tavurvur ... erupted throughout 2008. The level of eruption was relatively mild during the first half of the year, but this changed during the second half when the mode of eruption changed from sporadic ash emissions occurring at long intervals to almost sub-continuous emissions. Between July and October/November SE winds blew the ash-rich plumes towards Rabaul Town and the surrounding areas and deposited significant volumes of ash and affected the everyday livelihood of people and gave rise to the emergence of health-related issues. The ash deposits turned into mudflows as soon as rain began to fall in October and severely affected the entire town of Rabaul and the surrounding areas.
"The eruption also affected the domestic aviation industry when ash-rich plumes frequented the air space of the flight path and deposited considerable amounts of ash on the runway. A flight service to the only main airport that serves East New Britain Province was disrupted, severely affecting the traveling public.
"The seismic monitoring network at Rabaul was maintained at a reasonable level. A couple of stations which had been off from the start of 2008 were restored. The tide gauge network consisting of three stations was partially restored after a long period of inactivity. An upgrade of the real-time Global Positioning System (GPS) of four stations for deformation measurements began during the last quarter of the year. By the end of the year three of the stations were restored . . . ."
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 utilized by what was the island's largest city prior to a major eruption in 1994. 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 east, where its floor is flooded by Blanche Bay and was formed about 1400 years ago. An earlier caldera-forming eruption about 7100 years ago is now considered to have originated from Tavui caldera, offshore to the north. Three small stratovolcanoes lie outside the northern and NE caldera rims of Rabaul. 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 power!
ful explosive eruption in 1994 occurred simultaneously from Vulcan and Tavurvur volcanoes and forced the temporary abandonment of Rabaul city.
Reference. Arumba, J., 2009, Agenda Item 3, Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP), 46th CCOP Annual Session, 18-23 October 2009, Vungtau, Vietnam; Member Country Report of Papua New Guinea, October 2009, Annual member country report, 16 p.
Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea (Email: hguria@xxxxxxxxxxxxx); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/).
Bagana
Bougainville Island, Papua New Guinea
6.140°S, 155.195°E; summit elev. 1,750 m
A report issued in October 2009 (Arumba, 2009) described Bagana as the most active in Papua New Guinea due to its sub-continuous effusive activity, which continued in 2009. "The effusive emissions of lava from the summit crater rolled down the western flanks of the volcano. The volume of lava was too insignificant to cause any alarm." The volcano is andesitic and its lava flows tend to be ten's of meters thick. Parks (1948) photographed Bagana in eruption, and Blake (1968) discussed its geology.
Emission of lava flows, intermittent ash plumes, and thermal anomalies that were evident through December 2009 (BGVN 34:11). Reports from the Rabaul Volcano Observatory (RVO) indicated activity continuing through February 2010.
According to RVO the S-flank lava flow resumed in January 2010, and there was occasional roaring and booming from the main vent. On 5 February observers saw dense gray eruption clouds, presumably signifying ash. Weak glow was seen on the nights of 2, 12, 13, and 19 February. For the rest of the month, variable volumes of white vapor were released from the summit vents;no noises were heard.
MODIS/MODVOLC thermal alerts continued. Alerts were recorded on 13, 24, 29, and 31 January; 7, 10, 14, and 19 February; and 16 March 2010. On 16 March, the Terra satellite recorded four hot pixels.
Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical, roughly 1,750-m-high lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is frequent and is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides.
References: Arumba, J., 2009, Agenda Item 3, Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP), 46th CCOP Annual Session, 18-23 October 2009, Vungtau, Vietnam; Member Country Report of Papua New Guinea, October 2009, Annual member country report, 16 p.
Blake, D.H., 1968, Post Miocene volcanoes on Bougainville Island, territory of Papua and New Guinea: Bull. Volcanology, v. 32(1), p. 121-138.
Parks, F.L. (photographer), 1948, Volcano erupts-A crater on Bougainville obliges high-ranking amateur photographer: Life Magazine, November 29, 1948, p. 42.
Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea (Email: hguria@xxxxxxxxxxxxx); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).
Yellowstone
Wyoming, USA
44.43°N, 110.67°W; summit elev. 2,805 m
All times are local (= UTC - 7 hours)
Monthly updates from the Yellowstone Volcano Observatory (YVO) summarize seismic activity (table 1) and ground deformation at Yellowstone caldera. Earthquake activity remained at low levels during the majority of the reporting interval (November 2006 through February 2010). There were several earthquake swarms during this time, including significant events in December 2008-January 2009 and January-February 2010. The early 2010 events comprised the second largest earthquake swarm recorded at Yellowstone, second only to the fall 1985 swarm (BVGN 17:03). The swarm that began in December 2008 was the third largest swarm recorded.
Table 1. Seismic data for Yellowstone organized by month, including the number of recorded earthquakes, the largest magnitude recorded, and earthquake swarm information. Note the large swarms during December 2008-January 2009 and during January-February 2010. Data courtesy of the USGS.
Month Number of Largest magnitude Earthquake swarms
earthquakes dates (number of events)
Nov 2006 87 2.7 on 04 Nov 04-07 Nov (47)
Dec 2006 36 2.0 on 16 Dec --
Jan 2007 93 2.8 on 30 Jan --
Feb 2007 113 2.9 on 27 Feb 27-28 Feb (5); 13-22 Feb (59)
Mar 2007 63 2.3 on 21 Mar 11 on 1 Mar
Apr 2007 53 2.1 on 22 Apr --
May 2007 59 2.7 on 01 May 01 May (14)
Jun 2007 73 1.5 on 27 Jun 20 June (26)
Jul 2007 80 2.2 on 26 Jul --
Aug 2007 74 2.8 on 03 Aug 19-21 Aug ("small" event)
Sep 2007 54 2.3 on 10 Sep --
Oct 2007 34 2.1 on 17 Oct --
Nov 2007 69 2.9 on 04 Nov --
Dec 2007 184 3.6 on 30 Dec 18-21 Dec (48)
Jan 2008 263 3.7 on 09 Jan 09 Jan (124); 25-26 Jan (32)
Feb 2008 130 2.4 on 03 Feb 03 Feb (47)
Mar 2008 147 4.2 on 25 Mar 11-16 Mar (73); 21-22 Mar (17)
Apr 2008 70 1.7 on 17 Apr --
May 2008 99 2.3 on 18 May 04-14 May (37)
Jun 2008 79 2.7 on 04 Jun 04-08 Jun (27)
Jul 2008 185 2.5 on 31 Jul 28-31 Jul (132)
Aug 2008 146 2.3 on 31 Aug 01-05 Aug (52); 03-07 Aug (28);
07-08 Aug (32)
Sep 2008 62 2.9 on 25 Sep 25 Sep (19)
Oct 2008 46 2.4 on 05 Oct --
Nov 2008 166 2.7 on 23 Nov 23-29 Nov (77)
Dec 2008 ~500 3.9 on 27 Dec 27 Dec-05 Jan (~ 813)
Jan 2009 315 3.5 on 02 Jan 09-12 Jan (35)
Feb 2009 51 2.1 on 19 Feb --
Mar 2009 66 2.4 on 03 Mar --
Apr 2009 242 2.7 on 28 Apr 13-18 Apr (62); 17-25 Apr (111);
29 Apr (19)
May 2009 133 3.0 on 25 May 25 May (68)
Jun 2009 77 3.3 on 30 Jun 30 Jun (25)
Jul 2009 98 2.7 on 08 Jul 01-03 Jul (12)
Aug 2009 86 2.1 on 14 Aug 08-12 Aug (29)
Sep 2009 177 2.3 on 20 Sep 12-17 Sep (39); 13-18 Sep (66)
Oct 2009 218 2.5 on 15 Oct 12-23 Oct (138)
Nov 2009 69 3.1 on 09 Nov --
Dec 2009 70 2.2 on 18 Dec --
Jan 2010 1620 3.8 on 20 Jan 17 Jan-25 Feb (1,809)
Feb 2010 244 3.1 on 02 Feb --
Earthquake swarm, December 2008-January 2009. An earthquake swarm from 26 December 2008 to 5 January 2009 was centered beneath the N end of Yellowstone Lake. The event consisted of ~ 900 earthquakes with magnitudes ranging up to 3.9; 19 events had magnitudes greater than 3.0, while 141 had magnitudes between 2.0 and 2.9.
Earthquake swarm, January-February 2010. The January-February 2010 earthquake swarm was centered about 16 km NW of Old Faithful, on the NW edge of the caldera. The event began with a few small earthquakes on 15 January and began to intensify on 17 January. A 3.7 magnitude earthquake was recorded at 2301 on 20 January, followed by a magnitude 3.8 event at 2316. The events were felt throughout the park and surrounding communities in Wyoming, Montana, and Idaho. By 25 February, YVO had recorded a total of 1,809 earthquakes, with 14 reaching magnitudes of over 3.0 and 136 with magnitudes between 2.0 and 2.9. By the end of February activity had returned to background levels.
The University of Utah Seismology Research Group stated that the total seismic energy released by all the earthquakes in this swarm corresponded to one earthquake with an approximate magnitude of 4.4. YVO emphasized that while this was an unusually large event, it did not indicate premonitory volcanic or hydrothermal activity. Rather, the swarm earthquakes were likely the result of slip on pre-existing faults.
Geologic Summary. The Yellowstone Plateau volcanic field developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions. Eruption of the >2,450 cu km Huckleberry Ridge Tuff about 2.1 million years ago created the more than 75-km-long Island Park caldera. The second cycle concluded with the eruption of the Mesa Falls Tuff around 1.3 million years ago, forming the 16-km-wide Henrys Fork caldera at the western end of the first caldera. Activity subsequently shifted to the present Yellowstone Plateau and culminated 640,000 years ago with the eruption of the >1,000 cu km Lava Creek Tuff and the formation of the present 45 x 85 km caldera. Resurgent doming subsequently occurred at both the NE and SW sides of the caldera and voluminous (1000 cu km) intracaldera rhyolitic lava flows were erupted between 150,000 and 70,000 years ago. No magmatic eruptions have occurred since the late Pleistocene, but large hydrothermal eru!
ptions took place near Yellowstone Lake during the Holocene. Yellowstone is presently the site of one of the world's largest hydrothermal systems including Earth's largest concentration of geysers.
Information Contacts: Yellowstone Volcano Observatory, U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, USA (URL: http://volcanoes.usgs.gov/yvo/).
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