Bulle tin of the Global Vol can ism Net work Vol ume 33, Num ber 2, February 2008

Ol Doinyo Lengai (Tan za nia) Explo sive erup tions of Decem ber 2007-March 2008; hazard warn ings .....2

Bar ren Is land (In dia) Satel lite imag ery of ash plume, 23 De cem ber 2007 ...... 7

Talang (In do ne sia) Ash emis sions in March, June, and Novem ber 2007 ...... 7

Batu Tara (In do ne sia) Sat el lite ther mal anom a lies in di cate that near-daily erup tions con tinue...... 7

Lokon-Empung (In do ne sia) June 2007-March 2008, variable seis mic ity and minor white plumes ...... 8

Langila (Pa pua New Guinea) Inter mittent ash emissions in May and August 2007 ...... 8

Garbuna Group (Pa pua New Guinea) Ash emis sions during March 2008...... 9

Bulusan (Phil ip pines) Ash ejec tions con tinued to at least late 2007 ...... 10

NW Rota-1 (Mariana Is lands) Visit on 24 Febru ary 2008 found eruption plume and acous tic signals .....11

Suwanose-jima (Ja pan) Small (~ 1 km) plumes noted during late 2007-early 2008 ...... 11

Cleve land (USA) Ther mal anom a lies and mi nor ex plo sions con tinue through Feb ru ary 2008 ...... 12

Ed itors: Rick Wunderman, Ed ward Venzke, and Sally Kuhn Sennert Vol un teer Staff: Phumtham Limwattananon, Rob ert Andrews, Hugh Replogle, Michael Young, Paul Berger, Jacquelyn Gluck, Margo Morell, Stephen Bentley, Antonia Book binder, Jeremy Book binder, and Ludmila Eichelberger

Global Vol canism Program · National Museum of Natural History, Room E-421, PO Box 37012 · Washing ton, DC 20013-7012 · USA Tele phone: (202) 633-1800 · Fax: (202) 357- 2476 · Email: [email protected] · URL: http://www.vol cano.si.edu/

The text of the Bul le tin is also distrib uted through the Volcano Listserv (vol [email protected]). 2 Ol Doinyo Lengai Smithsonian Institution — Bulletin of the Global

An acci dent last August high lights the haz ards of sum- Ol Doinyo Lengai mit access. On his 21 August 2007 ascent, Chris Weber’s group evacu ated a local Maasai porter who had fallen into Tan za nia, East ern Af rica an ac tive lava flow (around 500°C) in the crater. The por ter 2.764°S, 35.914°E; summit elev. 2,962 m had managed to get out of the lava, but with both legs and All times are local (= UTC + 3 hours) one arm seri ously burned. Initial treatment at an Arusha hospi tal was fi nanced by Weber's tour com pany. As of Jan - The previous report on Ol Doinyo Lengai (BGVN u ary 2008 he was bedrid den in his home near Engare Sero, 32:11), often sim ply called Lengai, sum marized seismic ity ex pe ri enc ing pain and mus cle wast ing. Celia Nyamweru and ener getic ash emissions during 2007. The devel op ment (see web address below) has appealed for fi nancial support of a single large cone with a promi nent venting crater sig- to assist the young man during his recov ery. nifi cantly changed the crater morphol ogy. Keller and Klaudius fieldwork, Decem ber 2007. Sub- This re port dis cusses field ob ser va tions by var i ous in di - se quent to pub li ca tion of BGVN 32:11, we received an un- vidu als during Decem ber 2007 through March 2008. The published report by Joerg Keller and Jurgis Klaudius on reports and photos from visi tors provided by Freder ick their fieldwork during 5-11 Decem ber 2007. Accord ing to Belton on his website form the source for much of which them, the 4 Septem ber eruption ended a period of about 25 fol lows. Ta ble 1 sum ma rizes the ob ser va tions from De cem - years of activ ity domi nated by the effu sion of highly fluid ber 2007 through March 2008. natrocarbonatite lavas within the summit crater. The deep

Brief ob ser va tion(s) (Key: CV= climbed vol cano; A=ae rial ob ser va tions/ Date(s) Ob server(s) photos from crater over flight; F = flank obser va tion)

7 Dec 2007 Joerg Keller, Jurgis Klaudius (CV) Geolog i cal sam ples collected; ash eruption with plumes rising to sev eral thousand meters above vol cano (see text) 25 Dec 2007 Jens Fissenebert, Paul Johns (A/CV) Ob serva tions of crater from heli cop ter and ground (see text) 31 Dec 2007 Ra phael Wolf (CV) Volcano “shook 3 times as my guide and I were climb ing”; vent of new cin der cone steam ing 6 Jan 2008 Paul Johns (A/CV) Heli cop ter landed in S crater, group walked to sum mit; eruption during flight to crater and 15 minutes after they left; large rocks (bombs?) had been thrown into the S crater 14 Jan 2008 Vegard Laukhammer (CV) Ex pe ri enced erup tion (see text) 17-21 Jan 2008 Tom Pfeiffer, group from Volcano (CV) (See text) Dis cov ery 18 Jan 2008 Thomas Holden (CV) New climb ing route on the SE described 19 Jan 2008 Bernhard Donth, Thomas (CV) Occa sional rain of fine gray ash and small white pebbles during as cent; Schulmeister, William (Maasai guide) small ash jets from the ac tive crater 04 Feb 2008 Mi chael Dal ton-Smith (F) (See text) 12 Feb 2008 Michel Picard (A) Photo graphed a dark ash cloud 13 Feb 2008 Walt Bilofsky (A) Ash rising from sum mit crater 15 Feb 2008 Gerrit Jan Plaisier, Rob Alakaposa (A) Plume over Lengai to al titude of 11 km 15 Feb 2008 Benoit Wangermez (pilot) (A) Summit crater heavily cloaked in fresh ash; ash cloud rising from crater; movie of erup tion on Celia Nyamweru’s website 20 Feb 2008 Nigel D’Aubrey (A) Plume over Lengai 21 Feb 2008 KLM pi lot (A) Erup tion 24 Feb 2008 Claude Humbert (CV) Party of 11 peo ple at tempted to climb the S side, but ter mi nated the climb about half-way up due to erup tion 27 Feb 2008 reported to Mi chael Dal ton-Smith (F) Eruptions getting stronger; ob served from Gol, massive cloud 27-28 Feb 2008 Flight crew (A) Ash emissions at 1030 and 1200 on 27 Feb and 0530 on 28 Feb; ash cloud moved SW and dissi pated 27-28 Feb 2008 Dave Rhys (F) Eruptions observed from the Serengeti Plain and Ngorongoro Crater 3; single ash plumes rose rap idly follow ing each eruption (none contin u ous) and dispersed S (thin ash coating on leaves around the rim of Ngorongoro crater) 01 Mar 2008 Max Voight (A) Photo of ash plume rising late Feb 2008, 1-2 Mar 2008 Benoît Wilhelmi (pi lot) (A) Photos of ash plumes 03 Mar-05 Mar 2008 Tony Drummond-Murray (F) Massive erup tions (see text) 05 Mar 2008 Benoît Wilhelmi (pi lot) (A) Plume to al titude of ~15.2 km 11 Mar-12 Mar 2008 Benoît Wilhelmi (pi lot) (A) Strong ash erup tion (see text) 18 Mar 2008 Benoît Wilhelmi (pi lot) (A) Pho tos of crater (see text) 22 Mar 2008 Benoît Wilhelmi (pi lot) (A) Pho tos of new crater (see text) 25 Mar 2008 Paul Westerman, friend, and Maasai (CV) Walked to the top of the ash cone and heard the tremen dous roar; no guide sulfur smell but some heat 26 Mar 2008 Paul Westerman (F) From shore of Lake Natron observed some smoke and ash fall (on the downwind side) start ing around 0930

Table 1. Sum mary of selected observ ers of Ol Doinyo Lengai from Decem ber 2007 through 26 March 2008. Obser va tions for 2007 were re ported in BGVN 32:11. Most of list is cour tesy of Freder ick Belton. Volcanism Network, Volume 33, Number 2, February 2008 Ol Doinyo Lengai 3 pit crater from the 1966/67 eruption period had gradu ally Dawson (reported in BGVN 32:11), who ana lyzed the min- filled by about 1999/2000. Accord ing to the report, the last eral ogy after the 24 Septem ber 2007 eruption, and their days of August 2007 were charac ter ized by Weber as dis- sugges tion that at the onset of the explo sive eruptive period playing seemingly increased lava output. A on 4 September 2007 a sili cate compo nent became involved natrocarbonatite lava, col lected by Weber dur ing his as cent in the eruptive activ ity. Mitchell and Dawson concluded on 23 August, was ana lyzed by Keller at Freiburg Univer - that “in lacking clinopyroxene, the mantling ash is not sity and was close to the aver age or standard compo si tion nephe lin ite or melilitite and is un like any other magma type for natrocarbonatite from the last 20 years. previ ously recorded from the volcano." During their field work on 5-11 De cem ber 2007, Keller During the Decem ber fieldwork, Keller and Klaudius and Klaudius ob served in ter mit tent but im pres sive ex plo- col lected samples and ex amined cross-sec tions of the 4 sions with ash plumes rising to several thousand meters Sep tem ber 2007 ash. Prox i mal (near-source) ac cu mu la tions above the volcano. This activ ity alter nated with peri ods of tephra in the S crater occurred to a thickness of ~ 20 cm domi nated by either minor puffing or degas sing, or with in the depres sion and on the upper slopes of the S flank, de- seemingly dormant phases up to several days long. This creasing to a thickness of 1 cm at the E starting point of the pattern seemed to be repre sen ta tive of the period fol lowing new trail. This compared with a thickness of ~ 5 cm at the the 4 Septem ber 2007 parox ysm, which Keller and upper parking site of the old W trail and the abandoned Klaudius had also studied. Maasai home closest to the volcano, 4.2 km away (figure Keller and Klaudius reported that an impres sive bomb 2). To wards Engare Sero village, rel ics of the ashfall were field with impacted blocks of up to 1 m in diam e ter ex- still locally preserved and indi cated an orig inal thickness of tended along the crater rim, on the E ridge to the summit, ~ 1 cm, consis tent with eyewit ness reports of ashfall over and on the flank down into the S crater. They noted that, the village during 4 September. given the observed sudden onset of explo sions from the Other ob ser va tions. Jens Fissenebert’s visit on 25 De- intra-crater vent, the summit area was poten tially danger - cember 2007 to the summit by heli cop ter again confirmed ous. They found that fumarolic activ ity in the N crater was that the ash cone had grown. He esti mated that it covered strong, espe cially along the N rim. It was also observed within the upper part of the N flank. Accord ing to Keller and Klaudius, the 4 Septem ber par- ox ysm com pli cated ac cess to the sum mit. With the help of Maasai guides, they used a newly opened route on 7 De- cem ber that follows a prom inent steep ridge and ends at the SE edge of the S crater. They re ported that the track was quite strenu ous and, while being rather direct, took much longer (7 hours) than the old trail from the W. They found that, with ongo ing explo sive activ ity, the S crater was the only safe arrival place. An attempt to use the old W route during their descent was un suc cess ful be cause the very ce - mented surface of the lapilli beds provided no grip on the steep en trance from above to the ascent chasm. While at the crater, Keller and Klaudius col lected fresh samples of black lapilli, ash, and bombs from the active cone. The large intra-crater cinder-and-ash cone (fig ure 1) occu pied more than half of the former crater platform, with Figure 1. The ash-and-cinder cone that domi nated the N crater of Ol a crater diam e ter of ~200 m. Its loca tion coin cided with the Doinyo Lengai. Taken 7 De cem ber 2008 from the sum mit looking N. large collapse structure formed during the March/April Courtesy of Joerg Keller. 2006 natrocarbonatite ef fu sive ac tiv ity (BGVN 32:02) (Kervyn and others, 2008), which has also been the area of strong lava emission before the explo sive eruption of 4 Septem ber 2007. It had a slightly N-S elonga tion, oval shape and, de spite the heavy fumes filling the crater, it ap - peared that two vents, a more northerly one and a more southerly one, were erupting. The cone was formed by and covered by ash, black-to-brown lapilli, cinders, angu lar blocks, and cored oval bombs. The magmatic lapilli contained macro scopic phenocrysts of nephel ine, garnet, and wollastonite. With time, the black lapilli and bombs on the slopes of the cone and in the ring plain around it turned white by weather ing of their com po nents. Products of the active cone have cov- ered al most all the old natrocarbonatite struc tures. Only the spiny remnant of the T49B horni to still stands out at the northern crater rim of the cone. The surface of a blocky flow was also still recog niz able at the foot of the N wall. Figure 2. The abandoned set tlement of the Lesele fam ily, located in the Anal yses of the mag matic mate rial were in har mony major ash fallout area W of the volcano. Note the ash on the roofs of the with the recent obser va tions of Roger Mitchell and Barry huts. Courtesy of J. Keller and J. Klaudius. 4 Ol Doinyo Lengai Smithsonian Institution — Bulletin of the Global nearly the north ern two-thirds of the crater floor. The N and W parts of the crater rim were indis tinct, having been mostly covered by the growing flank of the new cone. Newly erupted ash and lapilli had filled in the flank area be- low the former crater rim and down through the “Pearly Gates” through which the former W climbing route passed. Several eruptions were noted by Paul Johns when land- ing by heli cop ter on 6 Janu ary 2008. During early 2008, there were also oc casional thermal anoma lies measured by MODIS (table 2). Vegard Laukhammer climbed the volcano with several others on 14 Janu ary 2008. Laukhammer reported arriv ing at the summit at 0652 (local time). “The vis ibil ity was so poor and there was so much smoke that we decided to try to climb down again after 10 minutes. . . . About 10 minutes later (0715), when we had been able to climb about 50 me- ters down from the summit, a thunder ing, ear-breaking Figure 3. View look ing N from the sum mit of Ol Doinyo Lengai, taken 18 sound came from the volcano. A large shower of rocks Janu ary 2008. The large cone in the crater was quiet at this time. Cour tesy (many the size of a football) were thrown out from the vol- of Vol cano Dis cov ery. cano directly towards us 4 on the top” (transla tion from Norwe gian by Sven Dahlgren, found on Belton’s website). The climbers managed to descend without serious injury. Tom Pfeiffer and a VolcanoDiscovery group stayed near and on Ol Doinyo Lengai dur ing 17-21 Jan u ary 2008. During this period epi sodic ash eruptions lasted several hours. These phases alter nated with quiet inter vals when there was only a weak plume of very fine gray ash and gas. After sunset on 17 Janu ary, strong ash eruptions started with plumes reaching about 500-1,000 m high, accom pa - nied by strong lightning. After around 2130, Randle Rob- ertson observed a fountain that appeared as a bright red-or- ange “blow-torch” rising from the summit crater to an esti mated height of 500 m above the crater. The light was steady in ap pear ance and lasted for at least 5 min utes. When the fountain died, a dark ash cloud emerged from the Figure 4. View look ing N over the ac tive crater from the sum mit of Ol crater, which did not reach a great height. The volcano was Doinyo Lengai, taken 18 Jan u ary 2008, showing the onset of ash eruption. more or less quiet during most of 18 Janu ary (figure 3). Cour tesy of Vol cano Dis cov ery. At around 1600 on 19 Janu ary, weak ex plosions set in, increas ing in inten sity until the ash plumes reached about 500 m above the crater at around 1730 (figure 4). Blocks Michael Dal ton-Smith ob served a fairly large eruption were ejected 300-400 m above the crater, and all explo sions at 1200 on 3 Febru ary 2008 from the Gol moun tains just E were near-ver tical jets from two vents in the crater’s W and of Sanjan gorge. He saw a cloud that rose about ~1 km cen tral por tions. Ac tiv ity de creased af ter sun set. No in can - above the summit. Ac tiv ity was pres ent all day, ceas ing descence was observed during the night. Activ ity inten si - around 1600, followed by renewed activ ity with ash rising fied during the night, with loud-explo sion sounds, and the 0.3-0.5 km above the crater. hissing sound of gas-and-ash jets. During their descent on At about 0600 on 4 Feb ruary there was a larger eruption 20 Janu ary, ash eruptions continued until early afternoon. with the ash rising about 1.4 km. It was a fairly dense cloud that flattened out at the top. The camp manger of Asilia (where Dal ton-Smith was stay ing) also said that there had Date (2008) Time (UTC) Pixels Satel lite been several large explo sive eruptions three days before (on 1 Febru ary). Two explo sions were heard, one in the morn - 08 Jan 2030 2 Terra ing and one in the evening. 17 Jan 2025 2 Terra On 6 Febru ary, Dalton-Smith opted to not climb be- 17 Feb 2240 3 Aqua cause of strong eruptions. When he drove past the vol cano 22 Feb 2300 1 Aqua he reported that "it was having some of the biggest erup- 28 Feb 1135 1 Aqua tions in a long time" with contin u ous ac tiv ity from sunrise 29 Feb 2305 1 Aqua to about 1400. 07 Mar 2310 1 Aqua During 3-5 March 2008, Tony Drummond-Murray and 10 Mar 2045 4 Terra his wife observed very strong eruptions (figure 5). Fig ure 6 03 Apr 1955 1 Terra shows pyroclastic flows from what appeared to be a col- Ta ble 2. MODIS/MODVOLC ther mal anoma lies measured at Ol Doinyo laps ing ash column. The valley between Lengai and the es - Lengai during Janu ary through early April 2008. Anom alies measured carpment itself was cov ered with a highly vis ible layer of during 2007 were reported in BGVN 32:11. Courtesy of the Hawai’i light ash after the eruption on 4 March. On 5 March the In sti tute of Geo phys ics and Plan e tol ogy (HIGP) Ther mal Alerts Sys tem. plume appeared even larger than the one seen on 4 March. Volcanism Network, Volume 33, Number 2, February 2008 Ol Doinyo Lengai 5

At 1010 on 5 March 2008, pilot Benoît Wilhelmi ob- served a plume rising to ~15 km alti tude. On 12 March, he also saw a strong ash erup tion; weaker ac tiv ity was also seen that day (figure 7). That photo indi cates that the pow- erful eruptions of 3-5 March did not signif i cantly alter the ash cone or crater rim. Large amounts of ash and cinders had piled up against the northward facing ridge below the summit. The S crater was cov ered in ash and cin der lay ers so deep that previ ously prom inent erosion gul lies were be- com ing in distinct. It ap peared that all vege ta tion had either died or been buried. Wilhelmi photo graphed the summit cone on 18 March at 1530 (figure 8). On 22 March, Wilhelmi photo graphed di rectly into the crater (fig ure 9). At that time there had been no reports of activ ity for three days, but the smell of hydro gen sulfide returned after being gone for days. Table 3 lists a number of volca nic ash advi so ries Figure 7. Ash erup tion from Ol Doinyo Lengai seen 12 March 2008 from (VAAs) issued in March 2008 by the Toulouse Volca nic the NNE. This im age shows that the E, N, and W flanks of the ash cone had Ash Ad vi sory Cen ter (VAAC). buried the origi nal crater rim. Oversteepening of the cone flank in places Thomas Holden reported that as of 29 March 2008 there resulted in small land slides which can be seen just be low the cone as dark had been no activ ity at Lengai for 10 days. Chris Daborn mate rial cov ering the lighter ar eas of older weath ered carbonatite. The peak beyond the ash plume is the sum mit. Photo cour tesy Benoît (Trop i cal Veter i nary Ser vices Ltd.) re ported on 2 April Wilhelmi. 2008 the follow ing: “Lengai has of late quieted down sig- nifi cantly–first in changing ash colour from a ‘salty’ white

Figure 8. Aerial photo highlight ing the sum mit pro file of Ol Doinyo Lengai, as seen look ing W at ~1530 (local time) on 18 March by Benoît Wilhelmi (pi lot). Cour tesy of Fred erick Belton. Figure 5. Large eruption of Ol Doinyo Lengai taken around 4 March 2008 from the Lake Natron area. Courtesy of Tony Drummond-Murray. to a more inert black and now with much smaller eruptions that barely extend above the mountain. We have heavy rains on at present which makes movement in the area diffi - cult–but are also washing ash resi due away.” Jurgis Klaudius reported that he checked MODIS data and found a ther mal anom aly in the N crater on 3 April 2008, indi cat ing on-going eruptions then (table 2). Warn ings of hazards. Celia Nyamweru posted the fol - lowing warning on her web site: “A team of Tan za nian, US, and French scien tists visited the region around the vol cano in Janu ary 2008, and inter viewed local porters who rou- tinely climb Ol Doinyo Lengai with tourists. Our obser va - tions and pho tos in di cate con tin u ing erup tive ac tiv ity, and a growing threat to the region, as outlined below. “Al most daily eruptions from the central caldera have filled the crater, and pro duced a steep lapilli-ash cone around the crater rim. A film clip of the crater made by a Figure 6. During an ener getic eruption, small pyroclastic or de bris flows Medecins Sans Frontieres pi lot con firms that the loose propa gated down the flanks of Ol Doinyo Lengai. This photo was taken lapilli is near col lapse. These con di tions mean that there are around 4 March 2008 from the Lake Natron area. Courtesy of Tony very high risks of one or more of the follow ing: 1) a debris Drummond-Murray. flow or lahar (mix of hot ash, water/mud) down the exist ing 6 Ol Doinyo Lengai Smithsonian Institution — Bulletin of the Global

Geo logic Sum mary. The symmet ri cal Ol Doinyo Lengai stratovolcano is the only volcano known to have erupted carbonatite tephras and lavas in histor i cal time. The prom inent vol cano, known to the Maasai as “The Mountain of God,” rises abruptly above the broad plain south of Lake Natron in the Gregory Rift Valley. The cone-building stage of the volcano ended about 15,000 years ago and was fol- lowed by pe riodic ejection of natrocarbonatitic and nephe- lin ite tephra dur ing the Ho lo cene. His tor i cal erup tions have consisted of smaller tephra eruptions and emission of nu- merous natrocarbonatitic lava flows on the floor of the sum mit crater and oc casion ally down the upper flanks. The depth and morphol ogy of the northern crater have changed dra mat i cally dur ing the course of his tor i cal erup tions, rang- ing from steep crater walls about 200 m deep in the mid-20th century to shal low plat forms mostly filling the Figure 9. Aerial photo at Ol Doinyo Lengai looking sub-verti cally, down crater. Long-term lava effu sion in the summit crater begin - into the new cone’s crater. Taken at about 0930 (local time) on 22 March ning in 1983 had by the turn of the century mostly filled the by Benoît Wilhelmi (pi lot). Cour tesy of Fred erick Belton. northern crater; by late 1998 lava had begun overflowing the crater rim. In for ma tion Con tacts: Joerg Keller and Jurgis channels around the volcano; 2) burns from hot lapilli and Klaudius, Mineralogisch-geochemisches Institut, Albertstr. ash; and 3) cata strophic collapse of the steep lapilli cones 23B D-79104 Freiburg, Germany (Email: joerg. around the crater. The risks in crease with increas ing rainfall [email protected], jurgis.klaudius@minpet. during the March-May rains. uni-freiburg.de); Jens Fissenebert, Molvaro-Lake Natron “We also urge ex treme cau tion to any one driv ing in the Tented Camp and Campsite (http://picasaweb.google.com/ river channels on the east ern and north ern slopes of Lengai Moivaro.Lake.Nat ron.Camp/Lengai25thDecember); be tween Engaruka and Ngare Sero. There are scars of im- Vegard Laukhammer (URL: http://www.vgb.no/perma/ mense debris flows on the flanks of Kerimasi, and smaller 280695); Fred er ick Belton, De vel op men tal Stud ies scars on Ol Doinyo Lengai. These scars attest to cata - Department, PO Box 16, Middle Tennes see State Univer - strophic flows in the past, some of which carried rock frag - sity, Murfreesboro, TN 37132, USA (URL: http://www. ments up to 50 cm in diam e ter for distances extend ing up to mtsu.edu/~fbelton/; http://www.oldoinyolengai.org; Email: 10 km from Ol Doinyo Lengai. Even smaller debris flows [email protected]); J. Barry Dawson, Grant In- could do great dam age to vehi cles and peo ple mov ing along stitute of Earth Science, University of Edin burgh, King’s the eastern and northern slopes of the volcano.” Building, Edin burgh EH9 3JW, U.K. (URL: Ref er ence. Kervyn, M., Ernst, G.G.J., Klaudius, J., [email protected]); Roger Mitchell , Lakehead Uni- Keller, J., Kervyn, F., Mattsson, H.B., Belton, F., Mbede, versity, 955 Oli ver Road, Thunder Bay, Ontario, Canada E., and Jacobs, P., 2008, Volu mi nous lava flows at Ol P7B 5EI (Email: [email protected]); Hawai’i In sti tute Doinyo Lengai in 2006: chronol ogy of events and insights of Geo physics and Plane tol ogy (HIGP) Thermal Alerts Sys- into the shal low magmatic system: Bulle tin of Vol ca nol- tem, School of Ocean and Earth Science and Technol ogy ogy, DOI 10.1007/s00445-007-0190-x. (SOEST), Univ. of Hawai’i, 2525 Correa Road, Hono lulu, HI 96822, USA (URL: http:// Date Time (UTC) Infor ma tion Source Observed details hotspot.higp.ha waii.edu/); Celia Nyamweru, Department of An- 04 Mar 2008 0900 Sat el lite Eruption occurred at 0630 (UTC), cloud thro pol ogy, St. Law rence Uni ver- rising to 12.2 km may con tain some ash; sity, Canton, NY 13617 USA stopped by 0900. (Email: cnyamweru@ya hoo.com; 05 Mar 2008 0854 Meterological watch of fice Eruption of very short dura tion; “sim ple URL: http://it.stlawu.edu/~cnya/); (MWO) Dar-Es-Sa laam puff”, ash cloud to 10.7 km alti tude. Toulouse Vol ca nic Ash Ad vi sory 06 Mar 2008 1730 MWO Dar-Es-Salaam Eruption occurred at 0830 (UTC); cloud Cen ter (VAAC) (http://www. top at 9.1 km alti tude, ash not identi fied from sat el lite. metro.fr/aeroweb/info/vaac/ 09 Mar 2008 0845 MartinAir Current eruption; ash plume to 8.8 km homepage/eindex.html and http:// al ti tude, ash not iden ti fied from sat el lite. www.ssd.noaa.gov/VAAC/OTH/ 10 Mar 2008 0711 Sat el lite Cloud to 7.3 km alti tude. FR/mes sage.html); Mi chael Dal- 11 Mar 2008 1800 In fra red sat el lite Possi ble brief erup tion at about 1700 ton-Smith (Email: (UTC); cloud up to 12.2 km alti tude, [email protected]); mov ing S. Lake Natron Camp (URL: http:// 13Mar 2008 1800 KLM pilot; MartinAir Volca nism with ash cloud rising to 12.2 www.ngare-sero-lodge.com/ km al ti tude. Natropn_camp.htm); Chris 16 Mar 2008 0450 Sat el lite Short eruption at ~0330 (UTC); plume reached 13.7 km alti tude. Weber, Vol cano Ex pe di tions 16 Mar 2008 2148 Sat el lite Ash cloud to 12.2 km alti tude. International (VEI) (Email: [email protected]; URL: http://www. Table 3. March 2008 Volca nic Ash Advi so ries (VAAs) relat ing to Ol Doinyo Lengai issued by Toulouse Volca nic v-e-i.de/). Ash Ad vi sory Cen ter (VAAC). Volcanism Network, Volume 33, Number 2, February 2008 Batu Tara 7

On 29 Novem ber CVGHM raised the Alert Level to 3 Bar ren Is land (on a scale of 1-4) based on visual obser va tions and seis- micity. During 27-29 Novem ber, ash and steam plumes Andaman Islands, Indian Ocean from multi ple craters rose to alti tudes of 3.1-4.1 km. A 12.278°N, 93.858°E; sum mit elev. 354 m strong smell of sulfur diox ide gas was reported. Visi tors were advised not to go within 3 km of the summit. Ther mal anom a lies as so ci ated with the erup tion that be- Dur ing 7-10 De cem ber, ob ser va tions were lim ited by gan in May 2005 were noted at Barren Island through 1 in clement weather. On 11 De cember, “smoke” rose from Sep tem ber 2007 (BGVN 32:07). Anoma lies detected on 4 the Main crater to a maxi mum alti tude of 3.3 km. Plumes and 5 Octo ber 2007 again gener ated MODIS thermal alerts. were also observed from the South crater and Gabuo Atas On 23 Decem ber 2007 the Darwin Vol canic Ash Advi sory solfatara field. On 14 Decem ber visual obser va tions and a Cen tre re ported that an ash plume seen on sat ellite im ag ery decrease in the number of earthquakes prompted a lower ing rose to an alti tude of 1.5 km and drifted S. of the Alert Level back to 2. Geo logic Sum mary. Barren Island, a posses sion of In- Geo logic Sum mary. Talang, which forms a twin vol- dia in the Andaman Sea about 135 km NE of Port Blair in cano with the extinct Pasar Arbaa volcano, lies ESE of the the Andaman Islands, is the only histor i cally active volcano major city of Padang and rises NW of Dibawah Lake. along the N-S-trending volca nic arc extend ing between Su- Talang has two crater lakes on its flanks; the largest of these matra and Burma (Myanmar). The 354-m-high island is the is 1 x 2 km wide Danau Talang. Most histor i cal eruptions emergent summit of a volcano that rises from a depth of have not occurred from the summit of the volcano, which about 2,250 m. The small, unin hab ited 3-km-wide island lacks a crater. Histor i cal eruptions from Gunung Talang contains a roughly 2-km-wide caldera with walls 250-350 vol cano have mostly in volved small-to-mod er ate ex plo sive m high. The caldera, which is open to the sea on the W, was activ ity first docu mented in the 19th century that origi nated created during a major explo sive eruption in the late Pleis- from a se ries of small craters in a valley on the upper NE tocene that produced pyroclastic-flow and -surge depos its. flank. The morphol ogy of a fresh pyroclastic cone that was con- In for ma tion Con tacts: Dar win Vol ca nic Ash Ad vi sory structed in the center of the caldera has varied during the Cen tre, Bu reau of Me te o rol ogy, Com mon wealth of Aus tra - course of histor i cal eruptions. Lava flows fill much of the lia (URL: http://www.bom.gov.au/info/vaac); Cen ter of caldera floor and have reached the sea along the west ern Vol ca nol ogy and Geo log i cal Haz ard Mit i ga tion coast dur ing his tor i cal erup tions. (CVGHM), Jalan Diponegoro 57, Bandung 40122, In do ne- In for ma tion Con tacts: HIGP MODIS Thermal Alert sia (Email: dali@vsi.esdm.go.id; URL: http://www.vsi. Sys tem, Hawai’i In sti tute of Geo phys ics and Plan e tol ogy esdm.go.id/). (HIGP), Univer sity of Hawaii and Manoa, 168 East-West Road, Post 602, Hono lulu, HI 96822, USA (URL: http:// modis.higp.ha waii.edu/); Dar win Vol ca nic Ash Ad vi sory Cen tre, Bu reau of Me te o rol ogy, North ern Ter ri tory Re- gional Office, PO Box 40050, Casua rina, Northern Terri - Batu Tara tory 0811, Austra lia (URL: http://www.bom.gov.au/info/ vaac/). Lesser Sunda Is lands, In do ne sia 7.792°S, 123.579°E; summit elev. 748 m

Our last report (the first ever for this volcano) covered Talang eruptive activ ity through 13 Octo ber 2007 (BGVN 32:12). This report contin ues cover age through early April 2008. Suma tra, Indo ne sia On 8 Janu ary 2007, gray plumes rose to 1.5 km alti tude 0.978°S, 100.679°E; sum mit elev. 2,597 m and drifted E. On 26 Janu ary, white plumes rose to alti tudes of 1.7 km and drifted E. On 30 Janu ary, white plumes rose The Center of Volca nol ogy and Geolog i cal Hazard Mit- to alti tudes of 1.5 km. and drifted E. The Darwin VAAC re- iga tion (CVGHM) low ered the Alert Level of Talang to 2 ported that eruption plumes were observed from a ship on (on a scale of 1-4) on 27 Janu ary 2007 due to a reduced 31 Janu ary, but ash was not seen in satel lite imag ery. The seismic ity between 23 Novem ber 2006 and 24 Janu ary Alert level re mained at 1 (on a scale of 1-4). 2007, although gas plumes origi nated from South and Main Ther mal anoma lies were first mea sured by the MODIS craters. There had been eruptive epi sodes in April 2005 and sat ellites on 17 Janu ary 2007 (1420 UTC). Accord ing to the el e vated ac tiv ity dur ing late 2006 (BGVN 32:01). Hawai’i In sti tute of Geo phys ics and Plan e tol ogy (HIGP) On 17 March 2007, CVGHM raised the Alert Level Thermal Alerts System, through the end of 2007 anoma lies based on increased “smoke” and trem ors to 3 (on a scale of were measured ev ery 1 to 7 days. This trend of nearly daily 1-4). The Darwin Volca nic Ash Ad visory Centre (VAAC) anoma lies contin ued up to 9 April 2008, with the follow ing reported that, based on infor ma tion from CVGHM, ash excep tions: a 10-day gap begin ning 21 Decem ber 2007, a plumes rose to alti tudes of 3.4-3.9 km on 19-20 March. Lo- 10-day gap begin ning 8 Janu ary 2008, and a 21-day gap be- cal au thor ities and res idents were ad vised to pre pare for a gin ning 2 Feb ru ary 2008. possi ble evacu ation. On 23 April 2007 the Alert Level was The reg u lar ity and re peat ing char ac ter of the ther mal reduced to 2. During 18-25 June, thick brown ash plumes anoma lies suggest ongo ing venting of hot fragmental mate - rose from Main crater to an alti tude of 3.1 km. Diffuse rial or lava flows, simi lar to March and April 2007 (BGVN "white ash" plumes rose from South crater to an al ti tude of 32:12). However, the late 2007 and early 2008 behav ior 3 km. and depos its have not been observed. 8 Lokon-Empung Smithsonian Institution — Bulletin of the Global

On 4 Febru ary 2008, the Center of Volca nol ogy and are among the most active volca noes of Sulawesi. Lokon, Geo log i cal Haz ard Mit i ga tion (CVGHM) re ported that the higher of the two peaks ( whose summits are only 2.2 since 9 Octo ber 2007, white plumes were a daily occur - km apart), has a flat, craterless top. The morpho log i cally rence. On 11 March the Dar win VAAC re ported that sat el- younger Empung volcano has a 400-m-wide, 150-m-deep lite imag ery that day re vealed an ash-and-steam plume from crater that erupted last in the 18th century, but all subse - Batu Tara that rose to an alti tude of 3 km and drifted SW. quent eruptions have origi nated from Tompaluan, a 150 x On 12 March satel lite imag ery re vealed an ash-and-steam 250 m wide double crater situ ated in the saddle between the plume at an alti tude of 2.1 km moving SE. two peaks. His tor i cal erup tions have pri mar ily pro duced Geo logic Sum mary. The small iso lated island of Batu small-to-mod er ate ash plumes that have oc ca sion ally dam- Tara in the Flores Sea about 50 km N of Lembata (fomerly aged croplands and houses, but lava-dome growth and Lomblen) Island con tains a scarp on the eastern side sim ilar pyroclastic flows have also oc curred. to the Sciara del Fuoco of Italy’s Stromboli volcano. Vege - In for ma tion Con tacts: Dali Ahmad, Hetty Triastuty, tation covers the flanks of Batu Tara to within 50 m of the Nia Haerani and Suswati, Cen ter of Volca nol ogy and Geo- 748-m-high sum mit. Batu Tara lies N of the main vol canic log i cal Haz ard Mit i ga tion (CVGHM), Jalan Diponegoro arc and is noted for its potassic leucite-bear ing basanitic 57, Bandung 40122, Indo ne sia (Email: [email protected]. and tephritic rocks. The first histor i cal eruption from Batu id; URL: http://www.vsi.esdm.go.id/). Tara, during 1847-52, produced explo sions and a lava flow. In for ma tion Con tacts: Dar win Vol ca nic Ash Ad vi sory Cen tre, Bu reau of Me te o rol ogy, Com mon wealth of Aus tra - lia (URL: http://www.bom.gov.au/info/vaac); Cen ter of Vol ca nol ogy and Geo log i cal Haz ard Mit i ga tion Langila (CVGHM), Jalan Diponegoro 57, Bandung 40122, In do ne- sia (Email: [email protected]; URL: http://www.vsi. New Britain, Papua New Guinea esdm.go.id/); Hawai’i In sti tute of Geo phys ics and Plan e tol - 5.525°S, 148.42°E; sum mit elev. 1,330 m ogy (HIGP) Thermal Alerts System , School of Ocean and All times are local (= UTC +10 hours) Earth Sci ence and Technol ogy (SOEST), Univ. of Hawai’i, 2525 Correa Road, Hono lulu, HI 96822, USA (URL: http:// Sat ellite ther mal anoma lies oc curred at or near Langila hotspot.higp.ha waii.edu/). on three differ ent days in early 2007 (BGVN 32:02). Al- though erupting regu larly, only one other anomaly (on 2 April 2007) was detected after that time through 6 March 2008. Langila is noted for its ongo ing fluctu at ing eruptions and occa sional ash clouds that rise to more than 5 km alti - Lokon-Empung tude and pose a threat to avia tion. Throughout this report - ing period, April 2007 to Janu ary 2008, ash emissions were Sulawesi, In do ne sia usually accom panied by weak to moder ately loud roaring. 1.358°N, 124.792°E; summit elev. 1,580 m During May 2007, the Rabaul Volca nic Obser va tory All times are local (= UTC + 8 hours) (RVO) reported the emission of ash clouds from Langila’s Crater 2. Ash plumes rose to an alti tude of 3.3-4.3 km and Our most recent report on Lokon-Empung discussed drifted NW. Weak roaring noises were heard on 11-12 May low seis mic ity and plume emis sions be tween Jan u ary-Oc to- and a weak glow was visi ble on 7-8, 11-12, and 15 May. ber 2005 (BGVN 31:03). Since then, available reports from Weak roaring noises were again heard on 20 May, and an the Cen ter of Vol ca nol ogy and Geo log i cal Haz ard Mit i ga- increased phase of eruptive activ ity that began on 22 May tion (CVGHM) discussed seismic events in June and De- contin ued until end of the month. The increased activ ity cember 2007, and Janu ary 2008. Plumes mentioned in these was char ac ter ized by force ful emission of thick pale-gray to reports were small, white in color, and only rose 15-40 m, dark gray-brown ash clouds from 22-27 May. The emission occa sion ally up to125 m, above the rim of the active vent changed to subcontinuous thick dark gray-brown ash area (Tompaluan crater), in the sad dle be tween the peaks of clouds on 28-29 May before changing back to occa sional Lokon and Empung. thick, pale-gray clouds on 30-31 May. Two large explo - During 11-24 June 2007 CVGHM reported 52 A-type sions on 30 May accom pa nied the ash emission. The ash and 156 B-type earthquakes, but no tremor. Only one earth- clouds from these two explo sions rose 4 km above the sum- quake was felt by resi dents. The Alert Level re mained at 2 mit before being blown NW. On the other days, the ash (on a scale of 1-4). clouds rose 2-3 km above the sum mit before drifting NW of On 9 Decem ber 2007, CVGHM raised the Alert Level the volcano. Contin u ous fine ashfall occurred at Kilenge from 2 to 3 based on visual ob serva tions, in fla tion detected Catho lic Mission (~10 km NW) and surround ing areas dur- by de for ma tion in stru ments, and an in crease in seis mic ity. ing 22-31 May. The ash emissions were accom pa nied by The water in the Tompaluan crater changed color from occa sional weak to loud roaring noises from the 22 to 28 green to gray and noises from degas sing became stronger. May before turning subcontinuous during 29-31 May. On Visi tors were advised not to go within 2 km of the crater. 30 May two large ex plosions produced ash plumes that rose After a short period of decline, seismic ity began to in- to ~5.3 km and drifted NW. A weak glow was visi ble on crease again on 22 Janu ary 2008, peaking on 3 Febru ary. 7-8, 11-12, 15, and 20 May and again on 29 and 31 May. Visi tors were prohib ited from going within 1 km of the Incan des cence was visi ble on 29 May. On 26 May, the seis- crater. mo graph de ployed at Kilenge be came op er a tional. Geo logic Sum mary. The twin volca noes Lokon and During June RVO re ported a slight decrease in eruptive Empung, rising about 800 m above the plain of Tondano, activ ity that began on 22 May, however, the emissions of Volcanism Network, Volume 33, Number 2, February 2008 Garbuna Group 9

ash plumes from Crater 2 were oc casion ally force ful. The Geo logic Sum mary. Langila, one of the most active emissions were contin u ous on 6, 7, and 10 June and accom - volca noes of New Britain, consists of a group of four small panied by roaring noises; booming noises were heard on 1 over lap ping com pos ite ba saltic-andesitic cones on the and 10 June. Ash plumes rose to ~ 2.3-4.3 km and drifted lower east ern flank of the ex tinct Talawe vol cano. Talawe NNW. Based on obser va tions of satel lite imag ery and in- is the highest volcano in the Cape Glouces ter area of NW for mation from RVO, the Darwin VAAC re ported that on 3 New Brit ain. A rectan gu lar, 2.5-km-long crater is breached June, an ash plume rose to an alti tude of 3 km and drifted widely to the SE; Langila volcano was constructed NE of W. Ashfall was again re ported at Kilenge Catho lic Mis sion the breached crater of Talawe. An ex ten sive lava field and surround ing areas. Seismic activ ity in June was at a reaches the coast on the north and NE sides of Langila. Fre- high level, domi nated by contin u ous tremor and occa sional quent mild-to-mod er ate ex plo sive erup tions, some times ac- explo sion signals. During the latter part of the month, seis- compa nied by lava flows, have been recorded since the mic activ ity decreased to a low-mod er ate level. It was dom- 19th century from three ac tive crat ers at the summit of i nated by con tin u ous ir reg u lar trem ors and oc ca sional har- Langila. The youn gest and smallest crater (Crater 3) was monic trem ors. Low-frequency earth quakes ranged from 1 formed in 1960 and has a diam e ter of 150 m. to 7 events per day. In for ma tion Con tacts: Herman Patia, Rabaul Vol cano During July 2007, eruptive activ ity contin ued at a low Obser va tory (RVO), PO Box 386, Rabaul, Papua New level but included thin-to-thick, pale-gray ash clouds. Weak Guinea; Dar win Vol ca nic Ash Ad vi sory Cen tre (VAAC), roaring noises were heard on 1 July, but glow was absent at Bu reau of Me te o rol ogy, North ern Ter ri tory Re gional Of- night. On 2 July ash clouds were ejected forcefully and rose fice, PO Box 40050, Casua rina, Northern Terri tory 0811, ~2 km, drifted NW, and resulted in a fine ashfall down- Aus tra lia (URL: http://www.bom.gov.au/info/vaac/); wind. On 6-7, and 9-13 July, ash clouds rose less than 1 km Hawai’i In sti tute of Geo phys ics and Plan e tol ogy (HIGP) above the summit before drifting NNW. Except for 1 July Ther mal Alerts System , School of Ocean and Earth Science when weak roaring noises were heard, the volcano was and Technol ogy (SOEST), Univ. of Hawai’i, 2525 Correa quiet and without appre cia ble night glow. Seismic ity reg is- Road, Hono lulu, HI 96822, USA (URL: http://hotspot.higp. tered at low-moder ate levels, domi nated by non-harmonic ha waii.edu/). and har monic tremor of con tin u ous, ir reg u lar, or banded charac ter. During July, the daily number of low-frequency earthquakes ranged between 1 and 12 events per day. The one high-frequency earthquake occurred on 27 July. RVO reports noted mild but contin u ous ash and white Garbuna Group vapor plumes from Crater 2 during 1 August-30 Septem ber. Ash plumes gener ally rose to alti tudes of ~1.8-3.3 km and New Brit ain, SW Pa cific drifted WNW. On 8 Au gust, a large explo sion produced an 5.45°S, 150.03°E; sum mit elev. 564 m ash plume that rose to an alti tude of 5.3 km and drifted SW. Ashfall was re ported down wind. In can des cent frag ments Garbuna again began to erupt in March 2008. Prior to were ejected from the summit on 21-22 Septem ber. that, during late June 2007, the summit contin ued to release During 1-7 Octo ber 2007, RVO reported low-to-moder - vari able vol umes of white va por. Oc casional in creases in ate erup tive ac tiv ity con sist ing of con tin u ous emis sion of vol ume caused con cern in lo cal com mu ni ties, al though pale gray ash clouds which rose to ~1.8-3.3 km and were noises and night-time glow were absent. An inves ti ga tion blown W to NW. During the second week, the white vapor by the West New Brit ain Di sas ter Of fice in di cated no other accom pa nied by pale gray ash clouds contin ued; these rose in creased activ ity or emission of solid mate rial. Va por less than 1 km before being blown to the NW of the vol- emissions from the active vent contin ued through Octo ber cano. On 19, 16, and 27 Octo ber, the ash clouds rose less 2007. Through the end of 2007 and into Janu ary and Febru - than 2 km before being blown WNW. Con sis tently, the ash ary 2008 ac tiv ity was char ac ter is ti cally un event ful, with no emis sions were ac com pa nied by oc ca sional weak-to-loud in di ca tion of an erup tion. roaring or booming noises. A new eruption began on 11 March 2008. Gray ash On most occa sions, there was no glow observed at clouds rose less than a kilo me ter above the summit before night, however, a weak-to-bright glow accom pa nied by being blown SW, causing fine ashfall. Oc casional boom ing pro jec tion of in can des cent lava frag ments was vis i ble on 12 noises were heard accom pa ny ing the ash emissions. Ash and 22 Oc to ber. Crater 3 re mained quiet. Seis mic activ ity emissions contin ued on 12-13 March, and reports in dicated was at low-to- mod erate level dom inated by low frequency most of the ash fell in the sum mit area. On 14-15 March the earthquakes and bands of harmonic and non-harmonic odor of sulfur was reported downwind. No glow was visi - tremors. The daily number of low-frequency earthquakes ble at night. Around this time, obser va tions from the ranged from 2-15. Less than 10 high-frequency events were Kulingai Volcano Obser va tory (15 km SE) noted white va - re corded dur ing Oc to ber. por emissions from numer ous vents at the summit area. In Jan u ary 2008, ac tiv ity gen er ally re mained low. Some During 17-18 March activ ity in creased slightly with force- ash fell on 6-7, and 9 Janu ary with fluc tuat ing glow visi ble. ful and contin u ous emission of white vapor. Emissions rose On 10, 13, and 25 Janu ary the incan des cent glow was ver ti cally less than a ki lo me ter be fore dis si pat ing. There bright. More direct obser va tions through late Febru ary were no noises heard and no glow visi ble at night. A strong 2008 by RVO staff and affil iates confirmed ongo ing erup- smell of sulfur was again noted to the E. tions. During Febru ary, Crater 2 contin ued to erupt. Most All of the moni tor ing equipment installed during 2005 days, these eruptions gener ated ash plumes typi cally rising and 2006 was destroyed. The two GPS sta tions at the sum- a few hun dred me ters. Ob serv ers noted in can des cent glow mit and at the base remained out of service, and for most of or noises on 7, 9, 11, and 21-23 Febru ary. the re port ing in ter val there was no func tion ing seis mom e- 10 Bulusan Smithsonian Institution — Bulletin of the Global ter. Seismic ity began to be moni tored using a KD1 re- three steaming fis sures. Sci en tists also ob served steam corder, along with a porta ble seismom e ter to the E, at SiSi plumes that rose to alti tudes of 1.6-1.7 km and drifted NW vil lage. Seis mic ity fluc tu ated be tween low and mod er ate and NE. The S flank had in flated by 3 mm. Resi dents near lev els. On 17 March, seis micity increased to a mod er ate the base of the volcano noted the odor of sulfur dioxide. level charac ter ized by non-overlap ping tremor. Only three No sig nif i cant ac tiv ity was re ported dur ing June 2007. high-fre quency vol cano-tec tonic earth quakes were noted Steam ing from the active vents and fissures gener ally con- during the first day of record ing; no low-frequency events sisted of weak to mod erate emissions of steam. On 13 July were recorded. Seismic ity declined on 18 March but rose to 2007, PHIVOLCS lowered the Alert Level to 1 due to a de- a mod er ate level on 19 March. cline in ac tiv ity in clud ing de creased seis mic ity, and lower Geo logic Sum mary. The ba saltic-to-dacitic Garbuna than baseline sulfur diox ide emissions. On 19-21 June the volcano group consists of three volca nic peaks, Krummel, NE and SE flanks were deflated when compared to previ - Garbuna, and Welcker. They are lo cated along a 7-km N-S ous surveys. Sulfur diox ide emission rates were 50-400 t/d. line above a shield-like founda tion at the southern end of On the morning of 31 July 2007 an explo sion produced the Willaumez Pen in sula. The cen tral and lower peaks of an ash plume that rose to an alti tude of 6.6 km and drifted the centrally located 564-m-high Garbuna volcano contain WSW and WNW. Initial field re ports indi cated that light a large veg e tation-free area that is prob a bly the most exten - ashfalls were expe ri enced in Cogon, Gulang-gulang, Puting sive ther mal field in Pa pua New Guinea. A prom inent lava Sapa, Bolos, Monbon and Gabao in Irosin, and Sangkayon dome and blocky lava flow in the center of thermal area and Buraburan in Juban. Small to moder ate sized earth- have re sisted de struc tion by thermal activ ity, and may be of quakes and ash explo sions contin ued. On 2 August, white Holo cene age. The 854-m-high Krummel volcano at the S steam plumes rose from active craters and fissures. end of the group contains a summit crater, breached to the On 28 Septem ber 2007 the number of volca nic earth- NW. The highest peak of the Garbuna group is quakes increased and PHIVOLCS noted a possi ble erup- 1,005-m-high Welcker volcano, which has fed blocky lava tion. Explo sions at 0134 and 0139 on 4 Octo ber 2007 flows that ex tend to the east ern coast of the penin sula. The caused a blanket of thick ashfall in sixteen vil lages that re- last major eruption from both it and Garbuna volca noes sulted in minor inju ries and damage. Instru ments recorded took place about 1800 years ago. The first histor i cal erup- 40 volca nic earthquakes and eight short harmonic tremors tion of the complex took place at Garbuna in Octo ber 2005. during a 24 hour inter val ending at 0526 that day. Moder ate Infor ma tion Contacts: Herman Patia, Steve Saunders, steaming from fissures were found on the SW flank. and Felix Taranu, Rabaul Volcano Obser va tory (RVO), PO Accord ing to the news source Southen Luzon Bureau , Box 3386, Rabaul, E.N.B.P, Papua New Guinea. on 15 Octo ber 2007 PHIVOLCS found an addi tional six points of emission around the volcano, three each on the NW and SE slopes. Several other emission points had stopped on the N, SSW, and SW slopes. Overall, nine emis- sion points were active. News reports also mentioned that Bulusan resi dents in the village of San Rogue noted bulging of the ground. A de for ma tion sur vey was al leg edly con ducted, but Luzon, Phil ip pines results were not available in PHIVOLCS reports. 12.770 N, 124.05 E; summit elev. 1,565 m In the 24 hours from 0800 on 6 Janu ary 2008, at least All times are local (= UTC + 8 hours) seven minor earthquakes were recorded, but no steaming was noted. Although the Alert Level remained at 1, author i - Our last report on Bulusan described explo sive erup- ties began to enforce a no-entry policy in a 4-km radius. tions and ashfall during 10 Octo ber 2006 to 12 May 2007 Geo logic Sum mary. Luzon’s southern most volcano, (BGVN 32:04). This current report will cover the events Bulusan, was constructed along the rim of the 11-km-diam - from late May 2007 to Janu ary 2008. There were ash-bear- eter dacitic-to-rhyolitic Irosin cal dera, which was formed ing erup tions on 31 July and 4 Octo ber 2007. Hazard con- about 35,000-40,000 years ago. Bulusan lies at the SE end cerns also included steam-driven explo sions, lahars, and of the Bicol volca nic arc occu py ing the penin sula of the related flooding. same name that forms the elongated SE tip of Luzon. A The Phil ip pine In sti tute of Vol ca nol ogy and Seis mol- broad, flat moat is located below the topo graph i cally prom- ogy (PHIVOLCS) reported on 20 May 2007 that seismic ity inent SW rim of Irosin cal dera; the NE rim is buried by the remained high follow ing an explo sion on 12 May (BGVN andesitic Bulusan complex. Bulusan is flanked by several 32:04). The seismic network detected 673 volca nic earth- other large intracaldera lava domes and cones, includ ing the quakes during five days. The epicen ters were located along prom inent Mount Jormajan lava dome on the SW flank and a NW-SE trend. Ground defor ma tion measure ments con- Sharp Peak to the NE. The summit of 1,565-m-high ducted on 17 May on the NE flank revealed 4 mm of infla - Bulusan volcano is unvegetated and contains a tion since 7 April, measure ments in a series which have 300-m-wide, 50-m-deep crater. Three small craters are lo - shown contin ued infla tion since June 2006. Sulfur diox ide cated on the SE flank. Many moder ate explo sive eruptions flux measure ments were 165-315 tons per day (t/d), below have been recorded at Bulusan since the mid-19th century. a base line level of 500 t/d. The Alert Level was raised in In for ma tion Con tacts: Phil ip pine In sti tute of Vol ca nol- mid-May from 1 to 2 (out of 5) due to the increased seis- ogy and Seismol ogy (PHIVOLCS), Uni ver sity of the Phil ip - micity and infla tion. On 22 May, heavy rain triggered pines Campus, Diliman, Quezon City, Philip pines (URL: lahars, but they were con fined and did not affect popu lated http://www.phivolcs.dost.gov.ph); Southern Luzon Bureau , areas. On 25 May 2007 sulfur emission reached 500 t/d. Philip pine Daily Inquirer, PO Box 2353, Makati Central During mid-2007, scien tists from PHIVOLCS conduct - Post Of fice, 1263 Makati City, Phil ip pines (URL: http:// ing an ae rial in ves ti ga tion dis cov ered lahar de pos its and newsinfo.in quirer.net/). Volcanism Network, Volume 33, Number 2, February 2008 Suwanose-jima 11

J., Lau, T.-K., Deardorff, N., and Merle, S.G., 2008, Di rect NW Rota-1 video and hydrophone ob ser va tions of sub ma rine ex plo sive eruptions at NW Rota-1 volcano, Mariana Arc: J. Geophys. Mariana Is lands, Cen tral Pa cific Res.-Solid Earth, doi:10.1029/2007JB005215 (in press). 14.601°N, 144.775°E; summit elev. -517 m Resing, J.A., Lebon, G., Baker, E.T., Lupton, J.E., All times are local (= UTC +10 hours) Embley, R.W., Massoth, G.J., Chadwick, Jr., W.W., and de Ronde, C.E.J., 2007, Venting of acid-sulfate fluids in a During an April 2006 expe di tion (BGVN 31:05), scien - high-sulfidation setting at NW Rota-1 subma rine volcano tists from the National Oceanic and Atmo spheric Agency on the Mariana Arc: Economic Geol ogy, v. 102, no. 6, p. (NOAA) and Ore gon State Univer sity aboard the research 1047-1061. ves sel Mel ville witnessed the volcano ejecting lava, bombs, Walker, S.L., Baker, E.T., Chadwick, Jr., W.W., and sul fur-rich (SO2 and H2S) plumes. This is the first site Resing, J.A., Lebon, G.T., Lupton, J.E., and Merle S.G., (in where explo sive subma rine eruptions have been directly press), Eruption-fed parti cle plumes and volcaniclastic de- observed from a submers ible (see Videos, below). posits at a subma rine volcano: NW-Rota-1, Mariana Arc: J. Ac cord ing to William Chadwick, a brief visit to NW Geophys. Res. Rota-1 was made on 24 Febru ary 2008. With support from Geo logic Sum mary. A subma rine volcano detected dur - the NOAA Ocean Explo ra tion Program and the U.S. Coast ing a 2003 NOAA bathymetric survey of the Mariana Is- Guard, the scien tists deployed a hydrophone and plume land arc was found to be hydro ther mally ac tive and named sensor. While on site, scien tists found that the volcano was NW Rota-1. The ba saltic to ba saltic-an de site seamount still erupt ing. There were no in stru ments left af ter the April rises to within 517 m of the sea surface SW of Esmeralda 2006 visit, so the ob ser va tional re cord was dis con tin u ous. Bank and lies 64 km NW of Rota Island and about 100 km On the other hand, sci en tists vis ited the site four times in north of Guam. When Northwest Rota-1 was revis ited in four years and consis tently found that it was active. More- 2004, a minor subma rine eruption from a vent named Brim- over, Chadwick and colleagues had collected multibeam stone Pit on the upper south flank about 40 m below the bathymetry in 2003 and 2006 (Walker and oth ers, in press). summit inter mittently ejected a plume sev eral hun dred me - Depth changes between those surveys were up to +40 m ters high contain ing ash, rock parti cles, and molten sulfur and extended from the eruptive vent at 550 m directly droplets that adhered to the surface of the remotely oper - downslope to at least 2,000 m. They were consis tent with ated submers ible ve hi cle. The ac tive vent was fun- volcaniclastic depos its from ongo ing eruptions. The sug- nel-shaped, about 20 m wide and 12 m deep. NW Rota-1 is gestion is that NW Rota-1 has been very active, if not con- large sub ma rine vol cano with prom i nent struc tural lin ea- tin u ously ac tive. ments about a kilo me ter apart cutting across the sum mit of On 24 Febru ary 2008 the Mel ville crew made a ver tical the edi fice and down the NE and SW flanks. cast over the eruptive vent with a light-scatter ing sensor In for ma tion Con tacts. Wil liam Chadwick and Rob ert and detected an eruption plume below 500 m depth. Dziak, Ore gon State Univer sity and NOAA Vents Program, Hydrophone data also indi cated eruptions with cyclic bursts Newport, Ore gon; 2115 SE OSU Drive, Newport, OR about once a minute. These ap pear very simi lar to the ex - 97365 USA (URL: http://oceanexplorer.noaa.gov/ex plo ra- plosions observed by ROV and hydrophone in 2006 tions/06fire/wel come.html). (Chadwick and others, 2008). The explo sion sounds were louder and more frequent in 2008 than in 2006. During the 2008 visit, explo sion signals filled the 24-hour acoustic re- cord. Before depar ture, the crew in stalled a hydrophone and Suwanose-jima plume sensor to record activ ity over the next year. Resing and others (2007) described two types of vent- Ryukyu Islands, Japan ing at NW Rota-1. The first was a focused plume rich in Al, 29.635°N, 129.716°E; sum mit elev. 799 m 3 S, Si, CO2, Fe, Mn, and He. The sec ond was a plume with All times are local (= UTC + 9 hours) 3 diffuse flow, rich in Fe, Mn, CO2, and He, but with out Al, S, and Si. Data suggested that the pH of these plumes were Our last Bul le tin (BGVN 3211) covered eruptive activ - less than 1.0, primar ily due to SO2 and possi bly HCl. The ity during July 2005 to Decem ber 2007. This issue covers authors claimed that the volcano is produc ing some of the eruptions recorded by the Tokyo Volca nic Ash Advi sory great est chem i cal anom a lies ever ob served in non-buoy ant Center (VAAC) from Decem ber 2007 to March 2008. hydro ther mal plumes and greatly differ ent from that ob- Kinoshita and others (2003) noted that Sakura-jima “has served in any other hydro ther mal setting. been the most eruptive in Japan, with the eruption columns Vid eos. Eruption videos taken from an unmanned sub- a few kilo meters above the crater oc casion ally.” mersible on 29 April 2006 can be found at http://www. Ta ble 4 sum ma rizes in for ma tion gath ered by the To kyo oceanexplorer.noaa.gov/ex plo ra tions/06fire/logs/april29/ VAAC from observ ers between 9 Decem ber 2007 and 21 april29.html website. The five vid eos are ti tled as follows: March 2008. In all cases the VAAC could not detect (1) The ex tremely dy namic Brimstone Pit, (2) Brimstone plumes us ing sat el lite data. An over view of sat el lite and im- Pit erupting with glowing red lava jetting out of the vent, age moni tor ing of Suwanose-jima appears in an arti cle by (3) Brimstone Pit erupting with glowing red lava and gas Kinoshita and others (2003). bubbles, (4) Brimstone Pit sulfur plume enve lopes the Ja- Ref er ence: Kinoshita, K., Kanagaki, C., Minaka, A., son ROV [remotely oper ated vehi cle], and (5) The pulse Tsuchida, S., Matsui, T., Tupper, A., Yakiwara, H., and and shake of the Brimstone Pit during another eruption. Iino, N., 2003, Ground and Satel lite Moni tor ing of Volca - Ref er ences: Chadwick, W.W., Jr., Cashman, K.V., nic Aerosols in Visi ble and Infra red Bands: The CEReS In- Embley, R.W., Matsumoto, H., Dziak, R.P., de Ronde, C.E. ter na tional Sym po sium on Re mote Sens ing - Mon i tor ing of 12 Cleve land Smithsonian Institution — Bulletin of the Global

Volcano Obser va tory (AVO) raised the Alert Level from Date Time (UTC) Ash cloud al titude Di rec tion Advi sory to Watch and the Avia tion Color Code from Yel- low to Orange, based upon an intense thermal anomaly in 09 Dec 2007 2340 1.5 km W the crater and an as so ciated steam-and-gas plume observed 10 Dec 2007 0734 1.8 km W on sat ellite imag ery. Three small SO2 clouds produced by 14 Dec2007 0914 — — small ex plo sions on 20 July were de tected in OMI sat el lite 15 Dec 2007 0016 1.8 km E data. Weak ther mal activ ity was observed by satellite 16 Dec 2007 0353 1.5 km E imagery throughout the month. 16 Dec 2007 2310 1.5 km E On 27 July AVO noted that low-level eruptive activ ity 08 Feb 2008 0248 1.8 km E contin ued. Photo graphs from 27 July and a pilot report 13 Feb 2008 0208 — — from 2 August in dicated fresh volca nic ejecta on the slopes 21 Mar 2008 1622 — — and summit. The E portion of Chuginadak Island was Table 4. A sum mary of To kyo VAAC reports on ash plumes from dusted with ash on 3 August. AVO lacks a local seismic Suwanose-jima during 9 Decem ber 2007 to 21 March 2008. Cases with system at the volcano was thus unable to track local only dashes in the data fields were when observ ers detected an explo sion volcanic earthquakes. but they were unable to say more about a result ing plume. In many of the ex am ples given, there were mul ti ple Vol ca nic Ash Ad vi so ries is sued, but Ther mal anom a lies con tin ued to be de tected on sat el lite no new data came to light. Cour tesy of the To kyo VAAC. imag ery, although clouds obscured satel lite and web cam- era views of the volcano on most days during August through 11 Sep tem ber. A few clear views of the crater dur- Envi ron men tal Change in Asia, Chiba, Japan, 16-17 De- ing this time re vealed mul tiple ther mal anoma lies at the cember 2003, 10 p. summit, in di cat ing that low-level eruptive activity Geo logic Sum mary. The 8-km-long, spindle-shaped is- continued. land of Suwanose-jima in the northern Ryukyu Islands con- On 6 Sep tember, AVO lowered the Vol canic Alert sists of an andesitic stratovolcano with two his tori cally ac - Level for Cleveland from Watch to Advi sory and the Avia - tive summit craters. Only about 50 persons live on the tion Color Code from Orange to Yellow, based on the ob- sparsely popu lated island. The summit of the volcano is serva tion that since late July, ash and gas plumes had been trun cated by a large breached crater ex tend ing to the sea on ab sent in sat el lite imag ery and no re ports of ac tiv ity had the east flank that was formed by ed ifice col lapse. been received. On 20 No vember the last weak ther mal Suwanose-jima, one of Japan’s most frequently active vol- anomaly was observed for the year. ca noes, was in a state of inter mittent strombolian ac tiv ity At 1200 on 17 Janu ary 2008, minor ash emission was from On-take (Otake), the NE summit crater, that be gan in detected, which drifted N. The plume height could not be 1949 and lasted until 1996, after which peri ods of inac tiv ity de ter mined. Ther mal anoma lies were found in the sat ellite lengthened. The largest histor i cal eruption took place in imag ery later that day. Accord ing to the AVO, on 8 Febru - 1813-14, when thick sco ria de pos its blan keted res i den tial ary, during a break in the cloud cover, sat ellite im agery de- ar eas, and the SW crater pro duced two lava flows that tected a diffuse ash plume extend ing about 12 km SE at an reached the western coast. At the end of the eruption the alti tude below 1.5 km. Later that day AVO received pilot summit of On-take collapsed forming a large debris ava - reports of a diffuse ash plume that rose to an alti tude of 6.1 lanche and creat ing the horse shoe-shaped Sakuchi cal dera, km and, accord ing to satel lite imag ery, drifted NW. Due to which extends to the eastern coast. The island remained un- the in creased ac tiv ity, the Vol canic Alert Level was raised inhab ited for about 70 years after the 1813-1814 eruption. to Watch and the Avia tion Color Code was raised to Or- Lava flows reached the eastern coast of the island in 1884. ange. During 10-11 Febru ary, a feeble thermal anomaly In for ma tion Con tacts: To kyo Vol ca nic Ash Ad vi sory was marginally visible on satellite imagery. Cen ter (VAAC), Tokyo, Japan (URL: http://www.jma.go. On 12 Feb ru ary, the Volca nic Alert Level was low ered jp/jma/jma-eng/jma-cen ter/vaac/vaac%20operation.htm). back to Advi sory and the Avia tion Color Code was lowered to Yellow. This occurred in response to the obser va tion that minor eruptive activ ity appeared to have subsided and no further evi dence of ash emission had been reported. Cleve land On 15 Febru ary, a minor explo sion from Cleveland pro - duced a small, diffuse ash plume that rose to an alti tude of Aleu tian Is lands, USA below 3 km and drifted NW. On 16 Febru ary, a brief explo - 52.825°N, 169.944°W; summit elev. 1,730 m sion oc curred. On 22 Feb ru ary, sat el lite im ag ery de tected a All times are local (= UTC -10 hours) low-level ash plume that drifted about 300 km SE. On 23 Feb ru ary, sat el lite im ag ery re vealed a ther mal anom aly. On Our previ ous reports on Cleveland discussed short dura - 29 Feb ru ary, sat el lite im ag ery de tected a weak ther mal tion explo sions on 6 Febru ary 2006 (BGVN 31:01), 23 May anomaly and a small ash plume that rose to an alti tude of 2006 (BGVN 31:07), and on 24 August and 28 Octo ber below 3 km. On 15, 27, and 30 March, weak thermal anom - 2006 (BGVN 31:09). alies were de tected. As of 4 April 2008, Cleve land re mains We received no further reports on Cleveland until June at Advisory and the Aviation code Yellow. 2007. On 12 June, steam emissions were observed. The Geo logic Sum mary. Beau ti fully sym met ri cal Mount plume rose to an alti tude of 3.7 km and drifted SE for 200 Cleveland stratovolcano is situ ated at the western end of the km. On 17 June, satel lite imag ery showed a signif i cant ther- un in hab ited, dumb bell-shaped Chuginadak Is land. It lies mal anomaly. Low level erup tive ac tiv ity was sug gested. SE across Carlisle Pass strait from Carlisle vol cano and NE No ash plume was de tected. On 26 June, sat ellite imag ery across Chuginadak Pass strait from Herbert volcano. Cleve- showed another thermal anomaly. On 20 July, the Alaska land is joined to the rest of Chuginadak Island by a low Volcanism Network, Volume 33, Number 2, February 2008 Cleve land 13

isthmus. The 1,730-m-high Mount Cleveland is the highest In for ma tion Con tacts: Alaska Vol cano Ob ser va tory of the Islands of the Four Mountains group and is one of the (AVO), a co op er a tive pro gram of the U.S. Geo log i cal Sur- most active of the Aleutian Islands. The native name for vey, 4200 Univer sity Drive, Anchor age, AK 99508-4667, Mount Cleveland, Chuginadak, refers to the Aleut goddess USA; Geo phys i cal In sti tute, Uni ver sity of Alaska, P.O. Box of fire, who was thought to reside on the volcano. Numer - 757320, Fairbanks, AK 99775-7320, USA; and Alaska Di- ous large lava flows descend the steep-sided flanks of the vi sion of Geo log i cal & Geo phys i cal Sur veys, 794 Uni ver- volcano. It is possi ble that some 18th-to-19th century erup- sity Ave., Suite 200, Fairbanks, AK 99709, USA (URL: tions at tributed to Carlisle should be as cribed to Cleve land http://www.avo.alaska.edu/); Vol ca nic Emis sions Group, (Miller et al., 1998). In 1944 Cleveland produced the only Ozone Mon i tor ing In stru ment (OMI)-To tal Ozone Mon i tor- known fatal ity from an Aleutian eruption. Recent eruptions ing Spec trom e ter (TOMS), Joint Center for Earth Sys tems from Mount Cleve land have been char acter ized by Tech nol ogy, Uni ver sity of Mary land Bal ti more County short-lived explo sive ash emissions, at times accom pa nied (UMBC), and NASA Goddard Space Flight Center (URL: by lava fountaining and lava flows down the flanks. http://toms.unbc.edu/).