Bul Le Tin of the Global Vol Can Ism Net Work

Bul letin of the Global Vol can ism Net work Vol ume 30, Num ber 11, November 2005

Karthala (Comoros Is lands) Eruption on 24 Novem ber 2005; big evacu a tion and one fatal ity ...... 2

Piton de la Fournaise (Re union Island) Eruption on 5 Oc tober follows four months of heightened ac tivity ..5

Montagu Island (S Sandwic h Islands ) N-coast delta grew during 14 Septem ber-4 Octo ber 2005 ...... 5

Aoba (Vanuatu) New eruption begins on 27 Novem ber 2005 and builds cone in crater lake ...... 7

Garbuna (Pa pua New Guinea) First his tor i cally wit nessed erup tion in Oc to ber 2005 ...... 10

Langila (Pa pua New Guinea) Ac tive dur ing Au gust-Sep tem ber, de creas ing dur ing Oc to ber-No vem ber ....13

Fukutoku-Okanoba (Ja pan) July 2005 subma rine eruption; dis colored water and debris ...... 13

Karymsky (Kamchatka Pen in sula) Ex plo sions con tin ued dur ing De cem ber 2004-June 2005 ...... 15

Bezymianny (Kamchatka Pen in sula) Ash plumes to 10 km al titude in 2005, hot ava lanche s from the dome..16

Ed itors: Rick Wunderman, Catherine Gal ley, Ed ward Venzke, and Gari May berry Vol un teer Staff: Robert Andrews, Jerome Hudis, Jackie Gluck, Angela Stavropoulos, Ve ron ica Bemis, Wil liam Henoch, and Ste phen Bentley

Global Vol canism Program · National Museum of Natu ral His tory, Room E-421, PO Box 37012 · Wash ington, DC 20013-7012 · USA Tele phone: (202) 633-1800 · Fax: (202) 357- 2476 · Email: gvn@vol cano.si.edu · 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]). Data are prelimi nary and sub ject to change; contact the original source or the Global Volcan ism Program bef ore using. 2 Karthala Smithsonian Institution — Bulletin of the Global

shortage of AIRS data stems from a com prom ise in instru - Karthala ment de sign, whereby when ac quiring im ages at low lat i tudes, po lar-or bit ing sat el lites fre quently lack suf fi cient Grand Comore Island, Comoros, West ern Indian Ocean overlap in their scanners to obtai n full cover age. The one 11.75°S, 43.38°E; sum mit elev. 2,361 m avail able sat isfac tory AIRS im age, ~ 13 hours later than the All times are lo cal (= UTC + 3 hours) MODIS im age, showed a dif fer ent plume con fig u ra tion that include d two sepa rat e zones of SO2 con cen tra tion rather The last erupti on at Karthala occurred in April 2005 than one. The mass of the SO2 measured by the AIRS in- (BGVN 30:04); this report discusse s the sec ond large erup- strum ent for the 25th was 2.0 ki lotons. This value about the tion of the year, on 24-25 Novem ber 2005. Karthala is a same as Prata ob tained in a MODIS re trieval for the same volcano with a lava lake and well-known for epi sodic out- 25 Novem ber erupti on. In addi ti on, the zones of el evate d bursts. This report be gins with im agery and maps, discusse s concen tra tions on both im ages stood in roughly the same sat elli te im ages of the 24-25 Novem ber ash plume, and then place–except for the blob near 11°S de tected by AIRS and sum mariz es press and United Nati ons reports. not by MODIS. Sat el lite im ag ery. El e ments of Karthala ge og ra phy ap- Regard ing his analy sis of the 25 Novem ber Karthala pear in figure 1. This and many other figures were produced erupti on, Prata goes on to say that “assum ing my fine ash by a United Nati ons consor ti um of publi c and pri vate orga - loading of 83 kt is right and (big as sumpti on now) this rep- ni za tions, UNOSAT, which pro vides sat el lite im ag ery and resent s ~ 1% of the total erupted mass, then the volum e of geo graphic in for ma tion to the hu man i tar ian com mu nity. erupted ash would be ~ 0.006 km3. This suggest s a VEI ~ 2. The is lands cap ital, Moroni, lies on the coast di rectly W of If the 1% es ti mate is robust (I’ve seen this quoted in Bill the sum mit com plex. Rose’s work) then the fine ash es tim ates from re mote sens - Perspec tive on the erupti on’s im pact can be seen on fig- ing may be quite helpful [in] assess ing the 'size' of an erup- ure 2, contai ning im ages from both pre- and post-erupti on tion. Coupled with cloud-height esti mates we may be mov - time frames (13 July 2004 and 5 Decem ber 2005). Conspic - ing towards some nice tools for volca nol o gist s.” uous new de posit s at distanc e from the sum mit area were Prata further com mented that he had hoped to im age an im aged on 5 De cem ber. Some new de posit s reside d in what algal bloom in the ocean where the Karthala ash had fallen. appear as channels to the N of the craters, suggest ing that Recent work on ocean chem istry and biol ogy (Boyd and freshly depos it ed tephra may have enter ed and fol lowed the drainage system s: see channels on figure 2, heading NE. These ten ta tive in fer ences by Bul le tin edi tors were not dis- cussed in avail able ground-based reports, so confir m ati on is lacking. No re ports were yet available discuss ing the morphology or poten ti al hazards of these new depos it s. Ash clouds. Charles Holliday (US Air Force Weather Agency, AFWA) assess ed the 25 Novem ber 2005 Karthala erupti on plume using a NASA Terra MODIS im age at 1010 local time (0710 UTC; figure 3). He measured the overall E-W extent of erupti ve clouds as ~ 150 nauti cal miles (~ 280 km). The W margin of the brown clouds lie up to 30-50 km W and NW of the vol cano. The light-colored clouds were blown SE, and they be came far less op tically dense towards the E where they extende d over the vicin it y of reef-fringed Mayotte Island. The im age shows light-colored (nearly white) clouds above and center ed SE of the visi ble brown clouds. Holliday inter preted this to repre sent a brown zone com posed of dom inantl y ash with a higher lighter-colored zone of ash and ice par ticles. The tall est clouds reached FL 380 (‘Flight Level 380,’ a height of 38,000 feet or ~ 11.6 km alti tude). Fred Prata (CSIRO) pro cessed both MODIS and AIRS im ages for the 25 Novem ber erupti on (figures 4 and 5). Both instru m ents are part of NASA’s Earth Observ ing Sys- tem: MODIS stands for Mod er ate Res o lu tion Im ag ing Spectro-Ra diom eter (fly ing onboard the Terra (EOS AM-1) sat el lite); AIRS stands for At mo spheric In fra red Sounder (which uses a grat ing spectrom eter on the Aqua satel li te). Prata used the MODIS im age to es tim ate the 25 No vember erupti on’s mass loading. This re sulted in an esti mate of fine ash amounting to 83 kilo tons (kt) in the grain-size ranges in di cated. Anal y sis of SO2 from the MODIS data for 0710 on the 25th yielded 2.85 kt. Prata also downloade d and proces sed the AIRS data Figure 1. A shaded relief map portra ys the island of Grand Comore, with available from 25 Novem ber but found only one good im- Karthala’s summ it com plex (the cratered, high est-elevation area) on the age (figure 2). Prata com mented that the reason for the S. Cour tesy of UNOSAT and their partner or gani za tions. Volcanism Network, Volume 30, Number 11, November 2005 Karthala 3

others, 2000) point to iron enric h- ment as a means of ocean fer til- iza tion. As briefly discusse d on the NASA Earth Obser va tory website, Anatahan plumes had re- cently been suggest ed to have triggered such blooms; however, with avail able re mote-sens ing data Prata was un able to con firm that the Karthala erup tion triggered such a plume. UN and relat ed re ports. The follow ing appeare d in a 28 No- vem ber 2005 report of the United Na tions Of fice for the Co or di na- tion of Hu man i tar ian Affairs. “The Karthala Vol cano forms most of the landm ass of Grande Comore (also called Ngazidja), the main island of the Un ion of the Comoros. The volcano is one of the largest volca noes in acti vit y in the world. Over the last two hundred years, it has erupted ev- ery eleven years on av er age. In April 2005, a vol canic erupti on project ed ashes and volca nic debris on the eastern part of the island, affect ing as many as 40,000 people. “[Karthala] had an erup tion for the sec ond time this year in the Figure 2. Karthala portra yed in two im ages (both with 10-m reso lu tion; bands 321 + IR (RGBI)). Both im ages are night of . . . 24 Novem ber, spill- at nearly, though not exactl y, the same scales. The im age at left is from before the eruption; taken by SPOT4 on 13 July 2004. The im age at right is from after the eruption; taken by SPOT5 on 5 Decem ber 2005. Both im ages are ing ashes and smoke over the partly masked by weather clouds. Large, clearly visi ble ar eas of new depos its appear in and around the sum mit south east ern and south west ern crater area. Cour tesy of UNOSAT and part ner orga ni zations. parts of Grande Comore Island, and the Comoros capi tal , Moroni. “During Fri day 25, the projec - tions of ashes and smoke recede d. How ever, seis mo graphic data col - lected by the Karthala Vol cano Obser va tory has shown that the seis mic ac tiv ity is con tin u ing. Ac - cording to the obser va tory , a lava lake is in for mation in the crater, as of yet confine d within the crater. Accord ing to the lo cal author i ties, ap prox i mately 2,000 people fled from their vil lages in the region of Bambao in the cen- tral part of the is land, and sought ref uge in less ex posed ar eas, such as Mitsamiouli, Mboudé, and Oichili.” “Con cerns ex ist re gard ing the avail abil ity of po ta ble wa ter in the areas exposed to smoke and ashes. Pre lim i nary re sults from the as sess ment in di cate that as many as 118,000 persons living in Fig ure 3. An image of the Karthala 25 No vem ber 2005 ash plume from NASA Terra MODIS. The im age was center ed over the Comoros is lands, with the islands Mayotte, Anjouan, and Moheli la beled, and Grand Comore 75 villages may be affected by the un der ash clouds but the loca tion of Karthala is indi cate d. For scale, the distance from Karthala to the S end of con tam i na tion of wa ter tanks. A Mayotte island is ~240 km. The im age shows AFWA inter preta tions of the ash cloud. Cour tesy of Charles fur ther as sess ment of the wa ter Holliday (AFWA). tanks is under way to as certai n the 4 Karthala Smithsonian Institution — Bulletin of the Global

Figure 5. An AIRS im age of the Karthala eruption’ s SO2 content for 25 Novem ber at about 2223 UTC. The measured mass total for SO2 was ~2.0 kilo tons. Courtesy of Fred Prata, CSIRO.

In a 9 Decem ber report the World Food Program esti - mated that the 24 No vember Karthala erup tion af fected 245,000 people. They briefly menti oned the issue of poten - tially con tam inate d drinking wa ter but noted that, although minor erupti ons conti nued, abundant rain in the weeks that followed helped reduce the poten ti al wa ter and air contam i- nati on problem s. As noted above, no reports were found discuss ing problem s from ash-choked drainages (lahars). Back ground. The southern m ost and largest of the two shield vol canoes form ing Grand Comore Island (also known as Ngazidja Island) , Karthala contai ns a 3 x 4 km Figure 4. MODIS satel lite im ages of the Karthala eruption plume on 25 sum mit cal dera gen er ated by re peated col lapse. Elon gated Novem ber 2005 at 0710 UTC. The top im age maps the com puted rift zones extend to the NNW and SE from the sum mit of atm ospheri c mass load ing asso ci ated with the ash cloud; inset por trays the the Ha wai ian-style ba saltic shield, which has an asym metri - ash grain-size es ti mates in the same cloud. The bot tom im age maps the cal pro file that is steeper to the south. The lower SE rift SO2 burden in the cloud, contoure d in Dobson Units; the total mass of SO2 on this im age was 2.85 kilo tons. For distance scales, 1° of lat itude zone forms the Mas sif du Badjini, a penin sula at the SE tip (dis tance N-S) equates to ~111 km. Courtesy of Fred Prata, CSIRO. of the island. Histor i cal erupti ons have modi fie d the mor- phol ogy of the com pound, ir reg u lar sum mit cal dera. More than twenty erupti ons have been re corded since the 19th exact scope of the needs. Concerns also exist regard ing the century from both sum mit and flank vents. Many lava flows im pact of the pollution by volcanic debris on ag ri cul ture have reached the sea on both sides of the island, includ ing and livestoc k.” during many 19th-century erupti ons from the sum mit cal- A 28 Novem ber news report by Agence France-Presse dera and vents on the northern and southern flanks. An (AFP) also noted some of the above detai ls, but added some 1860 lava flow from the sum mit cal dera travele d ~ 13 km to new points. They said that the erupti on had the effect of “ . . the NW, reach ing the western coast north of the capital city .killing at least one infant , infil trating homes, shops and of- of Moroni. fices and contam inat ing wa ter in cister ns during the height In for ma tion Con tacts: UNOSAT, United Na tions In sti - of the dry season. ‘We have two problem s with water : one, tute for Train ing and Researc h (UNITAR), Palais des Na- we are in the dry sea son and two, the reserve s in many pri- tions, CH - 1211 Geneva 10, Swit zerland (Email: vate cis terns are now pollut ed,’ minis ter of state for defense [email protected]; http://unosat.web.cern.ch/unosat/); Abdu Madi Mari told AFP.” Charles Holliday, U.S. Air Force Weather Agency “He said cister n water suppli es for about 120,000 resi - (AFWA)/XOGM, Offutt Air Force Base, NE 68113, USA dents mainly from rural vil lages near the volcano had been (Email: [email protected]); Fred Prata, con tam inated by the ash, which has also raised fears of re - CSIRO Ma rine and At mospheri c Re search, 107-121 Sta- spi ra tory ailments.” tion Street, PMB 1, Aspen dale, Vic to ria 3195, Aus tra lia “Author i ti es on Grand Comore, the largest of the three (Email: [email protected]); NASA Earth Ob ser va tory, semi-auton o m ous is lands in the Comoros, had appeal ed for NASA Goddard Space Flight Center , Code 900, Greenbelt, in ter na tional as sis tance to help in dis trib ut ing po ta ble wa ter MD 20771, USA (URL: http://earthobservatory.nasa.gov/; to those in need, Mari said.” http://eospso.gsfc.nasa.gov/); MODIS Rapid Response The AFP news re port stated the erupti on sent only Team, Goddard Space Flight Center , Code 923, Greenbelt, “about 500 vil lagers fleeing from their homes in the MD 20771, USA; Agence France-Presse (AFP); United shadow of the mountai n.” and said that de spite conti nued Na tions, Of fice for the Co or di na tion of Hu man i tar ian Af- tremor reporte d by the obser va tory , “al most all have now fairs (OCHA) and the World Food Program (WFP) (URLs: returned.” http://www.reliefweb.int/; http://www.wfp.org/). Volcanism Network, Volume 30, Number 11, November 2005 Montagu Is land 5

On 29 Novem ber 2005 at 0559 a seism ic crisis began, and Piton de la Fournaise at 0625 tremor indi cat ed the begin ning of an erupti on. A vent opened in the western part of Dolomieu crater and an - West ern In dian Ocean other vent opened on the N flank. Very littl e project ed vol- 21.229°S, 55.713°E; sum mit elev. 2,631 m ca nic mate rial was vis ible. A large, fast-mov ing lava flow All times are lo cal (= UTC +4 hours) trav eled down the N flank in the direc ti on of Piton Kapor. In clem ent weather pro hib ited fur ther ob ser va tions. The In creased seis mic ity and ground de for ma tion from late Toulouse VAAC reporte d that ash from the eruption was June 2004 through 9 August pre ceded the third erupti on of not visible on satellite imagery. 2004, which started on 13 August (BGVN 29:12). During Following the 29 Novem ber erupti on, further sum mit that erupti on ~ 750 m of Nati onal Road 2 was overrun by infla tion was re corded by the perm anent GPS net work. On lava. Erupti ve ac tivit y ceased on the morning of 7 Septem - 26 Decem ber at 1444 a seis mic crisis started be neath ber 2004 (BGVN 29:12). Erupti ons occurred again dur ing Dolomieu crater. Within the next 2 hours seis mic activ ity Feb ru ary and Oc to ber-De cem ber 2005. shifted to the NE, towards Nez Coupé de Sainte Rose. A Erup tion dur ing Feb ru ary 2005. A new period of first fissure opened at 1715 at the NE base of Pi ton de la height ened seis micit y began on 17 Febru ary 2005 around Fournaise; at 2200 erupti ve fissures opened in the caldera 1300, consis ting of about 100 seism ic events within 90 wall about 500 m E of Nez Coupé de Sainte Rose and lava minutes . After that, the num ber of events de creased, but re- flowed into the Plaine des Osmondes. By 28 De cem ber, com menced at 1638 with several hundred events. Strong erup tive ac tiv ity was alm ost con stant. An aa-type lava flow de for mation was record ed at the same time by tiltmeters crossed the Grandes Brûlé and reached a point 3 km and the extensometer net work. Erupti on tremor began upslope from the national road. around 2035, be com ing strong at 2050. The erupti on site Back ground. The massive Piton de la Fournaise ba- seemed to be situ ated close to Nez Coupé de Sainte Rose saltic shield vol cano on the French is land of Réunion in the (on the N side of the volcano), and lava flows were ob- west ern Indian Ocean is one of the world’s most acti ve vol- served in the Grand Brûlé area. canoes. Much of its >530,000 year history overlappe d with After a period of rela ti ve quiet on 19 Febru ary , erupti on erupti ons of the deeply dissec ted Piton des Neiges shield tremor increa sed to high levels again on 21 Febru ary . Two volcano to the NW. Three calde ras formed at about erupti on sites were ac tive: the princi pal vent at 1,600-m ele - 250,000, 65,000, and less than 5000 years ago by progres - vati on above the Plaine des Osmondes, and a vent at about sive eastward slumping of the volcano. Num erous 1,200-m ele va ti on in the Plaine des Osmondes. The princi - pyroclastic cones dot the floor of the cal deras and their pal vent released a volca nic plume and sev eral pahoehoe outer flanks. Most histor i cal erupti ons have origi nate d from lava flows, but no lava fountai ns were visi ble. The second the sum mit and flanks of Dolomieu, a 400-m-high lava vent also re leased a very fluid pahoehoe lava flow. The shield that has grown within the youngest cal dera, which is flows cov ered a large area within the Plaine des Osmondes, 8 km wide and breached to below sea level on the eastern and smaller lava flows travele d to about 600-m ele va ti on in side. More than 150 erupti ons, most of which have pro- the Grand Brûlé. duced fluid basal tic lava flows, have occurred since the On 24 Feb ru ary, shal low seis mic ity be gan be neath 17th century . Only six erupti ons, in 1708, 1774, 1776, Dolomieu crater. It increa sed over time and by 26 Febru ary , 1800, 1977, and 1986, have origi nate d from fissures on the several hundreds of seis mic events up to M 3 occurred. Ac- outer flanks of the cal dera. The Pi ton de la Fournaise Vol- cording to the Observatoire Volcanologique du Piton de la cano Obser va tory , oper ate d by the Institut de Physique du Fournaise (OVPDLF), these events may have in di cated for - Globe de Paris, monitors this very active volcano. mati on of a new pit crater within Dolomieu crater. On 24 In for ma tion Con tacts: Thomas Staudacher, Febru ary , visi ble signs of acti vit y stopped within the Plaine Observatoire Volcanologique du Piton de la Fournaise, des Osmondes, while erupti on tremor slowly increased. Institut de Phy sique du Globe de Paris, 14 RN3 le 27 ème On the evening of 25 Febru ary , a lava flow from Plaine km, F-97418 La Plaine des Cafres, La Réun ion, France des Osmondes travele d down the Grandes Pentes, cutti ng (URL: http://vol cano.ipgp.jussieu.fr:8080/re union/ the Nati onal Road on its way to the sea. The lava flow cov - stationreu2.html; Email: Thomas.Staudacher@univ-re- ered a distanc e of ~ 5 km in about 2 hours. At the same union.fr); Toulouse Vol ca nic Ash Ad vi sory Cen ter time, seis micity increased on the NE rift zone above Bois (VAAC), Météo-France, 42 Ave nue G. Coriolis, 31057 Blanc, and a new vent opened within the Trou de Sable on Toulouse Cedex, France (Email: [email protected]; URL: the N border of the caldera at 450-m ele va ti on. This vents http://www.meteo.fr/aeroweb/info/vaac/). lava flow stopped about 100 m from the National Road. Erup tions dur ing Oc to ber-De cem ber 2005. Another erupti on started on 4 Octo ber 2005 at 1426 after 4 months of al most con tin u ous in fla tion and in creased seis mic ity. Montagu Island The erupti on was im medi ate ly precede d by a 56-minute-long se quence of seism icity and strong sum mit infla - South Sand wich Islands , Antarctica tion. A low-inten sit y erupti on at Dolomieu crater produced 58.42°S, 26.33°W; sum mit elev. 1,370 m pahoehoe lava flows that cov ered a small area of the western part of the crater. MODVOLC ra diant heat-flux data and ASTER Immediately af ter the end of the 4 Octo ber erupti on at high-res o lu tion sat el lite im ag ery re vealed dis charg ing lava Dolomieu crater, the perm anent GPS net work and flows that trav eled N to the sea where they con structed a extensometer net work conti nued to show strong surface de- lava delta. The large ef fu sive ep isode described in BGVN form ati on, which was a precur sor for a new erupti ve event. 30:09 had ceased, fol lowed by a smaller epi sode in Novem - 6 Montagu Is land Smithsonian Institution — Bulletin of the Global

Figure 6. Plots of MODVOLC data at Belinda volcano on Montagu Island. Courtesy of Matt Patric k, HIGP. ber. MODVOLC responses were most intens e during 14 ure 6b in di cates the dis tance of each alert pixel from the Septem ber to 4 Octo ber 2005. Figure 6a shows the radi ant vent, giving insight s into the timing of significant effusive heat flux for the volcano since the start of the erupti on in episodes. Oc to ber 2001, pro vid ing rough idea erup tive in ten sity. Fig- As figure 6b suggest s, the Septem ber-Octo ber 2005 epi - sode was likely the larg est ef fu- sive epi sode of the erupti on in that it involved the only sustai ned oc cur rence of alert pix els (i.e. ac - tive lava) more than 2 km from the vent. Fol lowing 4 Oc tober 2005, a single alert pixel appeare d more than 3 km from the vent on 17 Novem ber 2005, but subse - quent alert pix els were all near-vent. It is not yet clear if this 17 No vem ber anom aly rep re sents the start of a sub stan tial additional episode of lava effusion. An AS TER im age col lected on 3 Novem ber 2005, shows the re sult from the Sep tem ber-Oc tober 2005 ef fu sive ep i sode (vis i ble wavelengt h im age shown in figure 7a). The shortwave infra red anom aly in this im age (not shown) is minor com pared to the 23 Septem ber 2005 im age (BGVN 30:09), suggest ing that any effu - sion had dropped to low levels by early Novem ber. The 3 Novem - ber image in di cates that a sig nif i - cant lava delta had formed on the N shore of the is land dur ing the Sep tem ber-Oc to ber ef fu sive phase (see arrow in figure 7a). The delta comprises two major lobes, and is approx i m ately 400-500 m in width and length, equat ing to ap prox i mately 0.2 km2. An enlar ged view of the visi - ble im age is provided in figure 7b, where the approx i m ate path of the Sep tem ber-Oc to ber 2005 lava flow is shown by the dot ted arrow. The current coastli ne is shown by the dotted line, with the lava delta (denoted by solid arrow) clearly jut ting out. Note the Figure 7. An ASTER im age and en largem ent on Montagu Island show ing Belinda as it appear ed in vis ible wavelength data on 3 Novem ber 2005 (a and b). An ASTER ther mal-infra red im age was obtaine d of the island on faint steam wisps extend ing E the same date (c). Cour tesy of Matt Pat rick, HIGP. from delta’s east ern margin. The Volcanism Network, Volume 30, Number 11, November 2005 Aoba 7 ther mal infra red im age (band 14, at 11-micron wave length) le développement (IRD), the New Zealand Insti tute of Geo- of the island is shown in figure 7c, and clearly indicates the log ical & Nu clear Sci ences (GNS), and New Zea land’s anomalously warm delta. Massey Uni ver sity be gan col lab o rat ing on ob ser va tions and A Royal Air Force overfli ght on 11 Oc tober 2005, cap- moni tor ing. The am pli tude of tremor recorded by DGMWR tured an oblique photo graph of the delta (not shown). The instru m ents from 30 Novem ber to 3 Decem ber was lower lava flow appears to have steeply cut through thick ice ap- than dur ing the March 1995 ac tivit y. proaching the shore, produc ing a broad and rela ti vely flat delta that is vigor ously steam ing from the delta margins in the photograph. Back ground. The largest of the South Sandwich Is- lands, Montagu consis ts of one or more stratovolcanoes with para sit ic cones and/or domes. The sum mit of the 10 x 12 km wide, poly go nal- shaped island rises about 3,000 m from the sea floor betwee n Bristol and Saunders Is lands. The name Mount Belinda has been appli ed both to the high point at the southern end of a 6-km-wide ice-filled sum mit cal dera and to the young centra l cone. Mount Oceanite, an isolat ed 900-m-high peak, lies at the SE tip of the is land and was the source of lava flows exposed at Mathias Point and Allen Point. There was no re cord of Holo cene or histor i cal erup tive ac tiv ity at Montagu un til MODIS sat el lite data, begin ning in late 2001, re vealed therm al anom ali es con sis tent with lava lake ac tiv ity that has been per sis tent since then. Appar ent plumes and single anom alous pixels were observe d inter mit tently on AVHRR im ages during the period March 1995 to Febru ary 1998, possi bly indicating earlier unconfirmed and more sporadic volcanic activity. In for ma tion Con tacts: Matt Patrick , Univer sit y of Ha- waii, Ha waii In sti tute of Geo phys ics and Plan e tol ogy (HIGP) Therm al Alerts Team, 2525 Correa Road, Hono - lulu, HI 96822 (URL: http://www.modis.higp.ha waii.edu, Email: pat [email protected] waii.edu); John Smelie, Brit ish Ant arc tic Sur vey, Natu ral En vi ron ment Re search Coun cil, High Cross, Madingly Road, Cam bridge CB3 0ET, United King dom (URL: http://www.anarctica.ac.uk, Email: [email protected]); NASA Earth Ob ser va tory (URL: http://earthobservatory.nasa.gov/). Figure 8. Map show ing the loca tion of volca noes, includ ing Aoba, in Vanuatu. Open tri an gles in di cate sub ma rine vol ca noes. Mod i fied from a map by IRD. Aoba Ambae Is land, Vanuatu 167.83°E, 15.40°S; sum mit elev. 1,496 m

A new erupti on began on 27 Novem ber 2005 when va - por plumes and ash colum ns were observe d origi nat ing from Lake Voui, a crater lake at the sum mit of Aoba (figure 8). The vol cano is also referred to local ly as Manaro or Lombenben. Prior to this ac tivit y, the most re cent reporte d volca nism consis ted of phreatic explo sions from the lake during March 1995 (BGVN 20:01, 20:02, and 20:08). Bathymetry conducte d by ORSTOM in 1996 showed that the vent feeding gases and magma into Lake Voui had a depth of about 150 m and a di am eter of about 50 m. The volum e of water in the lake (1 x 2 km) total s some 40 mil - Figure 9. Digi tal im age of Aoba cre ated by combing shading and color lion cubic meter s, with a mean pH of 1.8. Lake Voui and coding of topo graphi c height. The shading indi cate s direc tion of the the Manaro Ngoro sum mit explo sion crat ers and cones slopes; NW slopes appear bright, while SE slopes appear dark. Color formed ~ 420 years ago (figure 9). Lake Manaro was coding shows height, with green at the lower ele va tions, rising through formed by the accu m ula ti on of water in a low-lying area of yel low and tan, to white at the highest ele va tions. The flattened- looking summ it shows that the new est crater is ac tu ally nested within older, larger the Manaro summit caldera. craters. Ele va tion data used in this image were ac quired by the Shut tle Starting on 3 De cem ber a team of volca nol o gist s from Radar To pog raphy Mission (SRTM) aboard the Space Shut tle Endeavour, the Vanuatu Depart ment of Geol ogy, Mines, and Water Re- launched on 11 Febru ary 2000. Anno tations added by Smithso nian sources (DGMWR), the French Institut de recher che pour ed i tors. Cour tesy of NASA. 8 Aoba Smithsonian Institution — Bulletin of the Global

Figure 10. Photo graph show ing a telephoto view of an explo sive eruption Figure 11. Photo graph show ing an explo sive eruption from Lake Voui at from Lake Voui at Aoba, 4 Decem ber 2005. View is approx i m ately Aoba on 4 De cem ber 2005. View is approx i m ately towar d the E from the towar ds the east from the crater rim. Cour tesy of Philipson Bani, IRD. crater rim. A large steam plume can be seen ris ing above the darker zone con tain ing pyroclastic mate rial. Three small is lands formed prior to this eruption can also be distin guished, with the active vent area closest to the Sci enti sts who visit ed the lake on 4 and 5 Decem ber west ern-most island. Courtesy of Philipson Bani, IRD. (figures 10 and 11) observe d a sim ilar style of erupti ve ac - tivit y on both days, but some indi vid ual explo sions appeared larger on the 5th. It was not pos sible to reach the above the crater; the plume did not contai n ash. There were lake to col lect a water sample. There ap peared to be two ac - no reports of ash falling on the is land since the start of the tive vents, side by side, in the lake. One was produc ing erupti ons the previ ous week. The team esti mated that the erupti ons of mud, rocks, and water , and the other appeare d cone be ing built in the lake, at an es ti mated height of more to be the source of the large conti nu ous steam plume rising than 20 m on the 4th, was about 70% com plete around the

Figure 12. Hazard map of Aoba, showing risk areas, infra struc ture, and settle m ents. See Cronin and others (2004) for addi tional detail s. Map produced by the United Na tions, OCHA-ROAP In for ma tion Man age ment Unit, 2 De cem ber 2005. Volcanism Network, Volume 30, Number 11, November 2005 Aoba 9

around the ac tive vents, enclos ing them on three sides, form ing an island about 200 m across and 50-60 m high. There were two vents, one erupting wa ter, rocks and mud, and the other produc ing a tall colum n of steam and gas. The erup tion had little ef fect out side the crater lake (mino r ashfall occurred only in the first three days of the erupti on). Five days of seism ic record ings show a moder ate level of seis mic activ ity (mostly vol canic tremor).No change was noted in the level of Lake Voui, and there was also no evidence of ground uplift or fractures near the lake. Sul fur di ox ide mea sure ments. SO2 data col lected us ing a DOAS spectrom eter on the Islande r planes of Unity Air Lines (3 De cem ber) and Air Vanuatu (5 Decem ber). On 3 Decem ber the flux was 32.6-33.6 kg/s (~ 2,900 metric tons/ day). By 5 Decem ber the flux had decrea sed about 25%, to Figure 13. Aeria l photo graph show ing a steam plume rising from Lake Voui at Aoba, 8 Decem ber 2005. Courtesy of Forces Armées en Nouvelle 24.7-26.4 kg/s (~ 2,300 metric tons/day). SO2 was clearly Calédonie (FANC). detec ted by the OMI (ozone moni tor ing instru m ent) sensor on the NASA Aura satel lit e (figure 14). One measure m ent of the volca nic gas output on 10 De cem ber showed a mod - acti ve vents, and grew 5-10% higher betwee n 4 and 5 De- erate level of sul fur diox ide (SO2) gas (about 2,000 t/d) cem ber. Conti nu ous tremor was recorded during this time, from the ac tive vents. and the level of eruptive and seismic activity seemed to be fairly stable. Cloud cover and rain prevente d a visit to the lake on 6 and 7 De cem ber. Earth quake re cord ers from the GNS were in stalled at the Pro vin cial Cen tre at Saratamata, the Longana Peoples Centre (Lovonda village ), and at Tahamamavi (“place of warm sea”) (fig ure 12). On 7 De- cem ber, a final re corder from the IRD was in stalled near Nduidui on the SW side of the is land. Over 6-7 De cem ber con tin u ous mod er ate-level vol ca nic tremor was re corded, with no signif i cant change in its level; there was no other significant seismic activity. On 8 Decem ber, the group noted that small-scale erup- tions conti nued in Lake Voui, building a vol canic cone in the lake and produc ing a tall (2.4-3.0 km) steam-and-gas plume. After noon obser va ti ons showed the cone growing taller and surround ing three sides of the acti ve vents. How- ever, the cone was not com plete on its E side, al lowing lake water to re act with the rising magma. Though the result ing explo sions becam e further apart and slightly larger, the total energy involved appeare d sim ilar to 4-5 De cem ber. There conti nued to be two acti ve vents, one produc ing the small explo sions , and the second the steam and gas emissions. Seis mic re cord ers con tin ued to re cord vol ca nic tremor, but very few local earthquakes . No volca nic ash was present in the plume. The erupti on had no im medi ate ef fect be yond Lake Voui. The Vol canic Alert Level re- mained at Level 2. The level of seis mic activ ity seemed to be stable. No other significant seismic activity was recorded. While depart ing by air on the evening of 8 De cem ber, the group clearly saw the acti ve vents (figure 13). The cone had grown to the W, joining and partly bury ing one of the old islands . All erupti ons occurred from inside the cone. The larg est in di vid ual erup tions threw ma te rial 150-200 m above the lake. There was also a gas-and-steam vent present within the cone, W of the other vent. The level of the lake appeared unchanged. On 10 De cem ber, the small-scale vol canic erup tion con - tin ued from active vents within the summit crater lake (Lake Voui). Mol ten mate rial en tered the crater lake and re - Figure 14. SO2 data from the Ozone Moni tor ing Instru m ent (OMI) on the Aura sat el lite, 5 De cem ber 2005. Cour tesy of NASA, the KNMI MOI acted with the water to produce small explo sive erupti ons Sci ence Team, and Si mon Carn, Uni ver sity of Mary land-Bal ti more and a plume of steam and gas. The erupti on built a cone County. 10 Garbuna Group Smithsonian Institution — Bulletin of the Global

Lake tem per a tures. A mon i tor ing sta tion for con tin u- 31.4°C (Aqua) on 21 Novem ber. On 25 Novem ber the tem - ous measure ments of wa ter tem per ature at Lake Voui was pera ture jumped to about 42°C. insta lled in Octo ber 1998. The sta tion used a sat elli te Back ground. Aoba is a massive 2,500 km3 ba saltic ARGOS transm ission system and recorded the last heating shield vol cano. A pronounced NE-SW-trending rift zone epi sode of 2001 (figure 15), but failed after three years due dotted with scoria cones gives the 16 x 38 km island an to the harsh acid envi ron m ent. ASTER ther mal infra red im - elongate d form. A broad pyroclastic cone contai ning three ages can also be used for moni tor ing lake surface tem pera - crater lakes is lo cated at the summ it of the Ha wai ian-style tures, and Aoba has a fresh wa ter lake (Manaro Lakua) shield vol cano within the youngest of at least two nested which can be used to rem ove the sea sonal/di urnal varia - calde ras, the larg est of which is 6 km in di am eter. Post-cal- tions in at mo spheric tem per a tures. Un for tu nately, the top of dera explo sive erupti ons formed the sum mit crat ers of Lake the vol cano is frequentl y cov ered by clouds and few AS- Voui (also spelled Vui) and Lake Manaro Ngoru about 360 TER im ages are ex ploit able. The most re cent AS TER im- years ago. A tuff cone was construc ted within Lake Voui age clearly showing both lakes was collec ted on 9 July about 60 years later. The lat est known flank erupti on, about 2005. Dif fer ence in temper atures between lake Voui and 300 years ago, destroy ed the popu la ti on of the Nduindui Lakua was 4.0°C, slightly above background val ues during area near the western coast. 2002-2003. Max i mum back ground tem per a tures mea sured Ref er ence: Cronin, S.J., Gaylord, D.R., Charley , D., with AS TER dur ing the Sep tem ber 2002-Oc to ber 2005 Alloway, B.V., Wallez, S., and Esau, J.W., 2004, Par tic ipa - were at 26.3°C. The last AS TER images before the tory meth ods of in cor po rat ing sci en tific with tra di tional eruption, on 5 October 2005, showed no unusual knowledge for vol canic hazard manage m ent on Ambae Is - temperatures at Lake Voui. land, Vanuatu: Bulle ti n of Volca nol ogy, v. 66, p. 652-668. MODIS satel lites have a more fre quent cov er age than (URL: http://www.proventionconsortium.org/files/ ASTER but their spati al reso lu ti on is only 1 km. The sur- tools_CRA/CS/Vanuatu.pdf) face area of Lake Voui (2.1 km2) is too small for an accu - In for ma tion Con tacts: Esline Garaebiti, Douglas rate measure ment of lake tem per ature, but MODIS can de - Char ley, Mor ris Har ri son, and Sandrine Wallez, De part- tect rough temper ature changes or an in creased ther mal ment of Geol ogy, Mines, and Water Resource s (DGMWR), anom aly. The MODIS pixel foot print is about 1 km along Port-Vila, Vanuatu (Email:[email protected]); track and 2 km across track, so the measured tem per atures Michel Lardy, Philipson Bani, Jean-Lam bert Join, and are a mixed signal corre spond ing to the lake and some sig - Claude Robin, Institut de recher che pour le développement nal from the adja cent tropi cal forest (much colder than the (IRD), BP A5, 98 848 Nouméa CEDEX, New Caledo nia lake at night at this el e va tion). MODIS SST imag ery (URL: http://www.mpl.ird.fr/suds-en-ligne/fr/volcan/ showed a strong therm al anom aly on 21 Novem ber 2005 vanu_eng/aoba1.htm; Email: [email protected], (fig ure 15). Ap prox i mate lake tem per a tures, likely a min i- [email protected], [email protected], crobin@cec. mum, were 30.4°C on 20 Novem ber and 29.5°C (Terra)/ uchile.cl); Brad Scott and Steve Sherburn, In sti tute of Geo - log ical & Nu clear Sci ences (GNS), Wairakei Re search Center , Taupo, New Zealand (Email: [email protected], s. [email protected]); Shane Cronin, In sti tute of Nat u ral Resour ces, Massey Uni ver sity, Palmerston, New Zea land (Email: [email protected], [email protected]); Alain Ber nard, IAVCEI Com mission on Vol canic Lakes, Université Li bre de Bruxelles, Brussels, Bel gium (URL: http://www.ulb.ac.be/sci ences/cvl/aoba/Ambae1.html); NASA Earth Ob ser va tory (URL: http://earthobservatory. nasa.gov/); United Na tions, Of fice for the Co or di na tion of Hu mani tar ian Affairs (OCHA), Regional Office for Asia and the Pacific.

Garbuna Group New Brit ain, SW Pa cific 5.45°S, 150.03°E; sum mit elev. 564 m All times are lo cal (= UTC + 10 hours)

This report concerns Garbuna vol cano’s first histor i - cally wit nessed erupti on. That occurred in mid-Oc tober 2005 after a felt earthquake. This re port contai ns a secti on by mem bers of the Rabaul Volcano Obser va tory (RVO) Figure 15. Tem pera ture data from Lake Voui at Aoba, Octo ber and another by Rodger Wil son, a NOAA mete o rol o gist , 1998-De cem ber 2005, from in-situ mea sure ments, AS TER sat el lite im ag ery, and MODIS sat el lite data. Delta T rep resents the ther mal who made an unof fi cia l visit in November. anom aly cal cu lated as the tem per a ture dif fer ences be tween the two lakes. Set ting. Garbuna is part of the 23 x 15 km The figure includes the first post-eruption AS TER data (24 Decem ber Krummel-Garbuna-Welcker complex (a vol canic field with 2005). ARGOS data from Michel Halbwachs (Université de Savoie) and these major topo graphi c highs locat ed in S-to-N progres - Michel Lardy (IRD). Cour tesy of Alain Ber nard. sion; figure 16). The field reside s at the S end of New Brit - Volcanism Network, Volume 30, Number 11, November 2005 Garbuna Group 11

sec ond vent opened quietl y during the night of the 18-19 Octo - ber, with two white vapor plumes visi ble at dawn on the 19th. Aeria l inspec tions on 19, 20, and 26 Octo ber showed the two vents sit u ated in the cen tral low area of Garbuna, his tor ically an area of high geo ther mal activ ity. Both vents are locat ed on or close to the edge of the youthful lava dome menti oned above. The center of the dome is at 05° 26’ 48" S, 150° 01’ 36" E, with the ac tive vents aligned SW-NE at across a NW sector of the old cone. Both Figure 16. Photo graph of Garbuna taken on 19 Oc tober 2005 from the SSE. View is northwar d along the acti ve vents are 60-75 m in di am - Krummel-Garbuna-Welcker ridge, across the gen eral area of Garbuna with Welcker on sky line; Krummel is eter and emit ted low to moder ate behind the cam era. The two fum ing vents can be seen on the periph ery of an old lava dome. The bare geother mal amounts of white fume, the south - nature of the area is appar ent. The in cised cone to the left is what locals refer to as Mount Garbuna. Photo by Steve Saunders provided cour tesy of RVO. erly plume being more volu m i- nous. On the first two visits fume billowed out gently. ain is land’s Willaumez (Talasea) pen in sula, a nar row pro- The SW vent seems to have been the source of the ini - jec tion jutting well N from the is land’s W-cen tral re gion. tial Oc to ber emission s. Be fore the 19th a small in complete The penin sula and some local reefs and is lands are known cone had formed around it. Within a ki lom eter of this vent for vol ca noes and hy dro ther mal fea tures (in clud ing, from N several ten’s of centi meter s of ash/mud had been depos it ed, to S, Dakatua cal dera and its large lake, Bola stratovolcano, which thinned very rapidl y away from the vent. Old records Garua Harbour volca nic field, and the Garbuna com plex). did not indi cat e the exis tenc e of the SW vent or other con- In addi ti on to young volcanics found at the com plex’s three spic uous fea ture prior to the onset of this erupti on. summ it (ridge) cen ters and their as so ciated domes and crat- The second, or NE, vent becam e ac tive on the night of ers, there have been prior flank and eccen tri c erupti ons, 18-19 Octo ber. Photo graphs from 1996 showed that prior most nota bly Numundo Maar. The com plex’s products are to the erupti on this vent was a small, wooded, fun- mostly high-SiO2 andesites to high-SiO2 dacites with more nel-shaped pit, with some evi dence of insta bil ity on its mafic erupti ves from Krummel and Numundo Maar. west ern side and vis i ble un-veg e tated scars. (McKee and others, 2005). Only 5-6 km to the E and W of Although ashfall was reporte d to the NW, im ages of the the vol canic field are some inhab it ed and intensively erupti on at first light on the 17th showed the fallout to re- cultivated strips along the coast. sem ble rain rather than dry ash. Vege ta ti on dam aged by the Garbuna and Welcker volca noes were thought to have fallout had brown blotches rather than uniform discol or - had a latest signif i cant /dat able erupti on at ~ 1,800 BP. ation, leading to the conclu sion that the ini tial colum n was Garbuna in par ticu lar was very geothermally active, with made up pri maril y of acidic water and mud. the cen tral area con tain ing 4 km2 of fumaroles, solfa ta ras, It appears that the NE vent is pre dom inantl y a collaps e hot and bubbli ng mud and water springs, and patches of hot feature , surrounded by a small apron of brownish-gra y ground. Con spic u ous from the bar ren, sul fu rous and mud, with a jagged edge and bright red/yellow walls. Fol- geothermally altered, clay-rich ar eas was a timber- cov ered low ing a lo cally felt earth quake, sum mit ob ser va tions on but undate d lava dome (or al ter nately, a short, thick lava the 20th showed that the NE vent had increa sed ~ 10-20 m flow to the S, a fea ture sometim es de scribed as a coulée). by concen tri c col lapse since the previ ous day and was This dome shows littl e geother mal alter ation, appears very 50-60 m deeper. At this time it contai ned a boiling mud lake youthful, and is not obvi ously mantl ed by the regional ~ 60-70 m below the rim. tephras from Witori or Dakataua, all feature s suggest ing a Ob ser va tions on the 26th showed the ash cone around com para ti vely young age. The low cone hosting the dome the SW vent had all but disap peare d as it had increa sed in stands ~ 500-600 m in diameter. size by collaps e. The result ing pit was irreg u lar in shape. Events surround ing the eruption. The RVO team re- Quite vigor ous steam emissions occurred and some ash was ported this sec tion and noted that the com plex was not in- visi bly mixed with the fume and dropping out as fine drop- stru men tally mon i tored. A sin gle, lo cally felt earth quake lets of di lute mud. Impact crat ers from pro jec tiles were ev i- occurred around midday on 16 Octo ber 2005. Jet-like dent around the vent, espe cia lly to the SW. Near the vent noises were noti ced about 2342 that night, rum bling noises these small pro jec tiles were vis ible and block-like. Up to started soon after , and at about midnight ash emissions be- 500-600 m to the SW small im pact crat ers could still be gan. The erupti on conti nued and by morning pale to dark seen but the pro jec tiles themselves were not apparent. gray ash clouds were being driven force fully into the sky. Close study of the old dome, on whose periph ery the By 1000 a 3-4-km-high erupti on colum n was visi ble; the vents have opened, suggest s that it has under gone littl e or main plume drift ed NW with a thin veil of falling mate rial no movem ent dur ing the onset of this erupti on. Fo- below it. The erupti on began to wane be tween midnight and liage-stripped trees are mainly up-right, and no fresh cracks the morning of 18 Oc tober, re ducing to slow pale-gray or heaved boulders are evi dent. Therm al im agery also emissions , with only white vapor by the end of the day. A showed no hot cracks in the dome, suggest ing that the erup- 12 Garbuna Group Smithsonian Institution — Bulletin of the Global tion was not precede d by intens e surface defor m ati on, and there was an area that I jok ingly re ferred to as, 'The Val ley that the vents are now enlar ging by concentric collapse. of Death,' where we all (four) felt nause ate d (on both A large area of grass N of the vents gave the impres sion climbs at the same loca ti on, both com ing and going), but of having been flattene d in a uni form direc ti on. Trees and did not detec t any odor of gas. On the second climb, we shrubs, although stripped of leaves, did not show this flat- found an im mature parrot on the ground at the (SE?) edge tening. This may suggest that floods of water were re spon- of this area (we re moved him from that area, and he seemed sible for the flat tened grass, rather than blast ef fects. To the fine af ter ward). Again, we were un able to get a GPS fix S, flooding is also suggest ed by the appar entl y re cent incis - there, but it occurs along a (NW to SE-running?) de pres- ing of the val ley floor (headwa ter s of the Garu-Haella sion just prior to a steeper climb to the sum mit. sulfur stream). The edge of the jungle also shows under cut - “Just before reaching the clearing at the sum mit, along a ting with trees having fallen toward the vents. more N-S-running depres sion, we encoun ter ed an area Since the start of the erupti on changes in the amount of where the trees ap peared to have been 'sprayed' hor izon tally discharge , along with unusual discol or ati on and dy ing fish as ev idenced by ash being 'plas tered' to their N (crater) were seen in the streams draining from Garbuna. On 26 Oc- sides. Bark on many of the larger trees ap peared to be at tober, aeria l observ ers fol lowed one of the Garu therm al least lightly abraded, but not rem oved. Num erous smaller streams from the Planta ti on-Garu village road on its ascent trees of ap prox im ately 6 cm or less in diam eter had been to the sum mit. At higher el e va tions the stream’s wa ter level neatly ‘clipped’ or sharply bent over at just less than 2 m dropped markedly , unti l within a few ki lom eter s of the height. There was no evi dence of high tem pera ture in con- summit, it dried out completely. The stream was not nec tion with the phys ical damage. Our visit was re stricted blocked or dammed, and the falling levels of streams and to along the S edge of the sum mit, bounded by the hy dro- drying of springs appeare d to be relat ed to the dry ing of the ther mal area on the W and the two old phreatic crat ers to sum mit, or frac tur ing, al low ing wa ter to per co late into the the E. This area of dam aged trees was, as far as we could mountai n rather than flow off the geothermally produced see, the only signif i cant dam age to the surround ing forest clay-rich area. At first light on the morning of 29 Oc tober, (by a base surge or a cold densit y cur rent?) in contra st to the water course com monly known as the Walindi river was the more complete dev as tation suf fered by the fewer trees milky white with a blue tinge. It was odorles s, of norm al and lower veg e ta tion at the summit. In ter est ingly, the trees tem per ature, and tasted simply of clayey wa ter with no bit - still standing at the sum mit, appeare d to be stripped solely ter ness. This is the first re corded case of one of the east ern by ver ti cally fall ing, not hor i zon tally mov ing, de bris. drainage system s exhib it ing this behavior, although it is “We exit ed the forest at the sum mit at about 1100, along common in the W and SW regions. a N-S bare ridge (old crater rim?), that is clearly vis ible in A few local ly felt earthquakes and sulfur odors were re- aeria l photos of the area. Copi ous fume em anate d sound- ported from areas not tradi ti onall y af fected by the com- lessly from the two new crat ers. White fume ex ited the plex’s sulfatara emissions . On several occa sions explo sions western crater, with yel low-tinged fume ris ing from the or boom ing noises from the Garbuna area were heard at eastern one. There was a fairly strong smell of H2S, but not Garu Plan ta tion. the eye-stinging or choking sensa ti on I’ve felt with SO2 at Two seism ic stati ons were insta lled on 18 Octo ber. A Etna and Stromboli. As we rested there, we noted the water 3-com ponent digi tal recorder was locat ed at Garu Planta - in our bot tles was in consta nt moti on and once we made our tion ~ 5.5 km SW of the acti ve vents. An ana log re corder way to the ther mal area, we clearly felt fre quent (sev eral was insta lled at Sisi near Walindi, ~ 5.6 km E of the vents. per minute) small shocks while we took tem pera ture s at Nota ble seis micit y was recorded on 20, 21, and 22 Oc tober. sev eral spots there. The high est tem per atures were all at On the 20th a ML ~ 2.5 local volcano-t ectoni c earthquake 100°C. During the first couple of hours at the sum mit, we was felt, which was fol lowed by a dozen smaller VT earth - had two brief bands of rain showers pass over head, but by quakes betwee n 1300 and 1500. Start ing about 0500 on 21 about 1330 the rain becam e sustai ned and heavy. Run-off in Oc to ber many very small (ML < 0.5) VT earthquakes began most of the surround ing gul lies had increa sed to several to occur. These events conti nued throughout 21 Oc tober inches deep. We . . . were picking our way back toward the and ceased about 1600 on 22 Octo ber. Random VT earth- forest when, just as we left the southern edge of the ther mal quakes num bering 1-4 per day were re corded on 23, 25, and area, we heard a loud roar and wit nessed a lahar issue from 28 Oc to ber. Other vol cano-re lated earth quakes re corded in- the gully draining the crater . . .. cluded some small low-fre quency earthquakes on 22 Octo - “Changes we noted dur ing the second visit 3 days later ber by the Sisi sta tion. Conti nu ous tremor was re corded im - were [as follows] : a low rum ble or rushing noise asso ci ate d me di ately when a new telemetered seis mome ter was with the sum mit vents which was heard through most of the insta lled about 0.9 km NE of the ac tive vents. At the end of journey to the sum mit, al though [they observe d] a com plete the month the trem ors were conti nu ing. lack of de tect able seis micity while at the summit. The in ter - The West New Brit ain Pro vin cial Di sas ter Com mit tee val be tween “huffs” of fume was shorter, on the order of has ensured a smooth civic response to this unfore see n maybe 4-5 minutes rather than the 8-10 minutes observe d event with pub lic ed u ca tion and prep a ra tions for a pos si ble during the first visit. Fume leaving the western vent re- evac u a tion being well advanced. mained white, while ash was clearly vis ible as it fell over Ob ser va tions dur ing mid-No vem ber 2005. Rodger the E flank of the volcano from the east ern plume. That Wilson subm it ted the fol lowing re port of his visit to plume also had a more yellow cast as it is sued from its Garbuna with John Seach. source, compared with a few days be fore. “We climbed Garbuna the first time on 14 Novem ber. “We heard low boom ing rum bles from near Walindi at We smelled H2S(?) from at least three lo cations at lower el- around 0530 on 17 Novem ber and loud roaring the next eva ti ons along the trek. Wind at the time was to the NE, so I morning at about 0700 from the same loca ti on. The latter don’t be lieve we were sensing the sum mit gas plume. Also, was pre ceded (by as much as 10 minutes ) by dogs at our lo - Volcanism Network, Volume 30, Number 11, November 2005 Fukutoku-Okanoba 13 ca tion be ing ag i tated and bark ing, si mul ta neously with oth- Back ground. Langila, one of the most acti ve volca noes ers in the distance. of New Brit ain, consis ts of a group of four small overlap - Back ground. The ba saltic-to-dacitic Garbuna vol cano ping com posit e basal tic-andesitic cones on the lower east- group consis ts of three vol canic peaks, Krummel, Garbuna, ern flank of the exti nct Talawe vol cano. Talawe is the high- and Welcker. They are locat ed along a 7-km N-S line above est vol cano in the Cape Glou ces ter area of NW New a shield-like founda ti on at the southern end of the Britain. A rect angu lar , 2.5-km-long crater is breached Willaumez Pen in sula. The cen tral and lower peaks of the widely to the SE; Langila volcano was construc ted NE of centra lly locat ed 564-m-high Garbuna vol cano contai n a the breached crater of Talawe. An ex ten sive lava field large veg eta tion-f ree area that is prob ably the most exten - reaches the coast on the north and NE sides of Langila. Fre- sive ther mal field in Pa pua New Guinea. A prom inent lava quent mild-to-mod er ate ex plo sive erup tions, some times ac- dome and blocky lava flow in the center of therm al area com panied by lava flows, have been recorded since the have re sisted de struc tion by therm al acti vit y, and may be of 19th cen tury from three ac tive crat ers at the summ it of Holo cene age. The 854-m-high Krummel vol cano at the S Langila. The youn gest and smallest crater (Crater 3) was end of the group contai ns a sum mit crater, breached to the formed in 1960 and has a diameter of 150 m. NW. The highest peak of the Garbuna group is In for ma tion Con tacts: Dar win Vol ca nic Ash Ad vi sory 1,005-m-high Welcker vol cano, which has fed blocky lava Cen tre (VAAC), Burea u of Met eo rol ogy , Northern Terri - flows that extend to the eastern coast of the peninsula. tory Regional Offic e, PO Box 40050, Ca suarina , NT 0811, Ref er ence: McKee, C.O., Patia, H., Kuduon, J., and Australia (URL: http://www.bom.gov.au/info/vaac); Torrence, R., 2005, Vol canic Hazard Assess ment of the Rabaul Vol cano Ob ser va tory (RVO), P.O. Box 386, Krummel-Garbuna-Welcker Vol ca nic Com plex, South ern Rabaul, Pa pua New Guinea; In ter na tional Fed er a tion of Willaumez Pen in sula, WNB, Pa pua New Guinea: Geo log i- Red Cross And Red Crescent Soci et ies (IFRC) (URL: http:// cal Survey of Papua New Guinea–Report 2005/4. www.reliefweb.int/). In for ma tion Con tacts: Steve Saunders, Ima Itikarai, and Herman Patia, Rabaul Volcano Obser va tory (RVO), P. O. Box 386, Rabaul, Papua New Guinea; Rodger Wil son, Me te o ro log i cal Tech ni cian, US Na tional Oce anic and At- mospheri c Adm ini stra ti on (NOAA) and Nati onal Weather Fukutoku-Okanoba Service (NWS), WSO, P.O. Box 1685, Valdez, AK 99686, USA (Email: rodger.wil [email protected]). Volc ano Isla nds, Japa n 24.28°N, 141.485°E; summit elev. -14 m All times are lo cal (= UTC + 9 hours)

Noti ce of Fukutoku-Okanoba unrest in 2005 first came Langila to Bul le tin edi tors from Olivier Hyvernaud, infor m ati on that was am pli fied by the Jap a nese Me te o ro log i cal Agency Papua New Guinea (JMA) Volca nic Acti vit y Reports of July and Octo ber 5.525°S, 148.42°E; sum mit elev. 1,330 m 2005. The JMA re ports contai n infor m ati on from the Japa - All times are lo cal (= UTC + 10 hours) nese Ma rine De fense Forces as well as the Ma rine Se cu rity and Safety Agency and the Tokyo Insti tute of Technol ogy. Rabaul Vol cano Obser va tory (RVO) re ported that dur- In addi ti on, a Ja pan Coast Guard website (see URL be low) ing 22-28 August 2005, modest erupti ve ac tivit y was ob- contai ns a more exten sive (and yet untra nslat ed) table on served at Langila’s Crater 2. Oc casional force ful emissions recent events at Fukutoku-Okanoba, which include s photos of ash produced plumes that rose ~ 1 km above the crater on and videos of the July erupti on. That table clearly il lustra tes 22 and 25 August, but reached only several hundred meter s acti vit y both earli er and later than the 2-3 July erupti on, and after that. The ash plumes drifted N and NW, result ing in several other detai ls not discusse d here, includ ing the ob- fine ashfall in downwind areas , includ ing the town of serva ti on of num erous large and steam ing blocks floating Kilenge. Seis micity was at low lev els, con sist ing mainly of on the ocean surface at mid-day on 3 July. Bul le tin ed i tors low-fre quency earthquakes . The Darwin Vol canic Ash Ad- hope to decipher this table and include more details in a visory Centre (VAAC) re ported that a plume was visi ble on later report. sat elli te imagery on 30 August extending NNW. The last five Bul le tin re ports dis cuss ing or men tion ing During 12-18 Septem ber, Crater 2 conti nued to force- Fukutoku-Okanoba appeare d in BGVN 22:01, 24:11, 24:12, fully erupt ash at ir reg u lar in ter vals. The re sul tant ash 25:05, and 28:06 (1997-2003). Note that the last four cases plumes drifted NW and W. In candes cenc e and weak pro- were consid ered am bigu ous and grouped along with reports jecti ons of volca nic mate ria l were vis ible on the eve ning of under the heading “Acousti c signals in 1999-2000 from un - 13 Sep tem ber. There was no ac tiv ity at Crater 3. Seis micity known source, Volcano Is lands, Japan” and only the first was at low levels at the volcano, consis ting mainly of case was listed under the volcano name). A 3-d view of the low-frequency earthquakes. volcano and its set ting appears as figure 17. During 20-23 Oc tober, low-level plumes from Langila JMA re ported that at about 1745 on 2 July 2005, a white were oc ca sion ally vis i ble on sat el lite im ag ery. On 29 Oc to - plume was wit nessed at Fukutoku-Okanoba. During an in- ber, a plume from Langila was vis ible on sat el lite imag ery vesti gati on at 1900 that same day, a white plume reached at an alti tude of ~ 2.7 km. ~ 1 km above the sea surface . A photo taken from consid er - During 11-12 Novem ber, low-level ash plumes emit ted able distanc e was include d in the JMA report, showing the from Langila were visi ble. The heights of the plumes were plume, but the image’ s limited con trast has led to its ex clu - not re ported. sion here. In addi ti on to the plume, other evi dence for an 14 Fukutoku-Okanoba Smithsonian Institution — Bulletin of the Global

“At the most dense discol ored sea wa ter area, reflectance of AS - TER band 1 is 3% higher [than] the sur round ing sea wa ter. The float ing ma te ri als are sim i lar in ASTER VNIR [Very Near-Infra - red Ra di om e ter] reflectance spec - tra to clouds, however, the floating ma te ri als can be sep a rated from clouds using their shape and stereo image fea tures. The ex ten- sions of dis col ored sea wa ter area and float ing ma te rial de tected by ASTER were 6.34 km2 and 1.14 km2, re spec tively. It is pos si ble to es tim ate the scale of [a] sub ma- rine erupti on using the quanti ta- tive data derived from satellite remote sensing.” Dis tant hydrophones. Robert Dziak and Haru Matsumoto mon - i tor N Pa cific vol cano seis mic ity Figure 17. Fukutoku-Okanoba and vicin ity shown in a 3-dim ensional dia gram , with shading (or color) with the Na tional Oce anic and At- rep re sent ing var i ous el e va tion ranges (see key above); ver ti cal ex ag ger a tion is con sid er able but was not stated. The inset con tains an index map showing the Volcano is lands along the Bonin trench. The di agram repre sents mo spheric Agency/Pa cific Ma- data from 1999 and views the region from the SE. Fukutoku-Okanoba is a subm arine vent ~ 5 km N of the island rine En vi ron men tal Lab o ra tory (Minami-Iwo-jima). Copyright ed im age cour tesy of the Japan Coast Guard. (NOAA/PMEL). They initially learned of the erupti on via the internet. Re garding the 2 July erupti on, Dziak wrote to the Bul- le tin staff on 22 Novem ber 2005. erupti on include d debris on the sea surface . When seen on 2 Some of his messages follow. July, the debris covered an area approx i m ately 100 m wide “. . . the [N] Pa cific hydrophone ar ray we use record ed and 300 m long. seism icit y during the Fukutoku-Okanoba erupti on near Iwo JMA noted that 3 July ae rial obser va ti ons suggest ed that Jima. I was aware of the erupti on at the time [mid 2005] com pared to the previ ous day, erupti ve vigor and the height thanks to Haru [Matsumoto—he designe d and built the in- of the white plume had de creased. The key obser va ti on then strum ents used there to record the T-wave events] forward - was a zone of discol ored sea wa ter (figure 18). ing a news im age of the dis colored water . Despit e being JMA’s report of 4 and 5 July aeria l inves ti gati ons noted only able to roughly lo cate the seis micity since it is way the lack of a white vapor plume over the sea. In other west of our array , I am pretty sure Fukutoku-Okanoba was words, the 2-3 July erupti on had calmed, but fresh de bris the source be cause the arriva l az im uths and tim ing of the and sea wa ter dis col or ation were still pres ent. Af ter that, ae - sig nals were a match. The last earth quake activ ity we re- rial inves ti gati ons on 15, 17, 20, and 21 July, again dis- corded from this area occurred on 25 Septem ber [2005] . . .. closed seawa ter discol or ati on, but not the presence of A few years ago I was contac ting you [Smithso nian Insti tu- floating debris. tion] about our re cording of harm onic tremor from a source The Mar itim e Se cu rity and Safety Agency con ducted an un der wa ter top o graph i cal sur vey on 20-22 July 2005, the result of which was the dis covery of two crat ers caused by the recent erupti on. The re sults suggest ed that the topog ra - phy just S of those crat ers was newly raised. Accord ing to a 3 Octo ber ae rial observe r, the ocean surface near Fukutoku-Okanoba, then dis played a pale, blue-white dis col or ation, in ter preted as in dic a tive of vol ca - nism. The area of discol or ati on extende d ~ 300 m in length to the E and was ~ 50 m wide (N-S) at its widest point. However, in the surround ing area they saw no floating debris or plumes contai ning ash or steam. On 27 Octo ber, an aeria l obser va ti on could not confirm the seawater discoloration. Sat el lite data. M. Urai (2005) re ported that three days after the 2 July 2005 erupti on of Fukutoku-Okanoba, satel - lite rem ote sensing using ASTER (Advance d Spaceborne Ther mal Emis sion and Re flec tion Ra di om e ter) ob served Figure 18. An aeria l view of Fukutoku-Okanoba taken on 3 July 2005 as the dis col ored sea wa ter and float ing ma te ri als within 40 km seen from the NE. De bris and discol or ation extend from the ar row. of the subm arine volcano. Some of this abstract follows. Cour tesy of the Mari time Se cu rity and Safety Agency. Volcanism Network, Volume 30, Number 11, November 2005 Karymsky 15 in the Vol cano Is lands. The conclu sion I publi shed in JGR [Dziak and Fox, 2002] was that ei ther Fukutoku-Okanoba Karymsky or Funka-asane ([N] of Iwo Jima) was the proba ble source becaus e of a history of subm arine volca nic acti vit y at both Kamchatka, Rus sia volca noes. We have still been record ing this tremor inter - 54.05°N, 159.43°E; sum mit elev. 1,536 m mit tently over the last few years and another pulse of it oc- All times are lo cal (= UTC +12 hours) curred dur ing the Fukutoku-Okanoba eruption on July 2, 2005. The last occurrence was on August 22. From Decem ber 2004 to June 2005 fre quent explo sions Accord ing to an Email from Dziak on 23 Novem ber and plumes were de tected at Karymsky (BGVN 30:06). In 2005, “...I think the tremor is com ing from June 2005, the alert level was briefly lowered from Orange [Fukutoku-Okanoba or Funka-asane]. I was only able to get to Yel low be cause of a de crease in seis mic and volca nic ac - synchro nous data from the French Poly nesia n seism ic net tivit y, but it was raised to Orange again on 23 June becaus e (Hyvernaud). They confirm ed the signals but it did not help of ash and gas plumes which rose to 3 km above the crater. much with lo cation be cause they were so far away. My Karymsky re mained at Concern Color Code Orange and thought is the source of earthquakes and tremor from these seis mic ity re mained above back ground lev els through out subm arine volca noes is at an ocean depth within the sound Au gust-De cem ber 2005. chan nel. This al lows for very ef fi cient seis mic-acous tic Throughout July 2005 ash-and-gas plumes fre quently cou pling and acous tic prop a ga tion through out the Pacific may have risen to 1-3 km above the crater. During 8-15 ocean basin.” July, 450-600 shal low earthquakes occurred daily. On 11 Ref er ences: Dziak, R.P., and Fox, C.G., 2002, Evi - July, an ash-and-gas plume extende d about 11 km SE. Dur- dence of harm onic tremor from a subm arine volcano de- ing 15-22 July, 350-700 shallow earthquakes occurred tected across the Pa cific Ocean basin: Jour nal of Geo phys i- daily. On 22 July, a weak ther mal anom aly and a short cal Resea rch, v. 107(B5), p. 2085; doi 10.1029/ E-drifting ash-and-gas plume were visi ble on satel li te 2001JB0001772085. imagery. Kato, Y., 1988, Gray pumices drifted from Seis mic ac tiv ity dur ing Au gust in di cated fre quent pos- Fukutoku-oka-no-ba to the Ryukyu Islands : Bulle ti n of the sible ash-and-gas plumes up to 4 km alti tude. A MODIS Volcanological Soci ety of Japan, Second Serie s, v. 33, p. satel lite ther mal anomaly was reg istered on 2 Au gust. On 21-30. 22 August, three ash plumes reached heights around 3-4 km Ossaka, J., Mitsuno, C., Shibata, T., Matsuda, T., alti tude and extende d ~ 130 km E. An ash plume was visi - Hirabayashi, J., Tsuchide, M., Sakurai, M., and Sato, H., ble at an alti tude of ~ 5.8 km on 27 August. 1986, The 1986 subm arine erupti on of Fukutoku-okanoba, Small ash and gas plumes conti nued to be emit ted in Part 2. Volca nic ejectas: Bull. Vol. Soc. Japan, v. 31, p. Sep tem ber. A ther mal anomaly was vis ible at the volcano 134-135. on sat elli te im agery on 15 September. Urai, M., 2005, Moni tor ing subm arine volcano with sat- Vi sual ob ser va tions on 17 Oc to ber re vealed that the elli te rem ote sensing: Eos Trans, AGU, v. 86(52), Fall lava dome in the volcano’s crater had been parti ally de- Meet. Suppl., Abstra ct 611A-1176. stroyed. Based on seism ic data, three ash-and-gas plumes Back ground. Fukutoku-Okanoba is a subm arine vol- may have risen to 2.5-4 km alti tude dur ing 14-16 Oc tober. cano locat ed 5 km NE of the py ram idal island of Five ash-and-gas plumes may have reached heights of 2. Minami-Iwo-jima. Wa ter dis col or ation is fre quently ob- 5-3.5 km alti tude on several days during the last week of served from the vol cano, and several ephem eral islands Octo ber 2005. A therm al anom aly at the volcano was vis i- have formed in the 20th century . The first of these formed ble on satellite imagery. Shin-Iwo-jima (“New Sulfur Island” ) in 1904, and the most The lava dome inside the vol cano’s crater conti nued to recent island was formed in 1986. Fukutoku-Okanoba is grow during Novem ber 2005. Based on seism ic data, three part of an elongate d edi fic e with two major topo graphi c gas plumes contai ning some ash possi bly rose 3-3.8 km al- highs trending NNW-SSE and is a trachyandesitic vol cano ti tude dur ing 29-31 Oc tober and 1 Novem ber. Ash plumes geochemically similar to Iwo-jima. were visi ble on satel li te im agery extend ing NE on 31 Oc to- In for ma tion Con tacts: Olivier Hyvernaud, Laboratoire ber and 2 Novem ber. During 4-11 Novem ber five de Géophysique, BP 640 Pamatai, Tahit i, French Polyne sia gas-and-steam plumes with some ash may have reached (Email: [email protected]); Jap a nese Me te o ro log i cal heights of 3-3.5 km altitude. Agency, (URL: http://www.jma.go.jp/JMA_HP/jma/ No seis mic data were available af ter 10 No vember. A indexe.html); Rob ert Dziak and Haru Matsumoto, NOAA ther mal anom aly was visi ble at the volcano on 15 and 17 PMEL, Hat field Ma rine Sci ence Cen ter, 2115 SE Or egon Novem ber. Ac cording to seism ic data, many weak shallow State Univer sit y Drive, Newport, OR 97365, USA (Email: earthquakes and possi ble gas-steam plumes with some Rob [email protected]; [email protected]); amount of ash up to 2.5 km alti tude were regis ter ed on Yukio Hayakawa (Email: [email protected]); Daily 20-23 Novem ber. A therm al anom aly was noted over the Yomiuri News (URL: http://www.yomiuri.co.jp/dy/na- volcano during the last week of Novem ber and the first tional/20050704TDY01003.htm); Reuters; As so ci ated week of De cem ber. Accord ing to sat ellite data from Rus sia Press; To kyo In sti tute of Tech nol ogy, 2-12-1 O-Okayama, and USA, ash clouds moving to the SE from the volcano Meguro-ku, Tokyo 152-8551, Japan; Japan Coast Guard, were noted on 6-7 December. Hy dro graphic and Ocean o graphic De part ment (URL: http:/ Af ter 3 De cem ber the availabil ity of seis mic data be- /www1.kaiho.mlit.go.jp/GIJUTSUKOKUSAI/kaiikiDB/ came very er ratic. A ther mal anomaly was reg istered on kaiyo24-2.htm); Ja pan Mar i time Se cu rity and Safety 9-11 De cem ber and 14-15 De cem ber. Ac cord ing to sat el lite Agency, Oce anic In for ma tion Sec tion (URL: http://www1. data, ash plumes and clouds were noted on 9 and on 10 De - kaiho.mlit.go.jp/). cem ber, moving SW and SE, and SE and E, respectively. 16 Bezymianny Smithsonian Institution — Bulletin of the Global

During the third week of Decem ber, many weak shallow earthquakes and possibly ten ash plumes up to 3.6 km Bezymianny al ti tude were reg is tered. Ac cord ing to Kamchatka Vol ca nic Erup tions Re sponse Team (KVERT) vol ca nol o gists who Kamchatka, Rus sia work near Karymsky, ash explo sions rose up to 2.5-3 km 55.978°N, 160.587°E; sum mit elev. 2,882 m alti tude on 17-21 Decem ber 2005, and extende d WSW and All times are lo cal (= UTC + 12 hours) ENE. A ther mal anomaly was reg istered over the volcano on 15-21 Decem ber. Seism icit y indi cat ed that ash explo - This report menti ons a se ries of note worthy events dur- sions from the summit crater continued. ing mid-Janu ary through late Decem ber 2005. On 11 Janu - Many weak shallow earthquakes were regis ter ed during ary 2005 an explo sive erupti on was inferred from seism ic the last week of De cem ber. Ash plumes rose up to 2.5-4 km data; it was thought to have produced an ash colum n to alti tude on 24 Decem ber and 26-27 De cem ber and ex- 8-10 km alti tude (BGVN 30:03). Seis mic ac tiv ity re turned tended mainly E and SE from the vol cano, and occa sion all y to background levels follow ing this erupti on and the Con- SW. Accord ing to KVERT volca nol o gist s, a new cone ap - cern Color Code was lowered from Orange to Yel low on 14 proxi m ately 60-80 m in di am eter was formed at the sum mit Janu ary and rem ained at Yellow until the end of November of Karymsky vol cano. A small lava dome 20-30 m in di am - 2005. eter was seen in the cone’s crater. Ac cord ing to sat ellite On 6-7 May 2005, weak gas-and-steam plumes were data from the USA and Rus sia, a ther mal anomaly was reg - observe d, but clouds fre quently obscure d the vol cano. istered over the volcano all week. Ther mal anoma lies at the dome were de tected in sat ellite Back ground. Karymsky, the most acti ve volcano of im agery on 6-8, 10, and 12 May. Kamchatka’s east ern vol canic zone, is a sym metri cal On 30 Novem ber, KVERT re ported that seism icit y at stratovolcano construc ted within a 5-km-wide cal dera that Bezymianny had increa sed during the previ ous two weeks. formed during the early Holo cene . The caldera cuts the Seis mic sig nals in di cated that hot av alanches from the lava south side of the Pleisto cene Dvor volcano and is locat ed dome had be gun on 29 Novem ber and the inten sit y of the outside the north margin of the large mid-Pleis tocene ther mal anomaly at the dome had in creased. Strong Polovinka caldera, which contai ns the smaller Akademia fumarolic acti vit y was capture d on video of 29 Novem ber. Nauk and Odnoboky cal deras. Most seis micit y pre ceding An explo sive erupti on began on 30 Novem ber at 2400 ac- Karymsky erupti ons origi nate d beneat h Akademia Nauk cording to seism ic data. Ash plumes were subse quentl y caldera, which is lo cated im medi ately south of Karymsky seen in sat el lite imag ery ex tend ing SW at an alti tud e of volcano. The caldera enclos ing Karymsky vol cano formed about 6 km. The Concern Color Code was raised to Orange. about 7600-7700 radio car bon years ago; construc tion of the After the erupti on on 30 Novem ber, seism ic acti vit y at Karymsky stratovolcano be gan about 2,000 years later. The the vol cano de creased to background levels . On 2 Decem - lat est erupti ve period be gan about 500 years ago, follow ing ber the Concern Color Code was reduced from Orange to a 2300-year qui escenc e. Much of the cone is mantl ed by Yellow. On 9 De cem ber, KVERT re ported that based on lava flows less than 200 years old. Histor i cal erupti ons have past ex pe ri ence with Bezymianny, a vis cous lava flow was been vulcanian or vulcanian-strombolian with moderate prob ably ac tive at the summ it lava dome and there were no explosive activity and occasional lava flows from the indi ca ti ons that an explo sive eruption was imminent. summit crater. A gas-steam plume was visi ble on 9-11 Decem ber and In for ma tion Con tacts: Olga Girina, Kamchatka Vol ca- fumarolic acti vit y at the lava dome conti nued through De- nic Erupti ons Re sponse Team (KVERT), a coop er a ti ve cem ber. Ther mal anoma lies were reg istered at the dome on program of the Insti tute of Vol canic Geol ogy and Geo- 9, 17, 21, 24-25, and 27-29 December. chemis try, Far East Divi sion, Rus sian Acad emy of Sci- Back ground. Prior to its noted 1955-56 erupti on, ences, Piip Ave. 9, Petropavlovsk-Kamchatskii 683006, Bezymianny volcano had been consid ered exti nct. The Russia (Email: [email protected]), the Kamchatka Exper i - modern Bezymianny volcano, much smaller in size than its men tal and Me thod i cal Seis mo log i cal De part ment massive neighbors Kamen and Kliuchevskoi, was formed (KEMSD), GS RAS (Russia ), and the Alaska Volcano Ob- about 4,700 years ago over a late-Pleisto cene lava-dome ser va tory (USA); Alaska Vol cano Ob ser va tory (AVO), a com plex and an ances tral vol cano that was built about co op er a tive pro gram of the U.S. Geo log i cal Sur vey, 4200 11,000-7,000 years ago. Three peri ods of inten si fie d acti v - Univer sit y Drive, Anchor age, AK 99508-4667, USA ity have occurred dur ing the past 3,000 years. The latest pe- (URL: http://www.avo.alaska.edu/; Email: tlmurray@ usgs. riod, which was precede d by a 1,000-year qui escenc e, be- gov), the Geo phys i cal In sti tute, Uni ver sity of Alaska, P.O. gan with the dram atic 1955-56 erupti on. This erupti on, Box 757320, Fairbanks, AK 99775-7320, USA (Email: sim ilar to that of Mount St. Helens in 1980, produced a [email protected]), and the Alaska Divi sion of large horse shoe-shaped crater that was formed by col lapse Geo log i cal and Geo phys i cal Sur veys, 794 Uni ver sity Ave., of the sum mit and an asso ci ate d lat eral blast. Subse quent Suite 200, Fairbanks, AK 99709, USA (Email: ep i sodic but on go ing lava-dome growth, ac com pa nied by [email protected]); To kyo Vol ca nic Ash Ad vi sory in ter mit tent ex plo sive ac tiv ity and pyroclastic flows, has Cen ter (VAAC) (URL: http://www.jma.go.jp/JMA_HP/ largely filled the 1956 crater. jma/jma-eng/jma-center/vaac/; Email: [email protected]. In for ma tion Con tacts: KVERT and AVO (see go.jp). Karymsky).