Bul Le Tin of the Global Vol Can Ism Net Work

Bul letin of the Global Vol can ism Net work Vol ume 29, Num ber 11, November 2004

Andaman Islands (In dia) False reports of eruptions and confu sion fol lowing the M 9 earthquake ...... 2

Ijen (In do ne sia) News re port cites incre ased ac tivity be ginning on 17 June 2004 ...... 4

Soputan (In do ne sia) 12 Decem ber eruption cov ered villages with ash up to 2 cm thick ...... 4

Manam (Pa pua New Guinea) Vigor ous late-2004 eruptions cause 5 deaths and lead to large evac ua tions ...5

Erta Ale (Ethi o pia) On 4-5 Decem ber 2004 visi tors noted ac tive horni tos but solid i fied lava lake ...... 9

Cotopaxi (Ec ua dor) Seis mically quiet in Janu ary- April 2004; planning for emer gency water supplies .....9

Reventador (Ec ua dor) Late 2004 visits find re newed vent ing and thick intracaldera lava flows 2 km long ..10

Fuego (Gua te mala) Ex plo sions and lava flows con tin ued in No vem ber-De cem ber 2004 ...... 12

Dedi cate d to victi ms and survi vors of the 26 Decem ber 2004 earth quake and tsunami

As we go to press with this is sue of the Bul le tin our thoughts repeat edly turn to the victi ms and sur vivors of the disas trous 26 Decem ber M 9 earthquake and tsunam i. Al though a differ ent geologi c proces s than we discuss here, tsuna m is are someti mes asso ci ate d with volca nism . Converse ly, large earthquakes can trigger erupti ons. The world has much to learn about these and relat ed geologi c phenom ena and about how to gauge, discuss, and prepare for infre quent but poten ti ally devas tat ing events. We offer our condo lenc es and encour age m ent as we look towards a more inte grat ed, edu cat ed world.

Edi tors: Rick Wunderman, Ed ward Venzke, and Gari May berry Vol un teer Staff: Rob ert An drews, Jacquelyn Gluck, Wil liam Henoch, and Aditi Bhaskar

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/

Subscrip tions are provided by the Ameri can Geo physical Union (see the box on the last page for details). Data are prelimi nary and sub ject to change; contact the original source or the Global Volcan ism Program bef ore using. 2 Andaman Is lands Smithsonian Institution — Bulletin of the Global

Andaman Islands Indian Ocean, India 12.29°N, 93.88°E; sum mit elev. 305 m All times are lo cal (= UTC + 5 ½ hours)

False re ports of vol ca nism sur faced de scrib ing eruptions at Barren Island and Narcondum volca noes (figure 1) follow ing the 26 Decem ber 2004, M 9 earthquake off the W coast of north ern Su ma tra. Clar i fi ca tion was pro vided by Dornadula Chandrasekharam of the Indian Insti tute of Tech nol ogy. He re ported an ab sence of vol ca nic ac tiv ity at these volca noes, and at Su matran volca noes, as re cently as 4 Jan u ary 2005. The er ro ne ous ac counts were dis cov ered by Chandrasekharam while watching tele vision news. He im- medi ate ly contac ted people in the Andaman region. Upon learn ing that these repor ts were in cor rect, he con tacted me - dia sources and the Global Vol canism Network. Many In- dian news sources that procla imed erupti ons at Bar ren Is- land later withdrew their reports. The erro ne ous Figure 2. Map show ing the broad tec tonic setting on which Bar ren Island infor m ati on prevail ed for a day to perhaps a week, although and Narcondam volca noes re side. The map began with the main shock of non-Indian news agencie s were slower to recog nize and ac - the M 9 earthquake and the earthquakes that followed dur ing the next 11 knowledge the error. days. USGS prelim inary tabu la tions com puted the main shock as Mw 9.0 with a fo cus at 30 km depth.

Re gional tec tonic set ting. Fig ure 2 il lus trates the ru di ments of the re gional tec tonic set ting, includ ing the pri mary M 9 earthquake and aftershocks for the next 10 days. The tec tonic recon struc - tions are far more com plex than shown here, and the detai ls are var i ously in ter preted. In terms of lo cal time (in the Andaman Islands and India, i.e. In dia Stan dard Time), the epicen - ters shown oc curred dur ing the time inter val 06:28:53 on 26 De- cem ber to about 06:57 on 6 Janu - ary. (In terms of UTC, this repre - sents the inter val 00:58:53 on 25 Decem ber to about 19:57 on 5 Jan u ary 2004). This dig i tal map was extra cted by apply ing a video sim u la tion of epi cen ters with time (Jones and others, 2002) to the recent seis mic data. The figure shows two prom i- nent curving tectoni c fea tures cross ing both Java-Su ma tra and the Andaman Sea (the Nicobar and Andaman Islands re gion). One such curving feature is the volca nic front, on which lie all the acti ve volca noes of Java and Su- matra, and farther N, Barren Is- land and Narcondam. Outboard of Figure 1. A map of the Andaman Islands show ing the only volca noes known to have erupted dur ing the Ho locene period (past 10,000 years), Narcondum and Bar ren Island (N and B, respec tivel y). Note that narrow straits break that (to the W) is the second curv- Andaman island into multi ple smaller islands (eg., Middle Andaman and Baratang islands) . Baratang Island ing feature , the Sunda trench and contains an estab lishe d, studied, active mud volcano that reactivated af ter the M 9 earthquake. is lands ad ja cent to it (the Volcanism Network, Volume 29, Number 11, November 2004 Andaman Is lands 3

Andaman Islands, and islands to the W of northern Sum atra “He [also] said the mud volcano was locat ed on one side hard-hit by the M 9 earthquake and tsunam i). The trench re - of the Baratang Island, which was about 100 km from Port flects the sea-floor expres sion of the subduction zone, and Blair. People live on the other side, but there is no cause for repre sent s the region where the M 9 earthquake oc curred. con cern." The offset , often termed a ‘megathrust,’ involved 1,200 km A report in the In dia Daily was nearly iden tical. De tails of rupture along the subduction zone, and suddenly shifted on a Geolog i cal Survey of India website noted that the the Indian Ocean’s floor ~ 15 m towards Sum atra (Hopkin, Baratang mud volcano be gan erupt ing on 27 De cem ber 2005). 2003 (figure 3 and capti on). Mud vol canoes may have also Regard ing the M 9 earthquake, accord ing to the USGS, oc curred else where in the re gion, but the available news re - the lo cal time and date in terms of lo cal time in N Su matra ports con sis tently failed to dis close lo ca tions. at the epi center was Sunday, 26 De cem ber 2004 at 07:58:53 Of ten as so ci ated with ac tive faults and with pe tro leum (i.e., roughly 8 am). The USGS provided a table showing fields, mud volca noes on land consis t of low-ly ing surface the time of the main shock in a vari ety of time zones. mud extru sions that vary in size from meter s to several kilo - Some ex cel lent tu to ri als have pro vided back ground on the tectoni c setti ng, the earthquake, and the tsunam i. These have appeare d in the press and on the web (eg. Sieh, 2004, 2005; NOAA, http://www.noaa.gov/tsuna m is.html). Al- though large earthquakes may trigger vol canism (Linde and Sacks, 1998), so far this does not appear to be the case, at least at the volca noes of Barren Island and Narcondum. Mud vol ca noes and en su ing con fu sion. Post-earthquake re ports of acti ve ‘mud volca noes’ in the Andaman Is- lands caused panic and confu sion in the region, and came at a parti cu lar ly bad time. Chandrasekharam pointed out that in Andaman, like many other arc province s, several mud vol canoes are pres ent. These are not real vol canoes in the usual sense, but be cause they may build a small, low-profil e cone of local extent around the hole through which the mud is thrown out, they are known as mud volca noes (figure 3). Some of the dif fi culty with the news re ports was that the mud vol ca noes’ lo ca tions, num bers, and im pacts re mained vague, and that Bar ren Is land be came in ter twined with story. An ex treme exam ple came from an irre spon sible re - port in the tabloi d In dia Daily (2 Janu ary 2005), which con- tained the ti tle “Vol cano[es] Bar ren-1 and Narcondam erupt in Andaman—Seis mic dis tur bance can cause more tsunam i.” It con tin ued with wild claims such as, “Severe seis mic activ ities are seen in these is lands . . . per son nel who have reached these re mote ar eas are fac ing shatter ing earth vibra ti ons and high waves,” and “Some scien ti sts are predict ing se vere earthquake again in the North of Andaman Nicobar Is lands. The ef fect can be severe on Myanmar, Andaman, Indi[a]’s east coast, Ban gla desh and Su matra . . ..” They added, “Andaman’s tribals strangely are unaf fect ed as most of them somehow went [to] higher ground before the tsunam i. So did the ani m als.” Science jour nal ism clearly has a lot to compete with (see Oldenburg, 2005, for more discus sion of these topics ). One al leged mud volcano ‘Barren-1’ has a name so close to the vol cano’s name (Barren Is land) that it was fre - quently con fused. The mud volcano’s name (if there is one) ap pears to be ab sent from the tech ni cal liter ature at the Geo log i cal Sur vey of In dia’s website. On a posi ti ve note, one mud volcano re ceived consis tent menti on in a num ber of news arti cles and provided cover - Figure 3. A 2003 photo graph show ing about a quarter to one half of a mud age gener all y con gruent with geolog i cal data posted by the volcano on Baratang island (top) and its largest crater (~ 20 cm in diam eter , ~ 28 cm in depth) (bottom ). This site was known as a minor Geo log i cal Sur vey of In dia. Ac cord ing to an ar ti cle in In dia fissure prior to 1983; but in that year the largest out burst oc curred, chiefly News (with the leader, “Port Blair, 30 Decem ber”), “A mud emitting warm (~ 30°C) mud. Mud again began emerg ing in Febru ary volcano at the inhab it ed Baratang Island in Middle 2003. The dom inant fea ture was a sub-circu lar mound of mud, ~ 30 m in Andaman has erupted but the adm inis tra tion said there was di am eter with a height of ~ 2 m at the cen ter. Ob serv ers noted a col or less, sulfurous smelling gas. The mud containe d angu lar to sub-rounded rock no cause for concern. ‘Mud keeps bubbli ng in the volcano, fragm ents from under ly ing strata. No photos nor sim ilar ly de tailed but on De cem ber 28, the erupti on was up to three meter s tech ni cal reports have been received show ing al leged re cent ac tiv ity that and there was con sid er able heat,’ In spec tor Gen eral of Po - began 27 Decem ber 2004 (see text for news re port). All photos and data lice S. B. Deol said here.” courtesy of the Geo logi cal Survey of In dia, East ern Re gion. 4 Ijen Smithsonian Institution — Bulletin of the Global meters across. They emit mud at temper atures sig nif icantly In for ma tion Con tacts: Dornadula Chandrasekharam, be low magm atic, which are typ ically at least 800°C. Erup - Depart ment of Earth Sci ences, Indian Insti tute of Technol - tions from mud volca noes can reach heights of several hun - ogy, Bom bay 400076, India (URL: http://www.geos.iitb. dred meter s and consis t of mud, fluids and gases, and some- ac.in/dchandra/biexp/, Email: [email protected]); In dia times burn ing hy dro car bons. Al though in sub ma rine News (URL: http://news.newkerala.com/in dia-news/); In- en vi ron ments mud vol ca noes can be ex ten sive, deadly mud dia Daily (URL: http://www.indiadaily.com/); The Wash- vol cano erup tions are ex tremely rare be cause their erup- ing ton Post, Washing ton DC, USA (URL: http://www. tions sel dom move far enough to af fect large areas of the washingtonpost.com/); Geo log i cal Sur vey of In dia, 27 land surface . Their great est danger may be to curi ous on- Jawaharlal Nehru road, Kolkata (Calcutta) 700016, India. lookers who venture too close. Ref er ences. Jones, A., Siebert, L., Kimberly, P., and Luhr, J.F., 2002, Earthquakes and Erupti ons, v. 2.0 (CD-ROM): Smith so nian In sti tu tion, Global Vol ca nism Ijen Pro gram, Dig i tal In for ma tion Se ries, GVP-2. Hopkin, M., 2005, Tri ple slip of tectoni c plates caused east ern Java, In do ne sia seafloor surge: Nature , v. 433, no. 3 (06 Jan 2005). 8.058°S, 114.242°E; sum mit elev. 2,386 m Linde, A.T., and Sacks, I.S., 1998, Trigger ing of vol ca- All times are lo cal (= UTC + 7 hours) nic erupti ons: Na ture, v. 395, p. 888-890. Oldenburg, D., 2005, A sense of doom: Ani m al insti nct The Chief of the local Nati onal Park has been quoted as for di sas ter—Sci en tists in ves ti gate wild life’s pos si ble having re ported an increa se in acti vit y begin ning on 17 warn ing sys tems: The Wash ing ton Post (8 Janu ary 2005), June 2004. This re sulted in closing the area to visi tors. p. C1, C3 (URL: http://www.washingtonpost.com/). Reuters quotes him as having said “There have been sulfu - Sieh, K., 2004, The science behind the Aceh earth- ric rocks com ing out of the edge of the crater and the fluid quake: Caltech Me dia Re la tions (30 Decem ber 2004), in it (the crater lake) has turned from green to white and has (URL: http://pr.caltech.edu/me dia/Press_Re leases/ emitted hot foam. There are also increasing tremors.” PR12628.html). Back ground. The Ijen volcano com plex at the east ern Sieh, K., 2005, In Sum atra : Notes From a Geol o gist in end of Java consis ts of a group of small stratovolcanoes the Field: Caltech To day (1 Janu ary 2005; URL: http://to- construc ted within the large 20-km-wide Ijen (Kendeng) day.caltech.edu/to day/). caldera. The N cal dera wall forms a promi nent ar cu ate U.S. Na tional Earth quake In for ma tion Cen ter (NEIC) ridge, but else where the caldera rim is buried by post-cal- (URL: http://earthquake.us gs.gov)./ dera vol canoes, includ ing Gunung Merapi stratovolcano, U.S. Na tional Oce anic and At mo spheric Ad min is tra tion which forms the 2,799-m-high point of the Ijen com plex. (NOAA) (URL: http://www.noaa.gov/tsu na mis.html). Im medi ate ly W of Gunung Merapi is the renowned histor i - Back ground. Barren Island, a posses sion of India in the cally active Kawah Ijen vol cano, which con tains a nearly Andaman Sea about 135 km NE of Port Blair in the 1-km-wide, turquoise -col ored, acid crater lake. Pictur esque Andaman Islands , is the only histor i cal ly acti ve volcano Kawah Ijen is the world’s largest highly acidic lake and is along the N-S-trending volca nic arc extend ing betwee n Su- the site of a la bor-in ten sive sul fur min ing op er a tion in matra and Burma (Myanmar). The 354-m-high island is the which sul fur-laden bas kets are hand-car ried from the crater emergent sum mit of a vol cano that rises from a depth of floor. Many other post-caldera cones and crat ers are lo cated about 2,250 m. The small, unin hab it ed 3-km-wide island within the caldera or along its rim. The largest concen tra - contai ns a roughly 2-km-wide cal dera with walls 250-350 tion of post-caldera cones forms an E- to W-trending zone m high. The caldera, which is open to the sea on the W, was across the southern side of the caldera. Coffee planta ti ons create d during a major explo sive erupti on in the late Pleis- cover much of the Ijen caldera floor, and tourist s are drawn tocene that produced pyroclastic-flow and -surge de posit s. to its waterfalls, hot springs, and dramatic volcanic scenery. The morphol ogy of a fresh pyroclastic cone that was con- In for ma tion Con tact: Reuters News Ser vice. structed in the center of the cal dera has varied dur ing the course of histor i cal erupti ons. Lava flows fill much of the caldera floor and have reached the sea along the west ern coast during erupti ons in the 19th century and more re- Soputan cently in 1991 and 1995. Narcondum volcano, an island pos session of India in Sulawesi, Indo ne si a the Andaman Sea, is part of a vol canic arc that con tin ues 1.11°N, 124.73°E; sum mit elev. 1,784 m northward from Sum atra to Burma (Myanmar). The small 3 All times are lo cal (= UTC + 8 hours) x 4 km wide coni cal island, locat ed about 130 km east of North Andaman Island, rises to 710 m, but its base lies an Soputan erupted again on 12 De cem ber 2004. The Di- addi ti onal 1,000 m beneat h the sea. The is land is densely rec tor ate of Vol ca nol ogy and Geo log i cal Haz ard Mit i ga tion vege tat ed, bounded by cliffs on the southern side, and (DVGHM) noted that an erupti on on 18 Octo ber 2004 sent capped by three peaks. No evi dence of histor i cal volca nism a cloud ~ 600 meter s above the crater. The previ ous erup- is present, although the sum mit region is less densely vege - tive epi sode oc curred dur ing July and August 2003 (Bul le - tated and vol canism at the andesitic vol cano is consid ered tin v. 28, nos. 8, 10, and 11). A sum mary of ash plumes to have conti nued into the Holo cene . The island’ s name from mid-2003 through 12 Decem ber 2004 appears in table means “pit of hell,” although the name could have been 1. Large dis crep an cies ap peared in re ported ash column mis tak enly trans ferred from the his tor i cally ac tive Bar ren heights; with the sat el lite es timates about 10 times larger Island vol cano, 140 km to the SSW. than ground-based estimates. Volcanism Network, Volume 29, Number 11, November 2004 Manam 5

a prom inent NE-flank vent that formed in 1906 and was the Date Height (km) (comment) Source source of inter mit tent major lava flows until 1924. In for ma tion Con tacts: Di rec tor ate of Vol ca nol ogy and 18 Jul 2003 ~ 2 km above sum mit DVGHM Geo log i cal Haz ard Mit i ga tion, Jalan Diponegoro 57, 02 Sep 2003 ~ 2 km altitude Dar win VAAC Bandung 40122, Indo ne sia (Email: [email protected]; 04 Sep 2003 ~ 3 km altitude (extend ing Sat el lite im ag ery, ~ 75 km N of the sum mit) Dar win VAAC URL: http://www.vsi.esdm.go.id/); Dar win Vol ca nic Ash 18 Oct 2004 ~ 600 m above sum mit DVGHM Ad vi sory Cen tre, Aus tra lian Bu reau of Me te o rol ogy (URL: 12 Dec 2004 ~ 1 km above sum mit DVGHM http://www.bom.gov.au/info/vaac); The Daily Reform Voice; Komentar; Thomas Dobat, Lorong Jerman, 12 Dec 2004 ~ 10.7 km altitude Dar win VAAC Kauditan II, 95372, Sulawesi Utara, Indo ne sia . Table 1. Reporte d ash plume alti tudes recorde d from Soputan, 18 July 2003-12 De cem ber 2004. Courtesy of DVGHM and Darwin VAAC.

The ear liest de tails men tioned by DVGHM re gard ing Manam the 2004 acti vit y discusse d 11 Decem ber 2004, a time when the tremor tended to rise, at taining peak-to-peak am pli tudes Papua New Guinea, Northeast of New Guinea of 0.5-3.0 mm. Observ ers also saw incan des cenc e at the 4.10°S, 145.061°E; sum mit elev. 1,807 m crater’s rim. All times are lo cal (= UTC - 10 hours) At 0046 on 12 De cem ber tremor again regis ter ed with maxi m um peak-to-peak am pli tudes of ~ 45 mm. At 0050 on Several peri ods of erupti on took place on the island of 12 Decem ber Soputan erupted, sending an ash cloud up to 1 Manam during the last months of 2004. Rabaul Vol cano km. This was followe d by discharge of a “hot cloud” Ob ser va tory (RVO) noted out bursts dur ing 24-31 Oc to ber (pyroclastic flow ?) to a distanc e of ~ 200 m E (from (Bul le tin v. 29, no. 10), 10-12 Novem ber, and on 6 Decem - ‘Aeseput,’ a prom inent NE-flank vent that formed in 1906). ber. Sev eral other plumes were noted as well. Sat el- A lava flow spread W and S of Soputan. Observ ers could lite-based alerts (MODVOLC) were notewor thy during this hear rum bling noise and thunder from their moni tor ing sta- inter val, having been absent for over 9 months. tion ~ 11 km from the crater. On 6 De cem ber, the news pa per The Nati onal reporte d White-to-gray ash went E. At 0130 on 12 Decem ber a that these erupti ons had killed five people, whose deaths problem arose with the seis mic sensors, perhaps be cause were pri mar ily re lated to re spi ra tory com pli ca tions from in - the solar panel was covered with ash. By 0600 the sensor hal ing vol ca nic ma te rial. Vol ca nic ash dam aged crops, wa - was down. At 0500 that day a hot cloud occurred with a run ter suppli es, and houses. News accounts discusse d evac ua - out distanc e of ~ 150 m and a height of 200 m. Acti vit y per - tions, with the pos si bil ity of evac u at ing all or most of the sisted unti l 1030. Soputan’s sum mit then be came visu all y island (figure 4). The news also menti oned food shortages obscure d by clouds, but observ ers could still make out a after the 24 October eruption. white thin-to-medium plume to 70-80 m above the crater, The govern m ent of Papua New Guinea pre sented a new and incandescence. website, The Na tional Di sas ter Cen ter, which broadly dis- On the 13 Decem ber at 1752 observ ers felt an earth- sem i nates gov ern ment di sas ter in for ma tion in clud ing vol- quake with a magni tude of MM I-II. The seism ograph was cano re ports and update s (see URL under Infor m ati on Con- then still in op er a ble. News reports. A 13 Decem ber news report in The Daily Re form Voice stated that hundreds of hectares of paddy-fields and other agri cul tura l land to the W of the Soputan was seri ously im pacted by tephra. Thomas Dobat, a Germ an expatriat living in Indo ne sia and concerne d about the situ a ti on, sent Bul le tin ed i tors a transla ti on of a 13 Decem ber 2004 arti cle on Soputan taken from the In do ne sian Jour nal Komentar. Simi lar to the above re port, it also noted that hundreds of village s in 13 dis tricts in Cen tral Minahasa and in South Minahasa suf- fered from tephra fall emit ted on 11-12 Decem ber. These erupti ons of Soputan were accom panied by heavy thunder and lightning, which were heard in the town of Amurang. Ash fell in nearly all of Cen tral Minahasa and in parts of South Minahasa. The re sult was that in all ar eas of Cen tral Minahasa, es pecia lly in the town of Tondano, houses, rice-fields, and roads were ash-covered up to 2 cm thick. Back ground. The small Soputan stratovolcano on the Figure 4. Geog ra phy of the area around Manam showing two named southern rim of the Quater nary Tondano caldera on the villages on the is land and num erous settle m ents on the main is land of New northern arm of Sulawesi Island is one of Sulawesi’s most Guinea. For scale, Manam Island is ~ 10 km in diam eter . The volcano is acti ve volca noes. The youthful, largely unvegetated vol- sometim es re ferred to as Mount Iabu in the regional press. The city of Wewak lies off the map, ~ 160 km W of Manam; the city of Madang lies cano rises to 1784 m and is locat ed SW of Sempu volcano. ~ 150 km to the E. The large mean der ing river at left is the Sepik. The It was construc ted at the southern end of a SSW-NNE island’ s res idents, a total of 9,467 people, rely on subsis tence farm ing and trending line of vents. During histor i cal time the locus of fishing for food, and copra and cocoa as a source of incom e. Map cour tesy erupti ons has include d both the sum mit crater and Aeseput, of Jorgen Aabech. 6 Manam Smithsonian Institution — Bulletin of the Global tacts, be low). The website con tained a Manam hazards lages. As of 2130 on 10 Novem ber ash reached 7 km alti - map. Other docu m ents on that site noted shift ing winds and tude and 147 km to the SW. As of 12 Novem ber, the ash the lack of a clearly safe area on the is land dur ing the late emissions reached 10 km alti tude and extende d laterally 74 2004 cri sis. It said that the govern m ent would sponsor km W to NW of the volcano. large-scale evac ua ti ons beginning on 27 November 2004. During this re porting inter val Darwin VAAC noted that The erupti ve episode that be gan on 24 Octo ber conti n- a SE-drift ing plume was vis i ble on sat el lite imag ery on 31 ued at least a week (figure 5). By 31 Oc tober, the erupti on Octo ber during 0813-1449 at an alti tude of ~ 13.7 km. at Main Crater con sisted of Strombolian ac tiv ity, with ash and scoria emissions . Tephra of ~ 1 cm di am e ter were de pos ited in Warisi village on the SE side of the is land. Small pyroclastic flows were gen er ated, and fresh lava flowed into the NE radial val ley. The lava flow fol lowed the Boakure side of the valley , cover ing older flows from the 1992-1994 erup tion. Be gin ning on the morning of the 31st, the amount of con tin u ous vol ca nic tremor increa sed to moder - ate-to-high levels , so the Alert Level was in creased from Stage 1 to Stage 2. Vil lag ers were ad vised to re main away from Manam’s four main radial valleys. The Dar win Vol ca nic Ash Ad vi sory Cen ter re ported the 24 Oc to ber out burst (Bul le tin v. 29, no. 11). On 31 Octo ber during 0813-1449 they noted a plume at ~ 13.7 km alti tude drift ing SE on Figure 5. Im age of Manam and vicin ity acquire d on 24 Octo ber 2004 by the Mod erate Reso lu tion Im aging vis i ble sat el lite im ag ery. The Avi - Spectroradiometer (MODIS), an instru ment on the Terra satel lite of the Na tional Aero nau tics and Space a tion Color Code was at Red, the Adm inis tra tion (NASA). Dark ash ris ing from Manam drifted NW along and then away from the N coast of the high est level. main is land, New Guinea. Cour tesy NASA Earth Ob ser va tory. Accord ing to a news report, “. . . [~ 0.3 m] of ash with hot pum - ice” landed on the roofs of houses, and ash drifted as far W as Wewak, ~ 100 km away. Re- portedly , ~ 4,000 villag ers moved to safer areas. On 2 Novem ber around 2325 a possi ble erupti on may have produced a plume to ~ 7.6 km alti - tude, which drifted SE. Ash was vis i ble on sat el lite im ag ery on 8 and 9 Novem ber at an al ti tude of ~ 3 km; on 9 Novem ber the plume extende d, ~ 55 km to the NE. A Strombolian erupti on occurred dur ing 10-11 Novem ber 2004. The ash col umn from the erupti on was esti mated to have risen ~ 5-6 km above the crater, and perhaps rose as high as ~ 9 km above the crater, ac cord ing to an Air Niugini pi lot. The ac tiv ity was ac com pa nied by con tin u ous weak to moder ate roaring and rum bling noises and fre quent loud Fig ure 6. Manam im age ac quired 15 No vem ber 2004 from Mod er ate Res o lu tion Im ag ing Spectroradiometer explo sions . Light ash and scoria (MODIS) pass ing over head on the Na tional Avi ation and Space Agency (NASA) Terra satel lite. Dark ash rises fall was re ported near lo cal vil- from Manam and drifts SW over New Guinea. Cour tesy NASA Earth Ob ser va tory. Volcanism Network, Volume 29, Number 11, November 2004 Manam 7

A sat el lite im age from the Terra Mod er ate Res o lu tion sco ria fell at the vil lages Abaria and Bokure 1. Fluc tu at ing Im aging Spectroradiometer (MODIS) on 15 Novem ber audi ble noises consis ted of low roars, ‘jet engine’ roars, and shows a large brown ash plume blowing SW (figure 6). oc ca sional still-louder roars. Al though vis i bil ity was gen er- Accord ing to RVO scien ti sts, on 23-24 Novem ber Main ally poor due to vol canic ash clouds from both craters, Crater ejected glowing lava and discharge d an ash cloud observers could still make out variable glow coming from that rose ~ 10 km high. A lava flow was also re ported to be the craters. heading for two vil lages on the island. At 1850 on 23 No- On 8 Decem ber 2004, The Nati onal re ported that, ac- vem ber, a phase of strong Strombolian erupti on began pro- cording to RVO, Manam erupted start ing on the morning of ducing a conti nu ous, thick ash colum n that rose about 10 6 Decem ber. Fist-sized scoria were thrown out of the vent km above the sum mit. The ash cloud emissions were ac- into the air, hitti ng houses in the village s below. The erup- com panied by projec ti on of glowing lava fragm ents, loud tion began at 0800 and peaked at 1150 with “seism icit y roaring and rum bling noises, and oc casiona l loud and bang- continuing.” ing noises that produced shock waves. A conti nu ous bright The Nati onal also reporte d that a pyroclastic flow oc- red glow visi ble down the NE val ley indicated curred in the SE val ley during the 6 Decem ber erupti on, emplacement of a lava flow. with ash and cloud di rected NW. On the 6th, res i dents of The lava flow was re ported heading NE towards vil- Madang (~ 150 km E of Manam) descri bed feeling tremor lages of Kolang and Bokure 1. In addi ti on to the lava, or ground moti on; those in Wewak (~ 160 km to the W) re- Manam emitted large rocks. Around this time the avi a tion ported sim i lar sen sa tions and also noted vol ca ni cally dered alert is sued for air craft noted that the ash plume ex- rived dust. Although ash from 6 Decem ber was appar entl y tended 130 km SE of Manam. widesprea d, Googling for news of Manam ash in Irian Jaya Press ac counts stated that emergency of fi cials said an failed to turn up any reports from there. area was be ing cleared on the mainland for a possi ble The Darwin VAAC reporte d ash plume sightings from full-scale evacu a ti on of Manam’s ~ 9,500 island ers. Evacu - sat elli tes during 12-14 De cem ber, and the RVO reporte d a tion was to be come com pul sory if ac tiv ity in ten si fied from mod er ate erup tions con tin u ing in that period. Stage 3 (which was set by 22 Novem ber) to Stage 4. Some Fa tal i ties. An ar ticle by Bon ney Bonsella in The Na- 20 bush homes had collaps ed due to ‘mud rain’ (presum - tional showed picture s of Manam Island ers in evac ua ti on. ably, falling tephra), and five people had been injured. They waded through shal low surf to board through the RVO re ported that a slight in crease in erup tive ac tiv ity open bow of a large beached landing craft. The arti cle dis- from Main Crater began after 1600 on 26 Novem ber, which cussed fa tal i ties dur ing the eruption. conti nued unti l 0800 on the 29th. Summit ac tiv ity con sisted “The volca nic erupti on on Manam Island in the Madang of conti nu ous force ful emission of thick dark gray ash province has so far claimed five lives–two el derly women clouds that rose less than 1 km above the sum mit before be- and three chil dren betwee n the ages of 5-13. The coor di na - ing blown NW. Fine ashfall to the NW at Zogari and Iassa tor of the Manam evac ua ti on exer cis e Camillus Dugumi vil lages was reporte d from about 1700. A single weak roar confirm ed the deaths, adding that the deaths were linked to was heard betwee n 0600 and 0700 on the 27th. re spi ra tory com pli ca tions re sult ing from in hal ing vol ca nic Seism icit y was moder ate to moder ate -high at 2300 on ashes and dust. Mr Dugumi, who is also the distri ct health the 26th and 0800 on the 27th. Vol ca nic trem ors con tin ued programme manager, said one of the deaths was that of an to be recorded suggest ing the system rem ained dynam ic elderl y women from Bokure vil lage recorded early last and ca pable of ongo ing variable erupti ons, with sporadi c week at the Bogia Dis trict hos pi tal. The women died af ter more vigorous phases. be ing ad mit ted to the hos pi tal for re spi ra tory com pli ca tions. On 28-29 Novem ber, RVO reporte d that ash clouds One child, a littl e boy, died on Friday at the Asuramba care were rising less than 1 km above the sum mit before being centre after suffering pneumonia.” blown by the shift ing NNE and NNW winds. Fine ashfall “Three others–a n adult women and two other chil- was re ported at Warisi. Weak roar ing noises were heard be - dren–had died during earli er vol canic acti vit y on Manam.” tween 1900-2400 on the 28th. A weak glow with weak pro- Dis placed res i dents. The above-men tioned ar ticle re- jec tions of in can des cent lava frag ments was vis i ble dur ing lated that three State-owned plan tations (called Asuramba, the night of the 28th, and South ern Crater re leased thin Potsdam, and Magem (and Daigul?)) were set aside, “. . . at white vapor only. least for the time be ing[,] to accom m o date a speedy re set- Some press reports de scribed 7,900 per sons evacu ate d tlem ent of the displac ed Manam island ers.” Another news from Manam. Accord ing to the Planet Di ary web site, ar ticle noted that these plan tations are near the town of about 9,000 people were evacu ate d by 1 De cem ber 2004 as Bogia (figure 4). The Na tional Di sas ter Cen ter website the erupti on grew more violent. noted that “The three planta ti ons were bought off from the Mid-after noon on 5 Decem ber RVO noted a slight les see in 1995 for K1.25 mil lion follow ing a Nati onal Exec - change in ac tivit y at Southern Crater marked by com- u tive Coun cil de ci sion for the pur pose of re set tle ment of mence ment of sub-con tin u ous weak to mod er ate roar ing Manam Is land ers dis placed by vol ca nic ac tiv ity.” Con tro- and rum bling noises. The noises conti nued unti l 1000 that ver sies re main with re spect to land is sues. Still , that day. As darkness fell, inter vals of visi bil ity occurred (eg., website noted that the long-term solu ti on advo cat ed by the during 1800-1808, 2030-2108, and 2130-2200); observ ers Pres ident, Manam Lo cal Level Gov ern ment is to re settle saw sub-conti nu ous lava fountaining. Meanwhil e, from the people of Manam on the mainland. For this purpose the Main Crater there came a series of sub-con tin u ous, force- Pro vin cial Di sas ter Committee has identified State land to ful, moder ate ly thick, gray-brown ash-laden clouds, which resettle the Manam Island people. were occa sion ally visi ble above the weather clouds. The MODVOLC. The MODIS infra red instru m ent flown on ash plume rose betwee n about 600 and 900 m above the the NASA Terra and Aqua sat ellites showed an impres sive sum mit and drifted to the E and NE. Light ashfall and fine set of therm al alerts be ginning 21 Oc tober 2004 (figure 7). 8 Manam Smithsonian Institution — Bulletin of the Global

Since the begin ning of MODVOLC oper a ti ons (Bul le tin v. small satellitic cen ters are lo cated near the island’s shore- 28, no. 1) therm al alerts oc curred at Manam during only line on the northern, southern and western sides. Two two pe riods. The first, 7 April-21 May 2002, was relat ed to summ it craters are pres ent; both are ac tive, al though most in creased Strombolian ac tiv ity (Bul le tin v. 27, no. 5). The his tor i cal erup tions have orig i nated from the south ern sec ond period, 21 Oc tober unti l at least 14 De cem ber 2004, crater, concen tra ting erupti ve products during the past cen - was as so ciated with the cur rent cri sis and was a time when tury into the SE ava lanc he val ley. Frequent histor i cal erup- alert ra tios and summed radiances reached higher val ues tions have been re corded at Manam since 1616. A major than dur ing the first pe riod. These param eter s are consis tent erupti on in 1919 produced pyroclastic flows that reached with a highly ac tive vent and/or lava flows, and in accord the coast, and in 1957-58 pyroclastic flows desce nded all with vigor ous Strombolian emissions seen in the field. four radial valleys. Lava flows reached the sea in 1946-47 This anal ysis of MODIS ther mal alerts (us ing the and 1958. MODVOLC alert-detec tion algo rit hm) is based on data ex - In for ma tion Con tacts: Rabaul Vol cano Ob ser va tory tracted from the MODIS Therm al Alerts website main- (RVO), P.O. Box 386, Rabaul, Pa pua New Guinea; Na- tained by the Univer sit y of Hawaii HIGP MODIS Therm al tional Di sas ter Centre, De part ment of Pro vin cial Af fairs Alerts team. and Local Level Govern m ent (Minis try of Inter-Govern - Thermal alerts are based on an ‘alert ra tio,’ and an alert ment Rela ti ons), PO Box 4970, Boroko, Na tional Capi tal is triggered whenever this ra tio has a value more posi ti ve Dis trict, Pa pua New Guinea (URL: http://www.pngndc. than -0.8. This threshold value was chosen em piri cal ly by gov.pg/); Da vid Innes, Flight Safety Of fice, Air Niugini in spec tion of im ages con tain ing known vol ca nic sites at (Email: [email protected] or deejayinnes@yahoo. high tem pera ture , and is the most nega ti ve value that avoids com); An drew Tupper, Dar win Vol ca nic Ash Ad vi sory nu mer ous false alarms. There are also some day-time alerts, Cen tre, Aus tra lian Bu reau of Me te o rol ogy (URL: http:// which are based on the same al gorit hm but incor po rat ing a www.bom.gov.au/info/vaac); Jorgen Aabech, Skogbrynet cor rec tion for es tim ated so lar re flec tion and a more strin- 40B, N-1709 Sarpsborg, Norway (Email: Jorgen. gent threshold whereby the alert ra tio is re quired to be more [email protected]; URL: http:// www.vulkaner.no); posi ti ve than -0.6 in order to trigger an alert. MODIS Ther mal Alert Sys tem, Ha waii In sti tute of Geo- Back ground. The 10-km-wide island of Manam, ly ing physics and Plane tol ogy (HIGP), School of Ocean and 13 km off the northern coast of the mainland Papua New Earth Sci ence and Technol ogy, Uni versit y of Ha waii at Guinea, is one of the country ’s most acti ve volca noes. Four Manoa (URL: http://www.modis.higp.ha waii.edu); Da vid large radial valley s extend from the unvegetated sum mit of Rothery and Charlot te Saunders, De part ment of Earth Sci - the coni cal 1,807-m-high ba saltic-andesitic stratovolcano ences, The Open Uni versit y, Mil ton Keynes, MK7 6AA, to its lower flanks. These “av alanche val leys,” reg u larly United Kingdom (Email: [email protected]); Kevin spaced 90 de grees apart, chan nel lava flows and pyroclastic Pamba and Bon ney Bonsella, The Na tional (URL: http:// av alanches that have sometim es reached the coast. Five www.thenational.com.pg/1206/).

Fig ure 7. MODVOLC therm al alert ratios, num ber of alert pix els, and summed 4 mm radi ance plots for Manam from 1 Janu ary 2001 until 31 Decem ber 2004. Alerts occurr ed only betwee n 7 April and 21 May 2002 and betwee n 21 Octo ber and 14 Decem ber 2004. Ther mal alerts collate d by Charlotte Saunders, and Da vid Rothery; data cour tesy of the Ha waii In sti tute of Geo phys ics and Plan etol ogy’s MODIS ther mal alert team. Volcanism Network, Volume 29, Number 11, November 2004 Cotopaxi 9

Erta Ale Ethi o pia 13.60°N, 40.67°E; sum mit elev. 613 m

Two teams sent reports on Erta Ale’s behav ior in De- cem ber 2004. On 1-5 De cem ber the vis it ing team include d Jacques-Marie Bardintzeff and a group from Ushuaia Na- ture, and on 4-5 De cem ber the team consis ted of the vol ca- nology travel group SVE-SVG. Both groups subm it ted sim ilar reports and com mented on substa nti al changes they observe d com pared to condi ti ons descri bed in past re ports (most recently, Bul le tin v. 29, no. 8). Al though Erta Ale fre- quently con tains a lava lake with an open surface of molten lava, that was not the case this time. The lava lake’s sur face had chilled within the small Fig ure 9. The S pit crater at Erta Ale as seen from the W on 5 De cem ber (~ 200-m-diam eter) S pit crater (fig ure 8). A solid i fied lava 2004, with the 4 hor nitos in the center of the photo. Two horni tos on the crust cov ered the crater floor. The crust’s sur face sat ~ 15 m left emit ted high tem per a ture SO2. The horni to in the right foreground be low the W crater rim, and ~ 30 m be low the E crater rim. containe d molten lava (which was sam pled). Photo provided by J. M. On top of this crust stood four coale sced horni tos in the SE Bardintzeff. part of the S crater (figure 9). They were ~ 10 m high and repre sent ed the only porti on of the crust where molten ma- teria l was in evi dence . Two horni tos emit ted high tem pera - 50-km-wide volcano rises more than 600 m from below sea ture (more than 500°C) SO2-rich gas. Another horni to con- level in the barren Danakil depres sion. Erta Ale is the tained glow ing molten lava. Dur ing the night of 4 namesake and most prom inent feature of the Erta Ale Decem ber the SVE-SVG group saw degas sing and incan - range. The 613-m-high vol cano contai ns a 0.7 x 1.6 km, el - descent lava at the sum mit of two of these horni tos. lip tical summit crater hous ing steep-sided pit crat ers. An- Bardintzeff descri bed sam pling molten mate ria l from 12 m other larger 1.8 x 3.1 km wide depres sion elongate d paral lel depth, in one of the hor nitos using a cable and an iron mass to the trend of the Erta Ale range is locat ed to the SE of the (fig ure 9). sum mit and is bounded by curvilinear fault scarps on the SE The SVE-SVG team noted re cent ac tiv ity within the side. Fresh-looking basal tic lava flows from these fissures North crater, where an up lifted area termed a ‘lava bulge’ have poured into the caldera and local ly overflowe d its rim. had soli di fie d. It covered ~ 80% of the crater floor and rose The sum mit cal dera is renowned for one, or someti mes two to about 20-25 m below the crater rim. In the lava bulge’s long-term lava lakes that have been active since at least centra l area, strong and noisy degas sing of SO2 spouted 1967, or possi bly since 1906. Recent fissure erupti ons have from several small horni tos. At the bulge’s periph ery the occurred on the northern flank of Erta Ale. ob serv ers saw ten small in can des cent vents. Sub se quently, In for ma tion Con tacts: Jacques-Ma rie Bardintzeff, two plumes rose above the volcano. Laboratoire de Pétrographie-Volcanologie, Bât. 504, Back ground. Erta Ale is an iso lated ba saltic shield vol - Université Paris-Sud, F-91405, Orsay, France (Email: cano that is the most acti ve volcano in Ethi opia. The broad, [email protected], URL: http://www.lave-volcans. com/bardintzeff.html); Henry Gaudru, Société Volcanologique Européenne (SVE), C.P.1-1211 Geneva 17- Swit zerland (Email: [email protected]; URL: http://www.sveurop.org/).

Cotopaxi Ec ua dor 0.677°S, 78.436°W; sum mit elev. 5,911 m All times are lo cal (= UTC - 5 hours)

Seism icit y at Cotopaxi dur ing De cem ber 2003 through De cem ber 2004 yielded av er ages that gen er ally re mained within norm al levels (ta ble 2). Steam emissions conti nued, and sul furous odors were occa sion all y re ported. A plot of total seism icit y each week during 2001-July 2004 portra yed num erous peaks and valley s in the range 50-200 events per Fig ure 8. The small S pit crater at Erta Ale as viewed from the E on 5 week. Occa siona l excur sions took the weekly total s to sev- Decem ber 2004. Horni tos had grown on the W part of the crater floor; except for these windows into the molten mate ria l at depth, the rest of the eral hundred events in late 2001 and early 2002 (peaking at lava lake sur face had com pletely so lidi fied. Photo provided by J. M. over 700 events per week during mid-Oc tober 2001). The Bardintzeff. 2004 data lacked such dramatic excursions. 10 Reventador Smithsonian Institution — Bulletin of the Global

Year Vol cano-tec tonic Hy brid Long-pe riod Tornillo Tremor To tal

2001 3.1 1.0 10.2 0.1 0.2 11.3 2002 2.9 3.0 14.6 0.1 0.4 18.2 2003 1.2 3.7 9.3 0.0 1.4 14.2 2004 0.41 3.59 11.10 0.0 1.56 15.11

Table 2. Annual sum marie s showing typi cal daily aver ages of vari ous kinds of seism icity at Cotopaxi dur ing 2001-2004. Courtesy of IG (shown on their website in the Janu ary 2005 report).

Plan ning for emergenc y water suppli es. Although seis- Politécnica Nacional, Apartado 17-01-2759, Quito, Ecua - mic ity and other mon i tored pa ram e ters were mod er ate to dor (URL: http://www.igepn.edu.ec/). low during most of 2003 (Bul le tin v. 28, nos.11 and 12), local author i ti es worked on a conti ngency plan for emergency drinking wa ter in the event of a crisis at Cotopaxi. The Quito met ro pol i tan san i ta tion and drink ing wa ter Reventador com pany (EMAAP-Q) prepared a conti ngency plan for res- idents around Cotopaxi. The challenge was to provide for Ec ua dor suf fi cient amounts of po ta ble and san i ta tion wa ter for some 0.078°S, 77.656°W, sum mit elev. 3,562 m half a mil lion people in the event of an erupti on that con- All times are lo cal (= UTC - 5 hours) tam i nates their nor mal wa ter sup plies. This con tin gency plan was drawn up using expe ri ence gained from the oper a - A 16 Decem ber 2004 report from the Instituto tional emergency plan used to recover from the erupti on in Geofisico (IG) of the Escuela Politecnica Nacional calls at - 1998-99 and the Reventador eruption in 2002. tenti on to re newed lava effu sion from the crater that lies During the Guagua Pichincha erupti on, pyroclastic ma- within Reventador’s large sum mit cone (figure 10). A te rial impacte d Quito, and ash fell into the wa ter treat ment block-lava flow es caped the cone’s crater. It ran out at a plants and threat ened the water supply sys tems. EMAAP-Q breach in the S wall, and by 16 Decem ber it had advance d devel oped an oper a ti onal and emergency plan. The plan ~ 2 km farther . The flow advance d SE along a narrow, was tested in 1999 when the volcano had two major erup- E-curving path, rem aining atop lavas from 2002. Thus far tions that heat dropped ash on Quito and its infrastructure. in 2004, lava flows rem ained well within the larger caldera. Back ground. Sym met ri cal, gla cier-clad Cotopaxi stratovolcano is Ecua dor’s most well-known volcano and one of its most ac tive. The steep-sided cone is capped by nested sum mit crat ers, the larg est of which is about 550 x 800 m in di am eter . Deep valleys scoured by lahars ra di ate from the summit of the andesitic vol cano, and large andesitic lava flows ex tend as far as the base of Cotopaxi. The modern coni cal volcano has been con- structed since a major ed ifice col - lapse someti me prior to about 5,000 years ago. Pyroclastic flows (of ten con fused in his tor i cal accounts with lava flows) have accom pa nied many ex plo sive eruptions of Cotopaxi, and lahars have fre quently dev as tated ad ja cent val leys. The most vi o lent his tor i- cal erupti ons took place in 1744, 1768, and 1877. Pyroclastic flows desce nded all sides of the volcano in 1877, and lahars travele d more Figure 10. An aeria l photo of Reventador’s 4-km-diam eter caldera as a base for mapping the lava flows of 2002 than 100 km into the Pacif ic and those of 2004 through mid-Decem ber. The 2002 flows are labeled Lava 1 and Lava 2. The 2004 lava flow Ocean and west ern Am azon ba- followed and partly covere d Lava 1. At a distance of ~ 1 km from the vent, the 2004 lava flow bifur cate d into two sin. The last significant eruption closely spaced paral lel lobes. The cal dera has an E-tilting floor, is open on its E side, and contains a prom inent of Cotopaxi took place in 1904. cone on its W side. The cone forms the vol cano’s sum mit, and contains an elongate crater that hosts the 2004 vent (“ac tive vent”). The crater has a rim that is in di cated by a solid curv ing line; the crater’s in ward-slop ing walls are In for ma tion Con tact: Geo- indi cate d by light shading and lines re sem bling the trends of gullies . The cone’s floor at its southern breach lies at phys i cal In sti tute (IG), Escuela ~ 3,200 m ele va tion. The aeria l photo was taken by Instituto Geográfico Militar in 1983. Figure courtesy of IG. Volcanism Network, Volume 29, Number 11, November 2004 Reventador 11

Reports in 2003 chiefly discusse d events outside the cal dera. A road, one gas pipeli ne, and two oil pipeli nes tra- verse Reventador’s flanks 7 km ESE of the ac tive vent. All of these insta lla ti ons were affect ed in 2003 (but not appre - cia bly since then). The pipeli nes were destroy ed due to heavy lahars com ing down the Reventador river on 6 May 2003 (Bul le tin v. 28, no. 6). Our last report (Bul le tin v. 28, no. 11) dis cussed events during July through most of November 2003. Lava venting in the crater likely began in early Novem - ber 2004, a time when seis mic stati on CONE regis ter ed dra matic increases in vol cano-tectonic events (fig ure 11). In respon se to the el evated seis micity, the IG-EPN be gan more in ten sive mon i tor ing, in clud ing over flights with ther - mal im aging, re peat visit s to the rem ote vol cano, and on 9 Novem ber 2004, inst all ati on of the addi t ional short-period seism ic stati on LAV3, ~ 2 km from the crater’s vent. Figure 12. Reventador’s 2004 lava flow/dome as seen on 28 Novem ber A heli copter overfli ght by IG-EPN staff on 10 Novem - 2004. The photo was taken looking W and downwar d from the cone’s ber 2004 confirm ed the presence of a small lava dome, east ern crater rim (see van tage point in di cated by the star on fig ure 11). which appeare d then to be confine d to the crater floor. This Courtesy of IG. feature was not present on photos taken during an IG over- flight on 19 Oc tober 2004. During the 10 Novem ber over- southern breach and into the surround ing caldera. Becaus e flight, a conti nu ous 2.5 km-high gas col umn escape d from of cloudy weather, the exact extent of the flow re mained in- the crater, accom panied by sulfu rous odors de tected by de ter minate. The sur face of this lava flow also ex tended to personnel in the helicopter. the N and reached a level ~ 20 m below the northern The date when lava began es cap ing the crater was not breach. Conti nu ous lava extru sion or flowing or both were precis ely known, but it was thought to have been around 22 heard within the crater, making sounds akin to glass break - No vem ber, co in ci dent with the emer gence of dis tinct seis- ing, and vigor ous roaring gas emissions origi nate d from the mic signals not pre viously observe d at Reventador (figure crater’s western margin. These gas emissions and other 11). The signals occurred in swarms and consis ted of smaller fumaroles contri buted to a plume that was conti nu - low-frequency (1-10 Hz) waves of rela tive ly low-am pli- ously present, extending at least 1 km above the vent. tude. Their seis mic re cords were emer gent (i.e. grow ing in IG ob serv ers es ti mated that the to tal mid-De cem ber am pli tude with time) and of long dura ti on (up to 60 sec- lava flow vol ume was ~ 3 x 106 m3. The inferred 22 No- onds). They are thought to have been pos sibly asso ci ate d vem ber date of flow onset would im ply a steady-state extru - with rock falls from lava flowing down the cone’s southern sion rate of ~ 0.1 x 106 m3 per day and a flow front advanc - flank. As many as 200 of these events were recorded each ing at ~ 80 m per day. These obser va ti ons appear to day at station CONE. con form with sat el lite ther mal in fra red ob ser va tions, which A return visit to the crater rim on 28 Novem ber (this noted no signif i cant anom ali es unti l the end of Novem ber, time on foot) docu m ented abundant fresh lava in the crater due presum ably in large part to the lava be ing confine d (fig ure 12), a dra matic increase in the vol ume of lava there. within the steep-walled crater. In clem ent weather oc curred At least 0.5 x 106 m3 of new lava then covered the enti re and also may have impeded some of the satellite thermal crater floor and appeare d to be already flowing out of the observations.

Figure 11. Seism icity (num ber of earthquakes) versus time regis ter ed at Reventador (station CONE) during mid-Febru ary 2003 through mid-Decem ber 2004. Anom alously ele vated seism icity consist ing mainly of volcano- tectonic be gan in August 2004. Activ ity incre ased on 4 Novem ber 2004 and included hy brid events. Previously unseen emer gent, extended- dura tion, broad-band earthquakes be gan on 22 Novem ber 2004. Courtesy of IG. 12 Fuego Smithsonian Institution — Bulletin of the Global

The most re cent visit to the crater rim, on 11 Decem ber dera. The largest histor i cal erupti on at Reventador took 2004, traced the source of degas sing and lava outflow to the place in 2002, produc ing a 17-km-high erupti on colum n, most ele vate d porti on of a small dome-like feature at the pyroclastic flows that travele d up to 8 km, and lava flows centra l western margin of the crater. Figure 13 shows how from summit and flank vents. in stru men tally aided night time in can des cence ob ser va tions In for ma tion Con tacts: Patricio Ramón, Dan iel disclos ed both the vent area and surficial flow-texture s ex- Andrade, Da vid Rivero, Alexandra Alvarado, Sandro Vaca, tending S towards the southern breach of the cone. Figure and Pete Hall, Geo phys i cal In sti tute (IG), Escuela 14 also docu m ents a com para ti vely narrow arm of lava Politécnica Nacional, Apartado 17-01-2759, Quito, Ecua - trending towards the cone’s northern breach. Night time in- dor (URL: http://www.igepn.edu.ec/; Email: can des cence from the lava flow was also vis ible from lo cal [email protected]; [email protected]; com muni ti es such as El Chaco, ~ 20 km distant. [email protected]); Jeffrey B. John son, Dept. of Earth Figure 14 illus tra tes the scene on 12 Decem ber 2004 Sci ences, James Hall Uni ver sity of New Hamp shire, Dur - during a visit to the front of the most advance d lobe of lava ham, NH 03824 ([email protected] du); MODIS Ther mal (for loca ti on, see star at end of flow lobe, figure 9). IG-EPN Alert Sys tem, Ha waii In sti tute of Geo phys ics and Plan e tol - staff esti mated the flow front at ~ 20 m high and saw in can- ogy (HIGP), School of Ocean and Earth Science and Tech- descent blocks falling off of it. nolog y, Univer sity of Ha waii at Manoa (URL: http://www. Back ground. Reventador is the most fre quently ac tive modis.higp.ha waii.edu). of a chain of Ec uador ian vol canoes in the Cordil lera Real, well E of the princi pal vol canic axis. The forest ed dom i- nantly andesitic stratovolcano rises to 3,562 m above the re- mote jungles of the west ern Am azon basin. A 4-km-wide Fuego caldera widely breached to the E was formed by ed ifice col - lapse and is parti ally filled by a young, unvegetated Gua te mala stratovolcano that rises about 1,300 m above the caldera 14.47°N, 90.88°W; sum mit elev. 3,763 m floor to a height above the caldera rim. Reventador has All times are lo cal (= UTC - 6 hours) been the source of num erous lava flows as well as explo - sive erupti ons that were vis ible from Quito in histor i cal Explo sions and lava flows at Fuego conti nued after Oc- time. Fre quent lahars in this re gion of heavy rainfal l have tober 2003 (Bul le tin v. 28, no. 10). Sim ilar acti vit y pre- construc ted a debris plain on the eastern floor of the cal- vailed through 2003 and 2004. This report discusse s events dur ing No vem ber-De cem ber 2003 and include s a table sum ma- riz ing Fuego’s 2003 behav ior (table 3). A future report will discuss 2004 acti vit y and will include a map show ing crit i cal place names. Sev eral pyroclastic flows occurred in 2003. Tremor was com mon and at times abundant dur ing 2003, in- cluding in the last two months of the year. On 21 Novem ber, al- most con tin u ous har monic tremor was de tected for a span of 21 hours. On 23 Novem ber inter vals of tremor lasted betwee n 0.5 and 3 hours. Figure 13. Ther mal im age of the lava flow in the inte rior of Reventador crater taken with a Forwar d Looking The Washing ton VAAC ar- Infra red (FLIR) imager at 2000 on 11 Decem ber 2004. Courtesy of IG. chive contai ns 48 ash advi so rie s

Figure 14. A N-looking view of Reventador’s gray-col ored lava-flow front taken on 12 Decem ber 2004 at ~ 2,600 m ele va tion. Per son at right indi cate s scale of the advanc ing flow front. The lava flow em anated from the breach in the S side of the cone’s crater, a spot seen in the photo’s upper left. Courtesy of IG. Volcanism Network, Volume 29, Number 11, November 2004 Fuego 13

Lava flows, in can des cent av a - Date lanches, and pyroclastic Ash col umn and ash fall Data source(s) flows (PFs)

08 Jan 2003 Lava flows. Two PFs (down Steam-and-ash to ~ 5.7 km a.s.l., drifted W. INSIVUMEH, CONRED, Sta. Teresa drain age). Wash ing ton VAAC, EFE via COMTEX, Prensa Li bra Mid Jan 2003 In can des cent av a lanches down ~ 2 km above sum mit, drifting S and SW, depos it ing fine ash. INSIVUMEH, Wash ing ton flank ing can yons. VAAC 28 Apr-01 May In can des cent av a lanches. Inter mittent ash eruptions, One ash plume reached ~ 7 km a.s.l., INSIVUMEH, Wash ing ton blown SW at 20-30 km/hour; some puffs visi ble over the coast. VAAC; US Air Force Weather Agency 29 Jun 2003 Lava flows and av alanches Ash fell in villages to W and SE; Ash clouds to ~ 900 m. INSIVUMEH down E flank (incan des cence seen from city of Antigua and the coast). PFs ex tended ~ 1.5 km down the W flank. 09 Jul 2003 Lava dome collapse PFs. Strong explo sions sent ash to ~ 2 km above sum mit; ash fell to W Wash ing ton VAAC, Prensa and SE of sum mit. Li bre 07 Aug 2003 – A small ash emission seen on sat el lite im ag ery. The ash cloud Wash ing ton VAAC drifted NW and covere d an area about 3.5 by 3.5 km. 08 Sep 2003 – Ash plumes; one drifted S and covere d an area of 5 x 5 km; another Wash ing ton VAAC rose to ~ 6 km a.s.l. 09 Oct 2003 – A pilot saw Fuego ash reaching ~ 4.6 a.s.l. No ash was visi ble on Wash ing ton VAAC sat el lite im ag ery. 17 Oct 2003 Small in can des cent av a lanche A 33-minute- long erup tion sent a gas-and-ash plume to ~ 1.5 km INSIVUMEH down the Sta. Teresa val ley. above the crater. Nov-Dec 2003 In can des cent av a lanches. 4 Novem ber ex plosions threw mate ria l 150 m above crater rim; INSIVUMEH 18-19 Novem ber, gas-and-ash plumes up to 1.2 km above the crater; 28 Nov.-1 Dec, 700-900 m above the crater; 7-9 Decem ber, 500 m above crater; 10-16 Decem ber, 200-1000 m above the crater, and 18-22 and 30 Decem ber, ‘low-level plumes.’

Table 3. Repre sen ta tive ex am ples of reporte d volca nism at Fuego during 2003. Cour tesy of INSIVUMEH. on Fuego. The num ber of these advi so rie s were as fol lows, fol lowed, con tin u ing the south ward mi gra tion of vol ca nism during the stated months of 2003: 14 advi so rie s in Janu ary that began at Acatenango. In contra st to the mostly (on the 8th, 9th, 11th, 12th, and 20th); 11 in April (on the andesitic Acatenango volcano, erupti ons at Fuego have be- 17th, 28th, 29th, and 30th); eight in May (1st and 2nd); come more mafic with time, and most his tor ical ac tiv ity has three in June (30th), six in July (1st, 9th, and 10th), two in pro duced ba saltic rocks. Fre quent vig or ous his tor i cal erup- August (7th), two in Septem ber (29th); and two in Octo ber tions have been re corded at Fuego since the onset of the (9th). The most im pressive plumes de picted in satel - Spanish era in 1524, and have produced major ashfalls, lite-based graphics were for 28 April-1 May 2003, when along with occasional pyroclastic flows and lava flows. they often stretched well out to sea, reaching ~ 160 km SW In for ma tion Con tacts: Instituto Nacional de from Fuego. Other wise , the graphics gener all y depict ed Sismologia, Vulcanologia, Meteorologia e Hidrologia much smaller plumes, in some cases very lo cal ones. The (INSIVUMEH), Unit of Volc anol ogy , Geol ogic Depart m ent graphic for 28 Septem ber showed small plumes from Fuego of In vesti gati on and Service s, 7a Av. 14-57, Zona 13, Gua- as well as si mul taneou s ones from Pacaya and Santa María. te mala City, Gua te mala (URL: http://www.insivumeh.gob. Back ground. Volcán Fuego, one of Centra l America ’s gt/); Wash ing ton Vol ca nic Ash Ad vi sory Cen ter (VAAC), most acti ve volca noes, is one of three large stratovolcanoes Sat el lite Anal y sis Branch, NOAA/NESDIS E/SP23, over look ing Gua te mala’s for mer cap i tal, Antigua. The NOAA Sci ence Center Room 401, 5200 Auth Road, Camp scarp of an older ed ifice, Meseta, lies be tween Springs, MD 20746 USA (URL: http://www.ssd.noaa.gov/ 3,763-m-high Fuego and its twin volcano to the N, ); Charles R. Holliday, Air Force Weather Agency, Offutt Acatenango. Col lapse of the an ces tral Meseta vol cano Air Force Base, Ne braska 68113 USA; Prensa Li bre about 8,500 years ago produced the massive Escuintla de- (newspa per), 13 calle 9-31 zona 1, 01001 Guate m ala City, bris-ava lanc he deposit , which extends about 50 km onto the Gua te mala (URL: http://www.prensalibre.com/). Pacif ic coastal plain. Growth of the modern Fuego volcano

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