******************************************************************************* INFORMATION on VF08: Active volcanism in the Vanuatu volcanic arc, SW Pacific - IUGG 2011 Fieldtrip From: "Nemeth, Karoly" <K.Nemeth@xxxxxxxxxxxx> ******************************************************************************* Location: Vanuatu (New Hebrides), SW-Pacific Leaders: Karoly Nemeth, Shane J Cronin (Massey University), Douglas Charley, Esline Garaebiti, Sylvan Charbon (DGMWR, Vila) Contact Details of Corresponding Leader: INR-CS, Ag/Hort Building, Riddet Rd, Massey University, Private Bag 11 222, Palmerston North, 4442, New Zealand, Tel: +64-6-356-9099 ext 7389, Fax: +64-6-356-5632; Mob: +64-27-479-1484; Email: k.nemeth@xxxxxxxxxxxx Pre-IAVCEI fieldtrip: 25 June - 1 July Fee: $3,025 AUD, (incl. $275 GST) Field Trip Fee includes: Melbourne - Vila - Melbourne return Air Vanuatu international flight Vila - Ambrym - Vila return domestic, chartered flight with Vanair Vila - Tanna - Villa return domestic Vanair flight First, fourth and last night in Hotel in Port Vila Food/water from first day evening in Vila until the morning we leave Vanuatu Kastom fees and Permit fees to enter sites Ground transportation and boat transportation if needed Local Guides and Carriers in Ambrym and Guides in Tanna Field guides, field trip guide book Start and End in Melbourne (Australia) Duration: 7 days Start Date: June 25 Start Location: Melbourne (International Ariport) End Date: July 1 End Location: Melbourne (International Ariport) Suggested Travel Arrangements from Melbourne to the start location and return: Not applicable. The field trip cost includes the international flight by Air Vanuatu from/to Melbourne to/from Port Vila (Vanuatu). The participants just need to arrange they transportation to the Melbourne International Airport by the check in time to the Air Vanuatu flight to Vanuatu. (A) Minimum Number of Participants (to be financially viable, or enjoyable): 8 (B) Minimum Number of Participants before cancellation (equal to or less than 'A'): 8 (C) Maximum Number of Participants: 18 Geological Highlights: Active volcanism in the Vanuatu volcanic arc, SW Pacific A chain of active island volcanoes in the middle of the Vanuatu archipelago lie approximately 150 km east of the New Hebrides trench and 150 - 200 km above the Benioff zone. These active volcanoes produce predominantly ongoing mafic explosive and effusive eruptions, however voluminous subordinate silicic eruptive products are also known from the arc sub-Recent part. This field trip will concentrate on the variety of eruption styles and deposits of two major islands undergoing active mafic explosive volcanism. The field trip will spend most of the time in Ambrym which is one of the most voluminous active volcanic islands in the Vanuatu. Ambrym has a 12 km-wide caldera structure that rises to between 600-800 m above sea level although its origin is under debate. For a long time, Ambrym was used as a type locality of a giant tuff cone formed due to a cataclysmic phreatomagmatic explosion which virtually blew off the top of the island and formed the 12-km across caldera. This theory however is not supported well, and the Ambrym caldera is rather a result of gradual (or episodic) subsidence associated with ongoing centrally focused basaltic volcanism and concomitant lateral fissure eruptions similar to those which formed a phreatomagmatic volcanic field along the western edge in 1913 AD. The trip also will also visit Tanna Island, with its 4 km diameter Quaternary andesitic Yenkahe caldera and associated perfectly exposed Siwi Pyroclastic Sequence. Within the caldera, along the margins of a rapidly rising, resurgent block structure, is a succession of overlapping scoria/tephra cones, including the presently active Yasur volcano. Yasur has been in semi-continual eruption for at least 300 years (witnessed by Captain Cook in his travels), producing hourly to daily strombolian, vulcanian and phreatomagmatic explosions. The rapidly growing Yasur cone has also gone through several collapse events, building a broad base of landslide and intercalated talus deposit. Most of Yasur's pyroclastic deposits have accumulated within the Yenkahe Caldera, forming a broad unvegetated ash plain, which at times has also been a shallow lake. In the afternoon of 8th of May, 2000 this lake, following a rainy period, broke out and drained within several hours causing a locally damaging flood. This 7-day field trip will expose participants to very active volcanic systems with differing mafic eruption styles, and deposits, as well as a dynamic caldera-sedimentation system. Some General References (indicative list only!): Dubois, J., Deplus, C., Diament, M., Daniel, J., Collot, J.Y., 1988. Subduction of the Bougainville Seamount (Vanuatu) - Mechanical and geodynamic implications. Tectonophysics 149(1-2), 111-119 Frater, M., 1917. Volcanic eruption, Ambrym Island (1913). Geological Magazine, 6(4): 496-503. Gregory, J.W., 1917. The Ambrym eruptions of 1913-1914. Geological Magazine, December 1917: 496-503 McCall, G.J.H., LeMaitre, R.W., Malahoff, A., Robinson, G.P., Stephenson, P.J., 1969. The geology and geophysics of the Ambrym Caldera. New Hebrides, Symposium Volcanoes and Their Roots, Oxford, England, pp. 682-696. Meffre, S., Crawford, A.J., 2001. Collision tectonics in the New Hebrides arc (Vanuatu). Island Arc 10(1), 33-50. Monzier, M., Robin, C., Eissen, J.P., Kuwae (Approximate-to-1425 AD) - The forgotten caldera. Journal of Volcanology and Geothermal Research, 1994, 59(3), 207-218. Németh, K., Cronin, S.J., 2009a. Phreatomagmatic volcanic hazards where rift-systems meet the sea, a study from Ambae Island, Vanuatu. Journal of Volcanology and Geothermal Research, 180(2-4): 246-258. Németh, K., Cronin, S.J., White, J.D.L., Kuwae caldera and climate confusion The Open Geology Journal (Bentham Sciences), 2007, 1, 7-11 [doi: 10.2174/1874262900701010007]. Peate, D.W., Pearce, J.A., Hawkesworth, C.J., Colley, H., Edwards, C.M.H., Hirose, K., 1997. Geochemical variations in Vanuatu arc lavas: the role of subducted material and a variable mantle wedge composition. Journal of Petrology 38(10), 1331-1358. Picard, C., Monzier, M., Eissen, J.-P., Robin, C., 1995. Concomitant evolution of tectonic environment and magma geochemistry, Ambrym volcano (Vanuatu, New Hebrides arc). In: J.L. Smellie (Editor), Volcanism Associated with Extension at Consumed Plate Margins. Geological Society of London, London, vol. 81, pp. 135-154 Raos, A.M., Crawford, A.J., 2004. Basalts from the Efate Island Group, central section of the Vanuatu arc, SW Pacific: geochemistry and petrogenesis. Journal of Volcanology and Geothermal Research, 134(1-2): 35-56. Robin, C., Eissen, J.P., Monzier, M., 1993. Giant tuff cone and 12-km-wide associated caldera at Ambrym Volcano (Vanuatu, New-Hebrides-Arc). Journal of Volcanology and Geothermal Research, 55(3-4): 225-238. Turner, S.P., Peate, D.W., Hawkesworth, C.J., Eggins, S.M., Crawford, A.J., 1999. Two mantle domains and the time scales of fluid transfer beneath the Vanuatu arc. Geology, 27(11): 963-966. Witter, J.B., Self, S., 2007. The Kuwae (Vanuatu) eruption of AD 1452: potential magnitude and volatile release. Bulletin of Volcanology 69(3), 301-318. Description of the field area: Vanuatu is located in the tropics with steady moderately high temperatures (26-32 °C) and high humidity. In locations where some of the volcanoes will be visited above 300 m elevation, conditions may be substantially cooler, windy and rainy. The field trip will be adventurous and will require good physical fitness levels and an open mind to respecting and behaving within the norms expected of the local culture. The trip beside the international Melbourne - Vila return flight will include two domestic flights. The Vila - Ambrym flight will be on an 18-Seater twin-engined aircraft operated by the Vanuatu national carrier, Vanair, while the flight to Tanna will be on a larger ATR- aircraft also operated by Vanair. On the islands, transport will be within and on the deck of open 4x4 pickup trucks and on foot. On Ambrym there will be a full day hike to the caldera (>700 m above sea level, over 10 km through pristine tropical rain forest, on local walking tracks. This is a challenging hike due to both temperature and humidity, but is not technically difficult for those familiar with back-country hiking. Local guides and carriers will be available. Within Ambrym caldera guided walks of up to 10 km per day will be made across relatively flat-lying and open ground. Accommodation will be a campsite located at the edge of the forest and Caldera, well away from active craters and the typical gas plume location. Also on Ambrym a short boat ride may be taken to visit one field site. This will involve groups of 4-5 being ferried by local fishing boat c. 4 km along the shoreline. At Tanna, a hike of only c. 1 hour is needed to ascend the volcano, which may be shortened by 4WD transportation. Description of Health and Safety Risks: Heat and humidity are the major weather concerns accompanied by evening tropical showers. However, the field trip will take place in a generally calm, pleasant and dry period of the year. During the field trip we will visit active volcanoes with constant degassing process, periodic mild Strombolian and phreatomagmatic explosive eruptions. Notably larger-scaled volcanic activity at both Ambrym and Tanna volcanoes can be expected at any time, and how closely we visit them will depend on their activity state. Vanuatu has very widespread Malaria in the rural village areas that we will pass through and at times live within. Therefore each participant must consult with their GP for advice regarding Malaria protection and ensure that other typical immunizations (e.g. Hepatitis A, Tetanus) are up to date. The field trip leaders will carry post-malaria treatment kits and will have contact with health authorities of Vanuatu, including local health officers on Ambrym and Tanna. During the trip one or more kava ceremonies will occur. Kava is made from pounded (or in some cases chewed) root of Piper Methysticum and contains a strong Alkaloid that typically induces dulled responses and tiredness. It is consumed by virtually every male adult during the early evening in rural Vanuatu. The drink is astringent and tastes like peppery dirty water. But the ceremonies and sensation is generally a lot of fun. The water used for this and all water consumed is usually rain-water, which on the whole is safe. There are no poisonous snakes or insects but mosquitoes are a common annoyance. Description of Gear to be Supplied by Leaders: The leaders will carry a basic medical and first aid kit, however, participants are recommended to carry a personal kit that includes insect repellent, and a range of typical travel medicinal supplies, plus of course any prescribed medication, asthma inhalers etc. Camping gear, cooking facilities and other base camp gear will be provided by the trip organisers. A lightweight sleeping bag and personal mosquito net is recommended. The leaders will have normal GSM mobile phone and Satellite phone. The participants' details will be registered in the New Zealand High Commission and the leaders will be in contact with the High Commission officials if anything special needed. Visa Requirements (if not Australia): There is no need for a VISA for most visiting nationalities to Vanuatu, but please check this with your foreign ministries and travel agents. Currency of Country: Currency of Vanuatu is the Vatu (December 2010). In July 2010: 1 AUD - 96 Vatu; 1 NZD - 72 Vatu; 1 Euro - 128 Vatu; 1 USD - 95 Vatu; 1 Japanese yen - 1.5 Vatu; 1 GBP - 151 Vatu; 1 Swiss Franc - 100 Vatu Vatu is relatively stable currency, but can be expected some changes over time. Please check http://www.xe.com/ Electricity of Country (voltage, plug-type, etc): 220-280 volts AC, mainly three-point plugs in hotels (same pattern as Australia & New Zealand). However in outer islands electricity is dependent on local generators and may only be available during evenings. Insurance: It is strongly recommended that participants take out their own personal travel insurance to cover the period of time they are attending this field trip/workshop. We request a written statement from the participants that they HAVE a personal travel insurance to Vanuatu which include medical as well as travel related insurance policies. Vanuatu has very low rates of violent or other crime toward visitors. However, equivalent health care to most western countries is entirely private and expensive. Because the trip will go to outer islands, there is a possibility that outbound and return flights are delayed. Hence make sure you have flexibility to alter outbound flight schedules. Other: Cellular phone coverage is mostly surprisingly good throughout the areas we will travel. Two local providers are available and most foreign phones with international roaming can access them. In addition, the leaders will carry a Satellite Phone for emergency use. TENTATIVE ITINERARY June 25: Leave Melbourne to Vila - short visit nearby sites around Vila, Efate Pumice Formation. Overnight in Vila in 2* Hotel (Probably the Kaiviti Village Motel) June 26: Flight to Ambrym in the morning, upon arrival, drive to Lalinda Village and climb to Ambrym caldera. En-route checking some small exposures along the walking path. Overnight in a Campsite at the edge of Ambrym caldera about 700 metres above sea level. June 27: Exploring the Ambrym intracaldera region, visiting (climbing) to Benbow active volcano, Marum crater, Niri Taten crater, numerous young lava flows and ash plains. The trip will be on foot, and will cover at least 15 km over open volcanic terrains. For relevant geological information please check the following papers: Károly Németh and Shane J. Cronin: Volcanic craters, pit craters and high-level magma-feeding systems of a mafic island-arc volcano: Ambrym, Vanuatu, South Pacific. Geological Society, London, Special Publications, 2008; 302: 87 - 102. Németh, K., Cronin, S.J., Stewart, R.B., Charley, D. 2009: Intra- and extra-caldera volcaniclastic facies and geomorphic characteristics of a frequently active mafic island-arc volcano, Ambrym Island, Vanuatu. Sedimentary Geology 220: 256-270. doi:10.1016/j.sedgeo.2009.04.019 Robin, C., Eissen, J.P., Monzier, M., 1993. Giant tuff cone and 12-km-wide associated caldera at Ambrym Volcano (Vanuatu, New-Hebrides-Arc). Journal of Volcanology and Geothermal Research, 55(3-4): 225-238. Nemeth K, Cronin SJ, 2011. Drivers of explosivity and elevated hazard in basaltic fissure eruptions: the 1913 eruption of Ambrym Volcano, Vanuatu (SW-Pacific). Journal of Volcanology and Geothermal Research [in press] June 28: Climb down in the morning from the summit, if time permits we will take a short boat ride to visit one of the 1913 phreatomagmatic eruption sites, alternatively, another young phreatomagmatic centre along the road will be visited. Afternoon flight from Ambrym to Vila, and overnight in Vila in a 2* Hotel. June 29: Morning flight from Vila to Tanna. During the day a slow drive across the island on "island taxi" exploring the Yenkahe Caldera eruptive products. Overnight in a beach-side resort in island style bamboo houses. In the afternoon, we will walk up to 1 hour to visit Yasur volcano, staying past dusk to watch the Strombolian explosive eruptions (depending on state of activity and level of safety). June 30: Morning further visit to key sites around Yasur and the Yankee Caldera. Afternoon, flight back to Vila, and overnight in Vila in a hotel. July 1: preparation for return from Vila to Melbourne, if time allows a morning visit to nearby sites to see the Efate Pumice Formation and/or a cultural site. Raos, A.M., McPhie, J., The submarine record of a large-scale explosive eruption in the Vanuatu Arc: ~ 1 Ma Efate Pumice Formation., in Explosive subaqueous volcanism, White, J.D.L., Smellie, J.L., Clague, D.A., Editors. 2003, American Geophysical Union: Washington D.C. p. 273-283. Stewart R B, Németh K, Cronin S J. 2010. Is Efate (Vanuatu, SW Pacific) a result of subaerial or submarine eruption? An alternative model for the 1 Ma Efate Pumice Formation. Central European Journal of Geosciences (ISSN: 1896-1517) 2: (3) pp. 306-320. For Registration please visit the official IUGG 2010 web site: http://www.iugg2011.com/fieldtrips.asp#ft6 ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
