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Team Members:Costas Synolakis Hideo Matsutomi Utku Kanoglu Shun-Ichi Koshimura Andrew Moore Christophe Ruscher Tomoyuki Takahashi |
From costas@usc.edu Sun Dec 19 17:47:40 1999Date: Sun, 19 Dec 1999 00:57:21 -0800 From: Professor Costas Synolakis <costas@usc.edu> To: F.Imamura <imamura@tsunami2.civil.tohoku.ac.jp>, jborrero@mizar.usc.edu Subject: Vanuatu survey... Friday morning Dec 17, Hideo, Costas, Kossy, Utku overnighted at Santos (island 70km west of Pentecost) to fuel chopper. No evidence of tsunami here, reports of past tsunamis 50 years earlier. Up at 6:00am, chopper fueling slow, arrived at Walli, base camp at 9:30am. Team restless, narrow weather break, had been raining all night. Hideo, Andy, Kossy and Utku start detailed survey of Bay Mairtele. Tomo, Charles (local geol), Jean Philip (local geol) dropped at Bay Barrier. Christophe, Adrian (local contact), Costas etc off to St. Henry, both locales on East Pentecost. Tsunami damage non existent, wave at 3 + m in Bay Barrier, less than 0.5 m in St. Henry. Substantial structural damage to churches, only "engineered" structures. Most impressive landslides team has seen, stopped counting at 10. Substantial risk to villages from landslides. Costas' team flew to 15.45S on west coast of Pentecost, no evidence of waves, rugged terrain, no villages. Returned Christophe/Adrian to Bay Mairtele (BM), Costas flew to pick up Tomo's team. Hideo continues with survey of BM. Tomo, Jean Philip, Charles, Costas off to east side of BM. Drenched, totally drenched. All except Utku without rain gear. In east side, 2.8m runup, substantial tsunami damage to school, Costas lectures elementary school, east side of bay is anglophone, west in francophone. Team returns to base camp at 5:00pm. Christophe and Adrian had been left behind, Hideo and Costas had assumed that they were with the others, visibility and rain helped. Boat sent back to pick them up, entire team at dinner in village hut at 7:00pm. Entire team shares hut, everyone under mosqito nets, mosqito coils burning nonstop. Team formulates plan for the following day. Evening unusually quiet, first night without rain. Team up at 5:00am, with church bells tolling. Hideo's boat team out at 7:30am for survey of west coast from Walli to Wailupu. Costas's team in clean up detail. Costas relates team's thanks, has to personally say goodbye each villagers. Team donates unused food, about $400 worth. Chopper in at 9:00am, Andy, Christophe, Costas off to bay west of BM. much less runup than 500m away from BM where flow depths were well over 2 m and a uniform runup much greater than that. Very telling. Light rain. Costas's team meets Hideo's at Wairupu. Quick change of plans, given window of good weather. Hideo, Tomo, Charles, Costas off at 11:45am to Ambrym, island on the south, 15min flight off Pentecost. Chopper returns to Pentecost for Andy, Kossy, Utku, Jean Philip, off to Maelukula island, 40min flight. Had planned earlier for Andy's team to return to base camp via boat and continue coastal survey and no Maelukula. Hideo etc stranded at Olal in Ambrym for 3.5hrs. Only one water bottle for 4 people and 6 cookies, supplies left in chopper, locals offer apples and mangoes for lunch. Chopper had to fuel at Santos after dropping Andy etc. Hideo etc board bed of pickup, start surveying north Ambrym. Runup is small, in the north, this almost directly across the straights from Bay Mairtele where the special effects happened. Pickup ride hazardous, team has to protect their heads from tree branches and falling coconuts. Unwanted adventure, driver asks and gets $50 US, but he is the chief of the village and owns only vehicle in area. Chopper returns after dropping Andy's team in Pentecost, they will return to Villa with fixed wing. Mercifully chopper notices Hideo etc from the air, so pickup "ride" back to Olal unnecssary. Hideo etc stop in east Ambrym, about 10km south of Olal, where there is evidence of giant mudslide. Chopper almost sunk in mud, tsunamistas did. 20-30m wide gap in hillside, locals report uniform 30min long mudslide about 7-10m deep. Gap keep widening, nearby village at risk. Had to leave, chopper pilot restless in account of closing weather and fuel. The entire ITST arrived safe in Villa on Saturday night, in two groups as above. Entire team wet. Andy's team reports 1.5m runup in Maelekula. Team met on Sunday morning for breakfast and payments of flights. Horrid costs, but great results. Surveyed entire south Pentecost, north Ambrym, west Maelekula, north Efate. Costas not joining flight to Brisbane, has to meet with SOPAC at Fiji for debriefing. Thus ends the survey of what hopefully will be the last tsunami of the millenium. Preliminary Lessons : Public awareness of tsunami hazards works surprizingly well. Don't live on hillsides in volcanic islands with slide potential. Slide again a prime suspect, does not seem easy to explain unusually large local runup otherwise, but we shall see. Local support essential in this survey. We know even less about tsunamis than we thought we knew post PNG.
Costas
PS1. For reference, mail is picked up and delivered in Pentecost via an old MV, which sails up and down the archipelago. When mail is to be picked up, locals light fire on shore, MV approaches, locals deliver packages/mail with outrigger. PS2. Why did the church bells toll and 5:00am on a Saturday ? It was not to wake up ITST, but that day was monthly village clean up day. All villagers cut grass by hand, clean up trash, pick up village streets. Despite sanitary conditions due to eq, the villagers in Pentecost live an enviably clean, sophisticated and neat life. Maybe Margaret Meade was partially right after all. |