Day 8: Field Report

November 3, 2009 by  
Filed under Daily Reports, General Info

Today was a change islands and countries. We flew Polynesian Airlines from Pago Pago to Apia in an 18 passenger prop plane that flew low enough to not need pressurization of air conditioning. No security screening and we can carry as many liquids on board as we wish. Checking in involves getting on a scale with all your luggage so they know the total cargo weight. I had a front row seat and there was no door to the cockpit so I could watch the pilot and the controls. We were able to see some of the tsunami-damaged areas on the east end of Tutuila (the main populated island of American Samoa). Much of Tutuilla is steep and the damaged areas were confined to pockets of low lying villages near the mouths of coastal rivers. The flight is just over 30 minutes. We can see some of the damaged areas along the SE coast of Upolo, the more populated eastern island of Samoa. Even from afar, the damage looks more continuous than on Tutuila. Apia is located on the north side of Upolo.

As in American Samoa, first on our itinerary is to introduce ourselves to UNESCO and government officials to sanction our field effort. First is a meeting with Jan Steffan, theUNESCO science coordinator for the Pacific region and the interface between scientific teams and the Samoan government. He had spent two years in Indonesia before this assignment and had spent much time in Padang in the aftermath of the 2004 Andaman-Sumatra earthquake and tsunami. He knew several of the people I had worked with on the 2005 Sumatra post-tsunami survey. We explained the purpose of our trip and how our work was not just a repeat of the previous team efforts. He agreed that our expertise and focus would add to what had already been done and forwarded his approval to the Samoan Government. We have an appointment to meet with an official of the Department of Environment and Meteorology tomorrow morning for the final ok.

After the meeting, there wasn’t much time left for work. We took a quick drive over to the south side of the island and looked at some of the areas that were hit. Samoa consists of two main islands Upolo and Savai’I both of which are larger than Tutuila. The population is more thant 2.5 times larger than American Samoa. Upolo was the hardest hit by the tsunami. Unlike Tutuila which was located nearly perpendicular to the orientation of the earthquake fault that caused the tsunami, Upolo was a little to the west of the maximum wave energy. Major damage was confined to the SE coast and no damage occurred on the north coast where Apia and the most populated part of Samoa is located. If a future tsunami generating event has a slightly different orientation, the outcome for Apia could be different. One of the major needs for both Samoa and American Samoa is a credible tsunami hazard map that addresses the likely maximum inundation for tsunami sources both nearby and elsewhere in the Pacific. It is very difficult to locate evacuation sites and evacuation routes if you don’t know where the safe areas are. On September 29, many people over-evacuated, driving as high up as they could, causing traffic problems. The lack of a well defined evacuation zone also may have encouraged people to use cars to evacuate as they didn’t realize that in many cases they didn’t need to go far to be in a safe area. Hazard assessments are based on numerical modeling efforts, past tsunami inundation and water height measurements and, when available, paleotsunami deposits. All of this information needs to be pulled together to see if what happened on September 29 was the worst likely event here, or what might produce a greater impact.

We looked at the Coconut Beach Resort near Maninoa. This was a well-landscaped, high-class resort with a beautiful beach and spa that catered to international visitors. There were about 90 guests on September 29. The earthquake was felt strongly but no one connected the earthquake and a possible tsunami. Fortunately the nearby resort of Sinelei was run by a general manager who was more aware to the relationship between shaking and tsunamis. Sinelei had installed a siren and also practiced evacuation drills. They also had developed a protocol for evacuation events with a staff person grabbing a list of the clients. On September 29, Sinalei was able to quickly ascertain that two guests had not left their rooms and staff were able to find them and help them evacuate before the worst surge arrived. People at nearby resorts including Coconut Beach heard the alarm and all but one person was able to escape. One woman tripped while evacuating and was caught in the water. Coconut Beach also provided an interesting example of tree resistance to the force of the water. Smaller diameter trees were bent while the larger ones resisted the flow. Although Coconut Beach did not have plans for a tsunami, they did respond quickly after the event – and were the first to arrive at the hospital, to deposit the 12 injured guests. They were quickly rebuilding and hope to be open for a limited number of guests in February – and they plan to include information about natural tsunami warnings in guest literature.

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