Cook Islands Tsunami Warning System

Transcription

1 Cook Islands Tsunami Warning System Arona Ngari Director Cook Islands Meteorological Service Introduction Location Risk EWS Alert Response SOP Conclusion Overview 1

2 Introduction Location 15 islands located 3000 km NE of NZ 240 km2 of land Approx 2 million km2 of ocean Bathymetry range from 2 6km Same lat. and long. with Hawaii but in SH 2

3 Risk RISKS 80% or more tsunamis go undetected Research that Goffdid on this island showed that one particular tsunamiwas 12 meters high and came more than 100 metres inland. But Mangaia is only one of up to 30,000 islands in the Pacific. Until many more of them are investigated, he said, it s impossible to know how often tsunamis strike in the region and whether or not they will be local phenomena or regional disasters. With that particular tsunami in Mangaia, only a few people knew about it, because they were there at the time. The tsunami went north on to the land, but to the south it met nothing, all the way to Antarctica. And local research of the kind he has been doing is the only way to get a crack at the problem. Most tsunamis go undetected, maybe 80% of them or more, Goff said. And with that bias comes great uncertainty. On these seven islands alone, I can see the traces of about two dozen submarine landslides. Did they happen in a few hundred years, or a few thousand? I don t know. My gut feeling says it s not a few million, he said. 3

4 Researchers blind to risk The reason so many Pacific islands have an unstable coast, with such severe consequences, is that they are basically like land on stilts. As Charles Darwin was the first to recognise, they start as the tops of undersea volcanoes. While coral reefs develop in the coastal waters, the volcano subsides. Gradually, it disappears, first leaving a much smaller island surrounded by a circular barrier reef, and eventually a circular island or system of islets, surrounding a lagoon, and standing on a steep wall of coral. Any landslide from the side of the volcano, any collapse of the reef itself, will fall deep, and can cause a big wave. That Darwin s theory has survived to this day is impressive, said Goff. But its elegance has blinded many scientists and is still blinding geologists to the many deviations from the ideal atoll form that he sees on the map. And with that, it blinds researchers to the very real risk of tsunamis that the islands and their inhabitants run. Take Pukapuka, Goff said, pointing to its completely irregular, almost spidery form as seen from the air. There s a legend that the population was almost wiped out by a tsunami, but for a few men and women. They made strenuous efforts to repopulate, the story says. In 1999, a tsunami killed about a hundred people in Vanuatu. That s not a huge number but it was a small island. [ ] ]If you have a population of four hundred, a hundred deaths would be disastrous. Goff s poster at the AGU conference is more a declaration of ignorance and a call to arms than the presentation of a scientific result, he said. I can count the number of people working on this on three fingers, he said. Doing this research properly on just one island probably costs a million dollars or more, but these countries themselves have no money. So it ll come down to aid agencies, I suppose. The question is: do we give a damn? Tsunami Early Warning System SMS received by CIMS and 5 key stakeholders Warnings received from PTWC by CIMS via e mail Warnings distributed to key stakeholders Warnings distributed to rest of stakeholders Pending of severity of warning, the Central Group for Response is advised Warning communicated to the nation Sirens sounded around Rarotonga to warn communities Warnings disseminated to others as requested 4

5 Alert Tsunami Warning Tsunami Watch Tsunami Advisory Tsunami Tests Response Warning and Watch are implemented ASAP Advisory is just information Tests are for PTWC and CIMS communication links Discussions can be generated once information is received by all 5

6 Standard Operating Plan CIMS strictly implements an SOP as the authoritative ti warning agency SOP SOP 6

7 Conclusions Location of the Cook Islands is vulnerable Vulnerability has been now realized Have an SOP in place SOP need to be re designed EWS is in place Evacuation Signs are in place Sirens are installed 7