Consequences of 2 tsunami exercises in 2005, in French Polynesia : evolution of the tsunami warning Dominique Reymond LDG/DASE/CEA : Laboratoire de Geophysique de Tahiti Departement d’Analyse Surveillance Environnement Commissariat a l’Energie Atomique Colonel Denis Musson DPC Direction de la Protection Civile, Haut-commissariat de la République en Polynésie Française

Summary Tsunami in French Polynesia : generalities Tsunami warning plan : share of competencies The different Levels of warning The basis of warning system The 2 excercices of 2005

The 20th century’s most dangerous tsunami in Polynesia (with amplitudes exceeding 2 m in French Polynesia) Kamchatka, Nov. 1952, M 9.0 Aléoutian, Mars 1957, M 8.7 Aleutian, 1 avr 1946, M 8.5 Alaska, Mars 1964, M 9.2 Peru, Fev. 1996, M 7.5 Chili, Jul 1995, M 8.0 French Polynesia South Chili, Mai 1960, M 9.5

The Marquesas islands, a vulnerable archipelago : measured heights in Hiva Oa and Nuku Hiva, April 1st 1946 Tsunami field survey of E. Okal & al. CEA/DASE/LDG

Hiva Oa (Marquesas) : the Chilean tsunami on July 30th 1995 (mag 8.0) CEA/DASE/LDG_Tahiti Hiva Oa (Marquesas) : the Chilean tsunami on July 30th 1995 (mag 8.0) Run-up # 3-4 m 1 Avril 1946 – Hilo - Hawaii 9 mars 1957 – Oahu - Hawaii

Propagation time from main subduction zones to French Polynesia Japan, Kuril, Kamchtaka 12-13 hours Aleutian 11 hours Tonga 3 -4 hours Chile - Peru 10 - 11 hours CPPT : Centre Polynésien de prévention des Tsunamis

The tsunami warning plan The role of the High-commissioner : He is the represantative of the French Government He is the authority in charge of the activation of the plan and the relief and emergency coordination. The activation of the whole, or a part, of the Plan is decided by the High-commissioner on the basis of the observations and recommendations submitted by the LDG. This Plan must be continued by local communities.

The tsunami warning plan: the role of the Mayor In accordance with the District Code, the mayor is in charge of anticipating, and providing all necessary assistance: He is in charge of the information of all inhabitants in his district. Each mayor ensures that population has taken all useful precautions for its security

Tremors : Overview of the automatic seismic warning system 3 components seismic data of a single station Seismologist 24h/24h on duty Warning from a given threshold (mag 7.0) N Z E Data acquisition Realtime analysis of seismic data by a PC computer Warning to Civil Defense Detection Location Magnitude, Mo TREMORS: Tsunami Risk Estimation through a Real-time System CEA/DASE/LDG

The tsunami warning plan: Alert levels

Territorial administrator Flow-chart of present warning to populations LDG LEVEL 2 HC - DPC Territorial administrator The warning could start at any level in function of available delays LEVEL 3 Mayor TV, radio LEVEL 4 Populations

Drills 2 exercises were organized in 2005: 1 - to test the tsunami plan about the international airport of Tahiti 2 - to test effective warning to the population in Marquesas islands. 1 valley on 3 islands was evacuated.

the case of the international airport of Tahiti The numerical simulation shows the inundation of technical installations : - carburant tanks zone, - part of the tarmac, - electrical supply installation, - flying lights and transmissions.

The case of the international airport of Tahiti If the airport could be out of order, some reflex rules were elaborated about, for example : - rerouting of the flying planes, sheltering landed planes - protection of technical equipments, engines and installations, - evacuation and security of the public zone, - measures for restarting quickly the airport. On the other hand, a restructuring of the airport is programmed for economical reasons. The result of numerical simulation will be integrated in the project.

Drill in Marquesas The warning chain was tested : LDG, HC-DPC, Territorial administrator, mayor, population. The usual supports, telephone, fax, local radio station and .. bells, were used. New other were tested: recorded message by phone and SMS. There is no siren in these island whose communities are isolated.

Drill in Marquesas test of new transmission supports * The recorded message concerned : local authorities, hotel with tourists, administrations of school, hospital, etc … * The message in French, Marquesian and English, was recorded in 30 minutes; * 90 min was necessary for the transmission. * 38 /40 addresses received this message. * The weakness of this option: there is nobody in 24h/24h on duty at the French Polynesian telephone service provider

Drill in Marquesas test of new transmission supports (cont.) * The diffusion of the warning by SMS require 65 minutes to input the message in three languages, and to find the phone references of foreigner tourists. * In one hour, 44% of the 1145 local cellular phones were contacted, but 0% of the 52 foreigners. *Furthermore, this system perturbed normal vocal channels. * Evidently, this interesting possibility is not adapted for a rapid warning.

Drill in Marquesas Evacuations : this exercise was prepared with the communal authorities and the communities : 200 to 1000 inhabitants. But 1h to 1h45 was necessary to evacuate. The real difficulty is to join these isolated communities. Recently, the French Polynesia was hit by a large swell. Some little atolls of Tuamotu archipelago needed 36 hours for joining them.

The new tsunami warning system the scattering of the communities on 5 million kilometer square Drill

The new tsunami warning system LDG DPC community TAHITI 150 remote controlled sirens by inmarsat C, will be installed in all of the communities on the territory in 2005 to 2007. This network is secured by 2 permanent satellites. The large hotels on lagoon will be equipped too.

Remote controlled siren 15000 us dollars, battery, solar panels and transceiver included. This equipment transmit informations about the status of siren and its battery. this siren network will be tested once/month.

The next excercise In February 2006, the topic will be to test this siren network and the evacuation of population of the 6 valleys of Hiva Oa (Marquesas).

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