Consequences of 2 tsunami exercises
in 2005, in French Polynesia :
evolution of the tsunami warning
Colonel Denis Musson
DPC
Direction de la Protection Civile,
Haut-commissariat de la République
en Polynésie Française
Dominique Reymond
LDG/DASE/CEA :
Laboratoire de Geophysique de Tahiti
Departement d’Analyse Surveillance Environnement
Commissariat a l’Energie Atomique
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
CEA/DASE/LDG_Tahiti
Hiva Oa (Marquesas) :
the Chilean tsunami on July 30th 1995 (mag 8.0)
Run-up # 3-4 m
9 mars 1957 – Oahu - Hawaii
1 Avril 1946 – Hilo - Hawaii
Propagation time from main subduction zones
to French Polynesia
Japan, Kuril,
Kamchtaka
12-13 hours
Aleutian
11 hours
Tonga
3 -4 hours
CPPT : Centre Polynésien de prévention des Tsunamis
Chile - Peru
10 - 11
hours
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
Warning from a
given threshold
(mag 7.0)
N
Z
E
Seismologist
24h/24h on
duty
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
Magnitude
Mm > 8
7 < Mm < 9
Location
coming from TONGA
any except TONGA
9
hours
level 2
6
hours
level 3
3
hours
return to normal
level 4
level 1
level 4
level 1
* Transfer from a level to another is automatic, except on information given by LDG
GREEN
YELLOW
ORANGE
RED
GREEN
level 1
level 2
level 3
level 4
level 1
normal situation (wakefulness)
central alert (HC + local government)
local alert (districts)
general alert (population evacuation)
return to normal situation,launched on LDG communication
Flow-chart of present warning to populations
LDG
LEVEL 2
HC - DPC
LEVEL 3
Mayor
TV, radio
LEVEL 4
The warning
could start at any
level in function of
available delays
Territorial
administrator
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
TAHITI
community
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).
End
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Populations’ alert, especially in case of tsunami