TSUNAMI: SAMOA PERSPECTIVE

Report
TSUNAMI: SAMOA PERSPECTIVE
Malaefatu Leavasa
Ministry of Natural Resources, Environment and
Meteorology
(Meteorology Division)
INTRODUCTION
 Tsunami (tidal wave) is coined differently in
Samoan terms: ‘galuafi’- in Samoa meaning a
wave of fire, associated with the high speed of
movement (300 – 600 miles per hour) compared
to the fast spread of a fire. It is an earthquake
generated tidal wave
 Not to be confused with ‘galulolo’ – tidal wave, or
storm surge – a tropical cyclone effect
Local Tsunami Procedures
 Organization that identifies and characterizes tsunamigenic
events in the immediate source area:
 At present, the national capability for identifying or characterizing
tsunamigenic events in the immediate local source area is weak. The
Samoa Meteorology Division (SMD) utilizes the single GSN seismic
station to calculate the magnitude and location of local seismic events
(using the DIMAS2003 single station software), and basis their decision
on whether to issue a tsunami watch/warning using the information
produced. This protocol is relatively unreliable. SMD relies heavily on
tsunami information bulletins issued by the Pacific Tsunami Warning
Center (PTWC), and basis their decision on whether to undertake
national procedures to issue a public watch or warning using that
information. This protocol of reliance on PTWC is only effective for
teletsunamis, and not for tsunamis generated in local geologic settings.
 Threshold for declaring a potential local tsunami emergency:
 Earthquake Magnitude (Mw) >= 6.5; Located in the Tonga, Samoa, or
Fiji Islands Region.
 Organization that acts in the information provided by the agency
responsible for characterizing the local tsunami threat:
 The National Disaster Management Office (NDMO) of SMD alerts the
National Disaster Council (NDC), (which is chaired by the Prime
Minister and comprises cabinet ministers and members of the foreign
diplomatic community), as well as local authorities of the threat for their
appropriate response.
 SMD also issue warnings directly to local media outlets (television and
radio station) based on the recommended approval by the NDC.
 How is the emergency situation
terminated?
 Based on the recommendation by SMD, and
executed through the decision of the NDC.
The NDMO alerts local authorities
accordingly based on the decision by the
NDC. Similarly, SMD alerts the public
through relevant media outlets.
Distance Tsunami Procedures
 SMD becomes aware of this information, by means of tsunami
information bulletins issued by the Pacific Tsunami Warning Center
(PTWC) via Fax, Email, and the EMWIN (Emergency Managers
Weather Information Network) system. Local verification systems
however, are weak.
 What actions does this organization take with regard to
tsunamigenic events from a distant source?
 The NDMO is contacted, and similar procedures followed in the event
of a local tsunami source threat are adhered to.
Con´t

What actions are taken in response to warnings issued by PTWC during
intersessional periods?

Where local capability permits, local information is checked, and the NDMO is notified for
their appropriate response actions. Monitoring using web-based sources is intensified,
and the procedures followed during the event of a tsunami generated from a local source
are implemented.


National Sea Level Network:
Samoa currently has one tide-gauge installed under the South Pacific Sea Level and
Climate Monitoring Project. The station was installed in 1991, and is located on the
northern coast of Upolu island, at the Apia wharf. Data is transmitted to the National Tidal
Center, Bureau of Meteorology, Australia, via the GOESS satellite system. The gauge is
insufficient however in verifying tsunamis generated on the southern coast of Samoa.
Information on tsunami occurrences:

No local or regional tsunami occurrences have affected Samoa in the last year.
Summary

Tsunami mitigation efforts in Samoa are still at their infancy stages. There
exists no national seismic network, although plans to establish this network
utilizing foreign aid are underway. A proposal has been submitted to JICA
(Japan International Cooperation Agency) for the deployment of a short-term
Senior JICA Volunteer with 15 years experience in the field of seismology, to
assist local authorities in planning the establishment of a national seismic
network, as well as national Tsunami and Seismic Operational Response
Plans. Assuming this initiative goes as planned, the next step for Samoa would
be to submit proposals to either Japan or other interested donors for the actual
implementation of these plans. National efforts are currently underway in the
development of a national tsunami operational response plan under the World
Bank funded Samoa Infrastructure Asset Management Project, Phase II, but
mainly in the context of capacity and awareness building. Efforts at the regional
level to establish a South Pacific Tsunami Warning Center are currently
underway, of which Samoa is involved in. Overall, Samoa still has long road to
walk in the area of developing efficient and effective tsunami early warnings
and hazard mitigation systems.
Narrative

Seismic Network and Data Center:

Samoa currently has one (1) GSN/IMS auxiliary seismic station installed, of
which events are viewed using the LISS (Live Internet Seismic Server) system.
Data is transferred to the CTBTO in Vienna, and onto ASL in New Mexico, via
GCI and GOESS satellite systems. The data is then transferred to IRIS-DMC in
Seattle where the data is archived. The DIMAS2003 software is used locally to
calculate the magnitude and location of events, as the software was designed
to calculate these parameters from a single station. The entire process
however is relatively obsolete in the context of a worse case scenario, where
the operational response time is within a window of approximately 1 to 2 hours.
Plans to establish a national seismic network are underway, and it is hoped
that the national capability to operate a seismic network will be developed in
the next 2 to 5 years.
 Communication System – Transmission of warning
messages:
 At the national level, tsunami warnings are communicated
via radio and television networks (media outlets), as well
as email and fax systems to relevant local authorities.
There exists no direct emergency communication system
to rural communities and local authorities, although this is
an area that is slowly being addressed. SMD intends to
utilize the new communication system to be established in
the
month
of
January
2006
by
the
local
telecommunications companies, which would enable the
transmission of tsunami warnings to cellular phones via
email.
 Education and information to the public:
 Tsunami awareness and education falls under the
jurisdiction of the NDMO, and the Annual National Disaster
Awareness Day to be held in the month of November 2005
will bear a strong emphasis on tsunami warnings and
disaster mitigation. SMd, in collaboration with the Samoa
Tourism Authority held a tsunami mitigation workshop in
the month of January 2005, aimed at raising local coastal
tourism resort operators’ awareness of tsunamis, as well as
possible methods of mitigating tsunami disasters.
 Tsunami Hazard Assessments:
 An updated national tsunami hazard assessment has not yet been
implemented. This is a planned activity in SMD’s 2005/2006 annual
management plan.
 Regional Cooperation:
 Samoa is party to the Pacific Tsunami Working Group (PTWG), which
is currently I the process of planning the establishment of a South
Pacific Tsunami Warning Center to be established in Fiji. It is
envisaged that this endeavour will yield fruitful results in the next 2 to 5
years.
SIGNIFICANT CASE STUDIES
 Historically, tsunamis of any significance that
affected Samoa: 1960 – Chilean earthquake,
generated a ‘tsunami’, reports of waves that swept
up Fagaloa Bay area, east Upolu Island [Samoa Times
ed.1960]
 August 31, 1981 – A South American region
earthquake generated a ‘tsunami’, waves swept
inland between 20 - 25 metres at Taga and
Manono [ Saifaleupolu et.al , 1981]
More information….TSUNAMI






PACIFIC TSUNAMI WARNING CENTER (PTWC)
Earthquakes are obtained from internet from NEIC.
1. Earthquakes >6.5 and <7.5mag or < 7.0 in the Aleutian Islands – Information
Bulletin is issued by PTWC.
2. Earthquakes > 7.5 (>7.0 in the Aleutian Is) – Tsunami Warning/Watch
Bulletins are issued.
Regions within 3 hours of tsunami travel time will receive warning .
Regions between 3 – 6 hrs of tsunami travel time will receive watch.
More information….TSUNAMI
 TRAVEL TIMES FOR
TSUNAMI WAVE
FROM PERU
EARTHQUAKE IN
JUNE 2001(SEA LEVEL AND
CLIMATE MONITORING PROJECT COUNTRY
REPORT – MARCH 2003)
More information….TSUNAMI
 TSUNAMI WAVE DUE
TO PERU
EARTHQUAKE
(SIMULATED
AMPLITUDE)
More information…..TSUNAMI
 APIA SEA LEVEL IN
RESPONSE TO PERU
EARTHQUAKE (JUNE
2001)
 PEAK TO TROUGH
AMPLITUDE ~30 CM

(SLCMP- COUNTRY REPORT - MARCH
2003)
Thank you for your attention
Faafetai tele lava

similar documents