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REGIONAL EARLY
TSUNAMI WARNING SYSTEMS UTILIZING SYSTEM TECHNOLOGY
George Pararas-Carayannis
(Excerpts
from a Paper Presented at the Pacific Congress on Marine Technology,
April 24-27, 1984, Honolulu, Hawaii.)
(NOTE: Although this
paper was written many years ago, the concepts described on the
need for regional tsunami (and other disaster) warning systems,
still hold true today. Although instrumentation may be enhanced
as satellite and other remote sensing technologies advance, the
methodology for developing regional tsunami (or other disaster)
warning systems, must employ a comprehensive approach. No matter
how advanced the technology may be - and to be effective - there
is a fundamental need to integrate it in warning dissemination
procedures that will be understood by the public.)
SUMMARY
There are areas in
the Pacific for which the Pacific Tsunami Warning Center (PTWC)
in Honolulu cannot provide suitable warning information within
one hourr after tsunami generation. A need exists for regional
early warning systems which can react within 3-1O minutes after
a potentially tsunamigenic event has occurred. The equipment
needed to assemble an early warning system, from land and sea
based sensors to satellite-based communications links is presently
available. Such hardware system can be tailored to the needs
of national disaster control authorities and skillfully adopted
to their existing response apparatus, to enhance the capability
to cope with their tsunami threat. Satellite telemetry can be
used, not only for data collection, but also to disseminate,
receive and display tsunami, warnings utilizing existing Geostationary
Operational Environmental Satellites such as G0ES, and Data Collection
Interrogation System (DCIS). The use of satellite telemetry allows
the lag between the event and the receipt of initial data to
be reduced to the order of a few minutes, thus providing enough
time for regional early warnings. Integrating this technology
into the infrastructure of an existing Civil Defense response
organization is necessary for effective tsunami hazard management
during an actual event.
 A pilot study named THRUST (Tsunami Hazard Reduction
Utilizing System Technology) was funded by the U.S. Foreign Disaster
Assistance (USFDA), Agency for International Development (AID)
(in 1984), to determine the feasibility of applying technological
advances to an early warning system centered on one tsunami susceptible
area - both to prove the concept and to develop a prototype for
similar early warning systems elsewhere. Valparaiso, Chile was
chosen as the site because it represented an urban area with
high probability of tsunami occurrence. (See photo: Extensive tsunami damage at Isla
Chiloe from the Great Ghilean Earthquake and Tsunami of May 22,
1960).
A program was developed
along specific elements of data collection and analysis in the
pre-event, and in the event phases. In the pre-event phase it
was necessary to compile historical and all available information
related to tsunami effects in the area under study. The purpose
of this data collection was to assemble into forms suitable for
use in model studies, emergency preparedness plans, training
exercises, etc., as part of a complete package. In the real-time
phase, the emphasis shifts to collecting quickly and reporting
seismic and water level data which can be used to identify the
sudden existence of a tsunami and to assess its potential threat.
The use of the satellite-based telemetry reduces the data collection
time to a minimum. The real-time analysis of the results of the
data collection must be combined with an incoming data stream
to provide continuous updating of predictions.
In the information
dissemination, complete and thorough knowledge of the post country's
tsunami response infrastructure is needed, as well as the development
of an educational program. The real-time phase of information
dissemination, the actual transmission of the warning information
to the threatened population must be interfaced with the automated,
satellite-based information gathering network, and the human
decision making process. It must be formulated so that the technological
hardware merges with the requirements and capabilities of the
local disaster response system. Standardization of the procedures
must be accomplished and the decision making must be made simpler
so that officials would have one set of procedures to follow
and should not find it necessary to improvise responses or evaluate
the data sugjectively. Also, because of the public education
awareness program the threatened population should know how to
respond to ensure their own safety.
The knowledge gained
from this study will be applicable to the development of better
hazard system management ability and the design of effective
regional tsunami warning systems.
REGIONAL EARLY TSUNAMI
WARNING SYSTEM UTILIZING SYSTEM TECHNOLOGY
There are areas in
the Pacific for which the Pacific Tsunami Warning Center (PTWC)
in Honolulu cannot provide suitable warning information within
one hour after tsunami generation. A need exists for regional
early warning systems which can react within 3-1O minutes after
a potentially tsunamigenic event has occurred.
As early as 1978 when
GOES tidal platforms were designed to communicate directly via
the satellite system, suggestions were made that the satellite
telemetry could be used, not only for data collection but, also
for warning dissemination. A proposal was written to demonstrate
the use of this advanced system technology to disseminate, receive,
and display tsunami warnings utilizing the Geostationary Operational
Environmental Satellite (GOES), Data Collection Interrogation
System (DCIS). The warning dissemination instrumentation was
to consist of the GOES_DCIS, a UNF receiver tuned to the GOES
down link (468 Mhz), a microprocessor, storage for 100 words,
and an inter/communications terminal. The study was to be comprised
of three tasks: l) system definition, 2) system implementation,
3) system test and evaluation. The basic concept was to develop
the technology for regional early warning systems for areas exposed
to tsunamis generated by local earthquakes, and for areas for
which PTWC could not provide suitable information within one
hour after tsunami, generation.
 In late 1982, the Office of U.S. Foreign Disaster
Assistance (USFDA) Agency for International Development (AID),
commissioned a study to determine the feasibility of applying
current technological advances to this problem of early warning.
The study panel concluded that all the equipment needed to assemble
an early warning system, from land and sea based sensors to satellite-based
communications links was available; that the cost of integrating
this existing hardware into a warning system would be relatively
small; that such a hardware system tailored to the needs of national
disaster control authorities and skillfully adapted to their
existing response apparatus, could significantly enhance the
capabilities of developing nations to cope with their tsunami
threat; and that such a network would also serve to enhance the
capability of PTWC to respond to the Pacific-wide threat inherent
in every tsunami.
The panel recommended
that a small pilot study, centered on one tsunami susceptible
area, be undertaken both to prove the concept and to develop
a prototype for similar early warning systems elsewhere. This
pilot study was named THRUST (Tsunami Hazard Reduction Utilizing
System Technology). The objective was to use Satellite telemetry
to disseminate, receive and display tsunami warnings utilizing
the existing Geostationary Operational Environmental Satellite
(G0ES), Data Collection Interrogation System (DCIS). The use
of satellite telemetry allows the lag between the event and the
receipt of initial data to be reduced to the order of a few minutes,
thus providing enough time for regional early warnings. Integrating
this technology into the infrastructure of an existing Civil
Defense response organization is necessary for effective tsunami
hazard management during an actual event.
In terms of conceptual
model framework the proposed early warning system would have
three broad tasks that needed to be completed and integrated:
data collection, data analysis, and information dissemination.
Application of this model had to reflect the geophysical, oceanographic,
and sociopolitical character of the specific site for which it
was to be used. For example the geophysical characteristics which
determine the seismic instrument design and placement; the oceanographic
characteristics which determine water level gauge placement and
design; and finally the sociopolitical characteristics which
determine the emergency system design. It was realized that integrating
these factors successfully into a prototype system was a difficult
task which had to be accomplished on a case-by-case basis. The
proposed program was further developed along specific elements
of data collection and analysis in the pre-event, and in the
event phases.
During the pre-event
phase, this task consists of compiling, cataloging, and synthesizing
all available information related to tsunami effects in the area
under study. This includes the historical studies of seismic
wave activity, run up and flood data, and land and sea topographies.
The purpose of this phase is to assemble these data into forms
suitable for use in model studies, emergency preparedness plans,
training exercises, etc., as part of a complete package. In the
real-time phase, the emphasis shifts to collecting quickly and
reporting seismic and water level data which can be used to identify
the sudden existence of a tsunami and to assess its potential
threat. Here, the use of the satellite-based communications technology,
in the form of the GOES system, allows the lag between the event
and the receipt of initial data to be reduced to the order of
several minutes, thus providing enough time for regional early
warnings. Other elements of the study include the data analysis
of the historical data in the pre-event phase, and in the real-time
analysis of the result to be combined with the incoming data
stream to provide continuous updating of both local and Pacific-wide
threat predictions.
Information Dissemination: In designing a complete regional
system, warning dissemination has to be based on complete and
thorough examination of the host country's tsunami response infrastructure
to determine lines of responsibility, how the system works, where
it could be improved, what its basic requirements are, and how
best to integrate the early warning technology into it. Developing
the education program is an integral part at heightening awareness
of the tsunami threat. In the real-time phase, the actual transmission
of the warning information to the threatened population areas
must be interfaced with the automated, satellite-based information
gathering network, and the human decision making process. It
must be formulated so that the technological hardware merges
with the requirements and capabilities of the local disaster
response system.
Description of the
Regional Prototype Systems Using THRUST Technology: 
The following scenario
evolves: An earthquake activates a seismic instrument. This instrument
transmits a signal to the G0ES platform, which responds by automatically
transmitting an alert code to an alarm device at the warning
site designated by local authorities. The alarm device instantly
responds by initiating a set of prerecorded instructions based
on procedures agreed upon prior to the tsunami. These instructions
may include transmitting printed or voice synthesized messages
to disaster control headquarters, automatic telephoning of on-duty
officials, turning on sirens in population centers, or a wide
number of other choices. In addition, GOES also alerts tide gauges
near the earthquake to begin sending data via satellite both
to local authorities and to PTWC to confirm the presence of a
tsunami as a result of the earthquake.
This process, which
is entirely automatic, takes no more than 3 minutes to complete.
No human decisions are made except possibly for a predetermined
one to sound a general alarm. Final authority to make a decision
whether to issue an alert or to sound the "all clear,. must
rest with human officials. Decision making would be simpler because
of the awareness facing them. Because the tsunami response plans
and procedures have been implemented in the pre-event phase,
these officials would only have a set of procedures to follow
and should not find it necessary to improvise responses or evaluate
the data. Also because of the public education and awareness
program, these officials should be confident that the threatened
population knows how to respond to ensure their own safety. Lastly,
they can be sure that the sensors and the real-time analysis
package are providing them with the most up-to-date information
available.
Following the study
of the conceptual model and its required components, as well
as the technical aspects of the satellite telemetry system, a
team of scientists consisting of Dr. Eddie Bernard (projects
leader), Mr. Paul Krumpe, Lt. Richard Behn, Mr. James Lander,
Mr. Peter McManonan and myself (then Director of ITIC) completed
in early October 1983 a site visit to Chile for the THRUST tsunami
project in that country. Chile was chosen because it has the
longest coastline and because of the likelihood of a large event
occurring along the Peru/Chile trench. The visit was sponsored
by the office of U.S. Foreign Disaster Assistance of the Agency
for International Development (OFDA). The project was envisioned
as a 3-year project. The primary objective of the project was
to develop, test, and evaluate an early Tsunami Warning System
for a tsunami-prone urban area. Valparaiso, Chile, was chosen
as the site for the THRUST project because it represents an urban
area with high probability of tsunami occurrence.
While in Chile, the
team met with the Chilean counterparts on the project and planning
and coordination meetings were held at the U.S. Embassy, at the
University of Chile, and at the National Emergency Office in
Santiago. In Valparaiso, coordination meetings were held at the
Headquarters of the Chilean Tsunami Warning Center at the Navy
Hydrographic Institute. The Hydrographic Institute is the lead
agency-in Chile responsible for data collection and tsunami warning
dissemination. Captain Eduardo Barison Roberts, the Institute's
Director, hosted the conference and members of his staff, Cmdr
Patricio Figueroa Mr. Richardo Montaner, Mr. Alfonso Campusano,
Hr. Emilio Lorca, Hr. Ricardo Rodas and Mr. Ariel Vera participated
and coordinated the decisions of site selection, data collection,
telemetry and integration with the existing tsunami warning system
in Chile.
In Santiago, the project
was coordinated with the Director of the National Emergency Office,
General Victor Lopez and his staff, and the Director of the Department
of Geophysics of the University of Chile, Dr. Edgar Kausel and
his staff. As a result of this site visit, a proposal was drafted
and submitted to AID to support a 3-year project to test and
evaluate the prototype system in Chile. ITIC's involvement is
to identify disaster response organizations, determine their
infrastructure, and make recommendations in the adaptation of
the THRUST technology. Additionally, ITIC is charged with the
responsibility of collecting historical data on tsunamis and
earthquakes in Chile to be used in a hazard analysis which will
identify source regions along the coast of Chile that can generate
destructive tsunamis; examine earthquake and tsunami frequency
of occurrence; prepare seismic energy release maps; prepare risk
analysis maps showing historical maximum tsunami run up values;
assess tsunami predictability and response; prepare inundation
and evacuation maps. ITIC will examine existing communications;
evaluate tsunami assessment capability in terms of proposed THRUST
technology; and assess effectiveness of tsunami warning dissemination
to the public. In terms of disaster reporting, ITIC will get
involved in the preparation of a report outlining disaster protective
measures that can play a role in mitigating the effects of the
tsunami, and will coordinate in the preparation of an operational
manual which describes tsunami response operations and responsibilities
to be followed in disseminating rapidly to the public tsunami
warning information.
To summarize the scope
of the work of the THRUST project, the project entails the development
of tsunami and earthquake data base, verification of a tsunami
numerical model, preparation of hazard assessment maps for the
coastline combining historical and modeling results, the establishment
of seismic and tidal sensors using satellite telemetry to provide
early warning information, and finally, the integration of the
new early warning technology to an existing local system.
In conclusion,
the experience gained from this prototype pilot study in Chile
utilizing the THRUST technology will be a very useful experience,
not only in terms of communication and instrumental capability,
but also from the point of integrating such technology into the
infrastructure of an existing Civil Defense response organization
for effective tsunami hazard management during an actual event.
The knowledge gained will be applicable to the development of
better hazard system management ability for other ITSU member
nations.
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