REGIONAL EARLY TSUNAMI WARNING SYSTEMS UTILIZING SYSTEM TECHNOLOGY
(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.)
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 (project leader), Mr. Paul Krumpe, Lt. Richard Behn, Mr. James Lander, Mr. Peter McManonan and myself, (George Pararas=Carayannis – 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.