3 Natural Hazards, Catastrophes, and Risk Mitigation I

Monday, 5 September 2011
11:00 AM - 4:40 PM
A 014

A PROTOTYPE SYSTEM FOR TSUNAMI EARLY WARNING BASED ON REAL-TIME GPS

Paper number: 3-4
Program: Theme Sessions
Time: 3:50 PM – 4:10 PM

Authors

Abstract

Reliable tsunami early warning requires a rapid assessment of the tsunamigenic potential of an earthquake as well as a prediction of the likely propagation pattern of the tsunami. Low-latency availability of the coseismic Earth's surface displacements can support the assessment of the tsunamigenic potential of an earthquake and improve predictions of the propagation pattern of the tsunami.

Here we present the GREAT Alert, which is a NASA-sponsored, real-time prototype system designed to enhance tsunami warning capability. The system takes advantage of the increasingly available global and regional real-time GPS data, as well as advanced fault and ocean dynamics models to enable more accurate and timely assessment of the magnitude and mechanism of large earthquakes, and the magnitude and direction of resulting tsunamis. We will describe the prototype operational system being developed in a multi-agency collaboration.

The key system components are:

(1) the operational real-time estimation of site coordinates from hundreds of GPS sites using a precise point positioning algorithm;

(2) the application of data filtering and quality control techniques to the real-time site position time series in order to enhance the accurate retrieval of co-seismic site motions;

(3) usage of either an empirical inversion model or a “fingerprint” model, which maps slip on a fault segment to surface displacement, for the rapid determination of the earthquake displacement field from the GPS-based records at each station;

(4) the input of detected and modeled seafloor displacements into a special ocean dynamics model to determine tsunami source energy and scales, and estimate the tsunami propagation;

(5) the dissemination of the results to the responsible agencies to help in their decision making processes.

We will discuss the actual and predicted performance of the system, particularly in light of recent great earthquakes around the globe, and in view of the rapid development of real time GPS stations being used to monitor the Cascadia subduction zone near the Pacific coast of the United States.