Abstract
Abstract. Coastal tide gauges play a very important role in a tsunami warning system, since sea-level data are needed for a correct evaluation of the tsunami threat, and the tsunami arrival has to be recognized as early as possible. Real-time tsunami detection algorithms serve this purpose. For an efficient detection, they have to be calibrated and adapted to the specific local characteristics of the site where they are installed, which is easily done when the station has recorded a sufficiently large number of tsunamis. In this case the recorded database can be used to select the best set of parameters enhancing the discrimination power of the algorithm and minimizing the detection time. This chance is however rare, since most of the coastal tide-gauge stations, either historical or of new installation, have recorded only a few tsunamis in their lifetimes, if any. In this case calibration must be carried out by using synthetic tsunami signals, which poses the problem of how to generate them and how to use them. This paper investigates this issue and proposes a calibration approach by using as an example a specific case, which is the calibration of a real-time detection algorithm called TEDA (Tsunami Early Detection Algorithm) for two stations (namely Tremestieri and Catania) in eastern Sicily, Italy, which were recently installed in the frame of the Italian project TSUNET, aiming at improving the tsunami monitoring capacity in a region that is one of the most hazardous tsunami areas of Italy and of the Mediterranean.
Highlights
Coastal tide gauges are the oldest, most used, easiest to maintain and cheapest instruments to record tsunami signals, and, in the frame of a centralized tsunami warning system (TWS) with real-time data processing, they provide information about the propagation and the magnitude of the occurring event
In order to evaluate and compare the different algorithm configurations, we have introduced two performance indicators, which are the number of event detections (ND) and the delay time (DT)
If we use the empirical frequency distributions (EFDs) mode, instead of the standard deviation, we find the same picture, which is stability over year-long bases and seasonal variability, with a strong inverse correlation between standard deviation and mode, which is a confirmation of the correctness of the assumption that EFDs of |IS| are oneparameter distributions
Summary
Coastal tide gauges are the oldest, most used, easiest to maintain and cheapest instruments to record tsunami signals, and, in the frame of a centralized tsunami warning system (TWS) with real-time data processing, they provide information about the propagation and the magnitude of the occurring event. One of the first algorithms was designed by Mofjeld (1997) and installed in the DART bottom pressure recorder (BPR) systems for the Pacific TWS. Others were later devised for GPS buoys and acoustic/pressure wave gauges in Japan by Shimizu et al (2006), and for coastal tide gauges in Canada (Rabinovich and Stephenson, 2004). Among the most recent efforts, one can mention the studies of tsunami detection algorithms for high-frequency (HF) radar installations (Gurgel et al, 2011; Lipa et al, 2012), for BPR sensors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
