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Measuring and Forecasting the Background Open Ocean Tsunami Spectrum

Description: 

he background open-ocean tsunami spectrum (BOOTS) is an under-studied topic in the tsunami sciences. It describes the spectrum of oscillations that occur out in the open-ocean within the tsunami band (1 min-2 hrs). It plays a key role in understanding the local site response at coastal sea level stations, which can be extended to show the tsunami site response at locations where no sea level data is available. The objective of our research is to measure the BOOTS and its noise and forecast these variables using a graphical neural network.

For the analysis, we use data from the recovered bottom pressure recorders of DART stations, which have a sampling rate of 15 seconds. With this sampling rate, it is possible to measure the BOOTS over the full tsunami band. The quality-controlled de-tided pressures are used in the calculation of power and amplitude spectra. These spectra are computed every two weeks for each DART station for as long as fidelity data are available. Tsunami events anywhere in the Pacific and Atlantic basins over the time frame of 2000-2022 are filtered out to ensure that the spectra are mainly that of the background oscillations. Spectra generally have a simple log-linear decay, so we utilize a least-squares inversion to compute the slope and intercept of the spectra— e.g., the energy and noise of the background state. From these spectra, we construct a time-series of the two parameters that shows the temporal variation for each DART station. We then use these data as inputs to forecast these parameters via a graphical neural network.

Session: Six Decades of Tsunami Science: From the Source of the 1964 Tsunami to Modern Community Preparedness [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Sean

Student Presenter: Yes

Invited Presentation: 

Authors