Underwater earthquake characterization by acoustic radiation analysis

Gomez Perez, Bernabe 2021. Underwater earthquake characterization by acoustic radiation analysis. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

A common cause of tsunami waves in the ocean is underwater seismic events, which also generate acoustic radiation. Three fundamental aspects of the introduced physical process are that the sound-induced by underwater tectonic events carries information about its source, it can be recorded by distant hydrophones and it travels much faster than tsunamis in the ocean. To predict tsunami propagation, it is first necessary to have reliable data relating to the rupture characteristics such as uplift speed, duration, fault geometry and epicentre location. In this thesis, particular attention is given to the development of a semi-analytical inverse approach that can be employed in near real-time on acoustic signals, assuming the fault is single, slender and uniform and the seabed is flat. Moreover, a methodology to apply the presented model to real hydrophone recordings was developed. To infer the remaining characteristics (slip type and magnitude of the event) of the studied recorded events, an algorithm that combines digital signal processing techniques with machine learning techniques has been produced and tested by analysing hydrophone recordings of 201 tectonic events, located in the Pacific and the Indian Ocean. Finally, tectonic event scenarios reported by NOAA to have triggered tsunamis were chosen to be replicated using the inverse problem model solutions. The earthquake parameters retrieved by the inverse problem model were used as input to the COMCOT numerical model which, in turn, output surface wave elevations (tsunami) to be validated against DART buoy data and tide gauges.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Mathematics
Date of First Compliant Deposit:	31 March 2022
Last Modified:	14 Dec 2022 02:24
URI:	https://orca.cardiff.ac.uk/id/eprint/148990

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