Estudo e análise dos efeitos do Tsunami de Tonganas regiões de Imbituba - SC, Arraial do Cabo, - RJ e Salvador - BA, com aplicação de técnicas de filtragem de dados de nível do mar

Abstract

This study aimed to analyze the effects of the Tonga tsunami that occurred in 2022 on the coasts of the regions of Imbituba, Arraial do Cabo, and Salvador, despite their considerable distances from the epicenter. To obtain the necessary data for this investigation, referring to the month of January 2022, the study relied on the National Oceanic Data Bank, from the Navy Hydrography Center, and the Permanent Mareographic Network for Geodesy, managed by the Brazilian Institute of Geography and Statistics. To understand the extent and nature of these effects in the three regions in question, we employed a series of sophisticated data analysis techniques. Initially, data quality control was carried out using the QARTOD method. Subsequently, the data underwent the Thompson filter, which provided an initial layer of interpretation regarding wave behavior, focusing on the frequencies of the tsunami. One of the main techniques used was the Hilbert-Huang Transform. Through it, it was possible to decompose the signals into their Intrinsic Mode Functions (IMFs). Each of these IMFs was individually subjected to the Fourier Transform, offering a detailed frequency analysis of the tsunami effects. In addition, to complement this analysis, the Wavelet Transform was used. This technique allowed the identification of nuances in the oscillations of the sea level in response to the tsunami. The results showed significant variations in the response of each region to the tsunami, with an approximate period between 2 and 3 hours. The study also concludes that underwater geography and the features of the continental shelf play a crucial role in how different Brazilian coastal regions respond to tsunami events.