abstract
Historical earthquake records are crucial for analyzing high-intensity earthquakes that occur over long periods. Since good instrumental data only date back to 1980, there are gaps in our knowledge, and qualitative assessments remain essential to expand our knowledge and integrate more information into the number of variables under analysis. This study examined the hydrological and hydrogeological effects of the 1755 Lisbon earthquake, focusing on regions near rivers and proposing new insights for intensity scales. This information is relevant for seismic risk management and mitigation, to be discussed in regional and national territorial planning strategies. Mapping revealed that most phenomena occurred along the Porto-Tomar tectonic fault, with some extending to other probable faults or geological contrasts. A comparative chart between existing intensity scales and the proposed descriptors highlights agreements and discrepancies, emphasizing the need for more detailed descriptors for intensity levels below X for river-related phenomena. The proposed descriptors include a flow increase with course alterations (intensities VI-VIII), flow suppression and eventual reset (intensity VIII or higher), abnormal current agitation and vertical wave movements (intensities VI-VIII), and cloudy (turbid) water (intensities V-VIII). This work also highlights the need to cross-reference data and the complexity of establishing correlations between effects, ancient descriptions, and descriptors for these intensity scales.
subject category
Water Resources
authors
Tavares, A; Costa, A; Oliveira, CS
our authors
Alice Tavares
Assistant ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
Civil Engineering And Geomatics Innovative Research On Heritage (ENGINEER)
acknowledgements
This research was funded by national funds through FCT/MCTES (PIDDAC) under grant numbers UIDB/50011/2020, UIDP/50011/2020, LA/P/0006/2020, and DOI 10.54499/2021.03830.CEECIND/CP1659/CT0032 and UIDB/04625/2020. This project also received funding from the European Union's Horizon Europe Framework Programme under grant agreement number 101079377, and from UKRI under project number 10050486.