Subaqueous spreading: characteristics, evolution and its suitability as a paleoseismic proxy

Descrizione del progetto

Lo studio del suolo compie passi avanti in Nuova Zelanda

L’espansione del suolo è un fenomeno osservato in tutto il globo e costituisce un pericolo per le infrastrutture subacquee e per quelle sulla terra ferma. Il progetto SubSpread, finanziato dall’UE, analizzerà i fattori geologici che influenzano la meccanica di tale fenomeno. Grazie all’analisi di dati pubblicati relativi all’espansione del suolo a livello subacqueo e sulla terra ferma, il progetto studierà gli elementi che lo provocano e i suoi meccanismi di sviluppo. Inoltre, la ricerca si concentrerà sul ruolo svolto dall’espansione del suolo come nuova base per il sostegno di analisi paleosismiche in ambienti subacquei e prenderà in esame le caratteristiche distintive di tale fenomeno grazie ai dati stratigrafici e batimetrici d’archivio del lago Tekapo, nell’Isola del Sud in Nuova Zelanda. I risultati raggiunti miglioreranno la comprensione dell’espansione del suolo lungo l’enorme frana di Storegga sul margine norvegese e getteranno luce sulle ricerche paleosismiche in corso presso i laghi alpini.

Obiettivo

Soil spreading is an extensional creeping movement occurring along a shear surface and caused by liquefaction of a gliding plane. Spreading has been documented at many sites worldwide, and it represents an hazard for subaqueous and land infrastructures. Geological factors influencing the mechanics of spreading and its development have not been extensively explored. This proposal focuses on characterising the subaqueous spreading and investigating its triggers and development mechanisms, with the final purpose of testing the use of the spreading signature as a new proxy for paleoseismic research. The methodology will involve a comprehensive analysis of published data on on-land and subaqueous spreading, gathered in two databases respectively. This information will support the development of a 2D Finite Element model implemented on the Tuaheni slide complex (North Island of New Zealand). The final part of the project will investigate the role of spreading as a new proxy for supporting palaeoseismic analysis in the subaqueous setting. Spreading signature will be investigated in the stratigraphic and bathymetric record of Lake Tekapo (South Island of New Zealand). Results from this research will be significant to the European community, as they will be exploited to improve the understanding of spreading along the giant Storegga Slide on the Norwegian margin, and in relation to the on-going palaeoseismic research on Alpine Lakes. The beneficiary of this funding would be the University of Malta, whereas GEOMAR (Germany) and NIWA (New Zealand) will be partner organizations. This funding represents an ideal opportunity for the fellow allowing her to transfer the knowledge on land liquefaction and palaeoseismology to the subaqueous setting. Through this project the fellow will learn about subaqueous geophysical interpretation (bathymetry, 2D and 3D seismic reflection), geomorphometry and finite element analysis, and to return to Europe to undertake high impact research.