Vertical ground motion and historical sea-level records in Dakar Senegal Vertical ground motion and historical sea-level records in Dakar SenegalReportar como inadecuado




Vertical ground motion and historical sea-level records in Dakar Senegal Vertical ground motion and historical sea-level records in Dakar Senegal - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

1 BRGM - Bureau de Recherches Géologiques et Minières 2 LGP - Laboratoire de géographie physique 3 LIENSs - LIttoral ENvironnement et Sociétés - UMR 7266 4 LEGOS - Laboratoire d-études en Géophysique et océanographie spatiales

Abstract : With growing concerns regarding future impacts of sea-level in major coastal cities, the most accurate information is required regarding local sea-level changes with respect to the coast. Besides global and regional sea-level changes, local coastal vertical ground motions can substantially contribute to local changes in sea-level. In some cases, such ground motions can also limit the usefulness of tide-gauge records, which are a unique source of information to evaluate global sea-level changes before the altimetry era. Using satellite synthetic aperture radar interferometry, this study aims at characterizing vertical coastal ground motion in Dakar Senegal, where a unique century-long record in Africa has been rediscovered. Given the limited number of available images, we use a stacking procedure to compute ground motion velocities in the line of sight over 1992–2010. Despite a complex geology and a rapid population growth and development, we show that the city as a whole is unaffected by differential ground motions larger than 1 mm year −1. Only the northern part of the harbor displays subsidence patterns after 2000, probably as a consequence of land reclamation works. However, these ground motions do not affect the historical tide gauge. Our results highlight the value of the historical sea-level records of Dakar, which cover a 100 year time-span in a tropical oceanic region of Africa, where little data are available for past sea-level reconstructions.

Keywords : geodetic instruments Dakar African coasts sea-level rise tide gauges vertical ground motions





Autor: Gonéri Le Cozannet - Daniel Raucoules - Guy Wöppelmann - Manuel Garcin - Sylvestre Da Sylva - Benoit Meyssignac - Médéric Gra

Fuente: https://hal.archives-ouvertes.fr/



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