Detection of subsidence in the Ebro Delta plain using DInSAR: analysis of the measurements and the factors that control the phenomenon

Xavier Rodriguez-Lloveras,Oscar Mora,Miquel Vilà,Jordi Marturià,Fernando Pérez,Roser Pi

doi:10.5194/piahs-382-803-2020

Xavier Rodriguez-Lloveras, Oscar Mora + Show 4 more

Open Access

https://doi.org/10.5194/piahs-382-803-2020

Copy DOI

Abstract

Abstract. The Ebro Delta is a highly vulnerable Mediterranean coastal ecosystems located on the northern Mediterranean coast of Spain. Determining its subsidence rate and sources is a key issue for the present and future management of this area. Differential Interferometry Synthetic Aperture Radar (DInSAR) compared with the contribution to subsidence of the compaction of delta's sediments and the lithosphere's deformation, indicated a general Ebro Delta subsidence ranging from <1 to ∼ 2.3 mm yr−1. Subsidence is determined to be mainly driven by natural sediment compaction (∼ 76 %), with areas strongly influenced by local processes associated to their sedimentary distribution and composition, or external factors such as sea level rise.

Highlights

Ebro Delta is one of the modern delta plains formed during the Holocene, which can be found in a variety of geographic and geologic settings on coastal margins worldwide (Stanley and Warne, 1997; Ibáñez et al, 2019)
Subsidence rate was measured through Differential Interferometry Synthetic Aperture Radar (DInSAR) techniques using satellite data obtained from European Space Agency (ESA) missions (Mora et al, 2018)
The obtained DInSAR results show subsidence movements ranging from < 1 to ∼ 17 mm with an average subsidence rate of 0.78 mm yr−1, a standard deviation of 0.89 mm yr−1 and a maximum of 4.04 mm yr−1, located in the domains with lower sedimentary thickness and closer to the main land (Fig. 2a)

Summary

Introduction

Ebro Delta is one of the modern delta plains formed during the Holocene, which can be found in a variety of geographic and geologic settings on coastal margins worldwide (Stanley and Warne, 1997; Ibáñez et al, 2019). As a consequence of its low aggradation ratio versus subsidence and eustatic sea-level rise (Ibáñez et al, 2014), some Ebro Delta plain areas are already below sea level and up to 40 % of its area is less than 50 cm above it (Fig. 1) For these reasons Ebro Delta is considered one of the most vulnerable Mediterranean coastal ecosystems to the effects of climate change (Fatoricand Chelleri, 2012; Giosan et al, 2014), and make determining the subsidence rate and sources a key issue for the present and future management of this area

Objectives

Methods

Results

Discussion

Conclusion