Natural compaction of sediments
P. Teatini, C. Zoccarato
Dept. of Civil, Environmental and Architectural Engineering, University of Padova, Padova, Italy
C. Da Lio, L. Tosi
Institute of Geosciences and Earth Resources, National Research Council, Padova, Italy
ABSTRACT
Land subsidence is a widespread phenomenon in coastal plains, particularly relevant in low-lying transitional coastal environments,
i.e., deltas, estuaries, lagoons, and wetlands, as most of them are already threatened by sea-level rise. Rapidly subsiding deltas
are home to millions of people worldwide, and their resilience in the face of the expected effects of climate change is largely
controlled by their absolute loss of elevation (Minderhoud et al. 2019; Hoitink et al. 2020).
Land subsidence is generally associated with anthropogenic stressors such as groundwater and hydrocarbon withdrawals, which can cause
tens of centimeters of settlement each year (Galloway and Burbey 2011; Gambolati and Teatini 2015) (See chapter "Land Subsidence Hazards:
A Case Study of Mexico City"). In contrast, in this chapter, we focus on natural subsidence. Natural subsidence is generally associated
with processes such as tectonics, glacial and sediment isostatic adjustment, and compaction of unconsolidated deposits (Allison et al. 2016;
Tosi et al. 2009; Wolstencroft et al. 2014). These processes act over geological periods, affect large areas, and are responsible
for land movements in the range of at most few mm/year (e.g., Doglioni 1993). However, recent studies have demonstrated that natural
compaction of Holocene deposits can vary over short time periods (years to millennia), contributing with significant rates
to the present ground dynamics
(Meckel et al. 2006; Tövist et al. 2008; Brown and Nicholls 2015; Zhang et al. 2015; Jankowski et al. 2017; Zoccarato et al. 2018).
