Assessing Spatio‐Temporal Variability of Free Gas in Surficial Cohesive Sediments Using Tidal Pressure Fluctuations

Abstract

Recognition of the widespread occurrence of gas in shallow marine sediments has sustained interest for its significance in offshore engineering activities, slope stability, and climate change (Egger et al., 2018;Fleischer et al., 2001;Kaminski et al., 2020;Sills & Wheeler, 1992). On continental shelves, methane is commonly produced by the biogenic degradation of buried organic matter (Fleisher et al., 2001;Mogollón et al., 2011). Due to the low solubility of methane in these shallow water settings, levels of dissolved gas can reach supersaturation and lead to the formation, growth, and rise of gas bubbles (Boudreau, 2012;Mogollón et al., 2011). Because temperature, pore pressure, and salinity influence biogenic reactions and determine

Transient Groundwater Flow Through a Coastal Confined Aquifer and Its Impact on Nearshore Submarine Slope Instability

“…Pore pressure at P18 fluctuated throughout the monitoring period while at P16 it became almost stable from 28 January 2017. Some of the shallow sensors (not shown in Figure 6) recorded pore pressure fluctuations which were correlated with tide fluctuations and the presence of free gas partially saturating the shallow sediments (Garziglia et al, 2019).…”