El Ouahabi et al. (2018) identify E5 at ~550 cm depth as a sand pillow (El Ouahabi et al., 2018:5). This feature reflects localized intrusion of sand into finer-grained sediments, indicating deformation of water-saturated deposits within an otherwise low-energy lacustrine environment.

The formation of a sand pillow is diagnostic of liquefaction, indicating that E5 most likely records an earthquake-triggered deformation event. Compared to overlying events such as E3 and E4, the deformation appears more localized, suggesting either lower shaking intensity or attenuation of seismic energy with distance from the causative rupture. However, within the tectonically active Amik basin, even relatively modest shaking can produce liquefaction in fine-grained, water-saturated sediments, supporting a seismic interpretation.

Chronologically, E5 is constrained through the authors’ age–depth model, which integrates radiocarbon dating of micro-charcoal, sedimentation rates, and regional environmental correlations. Based on its position near the base of the core within unit 1, E5 likely dates to approximately 2200 BCE, although this estimate remains model-dependent and is not directly tied to a specific historical earthquake.

Fig. 3b - Age–depth diagram for Amik Lake based on calibrated ¹⁴C age results obtained from micro-charcoal remains, ²¹⁰Pb and ¹³⁵Cs activities, correlation with other dated sedimentary sections in the Amik Basin, and historical earthquake tie point - click on image to open in a new tab - El Ouahabi et al. (2018)