El Ouahabi et al. (2018) identify E4 at ~480 cm depth as a ~10 cm thick disturbed sandy layer enriched in shells (El Ouahabi et al., 2018:5). The unit contrasts sharply with the surrounding finer-grained deposits and reflects a sudden influx of coarser material, accompanied by sediment disturbance and reworking. The presence of coarse grains and shell-rich material indicates significant sediment remobilization within an otherwise low-energy lacustrine environment.

Although E4 is not described as containing clear sand dikes or well-developed sand pillows, the thickness of the deposit, its coarse grain size, and the abundance of reworked shells suggest a high-energy disturbance. In the tectonically active Amik basin, such features are consistent with strong seismic shaking capable of mobilizing shallow sediments and redistributing bioclastic material. However, in the absence of diagnostic liquefaction structures, an earthquake origin remains probable but not unequivocal, and high-energy hydrological processes cannot be entirely excluded.

Chronologically, E4 is constrained by the authors’ age–depth model, which integrates radiocarbon dating of micro-charcoal, sedimentation rates, and regional environmental tie points. Based on its position within unit 1, E4 likely dates to the late Bronze Age, approximately 1900–1800 BCE, although this estimate remains model-dependent and is not directly tied to a known 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)