Evidence from shoreline sediments and archaeological remains at Tiberias suggests significant tectonic subsidence prior to the mid-8th century Sabbatical Year earthquakes. Hazan et al. (2004) observed lake sediments, including beach deposits lying above Roman-age– Umayyad period structures at Galei Kinneret. Because a Dead Sea low-stand period (600–1000 CE) indicates relatively dry regional conditions, the authors argue that the observed deposits are unlikely to represent a simple rise in lake level and instead reflect local tectonic subsidence.

Based on the elevation of the Roman stadium and the relationship between the sediments and Umayyad buildings, Hazan et al. (2004) estimate that more than 4 m of subsidence affected the Roman–Umayyad structures before the mid-8th century earthquake(s), which later offset the deposits. The Umayyad buildings provide a terminus post quem of about 661 CE, while the mid-8th century earthquake provides the terminus ante quem. The authors further suggest that this tectonic subsidence may explain the disappearance of the Roman harbor of Tiberias.

Figure 4 - A schematic E–W section in the Tiberias area - JW: Alleged tectonic subsidence in question is to the right
Click on image to open in a new tab - Hazan et al (2004)