Haynes et al. (2006) identify a ground-rupturing earthquake, labeled Event III, in the trench stratigraphy. This event displaced units f, g, h, and k, and its rupture trace is buried by unit e, showing that the earthquake occurred before the deposition of that layer (e).

The tops of units f and g appear to have formed the ground surface at the time of the rupture, indicating that Event III took place after Event IV which ruptured units f and g in the 7th century. These underlying units (f and g) contain aqueduct rubble and potsherds dating to the 7th century, providing a terminus post quem for the earthquake. Unit e, which seals the rupture, lies beneath unit d, a layer with a radiocarbon-constrained age between the 10th and 12th centuries. This provides a terminus ante quem for the event. Taken together, these relationships indicate that Event III occurred sometime between the 7th and 12th centuries CE.

Left - Figure 5 - Schematic diagram of Trench A.7 north wall. Stratigraphic units are identified by lowercase letters. Faults are emphasized by heavy lines. Earthquakes are identified by Roman numerals, with IV as the oldest. Dashed lines indicate unexcavated portion of aqueduct floor.

Right - Figure 4 - Schematic stratigraphic column of Trench A.7. Thicknesses of units are generalized from measurements of unit throughout the trench. Listed artifacts provide age control for constraining deposition and earthquake history in units where they were discovered. Age constraints come from radiocarbon data and typological dating of sherds.

Click on either image to open in a new tab - Both figures from Haynes et al. (2006)