At Tel Yavne, archaeological destruction dated to the seventh century CE could initially be attributed to either of two candidate earthquakes: the Sword in the Sky Quake of September 634 CE or the Jordan Valley Quake of June 659 CE. Conventional archaeological dating alone was unable to distinguish between these two events because both occurred within the same century.

The distinction between the earthquakes became possible through a seasonal palynology study. Langgut et al. (2015) analyzed pollen preserved in dust trapped on the floor of pottery kilns excavated in Area C on the eastern foot of the mound. The dust had accumulated beneath intact vessels during the cooling stage after firing and before the sudden collapse of the kiln structure. The palynological assemblage contained pollen from spring-flowering plants such as Olea europaea and Sarcopoterium spinosum, but lacked pollen from common regional autumn bloomers such as Artemisia. The pollen data indicate that the palynomorphs were derived from plants that flourished between March and May, suggesting that the collapse of the kiln occurred during the spring. Since this seasonal signal fits well with an earthquake reported in early June, the researchers concluded that the kiln was abandoned following the first Jordan Valley Quake which struck in early June 659 CE.

The destruction of the kiln complex may also help explain broader economic changes observed in the archaeological record. During the Byzantine period, the kilns at Yavne produced large numbers of Gaza jars used for exporting agricultural products. These jars are extremely common in fifth- and sixth-century contexts throughout the eastern Mediterranean, including Constantinople. By the seventh century, however, their distribution declines sharply. According to Yannai (2014), the collapse of kilns along the coastal plain during the earthquake of 659 CE may have contributed to the abrupt decline in the production and trade of these containers.

Figure 6 - The kiln during the excavation. We were able to collect four in situ sealed dust samples for palynological investigation from the kiln’s floor, underneath unbroken ceramic vessels. An additional sample was collected 2-3 cm above the kiln’s floor. The black arrow points to the debris/clay fragments (which were used to cover the kiln during the heating process) and were deposited after the earthquake. - click on image to open in a new tab - Langgut et al (2015)