New study confirms: Tsunami destroyed Caesaria in 8th Century


New study confirms: Tsunami destroyed Caesaria in 8th Century

New research indicates that a tsunami in 749 CE caused by an earthquake was the final destructive element that finished off the coastal city of Caesarea Maritima. The research will help understand how the region reacted in the past to such natural catastrophes and will also help predict future events.

A team from the University of Haifa School of Marine Sciences, in collaboration with the Israel Antiques Authority (IAA) led by National Geographic Explorer Dr. Beverly Goodman Tchernov and Charles J. Everhardt IV of the University of Haifa published its research in an article titled Earthquake, Fire, and Water: Destruction Sequence Identified in an 8th Century Early Islamic Harbor Warehouse in Caesarea, Israel in the peer-reviewed Geosciences journal

The site was initially excavated 30 years ago, but in 2016 the project was reopened by the Israel Antiquities Authority with support from the Caesarea Development Corporation as part of current Caesarea National Park renovations. 

Before 640 CE, Caesarea Maritima transitioned from a capital Byzantine city to a smaller early Islamic settlement from the mid-7th century onward. With the transition, usage of the harbor declined until it fell out of use during the late 7th century and was abandoned. 

The earthquake in the 8th century CE is well recorded in severely damaged inland cities across the southern-central Levant but reported evidence of this earthquake along the coastline is scarce. While Caesarea Maritima did not bear the brunt of the impact, the tremors were strong enough to shake the warehouse complex, causing the roof to collapse and fire to spread. 

The earthquake created a tsunami that hit the harbor from the west, causing further damage. 

The damage was left in place for several decades until well after the incorporation of the city into the Abbasid Caliphate (beginning 750 CE). The sand deposits were not removed but were merely flattened and built over during the resettlement of the area, effectively preserving the remains of the tsunami deposit. 

The new study was to determine if preserved sand deposits found at the coastal site were construction fill or debris, or whether they were the result of a tsunami. Tsunamis are a relatively common event along the eastern Mediterranean coastline, with historical records and geographic data showing one tsunami occurring per century over the last 6,000 years. The record for earlier tsunami events, however, is less clear. 

“This study recognizes how coastal sites suffer from earthquakes and tsunamis. In the past 10-15 years, we’ve come to understand that tsunamis pose more of a risk than we were originally aware of. This study is the first published evidence of a tsunami deposit on land at the site,” Dr. Goodman Tchernov said.

The tsunami deposit was found in what was thought to be an ancient warehouse that remained in use most likely until the 8th century. Discoveries within this overlying stratum include late 7th-century Aegean Imported amphorae and Umayyad cooking utensils and tableware. Above this is a destruction layer consisting of roof tiles, collapsed columns, and charcoal remains, along with fire-reddened walls. Eventually, another layer was built during the late-8th to 9th century, covering the tsunami deposit.

The study used multi-proxy analysis and comparison to characteristics of local sediments representing a wide assortment of local environments and processes affecting animal and plant remains as they become fossilized. The essential feature of multiproxy studies is that several stratigraphical proxies are used to investigate a common aim. Two sediment cores from the deposit, as well as comparative reference samples from defined contexts, were analyzed. Researchers concluded that the samples were most likely derived from the transport of offshore marine sediments during a high-energy inundation event, most likely a tsunami associated with the 749 CE earthquake.

-This discovery could contribute to a broader understanding of tsunami dynamics, tsunami deposit preservation, and the overall history of the Caesarea Maritima, as modern, historical, and paleotsunami deposits are critical for guiding coastal disaster management and risk assessment.

“This study gives us very important data points for potential tsunamis that will arrive in the future. It informs us about potential risks and what we need to be prepared for. By examining a portion of the remains of a disaster of the past, it gives us a better sense of where the risk zones along the coast are.”

“Once we know the level of risk an area has, we can make good decisions as to what structures are kept there. This will help with decisions moving forward, like, for example, not putting daycares and hospitals in high-risk areas. It also reinforces our ability to explain why tsunamis should be part of disaster management and emergency response plans in Israel,” she said.

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