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Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
The southwestern coast of the Gulf of Corinth, known as Aigialeia, lies in a region of rapid tectonic uplift and extension. Using age and elevation data from raised relic shorelines, and Lambeck’s model for local isostatic sea-level rise, I re-examine the uplift of the coastal footwall block in Aigialeia. The average Holocene uplift rate is 2.4±0.8m ka–1, significantly higher than the Quaternary uplift rates associated with the raised terraces near Corinth on the southeastern coast. The footwall movement in Aigialeia consists of coseismic uplift events separating periods of relatively aseismic uplift. A footwall uplift of about 2 m apparently accompanied the earthquake that destroyed and submerged ancient Helike 373 BC. The city was built on a Gilbert-type fan delta adjacent to the area of raised relic shorelines. Using dated samples from bore holes drilled in the delta, I estimate that the delta itself subsided by at least 3 m during the earthquake. The opposition between gradual uplift and coseismic subsidence events apparently resulted in a relatively small absolute net displacement of the delta during Holocene time.
