Rion-Antirion bridge, Greece: measuring a moving gap

A spectacular 2·8 km long bridge is being built across the deep and earthquake-prone Corinthian Gulf in Greece. However, designing bridge foundations in 60 m of water overlying 80 m of soft alluvium across an active geological fault-line is not without its difficulties – not least since the land masses on either side are constantly moving independently. The bridge has been designed to allow for a total movement of 2·5 m in 125 years. This paper describes a three-year GPS survey to determine how much and in which direction the land is really moving. It found movements up to 52 mm but with no pattern whatsoever. It also proved that local earthquakes can have a dramatic and unpredictable effect.