The geomagnetic team at work on the tidal flats near Hooge. Photo: Ruth Blankenfeldt, ZBSA.

The Wadden Sea Project, as part of the Subcluster ROOTS of Socio-Environmental Hazards (Link), started its fieldwork last July with two short geophysical measurements on the tidal flats near the small North Frisian island of Hallig Hooge.

Hooge is one of the small islets (“Halligen”) in the Wadden Sea without a protective dyke. The marshland of the island is therefore open to the sea and often flooded during storm surges, forcing the inhabitants to settle on high terps. This way of life does not differ much from that of the early settlers during the High Medieval period, when the marshlands around Hooge had a much larger extent than today. In 1362, the “Grote Mandränke” flood significantly impacted the area, whereby large portions of the land were submerged and turned into tidal flats, leading to large losses of settlements and cultivated marshes.
Applying geomagnetic gradiometry, electromagnetic induction and drone photography, the first geophysical campaign of our project set out to find traces of the High Medieval settlements in the tidal flats south of Hooge. The starting point was an archaeological area documented in the 1970s, when erosion uncovered remains of a terp and several graves, which led to the assumption of the presence of a church. The results of our investigations surpassed all expectation. The geomagnetic prospections documented archaeological structures with high visibility and clarity. Three closely connected terps show traces of buildings and rectangular graves, and possibly also a west-to-east aligned outline of what might have been a church building. Furthermore, the surroundings of the terps show dense signatures of peat quarrying, probably dug in the aftermath of the inundation of the cultural landscape.
Further activities included measurements at the on-land site of an early medieval settlement and an excursion to further early- to high medieval sites on the tidal flats. Hooge has proven to be an excellent test area to map and analyse settlements of various periods and we look forward to the results of the next campaigns.

Geomagnetic prospections on the tidal flats near Hooge. Drone photo: Dirk Bienen-Scholt, municipality of Hooge.