Land uplift started 20 000 years ago, at the beginning of deglaciation. During the first thousand years of land uplift, the rebound rate was up to 100 mm per year (10 m in 100 years). The total initial depression is assumed to have been in the magnitude of 900-100 m when the Scandinavian Ice Sheet was 3400-3700 m thick. Isostatic rebound presumably will continue for 10 000 to 12 500 years in the Kvarken area and the remaining land uplift will probably be 100-125 metres.
Isostatic land uplift not only exposes new land but it also creates many practical problems in the Kvarken area. For example, all old harbours are now far from the coast. The old harbour of Wasa-Korsholm from the 13 th century is now situated 10 km inland from the present Vasklot harbour founded in 1890. New land emerges rapidly from the shallow sea, for example, 35 ha annually in the Replot and Björköby villages.
Changes from year 1978 to 2006 in the Kvarken archipelago as a result of land uplift.
|According to the current results from three precise levellings in Finland, the current absolute annual land uplift is about 8.0 mm on the Finnish side and about 8.5 mm on the Swedish side of the Northern Kvarken.|