For magnitude estimation of historical, pre-instrumental earthquakes it is useful to estimate felt areas for several intensities. From several macroseismic surveys it has been observed that an old shield such as the Fennoscandian Shield has especially large felt areas compared to California where the magnitude formula was developed. However, the newest Danish observations of felt areas and associated digitally determined magnitudes presented in this study show that the subsurface of Denmark has a response to shaking which is similar to that of the Fennoscandian Shield. This study covers the period 1996–2012 and includes an analysis of the macroseismic surveys of all felt earthquakes. Eight of these earthquakes provided new information on intensity areas in Denmark. An aim for the future is to use the felt areas of old earthquakes in Denmark for improved estimations of their magnitudes.
- Programområde 3: Energiressourcer