The seismicity of Western Scandinavia

• Published in: Earthquake Engineering & Structural Dynamics
• Main Author: Ambraseys, N. N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1985
• Subjects: Fennoscandia
• Online Access: http://dx.doi.org/10.1002/eqe.4290130309; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Feqe.4290130309; https://onlinelibrary.wiley.com/doi/pdf/10.1002/eqe.4290130309

Abstract The purpose of this paper is to present the results of an evaluation of the seismicity of western Scandinavia. Intensities, with reference to the MSK scale, have been assessed for the larger earthquakes, in most cases from primary sources, and isoseismal maps have been constructed for the most important events, while for smaller shocks one or more isoseismal radii were estimated. In all, over 3,200 earthquakes have been retrieved for Northwest Europe including about 300 artificial events such as chemical explosions, rock‐bursts and mine explosions. Of these, 500 events occurred in western Scandinavia. Surface‐wave magnitudes were reassessed for 205 events, using surface‐wave amplitude‐period data, and all earthquakes recorded by more than 6 stations were relocated for the period prior to 1955. A calibration formula, obtained from the combination of macroseismic and instrumental data of the 20th century, has been used to assign magnitudes to all events for which there is macroseismic information available, thus deriving a homogeneous body of data covering a period of 180 years. It is shown that the largest earthquake in the region since 1800 occurred on land and that it had a magnitude in excess of 6.0. This is contrary to the current belief, based on short‐term data, that the larger events in western Fennoscandia occur offshore in the continental shelf areas.