A comparison of strain rates and seismicity for Fennoscandia: depth dependency of deformation from glacial isostatic adjustment

We investigate the influence of the glacial isostatic adjustment (GIA) on the deformation at the surface and at seismogenic depths in Fennoscandia. The surface strain rate field, derived from geodetic data, is controlled by GIA which causes NW-SE extension of up to 4 x 10(-)(9) yr(-1) in most of mai...

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Bibliographic Details
Published in:Geophysical Journal International
Main Authors: Keiding, M., Kreemer, Corne, Lindholm, C. D., Gradmann, S., Olesen, O., Kierulf, H. P.
Format: Article in Journal/Newspaper
Language:unknown
Published: 2015
Subjects:
Neotectonics
Seismicity and tectonics
Intra-plate processes
Lithospheric flexure
Fennoscandia
Online Access:http://hdl.handle.net/11714/5934
https://doi.org/10.1093/gji/ggv207
Description
Summary:We investigate the influence of the glacial isostatic adjustment (GIA) on the deformation at the surface and at seismogenic depths in Fennoscandia. The surface strain rate field, derived from geodetic data, is controlled by GIA which causes NW-SE extension of up to 4 x 10(-)(9) yr(-1) in most of mainland Fennoscandia, surrounded by regions of radial shortening towards the centre of uplift. The seismic deformation field, derived from a new compilation of focal mechanisms, shows consistent NW-SE compression on the Norwegian continental margin and a tendency towards tension in mainland Fennoscandia. The seismic moment rate is at least two orders of magnitude smaller than the geodetic moment rate. We propose that the low level of seismicity and the tendency towards tensional focal mechanisms in mainland Fennoscandia may be explained by the destructive interference of the regional stress from ridge push with the flexural stress due to GIA.

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