Seismicity of the Arctic in the Early Twentieth Century: Relocation of the 1904–1920 Earthquakes

Abstract

Abstract The parameters of earthquake hypocenters in the Arctic at the beginning of the twentieth century, published by researchers in the first half of the twentieth century, are still used today for building maps of epicenters of instrumental earthquakes. However, they are based on bulletins that did not use data from all seismic stations operating during that period, and on approximate ideas about the propagation of seismic waves in the Earth. We relocated earthquakes recorded within the Arctic region beginning from the early twentieth century with a view to creating a relocated catalog. For the relocation, we collected all available seismic bulletins from the global network using data acquired for the International Seismological Centre–Global Earthquake Model (ISC-GEM) catalog, the EuroSeismos project, the Geophysical Survey of the Russian Academy of Sciences, and the Russian State Library. The relocation was performed using a modified method of generalized beamforming and the ak135 velocity model. The relocation procedure was applied to 18 of 25 earthquakes in the Arctic region. The new coordinates of some earthquakes turned out to be significantly different from those that were determined previously. As a result, this may have a significant impact on the final seismic hazard assessment of the territory of the Severnaya Zemlya and Franz Josef Land archipelagoes, which are characterized by weak seismicity. Most of the relocated earthquake epicenters are confined to major seismic zones in the Arctic, namely, mid-ocean ridges, the Svalbard Archipelago, and the Laptev Sea shelf. One earthquake, that of 14 October 1914 with magnitude Mw(ISC-GEM)=6.6, occurred in the shelf of the Barents Sea in the “continent–ocean” transition zone near the Franz Victoria graben.