15:30 〜 16:30
[S09-P-01] The relation between the deep lithospheric structure and observed seismicity in the European Arctic
Installation of new seismic stations on Franz Josef Land allows us to use also weak earthquakes to refine the seismicity of the European Arctic (mb 0.9-6.6, representative magnitude 2.9, assumed location uncertainty 5-10 km). The new data are used as the base for studying the geodynamics of the area i.e., to investigate the relation between the lithospheric structure and seismic activity. Profiles of lithospheric structure were taken from published DSS data. One long north-south profile intersects the Gakkel Ridge, the Nansen Basin, the Barents shelf, part of the Fennoscandian shield, the White Sea and the continental uplift of the East European platform. One long west-east profile intersects the Svalbard anticline, the North Barents Basin, the North Kara Basin and the Taimyr-North-Zemaljskaya fold systems.
The correlation of the earthquake spatial distribution with the lithosphere structure of the European Arctic region was studied and the agreement of seismicity with different morphological structures was shown. A new approach was applied to identify zones with different seismicity. It is based on the events grouping on grounds of similar spectra. For this, spectral-temporal analysis of earthquakes was performed. By the spectra we observed a clear distinction of earthquakes occurring at the junction of continental and oceanic lithosphere from earthquakes occurring at the Graben Franz-Victoria and falling in the ruptured zone. There are two groups of events on the Gakkel Ridge, associated, probably, with volcanic and tectonic processes. Also two groups of events were defined on the shelf, which are representing the different tectonic structures of the South-Barents depression and Novaya Zemlya Foreland Basin.
Our study allows for the first time to propose a geodynamic zoning of the lithosphere in the European Arctic. This result is important for seismic hazard studies in the region, in particular in the case of future industrial development of the offshore areas.
The correlation of the earthquake spatial distribution with the lithosphere structure of the European Arctic region was studied and the agreement of seismicity with different morphological structures was shown. A new approach was applied to identify zones with different seismicity. It is based on the events grouping on grounds of similar spectra. For this, spectral-temporal analysis of earthquakes was performed. By the spectra we observed a clear distinction of earthquakes occurring at the junction of continental and oceanic lithosphere from earthquakes occurring at the Graben Franz-Victoria and falling in the ruptured zone. There are two groups of events on the Gakkel Ridge, associated, probably, with volcanic and tectonic processes. Also two groups of events were defined on the shelf, which are representing the different tectonic structures of the South-Barents depression and Novaya Zemlya Foreland Basin.
Our study allows for the first time to propose a geodynamic zoning of the lithosphere in the European Arctic. This result is important for seismic hazard studies in the region, in particular in the case of future industrial development of the offshore areas.