Seismotectonic Regions for Germany - Concept and Results

Session: Seismicity and Tectonics of Stable Continental Interiors
Type: Oral
Date: 4/30/2020
Time: 08:30 AM
Room: 240
Description: 

Seismotectonic regions are a basic input in seismic hazard assessment. Several seismotectonic regionalizations for Germany were proposed in the past. We are presently developing a new regionalization based on the definition in the Safety Standard of the Nuclear Safety Standards Commission KTA 2201.1 (2011-11): “A seismotectonic unit is a region for which uniformity is assumed regarding seismic activity, geological structure and development and, in particular, regarding neotectonic conditions. A seismotectonic unit may also be an earthquake source region.” Our new concept focusses on a transparent implementation of the required geological criteria. Our approach is to initially analyze those separately from present-day seismicity. Compared to existing source area models we strive for a better documentation and justification of the geological elements used to delimit seismotectonic regions. This includes an analysis of the geological history of structures in six time slices from the Permian to the Present that will be considered in the regionalization. The tectonic characteristics of the time slices are briefly described. The present-day observable fault network comprises faults from all time slices. For each time slice, a subset of active faults will be extracted based on geological evidence for fault activity at that time, e.g. syntectonic deposits. The uncertainties of these age assignments will be documented. The fault subset will be used to estimate overall kinematics, a paleo-stress field and to delimit little deformed or stable areas. Faults, kinematics, stress and stable areas can then be compared to present-day seismicity/active faults, slip directions, stress and undeformed areas as well as other parameters such as crustal and lithospheric thickness. These steps are repeated for each time slice. The superposition of active faults and stable regions across all time slices will identify faults prone to reactivation and regions that remained undeformed over geological time, potentially indicating areas of increased or reduced present-day seismic hazard.

Presenting Author: Tim Hahn

Authors