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Abstract

Seismic hazard assessments can only be as good as the historical past is known. Therefore, reliable seismicity records have to be extended back into history as far as possible. Hence, historical seismological investigation is of utmost importance in order to achieve long-term earthquake catalogue data of high quality. This basic research has been performed at the GFZ German Research Centre for Geosciences as a multidisciplinary approach of seismologists and historians for many years. Seismic activity before the installation of the first seismographs in the beginning of the 20th century can only be reconstructed based on written sources For Central Europe, these documents date back up to the middle of the 8th century. The historical information for each earthquake has to be source-critically analyzed and transferred into parameterized information, which is then catalogued. During the long tradition of collecting past seismic information starting more than a century ago, many mistakes were made, like duplications of events, misinterpreted strength, location and wrong dating of earthquakes, which could be identified by our investigation. We show exemplarily how these uncertainties can be mitigated. Historical passing on of information is transferred to modern seismicity parameters by applying historic-critical methods. Thus, we are able to acquire better and more reliable long-term data for historical earthquake catalogues and for trustworthy long-term seismic hazard assessments.