Section 2.6: "Seismic Hazard and Stress Field"

The first step concerns probabilistic hazard maps based on methods of likelihood calculations. To achieve realistic estimations, we thereby compile regional, homogeneous earthquake catalogues, reaching as far back in history as possible, as well as models of the decrease of strong ground motion with distance from the earthquake source (attenuation). Besides seismic information and stress field data, other geoscientific components are integrated, e.g., the results from paleoseismological, geodetic and neotectonic investigations.

These analyses will be included in future German as well as European construction standards. Due to these rules and standards, civil engineers have to design their buildings according to the local seismic hazard. Furthermore, we develop methods for probabilistic estimation of the tsunami hazard, i.e., the likelihood of flooding heights, for the Mediterranean area among others.

The application of our investigations in engineering seismology is also noted in the European Macroseismic Scale (EMS-98). According to this the local intensity of an earthquake is determined from the damage occurring in combination with the vulnerability of the respective buildings. With this globally spread scale we provide a methodical concept for risk analyses. In this connection it is investigated what degree of damage is to be expected with what likelihood in a region on the basis of the spatial distribution of residential buildings of different vulnerability.

We supplement our estimations of the seismic hazard with different fundamental investigations. These include the development of new procedures for evaluation of hazard calculations and for tests in what regions time-dependent hazard maps are required. In order to understand the potential of tectonic faults to generate earthquakes, we investigate the change with time of the state of crustal stress and its causes. In addition to our systematic compilation of stress data, we simulate these with computer models. Our laboratory measurements with neutron radiation show how these stresses have an impact on different types of rock.