@article{BlaserKruegerOhrnbergeretal.2010, author = {Blaser, Lilian and Kr{\"u}ger, Frank and Ohrnberger, Matthias and Scherbaum, Frank}, title = {Scaling relations of earthquake source parameter estimates with special focus on subduction environment}, issn = {0037-1106}, doi = {10.1785/0120100111}, year = {2010}, abstract = {Earthquake rupture length and width estimates are in demand in many seismological applications. Earthquake magnitude estimates are often available, whereas the geometrical extensions of the rupture fault mostly are lacking. Therefore, scaling relations are needed to derive length and width from magnitude. Most frequently used are the relationships of Wells and Coppersmith (1994) derived on the basis of a large dataset including all slip types with the exception of thrust faulting events in subduction environments. However, there are many applications dealing with earthquakes in subduction zones because of their high seismic and tsunamigenic potential. There are no well-established scaling relations for moment magnitude and length/width for subduction events. Within this study, we compiled a large database of source parameter estimates of 283 earthquakes. All focal mechanisms are represented, but special focus is set on (large) subduction zone events, in particular. Scaling relations were fitted with linear least-square as well as orthogonal regression and analyzed regarding the difference between continental and subduction zone/oceanic relationships. Additionally, the effect of technical progress in earthquake parameter estimation on scaling relations was tested as well as the influence of different fault mechanisms. For a given moment magnitude we found shorter but wider rupture areas of thrust events compared to Wells and Coppersmith (1994). The thrust event relationships for pure continental and pure subduction zone rupture areas were found to be almost identical. The scaling relations differ significantly for slip types. The exclusion of events prior to 1964 when the worldwide standard seismic network was established resulted in a remarkable effect on strike-slip scaling relations: the data do not show any saturation of rupture width of strike- slip earthquakes. Generally, rupture area seems to scale with mean slip independent of magnitude. The aspect ratio L/W, however, depends on moment and differs for each slip type.}, language = {en} } @article{BeauvalHainzlScherbaum2006, author = {Beauval, C{\´e}line and Hainzl, Sebastian and Scherbaum, Frank}, title = {Probabilistic seismic hazard estimation in low-seismicity regions considering non-Poissonian seismic occurrence}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2006.02863.x}, year = {2006}, abstract = {In low-seismicity regions, such as France or Germany, the estimation of probabilistic seismic hazard must cope with the difficult identification of active faults and with the low amount of seismic data available. Since the probabilistic hazard method was initiated, most studies assume a Poissonian occurrence of earthquakes. Here we propose a method that enables the inclusion of time and space dependences between earthquakes into the probabilistic estimation of hazard. Combining the seismicity model Epidemic Type Aftershocks-Sequence (ETAS) with a Monte Carlo technique, aftershocks are naturally accounted for in the hazard determination. The method is applied to the Pyrenees region in Southern France. The impact on hazard of declustering and of the usual assumption that earthquakes occur according to a Poisson process is quantified, showing that aftershocks contribute on average less than 5 per cent to the probabilistic hazard, with an upper bound around 18 per cent}, language = {en} } @article{BeauvalHainzlScherbaum2006, author = {Beauval, Celine and Hainzl, Sebastian and Scherbaum, Frank}, title = {The impact of the spatial uniform distribution of seismicity on probabilistic seismic-hazard estimation}, series = {Bulletin of the Seismological Society of America}, volume = {96}, journal = {Bulletin of the Seismological Society of America}, number = {6}, publisher = {GeoScienceWorld}, address = {Alexandria, Va.}, issn = {0037-1106}, doi = {10.1785/0120060073}, pages = {2465 -- 2471}, year = {2006}, abstract = {The first step in the estimation of probabilistic seismic hazard in a region commonly consists of the definition and characterization of the relevant seismic sources. Because in low-seismicity regions seismicity is often rather diffuse and faults are difficult to identify, large areal source zones are mostly used. The corresponding hypothesis is that seismicity is uniformly distributed inside each areal seismic source zone. In this study, the impact of this hypothesis on the probabilistic hazard estimation is quantified through the generation of synthetic spatial seismicity distributions. Fractal seismicity distributions are generated inside a given source zone and probabilistic hazard is computed for a set of sites located inside this zone. In our study, the impact of the spatial seismicity distribution is defined as the deviation from the hazard value obtained for a spatially uniform seismicity distribution. From the generation of a large number of synthetic distributions, the correlation between the fractal dimension D and the impact is derived. The results show that the assumption of spatially uniform seismicity tends to bias the hazard to higher values. The correlation can be used to determine the systematic biases and uncertainties for hazard estimations in real cases, where the fractal dimension has been determined. We apply the technique in Germany (Cologne area) and in France (Alps).}, language = {en} } @article{AlAtikAbrahamsonBommeretal.2010, author = {Al Atik, Linda and Abrahamson, Norman A. and Bommer, Julian J. and Scherbaum, Frank and Cotton, Fabrice and Kuehn, Nicolas}, title = {The variability of ground-motion prediction models and its components}, issn = {0895-0695}, doi = {10.1785/gssrl.81.5.794}, year = {2010}, language = {en} }