Seismic hazard estimate using spatially smoothed seismicity model as spatial distribution function

In this study, we established four spatially smoothed seismicity models based on the earthquake catalog of North China. Taking these models as the spatial distribution function, we distributed the seismic annual rates into grid cells of every seismic belt in North China seismic area, and calculated the seismic hazard in this region. The result shows that, first, the seismic activity model and seismic hazard result both calculated by using instrumental earthquake catalog, can reflect the contemporary seismic activity level and seismic hazard level of North China area; second, the seismic activity model and seismic hazard result, bothcalculated by using historical earthquakes (Mge;4.7), represent the seismic hazard level of moderate earthquakes in North China quite well; third, the seismic activity, which is based on the calculation using point-ellipse model and linear-ellipse model involving seismic activity rate derived from seismic strain, can fairly well exhibit strong earthquakesrsquo;activity level and relevant tectonic characteristics. The PGA distribution in North China region is the average with an equal weight of four PGA values obtained from four seismicity models for 10% P.E. in 50 a. Comparing this PGA distribution with another PGA distribution for 10% P.E. in 50 a, which is calculated by combined potential seismic sources according to ldquo;National Seismic Zoning Maprdquo;, we find that there is no essential difference between them, and both of them can reflect the seismic hazard level of North China seismic region. Admittedly, there are still some differences between these two distributions: the area satisfying the condition of PGAge;100 cm/s2 calculated from the former is obviously larger than that calculated from the latter; nevertheless, the area satisfying PGAge;100 cm/s2calculated from the former is smaller than the one calculated from the latter. It is principally due to the differences of potential seismic sources and spatial distribution functions.