7/13/2023 0 Comments Texas seismac categoryThese polygons, sometimes have a complex shape, which reflects the complexity of the different faults and tectonic trends (e.g., ). Recent PSHA at a local or a regional scale is usually based on approaches and computer codes (e.g., FRISK: SEISRISK III: CRISIS 2014:, etc.) that require the study area to be subdivided into seismic source zones which can be generated by delineating a number of polygons over active seismic areas. In the classic form, earthquake sources range from clearly understood and well defined faults to less well understood and less well-defined geologic structures to hypothetical seismotectonic provinces extending over many thousands of square kilometers whose specific relationship to the earthquake generating process is not well known. It has been common practice since the development of PSHA by Cornell and McGuire, to utilize areal source zones of seismic homogeneity. The issue of seismic source delineation and characterization is often a controversial one in the practice of seismic hazard analyses, both deterministic and probabilistic, as the information available relating to geology and seismotectonics can vary from region to another region. Modern investigations on Probabilistic Seismic Hazard Assessment (PSHA) for any region at any scale, requires that the study region should be subdivided into different seismic sources. In addition, the characterization depends on the definition of different surface and sub-surface active faults. In fact, the characterization of seismic source zones depends on the interpretation of the available geological, geophysical and seismological data obtained by many tools such as tectonic studies, seismicity, surface geological investigations and subsurface geophysical techniques. Identification and characterization of the potential seismic sources in any region is one of the most important and critical inputs for doing seismic hazard analysis. Since the pioneering work of Cornell, it is clear that seismic hazard assessment depends on several models, among them perhaps one of the most significant, and usually poorly understood, is the delineation and characterization of the seismic source model for a particular region.
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