Tectonic Model-Based Critique on Conventional Seismic Hazard Evaluations; Implications for the Role of the South Caspian Basin on Seismicity of Northern Iran

Reconnaissance, definition, mapping, and mechanism(s) of the earthquake sources are the preliminary earthquake hazard analysis strategies. Heterogeneity of the crust, change in stress, and diffuse and distributed nature of the present-day continental deformation are the features that may influence the seismic sources, which, in turn, determine the seismic hazard assessment policy. The mechanisms and geometry of the sources potentially relate to the physics of the crust and then the magnitude, duration, and depth of generated earthquakes, etc. Tectonics, on the other hand, deals with recovering the stress state, and consequent deformations represented by geostructures, including the faults and folds. Therefore, the tectonic investigations and modeling may lead to better definitions and characteristics of the seismic sources. This study introduces a new approach to defining earthquake sources and segmentation, providing a practical guideline for evaluating earthquake occurrences. This evaluation model is supported by geological evidence that forms a crucial component of Probabilistic Seismic Hazard Assessment (PSHA) and Deterministic Seismic Hazard Analysis (DSHA) programs. The tectonic model's key output is the segmentation of fault zones responsible for earthquakes, some of which could be blind faults or faults yet to be identified as active faults. These regions might be regarded as seismic areas in conventional seismic evaluations. The study recommends distinguishing between seismic hazard and seismic risk maps in regions where the potential for seismic activity is the same, but the population densities differ.

کلیدواژه ها:

Tectonic model ، Seismicity ، zipper tectonics ، Segmentation