Previous chapters have described how plate tectonics is the driving mechanism for tectonic hazards at the surface of the Earth. This chapter provides an overview of the methodologies being used today to quantify these hazards, describes some of the long-standing methodology-related issues that are being addressed as a result of the engineering demands of the nuclear industry, and presents a case study of evolving probabilistic methods to evaluate tectonic hazards for high-level radioactive waste disposal in Japan.

Traditionally, seismic catalogs and active fault data sets have been the basis for earthquake shaking (seismic) hazard assessment, and to a lesser extent surface rupture (fault displacement or rock deformation) hazard. These data sets are frequently criticized for being “patchy,” in that there is considerable uncertainty regarding the completeness of the active fault databases, and the questionable long-term representativeness of seismicity catalogs. Not surprisingly, the advent of global positioning system (GPS) techniques as a means for quantifying the contemporary rates of active tectonic processes has been seen as a much needed augmentation of the other data sets for tectonic hazard analysis. Such data sets are very likely to become major components of tectonic hazard analysis, once a better understanding of the relevance of GPS-derived crustal strain rates to tectonic hazards has been achieved (Wallace et al., Chapter 6, this volume). In this context, a new method for the melding of GPS data with the traditional data sets of tectonic hazard analysis (seismological and geologically based surface deformation/active fault data) is presented in this chapter.