PROBABILITY DENSITY FUNCTIONS AND MEASURES OF CENTRAL TENDENCY FOR FAULT SLIP RATES (Invited Presentation)

In their simplest form, fault slip rates are calculated by dividing fault offset by a time interval. However, these calculations can become complicated by uncertainties in the measurement of offset landforms and dating of offset events. Uncertainties are introduced by our geologic interpretations, measurement methods, limits in the geologic record, and other factors. Users of fault slip rates (e.g., hazard modelers) sometimes need preferred slip rate values rather than ranges. Probability density functions are one way to quantify measurements and uncertainties in a precise and unambiguous way and provide a central or preferred value. I review several slip rate calculators and describe some approaches to calculating fault slip rates, focusing on how to incorporate uncertainties into those calculations. Finally, I discuss the measures of central tendency (e.g., mean, mode, and median) and which might be most appropriate for reporting fault slip rates.