Are ground-motion models derived from natural events applicable to the estimation of expected motions for induced earthquakes?

Natural earthquakes in western North America can be reasonable proxies for induced earthquakes in central and eastern North America because of the opposing effects that source depth and tectonic setting have on the stress parameter that scales high-frequency ground-motion amplitudes. It is critical that ground-motion prediction equations selected as induced-event proxies have appropriate near-distance scaling behavior for small-to-moderate shallow events. In this article, we describe the conditions under which natural-earthquake models are suitable for induced-seismicity applications. Using examples from Oklahoma and Alberta, we identify at least three models (Abrahamson et al., 2014; Atkinson, 2015; Yenier and Atkinson, 2015b) that are reasonable proxy estimates of median motions from induced earthquakes in the east for the magnitude-distance range of most concern to hazard estimation from such events: M 3.5-6 at distances to 50 km.