This ShakeMap 3.5 Manual is deprecated. Please see the ShakeMap 4 Manual.

2.4. Ground Motion and Intensity Predictions

In areas distant from the control of seismic instrumentation or reported intensity, ground motions must be estimated using the available earthquake source parameters and GMPEs or Intensity Prediction Equations (IPEs). GMPEs are available for a wide range of magnitudes, source mechanisms, and tectonic settings. IPEs are still comparatively uncommon, with only a handful of published relations, focused on active tectonic and stable shield (cratonic) environments (e.g., Atkinson and Wald, 2007; Allen et al., 2012). To supplement the available IPEs, we have developed a “virtual IPE” which is a combination of the operator’s selected GMPE and Ground Motion/Intensity Conversion Equation (GMICE), which work together to present the same interface and behaviors as a direct IPE, while being available for a wider range of regional and tectonic environments.

We describe the way ShakeMap employs ground-motion and intensity predictions in ShakeMap Processing. An up-to-date list of the GMPEs and IPEs available for ShakeMap can be found in the Software Guide.