are in g and the red numbers show observed PGA in units of %g. Red circles show where predicted PGA
values are used in the contouring of the shakemap. The predictions are made every 22 km and used only when there
is not strong motion station located within 22 km. Thus if there is a recording available it is used in the
shakemap generation and the model values are used only where there are no
observations. Following the method
outlined by Wald et al. (1999) we interpolate the sparse data/model grid
shown prior to contouring the map.
This tends to smooth the integration of observed and predicted values.