The northern Baja California earthquake of December 30, 2009, occurred on the principal plate boundary between the North America and Pacific plate. At the latitude of the earthquake, the Pacific plate moves northwest with respect to the North America plate at 45 mm/y. (USGS National Earthquake Information Center)
9 slide powerpoint (zipped, includes animation)
University of Portland/IRIS Earthquake Notice (pdf)
Converted powerpoint (pdf)
Seismic wave propagation (Quicktime Animation)
Presentación en Español (Archivo Zip)
Propagación de Ondas Sísmicas (Animación Quicktime)