Static deformation is the permanent displacement of the ground due to the event.
The earthquake cycle progresses from a fault that is not under stress, to a stressed fault as the plate tectonic motions driving the fault slowly proceed, to rupture during an earthquake and a newly-relaxed but deformed state. Typically, someone will build a straight reference line such as a road, railroad, pole line, or fence line across the fault while it is in the pre-rupture stressed state. After the earthquake, the formerly stright line is distorted into a shape having increasing displacement near the fault, a process known as elastic rebound . The second type of deformation, dynamic motions, are essentially sound waves radiated from the earthquake as it ruptures. The mechanical properties of the rocks that seismic waves travel through quickly organize the waves into two types.