Dependent Positioning Horizontal velocities across Southern California. Colors specify speed and arrows specify corresponding directions of motion relative to a fixed North American plate reference frame.
Curved lines represent geologic faults.
The software employs models that address both the continuous and the episodic components of crustal motion. For characterizing continuous motion, the models assume that points on the Earth's surface move with constant horizontal velocities. For characterizing the episodic motion associated with earthquakes, the models use the equations of dislocation theory. Browse the HTDP FTP site for sample data files, program development log, etc. Interactively predict velocities.