An array of GPS instruments near the San Andreas Fault System in Southern California detects constant motion of soil's crust—sometimes large,sudden motion during an earthquake and often subtle, creeping motion. By carefully analyzing the data recorded by the EarthScope Plate Boundary Observatory's GPS array researchers from the University of Hawai'i at Mānoa (UHM), or University of Washington and Scripps Institution of Oceanography (SIO) discovered nearly 125 mile-wide "lobes" of uplift and subsidence—a few millimeters of motion each year—straddling the fault system. This large scale motion was previously predicted in models but until now had not been documented.
Source: phys.org