Earthquake potential along the northern Hayward fault, California

The Hayward fault slips in large earthquakes and by aseismic creep observed along its surface trace. Dislocation models of the surface deformation adj acent to the Hayward fault measured with the global positioning system and interferometric synthetic aperture radar favor creep at similar to 7 millim eters per year to the bottom of the seismogenic zone along a similar to 20- kilometer-long northern fault segment, Microearthquakes with the same wavef orm repeatedly occur at 4- to 10-kilometer depths and indicate deep creep a t 5 to 7 millimeters per year. The difference between current creep rates a nd the long-term slip rate of similar to 10 millimeters per year can be rec onciled in a mechanical model of a freely slipping northern Hayward fault a djacent to the locked 1868 earthquake rupture, which brake the southern 40 to 50 kilometers of the fault. The potential for a major independent earthq uake of the northern Hayward fault might be Less than previously thought.