More than a decade of processed continuous creep data from the Hayward fault reveals steady creep at rates of approximately 5 mm/year, contaminated by surface signals of less than 1.5 mm/year. The mean rates measured by the creepmeters are smaller than those measured by hundred-meter-wide alignment arrays at similar locations because the creepmeters span only 15 m of the fault zone. For example, at Palisades Road, Hayward the fault is known to be roughly 50 m wide. At both Oakland and Fremont the fault experiences small creep events, that are absent in the data from other creepmeters. The rates shown are based on least squares fits that are sensitive to the span of dat selected for their calculation. Mean rates are accurate to ±0.1 mm/yr. Daily rates may show significant departures from these rates caused by thermoelastic or thermal effects. These have been suppressed in the Pinole and Temescal data below, but are retained in the Zoo and Palisades data.

Access to numeric data and site descriptions for each creepmeter may be obtained by clicking on the map below.

Below: processed data to 2004 with annual terms suppressed in the cph and coz data. The cph1 creep rate here is erroneous, based on an incorrectly applied 30° obliquity of the measurement rod to the fault. In fact the obliquity is 45° requiring the slope to be increase by cos30/cos45, i.e.1.22 to a rate of 4.24 mm/yr. The average creep rate at Fremont since 1890 has been 9 mm/year, a rate similar to that measured 1994-1997. However, on average the creep rate at Fremont in the past decade has been only 6.6-6.9 mm/yr. The circles on the Fremont trace indicate independent measures of creep at the creepmeter: the open circles are micrometer measurements whereas the opaque circles correspond to creep at a depth of 21 m.