thumb|A house sitting on the [[Calaveras Fault in 2003. It was demolished in 2009.|200x200px]]
In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes. Aseismic creep may also occur as "after-slip" days to years after an earthquake. Notable examples of aseismic slip include faults in California (e.g. Calaveras Fault, Hayward Fault, and San Andreas Fault).
Causes
thumb|Simulation of aseismic creep in [[Parkfield, California. (The plaques were erected as they appear here in 1995 to represent the fault's movement since 1931.)|167x167px]]
Aseismic creep accommodates far-field motions on localized zones of deformation at tectonic plate boundaries. The underlying causes of aseismic creep are primarily attributed to poor frictional strength of the fault, low normal stress acting on the fault in the shallow crust, and excessive pore-fluid pressures, which limit the viable amount of normal stress on a fault. The frictional reaction of geologic materials can explain the transition from seismic to aseismic deformation with depth. Friction along faults can cause sudden slips with associated stress drops (earthquakes), along with phases of no motion as stress recharges. The emergence of space-based geodesy and newly developed remote sensing techniques are used to monitor crustal deformation in order to track aseismic creep on a fault. Creep along the Maacama Fault is about per year, consistent with the steady movement along the rest of the Hayward Fault system.thumb|Offset in the [[California Memorial Stadium.|133x133px]]
See also
- Slow earthquake
- Surface rupture
- Hayward Fault Zone
- Maacama Fault
- Echelon cracks