If you know the rate of movement along a fault, the amount of offset over a period of time can be calculated. The basic relationship is

Question

Rate = distance/time
Movement along the San Andreas Fault is about 3.5 cm/yr.

If a fence were built across the fault in 2005, how far apart will the two sections of the now-broken fence be in 2030?

Answer 1

Was the fence built Jan 1, 2005 or December 31, 2005? I'll assume Jan 1, 2005
distance = rate x time
d = 3.5 cm/yr x #years.
Plug in the # years between the time the fence was built and 2030 and solve for distance in cm. Approximately 90 cm if I plug in 26 years.