A creepmeter helps assess the amount of stress that builds up along the fault from the movement of the earth's crust, according to PBS. The day-to-day movement along a fault may be barely detectable, but if the stress eventually exceeds a threshold limit, the sides of the fault move suddenly, releasing the energy as an earthquake.
The creepmeter electronically measures the displacement between two markers on opposite sides of the fault. A creepmeter typically has a measurement range between 10 to 30 mm, or about 0.4 to 1.2 inches, according to the Museum of Learning.
Measuring fault creep requires the measurement of the total width of the creeping zone so as not to underestimate displacement, according to the Department of Geosciences at San Francisco State University.