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Water Level Observations at Parkfield, California

Fluid pressure transducers in well boreholes measure changes in the height of the ground water table associated with each well-aquifer system. Over short time periods they can detect water level changes of a few millimeters. For time periods of a week or less most of the changes in water level can be ascribed to the crustal deformation of the surrounding aquifer due to barometric pressure changes and earth tide stresses. Over longer time periods of thirty to ninety days the water level signal is a mixture of crustal deformation and seasonal hydrological trends. For time periods measured by years the predominant part of the signal is the seasonal hydrological trend.

Recent Observations

• Water level data from selected wells in the Parkfield network for the last thirty days.
• Water level data from selected wells in the Parkfield network for the last ninety days.
  (Note: All data should be used with caution.)

Map of well locations in the Parkfield area and the epicenter of the 1966 "Parkfield characteristic earthquake".