GPS stations like this one have been used to show that land around California’s San Joaquin valley is rising in response to a sinking valley floor, and that this flexing – due to groundwater depletion – may explain a rise in tiny earthquakes. (Photo credit: UNAVCO)
Removal of groundwater in California’s San Joaquin valley may be causing small seismic events, according to a new paper.
Researchers used GPS measurements to show that land surrounding the valley is rising by between 1 and 3 mm per year, in response to draining of the underlying aquifer. The pattern is correlated with wet and dry seasons, and the land motion is sufficient to alter stresses on the nearby San Andreas Fault.
The authors infer that this process could explain a local increase in microseismic events.
Original research paper published in the the journal Nature on May 14, 2014.
Names and affiliations of selected authors
