Report: Groundwater Removal During Drought Could Cause Earthquakes
STOCKTON (CBS13) — The drought has forced many homeowners and farmers to dig deeper wells, tapping into the California aquifer. A recent Take Part web publication, citing NASA scientists, suggests using too much of this underground water could cause earthquakes.
University of the Pacific geology professor Kurt Burmiester said the possibility is a “maybe.”
Burmiester said scientists have found that adding water, like in oil fracking, can cause the plates to slip, but removing water may produce smaller earthquakes outside of the faults.
“Water weighs a lot,” said Burmiester. “It’s very heavy, so if you’re removing lots of water from the crust, from the subsurface in California, you’re shifting the weight around in California and as a result, the crust is going to have to readjust itself.”
As the earth’s crust adjusts, it puts more or less force on different parts of the crust across the state. Burmiester said a more immediate concern is the potential to collapse the aquifer.
“If you remove that water and leave open air or open spaces in between the sand grains, gravity will cause them to compact into a smaller space,” said Burmiester.
Once that space is gone, so is the underground water storage. It will be impossible to collect new underground water reserves.
Burmiester said research shows San Joaquin Valley has been sinking for years.
“The surface has dropped over 30 feet in some places.”
The Turlock Irrigation District said it’s not actively researching aquifer collapse, but said it’s being very conservative this year. The TID is giving farmers 60 percent less water. District farmers normally receive 48 inches of water per acre, but in 2014 they receive only 20 inches of water per acre.
TID said it keeps track of its water’s evaporation rate and allotment to farmers. It says during farm irrigation, 30 billion gallons of water goes back into the aquifer every year.
However, across the state, farmers and homeowners are being issued well permits. Stanislaus County said from January to July 23, 2014, it has given out 340 well permits. The state doesn’t regulate the amount of water being pumped from from the aquifer.