According to a new study conducted by researchers from several California universities, disposing water from oil and gas drilling in California is likely contributing to a swarm of earthquakes.
This is the first conclusive study to link California fracking water to earthquakes, but not the first to link waste water to earthquakes in other states. In Oklahoma the number of earthquakes has grown since the start of fracking and oil booms from just a handful yearly to over 900 in 2015 alone. This new study however shows that there is more wastewater being disposed in California than in Oklahoma.
Earthquakes have also been connected to wastewater disposal in Colorado and New Mexico.
Fracking wastewater is produced when chemical saline water is injected underground in order to loosen deposits of oil and gas. Some estimates show that for every barrel of oil that is made, there’s another 20 barrels of waste water that needs to be disposed of. The water is then disposed either by injecting it into storage wells, reused in agriculture, or dumped into the ocean.
Wastewater disposal in California has doubled in the last 20 years, but oil production has fallen. Although operators are required to monitor seismic activities during oil and gas extraction, they are not required to do so during wastewater disposal.
Earthquakes are said to result from built up pressure over time from the large volumes of water injected into certain areas during disposal. This can cause a fault in the earth to slip, which causes an earthquake.
Environmentalists have recently succeeded in halting permits for offshore drilling in California, but despite lawsuits, onshore fracking has been growing in California.
Scientists that conducted the research studied a abnormal grouping of earthquakes that took place in 2005 in Kern County, California near several waste water injection sites. Kern County is also only 50 miles from the San Andrea fault.
The study was published this week in the journal Geophysical Research Letters.