During the past decade or so the oil and gas industry has injected wastewater into deep rocks in eastern Texas, causing Earth’s surface to bulge ever so slightly—and likely triggering a series of tremors there in 2012, a new study suggests. Scientists say the work offers hope that similar analyses of the landscape in other oil- and gas-producing regions could help identify areas at risk of human-caused earthquakes.
The 2012 quakes shook the small town of Timpson, Texas, which lies northeast of Houston near the Louisiana state line. The largest, a 4.8-magnitude quake, and three more magnitude-4 or higher that followed, all originated in a suspicious spot: directly beneath two wells where wastewater generated during oil and gas production in the region is pumped into porous sandstone layers about 1.8 kilometers underground.
Oil and gas producers dispose of their wastewater deep underground for a variety of reasons; sometimes pumping fluid into the reservoir helps boost production, and in other cases it’s a convenient method of getting polluted water out of retention ponds on the surface so that it doesn’t inadvertently spill to pollute rivers, streams, or other sources of drinking water.