With the help of certified pilots and a twin-engine plane, the U.S. Geological Survey (USGS) has begun to map rock formations buried beneath the surface of the Sacramento Delta, including the Davis area. This will be the first comprehensive survey of fault lines and hydrology in the area, and researchers hope to learn more about how underground geology affects the stability of river levees.
For the next few weeks, the plane will motor over areas of the Sacramento Delta equipped with a magnetometer, an instrument that measures the magnetic fields of different kinds of rocks.
“If there’s more iron in rocks, then there’s a different magnetic signal,” said Vicki Langenheim, research geophysicist with USGS.
The magnetometer can sense rocks buried under the Earth’s surface, so it’s a good way of mapping rocks that make up fault lines or underground water channels. Magnetometer surveys have previously been conducted over the Bay Area and Los Angeles areas to access earthquake risk.
“There are buried faults that haven’t ruptured completely to the surface,” Langenheim said.
Geology fans can spot the plane over Davis during the next couple weeks.
– Madeline McCurry-Schmidt