Looking for microearthquakes in Death Valley National Park

In January 2012, Paul Bodin and I sited the first two of ten seismic stations on the fans on the west side of Death Valley. Our project was inspired by the successful Italian experiment that discovered that the low-angle Alto Tiberina normal fault in the central Apennines is decorated by microearthquakes: this detachment is actively slipping. Our sites are situated about 8 km above the projected position of the detachment faults, which we infer dip beneath the sites from the base of the Black Mountains visible across the valley to the east. We use Reftek units, supplied by PASSCAL, employing short-period, three-component sensors. Because there is no cellphone service in Death Valley, we needed to make service calls every two-three months to retrieve and replace the data cards.

Our results are unexpected and exciting. The approximately 330 hypocenters beneath our network define a planedipping about 9° at an azimuth of 345°. We conclude that the iconic Death Valley pull-apart basin is opening by top-northwest transport of the hanging wall on an active, seismogenic detachment fault. We presented our data and results at a forum sponsored by GSA's Division of Structural Geology & Tectonics at Sonoma State University in August 2016. Please see the abstract below.

In this photo, I am looking east from the fan at Hanaupah Canyon toward the active normal-fault system bounding the west front of the Black Mountains in the distance. Paul is servicing one of our stations. Each Pelican case is surmounted by a small solar panel. Click on the photo for a larger image.

Click on the subpage for a map of our stations, and a subordinate subpage showing the plane defined by hypocenteres..