Citizens and visitors should not be alarmed if they witness a low-flying helicopter, with a large boom extending from its nose, flying back and forth in the northern San Luis Valley or near Salida during October and November.

Starting on or near Thursday, Oct. 20, and lasting for four to six weeks, a low-flying helicopter under contract to the U.S. Geological Survey will begin collecting and recording geophysical measurements for scientific research purposes. The helicopter will fly low to the ground in a back and forth pattern to passively measure the magnetic properties of the earth’s crust. The survey area will extend over the northern part of Great Sand Dunes National Park, Poncha Pass and vicinity, and the communities of Crestone, Villa Grove, Saguache, and Salida.

This study should help answer a variety of scientific questions about the subsurface of this area, such as: Where are ancient faults buried? Do the faults act as a plumbing system for groundwater or geothermal hot springs? Are lava flows that erupted millions of years ago in the nearby mountains also present underneath the valley fill? These answers could potentially refine existing knowledge about the nature of aquifers, the potential for geothermal energy resources, and the likelihood of seismic hazards.

Several USGS programs and the Colorado Geological Survey are funding the helicopter survey, which is the second in a series of airborne geophysical surveys to be conducted in and around San Luis Valley this fall. It is similar to one conducted in 2008 over the Poncha Springs area to research the science behind potential geothermal energy resources, and is part of a larger USGS study of the geology of the San Luis Valley that has been active since 2005.

The company conducting the geophysical survey under contract to the USGS is EON Geosciences Inc. headquartered in Montreal, Canada. The helicopter is controlled by experienced pilots from New Air Helicopters, LLC, based out of Durango, Colo., who are specially trained for low-level flying. The companies are working with the Federal Aviation Administration to ensure flights are in accordance with U.S. law.