PRE-HYDROFRACKING REGIONAL ASSESSMENT OF CENTRAL CAROLINA SEISMICITY

The Deep River Basin in central North Carolina is a Triassic basin comprised of three main formations: the Sanford Formation, the Cumnock Formation, and the Pekin Formation. The Cumnock Formation, consisting mostly of black shale, is believed to contain large reserves of natural gas, and this belief has been confirmed through extensive mining and drilling in the area over of the past century. In order to encourage the development of this potential natural resource, North Carolina state law has recently been changed to allow for hydrolic fracturing in the near future. In March we installed a 12 station broadband seismic network surrounding the Sanford Sub-Basin of the Deep River Basin and expect to keep the array installed for at least 12 months. With this array we are measuring the natural seismicity that occurs in the basin before the area is disrupted by hydraulic fracturing. In the first month of data collection, we detected and located more than 20 low magnitude events within the array despite being in an area that is believed to be seismically quiet. Over the following year we will continue to measure the natural seismicity to determine what causes these low magnitude earthquakes. If hydraulic fracturing operations begin in the basin, this information can be used as a baseline to quantify how much if any seismicity is induced by the hydraulic fracturing process.