Does 3D Seismic Acquisition Impact Giant Kangaroo Rat Populations? A Study in the BLM Lokern Parcel, Kern Co.
Occidental of Elk Hills, Inc. (OEHI) plans to acquire a large 3D seismic survey in the Buena Vista Hills area in Kern County. Permitting surface and minerals is a complex exercise made more so by numerous regulations imposed by federal and state environmental agencies. In an effort to demonstrate the low impact and transitory nature of a 3D seismic survey, OEHI collaborated with the Bakersfield BLM Field Office and biologists from the Endangered Species Recovery Program (ESRP) at California State University-Stanislaw to design a field experiment that would provide quantitative data regarding surface seismic “noise” and population changes in one endangered species with hearing sensitivity in the low frequency range, the Giant Kangaroo Rat (Dipodomys ingens), or the GKR.
The study involved capture and recapture of three species of individually marked kangaroo rats including endangered D. ingens by ESRP biologists over a two month period before and after a simulated seismic exploration source effort using both Vibroseis and dynamite conducted by OEHI geophysical staff. Ten 20-ft shot-holes, loaded with 2.2 lb dBX pentalite, and ten Vibroseis points, shaken with 3 linear 8-100 Hz sweeps each using one 49,000# truck-mounted vibe at 80% drive, were conducted along previously disturbed roadways in close proximity to known active GKR burrow complexes.
The highest peak particle velocity (PPV) measured in the shothole burrow study was 6.040 in/sec at a distance of 9 ft. The highest air-over pressure was 133.7 at this location but ranged from 90-115 dBL. The highest PPV measured in the Vibroseis burrow study was 0.310 in/sec at 56 ft and highest air-over pressure was 111.2 dBL at 51 ft. The trapping data indicated no adverse impact with no changes in numbers in study or control areas. Results of this study have positively influenced geophysical programmatic permit negotiations with environmental agencies.
AAPG Search and Discovery Article #90088©2009 Pacific Section Meeting, Ventura, California, May 3-5, 2009