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International Journal of Geophysics
Volume 2013 (2013), Article ID 804216, 26 pages
http://dx.doi.org/10.1155/2013/804216
Research Article

Identifying Buried Segments of Active Faults in the Northern Rio Grande Rift Using Aeromagnetic, LiDAR, and Gravity Data, South-Central Colorado, USA

1U. S. Geological Survey, MS 964, Federal Center, Denver, CO 80225, USA
2U. S. Geological Survey, MS 980, Federal Center, Denver, CO 80225, USA

Received 1 November 2012; Revised 15 February 2013; Accepted 4 March 2013

Academic Editor: Luciano Scarfi

Copyright © 2013 V. J. S. Grauch and C. A. Ruleman. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Combined interpretation of aeromagnetic and LiDAR data builds on the strength of the aeromagnetic method to locate normal faults with significant offset under cover and the strength of LiDAR interpretation to identify the age and sense of motion of faults. Each data set helps resolve ambiguities in interpreting the other. In addition, gravity data can be used to infer the sense of motion for totally buried faults inferred solely from aeromagnetic data. Combined interpretation to identify active faults at the northern end of the San Luis Basin of the northern Rio Grande rift has confirmed general aspects of previous geologic mapping but has also provided significant improvements. The interpretation revises and extends mapped fault traces, confirms tectonic versus fluvial origins of steep stream banks, and gains additional information on the nature of active and potentially active partially and totally buried faults. Detailed morphology of surfaces mapped from the LiDAR data helps constrain ages of the faults that displace the deposits. The aeromagnetic data provide additional information about their extents in between discontinuous scarps and suggest that several totally buried, potentially active faults are present on both sides of the valley.