Geological faulting has been implicated as a contributor to subsidence, coastal land-loss and submergence of marshlands in southern Louisiana. This report reviews whether fault motion, either by slow creep or more sudden slip, can cause deformation of engineered structures resulting in increased infrastructure maintenance and repair costs. The impact of surface, or near-surface, geologic faulting on critical infrastructure is insufficiently documented in southeastern Louisiana, but the state has a vast amount of energy-sector subsurface data that to date has been under-utilized for transportation and other near-surface engineering applications. Recent and on-going work by research groups at Tulane University, University of New Orleans, and University of Louisiana at Lafayette use energy industry subsurface data, including well data and 2D and 3D seismic reflection data to map and project deep-seated faults that have been in place for millions of years, to create provisional surface fault trace maps. Accurate characterization of active fault locations and effects using both subsurface and surface methods will aid in the design and placement of infrastructure, as well as in developing appropriate mitigation methods. Descriptive criteria for reliability of fault locations were developed and are based on resources used in the interpretation and map scale: Level 1 suspected faults – described in the literature and included here from georeferenced maps; Level 2 identified faults – those observed on 2D or 3D seismic and mapped in a geographic reference system; Level 3 confirmed faults – mapped on seismic and ground-truthed with field methods including age-dated sediment borings and high-resolution seismic. We have compiled data resources in a GIS-based system for simple retrieval and map-based review so that additional work specific to critical infrastructure projects can be prioritized. The intent is to give the public information, so that they may better assess the importance of faulting in any particular project area and as a resource to identify areas that already have energy industry seismic available.
Culpepper, D., McDade, E. C., Dawers, N., Kulp, M., & Zhang, R. (2019). Synthesis of Fault Traces in SE Louisiana Relative to Infrastructure. Retrieved from https://digitalcommons.lsu.edu/transet_pubs/30