Building a GIS database in the Eastern Tennessee Seismic Zone

Eastern Tennessee contains one of the most seismically active regions in the eastern North America. The Eastern Tennessee Seismic Zone (ETSZ) is about 300 kilometers long and extends from northwestern Georgia through eastern Tennessee [Study Area: 34°N to 37°N; 86°W to 82.5°W]. It is the second most active earthquake zone of the United States east of the Rocky Mountains. Only the New Madrid Seismic Zone is releasing more seismic strain energy. Unlike the New Madrid Seismic Zone, the ETSZ did not experience any destructive earthquake in historical time; however, its seismogenic potential is not well understood. The spatial dimensions of the ETSZ and its association with potential field anomalies suggest that collecting and organizing all the relevant data into a GIS geodatabase could increase our understanding of that region. Geographic Information System (GIS) software can be used to acquire, share, maintain and modify geospatial data sets. In this work, ArcGIS 9.3.2 is used to build a geodatabase which includes topography, earthquake information such as locations, magnitudes and focal mechanisms, potential field data, P and S wave velocity anomalies inferred from local tomographic inversions of local events, seismic transects, digital geological maps and others relevant datasets. Raw datasets were downloaded from several earth science institutions and were edited before being imported to ArcGIS. Various geoprocessing techniques, such as geo-referencing, digitizing, and surface interpolation were used to manipulate and analyze these data. We show how this compilation can be used to analyze the spatial relationships between earthquake locations and other data layers. The long-term idea behind this project is to build an information resource that will be continuously updated and will eventually encompass data related to intraplate seismicity in the entire central and eastern United States. It will be made available to researchers, students, the general public and engineers concerned with geohazards, and will be used to develop educational materials for upper level and gradate GIS and earth science courses at North Carolina Central University.