LINEAMENT ANALYSIS OF THE PROPOSED POCATELLO SEGMENT OF THE WASATCH FAULT, SE IDAHO

The Wasatch fault consists of ten fault segments that collectively extend from Fayette, Utah to north of Malad City, Idaho. On the basis of field mapping, researchers have proposed an 11th Wasatch fault segment which would extend the Wasatch fault zone from north of Malad City to Pocatello, Idaho. This study analyzes 10 meter digital elevation model (DEM) data acquired from the United States Geological Survey’s (USGS) National Elevation Dataset (NED) to test this hypothesis. Hillshade was derived from 10m DEM to display prominence of the Pocatello segment. ESRI ArcMap 10.2 and GIS data were used to document the significant lineament feature that correlates with the proposed Pocatello segment of the Wasatch fault zone, 80 km north of its previously recognized terminus. Lineament analysis supports the extension of the seismically active Wasatch normal fault zone northward to Pocatello, Idaho. Based upon our analysis, we propose that: 1) lineaments clearly identify a conspicuous feature that correlates with the proposed Pocatello fault segment. 2) the Wasatch normal fault continues at least 80 km northward beyond its previously documented northern terminus in Malad City to Pocatello, Idaho; 3) the Pocatello segment has the potential to generate greater than M 6 earthquakes in southeastern Idaho, as has been observed to occur to the south in Utah and to the north in Borah Peak Idaho.