Perspectives for Systematic Landslide Monitoring

Abstract

For most geologists, monitoring conjures up actions involving field measurements and data analysis. This is consistent with the definitions of monitoring, which include: “to keep track of systematically with a view to collecting information” and “to test or sample, especially on a regular or ongoing basis” (Dictionary.com, 2010). A major rockslide in Tennessee illustrates the basics of monitoring as applied to landslides. On November 10, 2009, a small mass of rock from an outcrop near mile marker 17.6 on U.S. Highway 64 slid onto the road (News.tennesseeanytime.org, 2009). This early morning rockslide impeded movement from one side of mountainous Polk County to the other. Consequently, Tennessee Department of Transportation (TDOT) maintenance forces quickly reached the site and began clearing rocks blocking the inside (westbound) lane. Among the TDOT employees dispatched to the scene was a geologist, who began observations of the rocks exposed above the work area. The geologist, Vanessa Bateman, noted popping and cracking noises as well as more small rocks rolling down slope (Sohn, 2009). About 12:30 p.m., she alerted personnel on site to the possibility of another rockslide. All personnel and equipment were moved a safe distance away prior to the second, and much larger, rockslide occurring at 1:00 p.m. (Figure 1) (News.tennesseeanytime.org, 2009). Figure 1. The November 10, 2009, rockslide blocking U.S. Highway 64 in Polk County, TN. Just prior to the rockslide, an excavator equipped with an impact hammer was breaking up one of the larger boulders that had slid earlier onto the inside lane. (Photo from Tennessee DOT website.) The timely conclusion that another rockslide was imminent was based on monitoring. The observations were sounds and small rocks rolling during the observational period. The data were collected by the ability of the observer to hear and see. The data were analyzed based …