New Mexico Geological Society Annual Spring Meeting — Abstracts

A detailed three-dimensional topographic map of the interiorof a natural cavern, if available, would be very useful in understanding its geomorphic development. However, obtaining such a map is extremely difficult and time-consuming, if one simply relies on conventional surveying techniques. Here we test the feasibility of using a 3-D laser scanner to quickly generate high-resolution topographic models of the interior of a cavern. A 3-D laser scanner is a type of land-based LIDAR (LIght Detection And Ranging) instrument. It sweeps the surrounding environment with optical rays. The rays produce reflections when they encounter solid objects. The instrument records the angle of each ray and measures the two-way travel time of the corresponding reflection. The survey data can be displayed on a computer screen as a cloud of reflection points that delineate the geometrical shape of the scanned objects. Individual reflection points can be spaced within 1 cm from one another. Here we report data from a 3-D scanning survey conducted in the Big Room of the Carlsbad Cavern. Almost 8 million reflection points were recorded in the vicinity of a flowstone feature called "Frozen Niagara Falls" during an overnight experiment. Later, we constructed a continuous, 3-D surface model of the flowstone by interpolating the point cloud.