Geologic and Topographical Influences on Military and Intelligence Operations

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Geologic and Topographical Influences on Military and Intelligence Operations

█ WILLIAM C. HANEBERG

Geology and topography have placed important constraints on military operations since the beginning of organized warfare. The movement of troops on foot, on horseback, or in motorized vehicles can be hindered by topography and soil conditions. Bedrock type and strength are important factors in the construction of fortifications, the availability of groundwater supplies can control the location of military installations, and mountainous terrain can offer cover to guerilla forces or small groups of operatives. The collection and analysis of geologic information relevant to military operations falls into the discipline of military geology, and military geologic information is often referred to as terrain intelligence.

Two people with knowledge of geology are reported to have participated in Napoleon's invasion of Egypt in 1798. The first military operation guided by terrain analysis, however, was the defeat of Napoleon's troops near the Katzback River in Silesia by the Prussian general von Blucher in 1813. In 1823, the United States Military Academy became one of the first institutions of higher learning to offer instruction in geology. Geologic and topographic considerations continued to play an important role in military operations throughout the nineteenth century, for example at the Battle of Gettysburg in 1863. Union soldiers occupied boulder covered terrain underlain by a hard igneous rock known as diabase, which provided protection from Confederate soldiers advancing unprotected through flat fields underlain by softer shale and sandstone. The first extensive use of geology in military operations was probably during the Russo-Japanese War (1904–1905), when the Russian Army used geologists to provide advice on the construction of fortifications. The use of geologic information became commonplace during World War I and World War II, and included the creation of a military geology branch within the United States Geological Survey. The United States Army Topographic Engineering Center and the National Imagery and Mapping Agency (NIMA) currently provide a variety of products and services directly related to terrain intelligence.

One of the principal concerns of military geologists is trafficability, or the ease with which a landscape can be traversed by troops. An assessment of trafficability requires knowledge of soil types (which are in turn controlled by the underlying bedrock type); the physical, chemical, and biological soil forming processes at work in an area; and meteorological conditions. Arctic areas underlain by permafrost, for example, may be trafficable in winter but impassible in summer when the upper portion melts. Likewise, desert lakebeds known as playas may be trafficable when dry but impassible after a short rainstorm. Trafficability can in some cases be assessed using published topographic maps, geologic reports, and soil surveys. In other cases, reconnaissance forces can use specialized trafficability instrument kits to conduct soil tests and obtain detailed information along potential routes.

Satellite or aircraft-based remote sensing technology can provide the information for terrain analysis and trafficability studies in denied or otherwise inaccessible areas. For example, multispectral satellite imagery can be used to remotely map soil and rock types based on the spectral reflectance of minerals. High-resolution satellite imagery can also be used to visually interpret geologic and topographic conditions. The Shuttle Radar Topography Mission, flown in February 2000, used synthetic aperture radar to produce an elevation data set covering 80% of Earth's land surface. The elevation data can be used to create topographic maps or three dimensional images of inaccessible areas for use in terrain analysis, virtual reality based training, flight simulators, and other military applications.

Manual terrain analysis is time consuming and requires the expertize of a trained specialist. The result is typically a map on which terrain is classified into three categories based upon trafficability: go, slow-go, and nogo. Current research is aimed at the creation of computer expert systems that will be able to combine map layers showing roads, soil types, topography, rivers, vegetation, and land use to produce probabilistic estimates of trafficability for specific vehicle types and weather conditions. These results will include estimates of the reliability of calculated trafficability values.

Geology also plays an important role in the survivability or penetrability of fortifications and facilities, particularly those constructed underground. Information about geology, particularly the strength of different rock types, is used in the design of underground structures that must resist conventional attack. Likewise, information about the geologic setting of an enemy facility can be used to select weapons and methods of attack that are most likely to be successful.

█ FURTHER READING:

BOOKS:

Underwood, James R., Jr. and Peter L. Guth. Military Geology in War and Peace. Boulder, CO: Geological Society of America, 1998.

Zen, E-An and A.S. Walker. Rocks and War: Geology and the Civil War Campaign of Second Manassas. Shippensburg, PA: White Mane Publishing, 2000.

ELECTRONIC:

Leith, William. "Military Geology in a Changing World." Geotimes. February, 2002. <http://www.agiweb.org/geotimes/feb02/feature_military.html> (11 February 2003).

Surdu, J.R., C. Gates, J. Sullivan, M. Rudak, N. Colvin, and K. Slocum. "Trafficability Analysis Engine." 23rd Army Science Conference. December 2–5, 2002. <http://www.asc2002.com/summaries/e/EP-17.pdf> (11 February 2003).

U.S. Army Corps of Engineers Topographic Engineering Center. "TEC Web Site." 2002. <http://www.tec.army.mil/> (11 February 2003).