CHANGES IN THE CENTRALIA COAL FIRE OVER FORTY YEARS

Centralia is located in the anthracite region of northeastern Pennsylvania. The town is part of the Western Middle Field, a large synclinorium in Columbia and Schuylkill Counties. Residents of Centralia set fire to a garbage dump in 1962 in order to reduce its volume and control rodents. In the process, the Buck Mountain coal vein, concealed behind refuse, was ignited. Fractured and moderately dipping strata in the region permit air to circulate into the subsurface, thereby promoting combustion and making it difficult to control the coal fire. During the 1960’s, 70’s and 80’s, the fire advanced along four fronts. State, local, and federal agencies made several sporadic, unsuccessful attempts to fight the fire. Consequently, residents of Centralia were relocated and the fire was left to burn uncontrollably. The fire currently appears to be advancing along two fronts only. According to the Pennsylvania Department of Environmental Protection, the Centralia fire advanced an average rate of 22.5 m/yr between 1962 and 2002. Our data indicates that the fire associated with the first or “cemetery” front advanced an average rate of 20 m/yr between 1982 and 2002. Data acquired by the authors for the second, third, and fourth fronts suggest that the fire in its entirety may actually be slowing in progression. As coal fires gas is exhaled from surficial vents and fissures and then cools, condensation products may form. The deposition of these materials in Centralia, some of which are multi-colored in shades of white, red, yellow, and gray, appears to be linked to seasonal variations. In addition, black shale of the Llewellyn formation, immediately adjacent to gas vents and fissures, is frequently altered to a white, red, or tan friable material.