TEMPORAL CHANGES IN VEGETATION PATTERNS ASSOCIATED WITH THE CENTRALIA, PA COAL FIRE

Since 1962, the anthracite coal fire in Centralia, PA has profoundly influenced the distribution of surface vegetation. Using black and white aerial photographs from 1938, 1959, 1969, and 1971 and high resolution orthoimagery from 1993 and 1999, false color infrared aerial photographs from 1983 and 1987 and color aerial photographs from 1974 and 2004 through 2011, shifts in vegetation patterns can be observed as the ground temperature changes. Patterns of plant communities containing moss and grasses, weeds and shrubs, and forested areas were identified and shaded different colors to map the vegetation changes across the landscape. Photos from 1938 to 1983 show new vegetative growth appearing in the region around Centralia, with surface evidence for a mine fire difficult to determine. In 1987, the surface expression of the fire becomes more prominent, as it progressively moves westward along the north-dipping limb of the Locust Mountain Anticline; vegetation patterns shift, trees die and the landscape appears covered by regolith and soil. By 2004, ground temperatures at exhaust vents are at a maximum of 450 °C, causing much of the large vegetation to die. From 2008 to 2011, gas exhaust temperatures measured from vents decrease to approximately 65 °C, and fire advance decreases. The dramatic change in surface temperatures, allows grass and weed populations to expand across once barren ground and new successional stands of sumac, white birch, oak, locust, and maple to flourish in cool zones around the fire. Currently, the fire appears to have reached a location in the subsurface mine workings where mine roof collapse has impeded its westward progress. With cooler temperatures, progressive succession is taking place in Centralia.