Abstract Burning and evolving for over 50 years, the anthracite coal fire in Centralia, Pennsylvania, has provided researchers with an ideal environment to study how shallow coal fires affect surface vegetation, nutrients and soil, landscape subsidence, organisms, fire migration, as well as human health. Ten years ago, surface temperatures from some gas exhaust vents were measured to be between 456° and 540 °C, and the fire was recorded to be moving rapidly at a rate of 20–22 m/yr. However, the fire has changed considerably since that time. Today, the average annual temperature of surface exhaust vents is ~65 °C, and its rate of movement is nearly unperceivable. In light of the changing parameters of the fire, Centralia continues to provide an interesting environment in which to study the effects of a subsurface anthracite coal fire on the landscape. This field trip will examine the geologic structure of the region, the Buck Mountain coal succession, the geomorphic features produced by the fire, the environmental consequences related to the removal of natural resources like coal, how a government responds to regional environmental disasters like coal fires, and the legacy of a coal fire on a region. Over the past decade, this fire and its influence on the landscape have changed considerably. However, there are still many interesting things to learn from this fire and the surrounding region.

Abstract A Marcellus-Burket/Geneseo field trip in the Appalachian Valley and Ridge features both brittle and ductile structures. The degree to which these structures have developed depends on both lithology, which is a function of the stratigraphic architecture of the Devonian Appalachian Basin and position relative to the foreland during the Alleghanian Orogeny. Joints are best developed in the black shales and the units immediately above with the J 2 joint set most prominent in the Brallier Formation just above the Burket/Geneseo Formation. Faults are seen in the form of cleavage duplexes and bedding-parallel slip accompanying flexural-slip folding. Cleavage duplexes are found in the Marcellus whereas bedding-parallel slip is more common in the overlying Mahantango Formation and further up the section in the Brallier Formation. Layer-parallel shortening decreases from greater than 50% to approximately 10% when crossing the Jacks Mountain–Berwick Anticline structural front from the hinterland portion to the foreland portion of the Valley and Ridge. Disjunctive cleavage, the primary mechanism for layer-parallel shortening, is best developed in carbonates whereas pencil cleavage is best developed in shales.