Figure 1.
Top left: image looking southwest showing patches of dead vegetation visible at a farm field near Gregs Run. Top right: a closer image of a patch of dead vegetation taken during winter. Bottom left: a map of the sites of interest in this study. Methane bubbles were observed in Gregs Run (near red star) and Sugar Run (yellow star) near Hughesville, PA. A nearby shale gas well (orange circle) has been cited by the Pennsylvania Department of Environmental Protection for integrity issues. Although this well is located greater than 2 km from Gregs Run, it is the closest oil and gas well to this site. As mentioned by Woda et al., 33.3% of unconventional wells within a 13 km × 13 km square centered around Sugar Run have received at least one citation relating to the well integrity.27 Bottom right: areas of methane emissions as identified by methane mole fraction enhancements measured using a Bascom-Turner Gas-Rover on April 18th, 23rd, and 27th, 2019. Stars indicate the location of the eddy covariance flux tower deployed at site 1 from 12-1-18 to 4-1-19 and site 2 from 4-2-19 to 5-31-19. Hexagons indicate the location of chamber flux measurements, and the study area is denoted by the transparent circle. Gregs Run is located within the trees to the left of the field.