A MORPHOLOGICAL ANALYSIS OF EUROPA’S BANDS IN THE E15 REGION

Europa, Jupiter’s second Galilean moon, was first imaged during a Voyager 2 flyby in 1979. Higher resolution imagery from the Galileo spacecraft in the 1990s revealed the surface in better detail during eight flybys of the moon, allowing for more precise distinctions to be made between geologic regions and for assignment of a broad stratigraphy to those features. Images revealed features such as plains, chaos material, bands, ridges, and crater material, which are categorized based on morphology, texture, albedo, and color [1]. Some bands are identified as boundaries of discrete plates in the Europan ice shell accommodating extensional, contractional, and/or transform motion [2]. Bands represent sites of crustal formation through mid ocean ridge-like spreading [3] and recycling of old crust through subsumption [4]. Band morphologies vary along their length, therefore we obtain qualitative and quantitative data on band morphology at discrete 5 km intervals along each band. We also attempt to discern a stratigraphy of intersecting bands and ridges within region E15, a portion of the trailing northern hemisphere, located on the antijovian side of the moon. Using a sequence of ArcGIS tools, we analyze widths along six intersecting bands, using transect lines perpendicular to an interpolated band center line. Bands have 10+ transects and range in average width from 3.9 to 14.9 km, with standard deviations from 0.9 km (4.8 km width) to 6.1 km (14.9 km width). Standard deviations <3.0 represent bands with significant changes in width along their length, for example wedge bands. Adding number and spacing of internal band-parallel lineations to our transect data will help us further characterize any apparent variation in stress regime along the band’s length. Future work includes using changes in band morphology in the stratigraphic sequence to investigate changes in the style of tectonic deformation through time as preserved in the E15 region.