On the Uniqueness of Enceladus’ “Tiger Stripes”

Image credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

Perhaps the most striking set of geologic features of Saturn’s approximately 500-kilometer-diameter moon, Enceladus, is concentrated along a series of lineaments in the south polar region known as the “tiger stripes.” The tiger stripes are thought to be fissures linked to a liquid water ocean beneath the moon’s outer ice shell. A new study examines the processes required to create the fissures and why they are seemingly unique to Enceladus. Hemingway et al. suggest that secular cooling results in ice shell thickening and global tensile stresses, causing fractures at one of the poles where the ice shell is thinnest due to tidal heating. Steady eruptions of water ice through the open fissure loads its flanks resulting in further tensile failure parallel to the original fracture – “a process that may be unique to Enceladus, where the gravity is too weak for compressive stresses to prevent fracture propagation through the thin ice shell.” READ MORE