Formation of Cycloidal Features on Europa
Gregory V. Hoppa,
B. Randall Tufts,
Richard Greenberg,
Paul E. Geissler
Cycloidal patterns are widely distributed on the surface
of Jupiter's moon Europa. Tensile cracks may have developed such a
pattern in response to diurnal variations in tidal stress in Europa's
outer ice shell. When the tensile strength of the ice is reached, a
crack may occur. Propagating cracks would move across an ever-changing
stress field, following a curving path to a place and time where the
tensile stress was insufficient to continue the propagation. A few
hours later, when the stress at the end of the crack again exceeded the
strength, propagation would continue in a new direction. Thus, one
arcuate segment of the cycloidal chain would be produced during each
day on Europa. For this model to work, the tensile strength of
Europa's ice crust must be less than 40 kilopascals, and there must be
a thick fluid layer below the ice to allow sufficient tidal amplitude.
Lunar and Planetary Laboratory, 1629 East University Boulevard,
University of Arizona, Tucson, AZ 85721-0092, USA.
To whom correspondence should be addressed. E-mail:
hoppa{at}lpl.arizona.edu
