Abstract
Diurnal tides due to orbital eccentricity may drive strike-slip motion on Europa through a process of "walking" in which faults open and close out of phase with alternate right- and left-lateral shear. Mapping of five different regions on Europa has revealed 121 strike-slip faults, including Astypalaea Linea, a 800-km-long fault with 42 km of right-lateral offset. At high southern latitudes near Astypalaea Linea all of the strike slip faults identified were right-lateral. Europa appears to preferentially form right-lateral faults in the southern hemisphere and left-lateral faults in the northern hemisphere, consistent with tidal walking. At the five locations, nonsynchronous rotation explains the azimuthal orientations and distribution of sense of shear, which fit formation ∼60° to 90° west of their current positions. Alternatively, stress due to differential rotation might also explain the observed shear patterns. Nearly all identified strike-slip faults were associated with double ridges or bands, but few were detected along ridgeless cracks (even older ones). Thus, cracks without ridges may not have penetrated to a decoupling layer, consistent with the models for ridge formation that require cracks to penetrate to a liquid water ocean.
Original language | English (US) |
---|---|
Pages (from-to) | 287-298 |
Number of pages | 12 |
Journal | Icarus |
Volume | 141 |
Issue number | 2 |
DOIs | |
State | Published - Oct 1 1999 |
Keywords
- Europa
- Satellites of Jupiter
- Tectonics
- Tides
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science