Variations observed in the strength of the steam jets leaving Enceladus may be due to the fact that the openings in its icy crust run in a manner similar to slip tectonics.
On Earth, this type of plate tectonics, with one side cutting into the other, corresponds to the fault movement that produces earthquakes along faults like the San Andreas in California. The energy required for such failure movement is considerably less than that required by the opening/closing mechanism.
It’s the finding of new research led by Caltech graduate student Alexander Berne, who used detailed geophysical modeling to characterize the movement of these tiger strip faults on this moon of Saturn, and provides new insights into the geophysical processes. that control the activity of the columns.
At the south pole of Enceladus, a large number of jets spew icy particles from a 150-kilometer-long set of irregular faults, known as tiger stripe faults, and this ejected material coalesces on the moon’s surface to form a column. Samples of this plume material analyzed by NASA’s Cassini mission suggest that the chemical conditions thought to be necessary for life may exist in the deep ocean beneath the surface of Enceladus.
Understanding these and other factors (such as to what extent the jet material represents this moon’s subsurface ocean, how long the jets have been active, the topography of its ice sheet, etc.) is crucial to obtaining a detailed picture of its potential habitability.
Berne and his colleagues developed a sophisticated numerical model to simulate strike-slip motion along the Enceladus faults. These models also consider the role of friction between the icy walls of the faults, which makes the deformation sensitive to both the compressive stresses that tend to clamp and release the fault, and the shear stresses that tend to cause fault slip. The numerical model is able to simulate gliding along the tiger’s stripes in a way that matches variations in plume brightness as well as spatial variations in surface temperature, suggesting that the Jets are effectively controlled by the gliding motion about Enceladus’s orbit.
The researchers theorize that the individual jets occur at “gaps” on the faults: bent sections of the fault that open up under regional strike-slip motion. Recent independent research from JPL also examined the tiger stripe region and found geological evidence of separations along the faults, located right at the location of the jets. “It now appears that we have both geological and geophysical reasons to suspect that jet activity occurs in the separation zones along Enceladus’ tiger stripes,” Berne says in a statement.
