Lapetus Ice Landslides

We are gradually coming to know the intimate details of our solar system much more clearly, and the giant planet Saturn certainly has some interesting moons. Not least of these is Lapetus, which often undergoes, on the surface, something that is rare elsewhere within the solar system, in the form of huge types of landslide or avalanche.

Known as long-run-out landslides – Sturzstroms – these events happen with much faster and farther impact than predictions by geological models might suggest to researchers, who have studied similar occurrences on both Earth and Mars, though what causes them is still the subject of fierce debate.

New Cassini space mission images have led to scientists suggesting that the heating of the moon’s icy surfaces – by the massive planetary gravity – must in part be responsible for their unusual frequency and range. Earth-bound landslides typically fall twice the distance that they travel horizontally. whereas, by contrast, long-run-out landslides often, travel up to 30 times further along the flat.

The explanations for this phenomenon are wide-ranging, though none seems in any way conclusive, though St. Louis, Washington University scientist Kelsi Singer believes that the Lapetus geography plays a huge part.  With landslides there a planetary scale, scientists are able to observe them as ice-slides, rather than rock, in a zero-gravity, zero-atmosphere scenario.  

This planetoid has a geologically interesting shape, being somewhat squashed in the middle, the equator wider than the poles, encircled for the most part by a huge ridge some 20km high in places, alongside several giant impact craters up to 25km deep. Not only that, but this strange body undergoes more giant landslides than any Solar System body other than Mars, due to the topography of this astral body.

Researchers studying the icy surface for stress fractures found evidence for   30 huge landslides, and  analysis of event images suggests that  Lapetan coefficient of friction is far lower than expected for ice by scientists in a normal environment, perhaps because tiny contact points – between ice debris fragments – greatly heat up, melting the ice for a far more fluid material mass, an idea earth-bound researchers are keen to test in the laboratory, to gain insights into earth geology.