15 January 2011

Snowy detachment

Posted by Callan Bentley

I think snow can act as a nice analogue for larger-scale rock deformation. I explored this a bit last February, and I was reminded of it again last week, when I walked to my car one morning and saw this:

Notice how the slab of snow on the hood (“bonnet” for British readers) of my Prius has slid en masse down”hill,” leaving the top portion of the hood bare of snow, and crumpling up just above the license plate as it encounters the resistant obstacle of the bumper.

Naturally enough, I was reminded of a detachment fault, a low-angle “normal” fault, where the upper block slides down the face of the lower block, as in this example from Arizona:

[image source]

In my analogy, the snow is the upper block, and the Prius hood is the lower block. The contact between the two is the “detachment fault.”

Have you seen snow do anything neat like this lately?