Slickensides

Slickensides form on rocks in fault planes as the rocks scrape past each other. They are polished surfaces with parallel (to fault motion) striations or grooves called slickenlines. This can happen suddenly during an earthquake, or gradually during creep.

Below are some slick (and famous) slickensides with mirror surfaces from San Francisco. More detail on these slickensides from Callan Bentley’s great AGU blog, Mountain Beltway: https://blogs.agu.org/mountainbeltway/2015/12/28/corona-heights-fault-san-francisco/

Bonus: See a collection of slickensides and more information from our own Andrew Alden @alden https://www.thoughtco.com/gallery-of-slickensides-4122857

#slickensides #slickenlines #EarthQuakeFaults #rocks #geology #ScienceMastodon @geology