Landslides on Mars
    Taken from a USGS website (ida.wr.usgs.gov) devoted to Mars Global Surveyor images.  This particular landslide is found at approximately 9° South Latitude and 78° West Longitude, along the wall of the giant canyon known as the Ius Chasma.  It's hard to tell the scale on this image, but I would estimate that the slump block is about 10-20 km across (plus-minus).  The head scarp is probably many kilometers high.  The slump block has a stepped appearance; perhaps the big slump is broken into smaller, secondary slump blocks.
 

Another one to the west, about the same scale.  A very nice curving headscarp.
Notice the feederless "stream channel" to the right, showing erosion from the valley floor up.
Do you see any craters in the landslide debris?

Meadow Mountain area, central North Cascades

    This spring 2002 debris flow wiped out Forest Service Road #41 where the road crossed a small unnamed creek, about 1 mile before Rd #41 crosses the south fork of Canyon Creek.   The debris flow originated somewhere upstream and "bulked up" on debris as it moved downhill.  The culvert (lower left) couldn't handle the volume, some of the trees carried down by the debris flow were twice as big as the culvert!  Note debris deposited on top of roadbed from photographer to stream.

Looking back downhill, the undamaged road is behind the debris pile near the top center of the photo.  Note scarring on large tree in upper right of photo.  Scars like this can be healed over.  Old scars, revealed by coring the tree, can give the history of past debris flows.

A view downstream, showing the slope steepness.  The road passed on the other side of the small trees to the right, so you can see how much road fill there was, and how much material was moved during the event.  The debris probably made it all the way to the valley bottom (small patch of light trees top center), where it entered Canyon Creek.

Looking across the stream, the former roadbed came right towards you.  Notice the dark gray fill, obtained from quarrying the hillside just a few meters down the road.  This "cut and fill" approach to roadbuilding is typical of Forest Service roads.  The culvert pipe has been rotated about 45 degrees during the debris flow event.

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