Both of these photos were taken after the 1988 slide event.  What is important to note is the groundwater seep in the hillside to the left of the escarpment; the darker signature on the left part of these photos is water coming out of the hillside.

This is a natural hydrologic feature. Groundwater seeps in the cliffs can been seen all along this section of the 101; during summer when of the surrounding vegetation is dry you can notice the patches of green indicating the presence of surface moisture from these seeps.