This page currently under construction.  Here's a brief sample of what's to come.

Excavation across the graben of a Pleistocene aged bedrock landslide in Antioch, California.  An extensive geotechnical engineering effort was undertaken to remove the upper portions of the landslide while stabilizing the lower portions.  Ground surface to bottom of excavation measured about 60 feet deep.  See diagram below.  This area is now crossed by the California Highway 4 Bypass.  Photography provided by Kevin Ryan.

              GEOLOGIC DIAGRAM 

Uphill facing scarps (back shadows) caused by 2002 M=7.9 Denali fault earthquake.   Location near Christochina Glacier area south-central Alaska.  Photography provided by Dr. Richard Koehler.

Landslide slip plane encountered at base of 80-feet deep Pleistocene aged bedrock Landslide.  The landslide failed along bedding planes of the Tulare formation in Pittsburgh, California.  Pencil is laying on the slide plane, a 2 to 3 inch thick layer of slickensided clay gouge.  Note striations trending parallel to the pencil.  Photography provided by Kevin Ryan.

 Left lateral offset of concrete drainage ditch caused by earthfow movement.  Offset measured about 12 feet at time of photograph.  Pre-existing landslide was not identified prior to development and impacted three homes.  Confidential location, California.    Photography provided by Kevin Ryan.

Our fealess leader, engineering geologist  Kevin Ryan pointing out geologic structures during mining of the  Caldecot tunnel 4th bore project.  Engineering geology is a critical element in the Sequential Excavation Method (SEM). 

Slide plane at base of 50-feet-deep pleistocene bedrock lanbdlside in the Tassajara formation.  Gouge (shiny surface below hard hat) ranged up to about 6 inches thick.  Note large aplitude striations indicating direction of movement to lower left of photographs.  Photography provided by Kevin Ryan.

HOME