An October Day at Fern Valley – The Mass Movement

A day at Fern Valley with a team of experts, from the left Dr. Judge, Nick and Arrow, Morgan and Ellen. The mission was to map the Fern Valley Slump (and Ellen took a bunch of tree cores from the second (or third) growth oaks).The slump from above. Note the arcuate scarp that marks the upper reaches of the slump block – a series of grabens and scarps stair-step their way into the valley.

Nick has installed wells in the slump blocks to monitor the pore water pressure of the materials.
Here Dr. Judge and Morgan decide where the boundaries of the block are located and then use the Trimble to gather the points.

The team standing at the head of the slump devising a three-part plan of attack.

Another monitoring strategy is the game camera in the tree, which has kept an eye on the movement for the past 8 years.

Morgan and Nick measure the water level in the lower well at the base of the slump.

The hillslope hydrology at the site is complex with much of the flow moving through natural through flow pipes.

The pipes are developed in the reddish sand layer at the base of a legacy (eroded soils) layer (bluish).

One of the well developed pipes in a sand and gravels layer. Note the oxidation of the water as they emerge. Oxidation is facilitated by the bacterial slime that forms at the exits of the pipes.