Cathy Perfect
Kern Valley Sun

Geologists studying the Kern Canyon fault that runs through the earth under Isabella Dam have been ‘entrenched’ in their work as of late. The 200-foot trench pictured on page A1 is the third such trench dug in the valley recently. It is located on the Havilah property of Janice and Wes Kutzner, approximately eight miles south of Lake Isabella. “The people in the area have been very gracious about letting us dig on their property,” said Ronn Rose, US Army Corps of Engineers Project Manager for the Sacramento District. “The Kutzners, especially, were very nice.”

Geologists working in the Havilah trench, measuring 15 feet deep in some spots, will be “logging the soil,” soon Rose said. “We look at the contact of the rock and the soil. That’s granite in there and it’s sheared from the force of earth's movement.”

Geologists studying the Kern Canyon Fault on Nov. 18 examine the soil in a 200-foot trench dug on the property of Janice and Wes Kutzner in Havilah.

The logging process, he explained, involves cleaning the walls of the trench and looking at soil units. “We are looking for artifacts, such as coal, that will help us date the activity in the soil. It will help us determine how often the fault has moved, how big it was and when the latest one occurred,” he said. “Logging the soil units and the activity, that is seeing how much they’ve been offset by the quake, helps us assess the risk,” Rose added.

The painstaking process allows scientists to understand the characteristics of the fault zone, thus Rose said, “We are ‘characterizing’ the fault. We want to know if, when seismic activity occurs, the entire fault moves or if it moves in sections.” Rose estimates the last seismic activity occurred, “likely several thousand years ago, which in geologic time is yesterday.” Rose added the Kern Canyon fault is a low slip rate fault, meaning there is less movement than there would be if the fault had a high slip rate.

Rose said he anticipates the work in Havilah will be completed some time next week. Then they will move on to work above Kernville.

Once data from the Kern Canyon fault is collected and analyzed, scientists will create computer-generated models that will provide them with options and alternative concepts for mitigating the elements that have put Isabella Dam at the top of the U.S. Army Corps of Engineers’ list of high-risk dams.