Faults in the Field:
Expedition to California

Students Zach Engstler from Iowa School for the Deaf and Delia Kimmel from University High School contributed writing and photography respectively to today's blog.

Landslides and Fault Slips

We started our day with an early morning gathering at the conference room at California School for the Deaf in Riverside. Dr. Michele Cooke, the tour leader, welcomed everyone and introduced our guests for the day, Dr. Katherine Kendrick, from University of California; Dr. Doug Morton U.S. Geological Survey, retired, Donald Burnes, science teacher from CSDR and students from CSDR who are joining our trip today and tomorrow. Cooke shared how her ultimate goal in her National Science Foundation grant was to see how secondary school students could conduct similar experiments to the ones she uses in her geological research lab. Cooke said there is a natural connection between the visualization skills a geologist needs and the visual skills of a deaf learner using American Sign Language.


At our morning meeting we divided up into teams for group activities on recognition of landslides and active faults. Cooke drew symbols on the white board, using arrows and layers to display how anything in the path of a landslide would be impacted. Some students suggested a landslide could result from a situation where diverse rocks could result in a mixture at the bottom of a slope, or how a slump would develop into the hill itself. Among other ideas, we listed how landslides could include dead vegetation and result in the collapse of homes. Then we moved on to how to recognize an active fault. The groups suggested causes such as collapse of any construction, signs of disrupted ground, or bent and mangled pipe, fence, and walls. We will see if our ideas about landslides and active faults match what we see on our road trips this week.



Canyon Town of Forest Falls

In the morning we drove through the San Bernardino Valley to the canyon town of Forest Falls. Dr. Morton showed us where a massive rock debris flow in 1999 caused great damage to houses, trees, and vegetation. The debris flow is a kind of erosion in the earth where many boulders and shards of stone laid waste all the rocks under our feet as we walked over on the steep hillside Burnes explained how a landslide can travel up from sixty to seventy miles per hour. The ravaged path we hiked along was lined with huge boulders, some the size of small cars. A landslide can destroy anything; it comes in “slugs,” masses of mud and rocks sliding like the rapids, and can shatter across barriers into new directions. Twelve homes were destroyed and one life was claimed in the 1999 incident. Every two years Forest Falls has a landslide, more often than anywhere else in California, in a random selection, either following the same path it made prior or carving another one. Dr. Morton called it the “most hazardous town in the U.S.” The rocks were both gneiss, with wavy dark lines, and chalky white granite. The color depends on how the layers of minerals, and also how temperature and pressure change. Giant cedar trees played an important factor in diverting the rocks in the debris flow; we saw tree which had its bark eaten through by the debris flow and it had nicks from the ricocheting stones, and one that had fallen determining the path of the rock flow. We noted it was a home to many nested spiders and enormous dropped pine cones. As we descended, we saw that one neighbor had built a wall of the stones left in the flow and cemented over them in order to divert impact– only it will hit the other houses, proving that it doesn’t help the problem at all.



San Andreas Fault and the Lost Lake

We had a picnic in the mountains for lunch. Passing the mountain town of Devore, where the San Andreas Fault runs, Cooke stated an interesting fact about the law in California that it is legal to build single homes directly on the fault line, but over four houses would not be permitted.

In the afternoon, we arrived to view a sag pond called Lost Lake that was surrounded by mountains that led down a straight series of valleys. The area where we were walking is directly on top of the San Andreas Fault between the edge of the Pacific plate and the North American Plate. We listened to geologist Dr. Scott Marshall explain how two faults would stretch and sink a region of land, which the rain filled in leading to the creation of a sag pond. One student compared the sag pond to a swimming pool because there isn’t a direction or flow for the water to flow out. Using colored pencils, a ruler, and mathematical skills with a map and graph, we measured how fast the fault would slip and determined whether it was left or right-lateral, which the concept was compared to a doorknob where your fingers and thumb would end up. And after a long and incredible learning experience in a day, we returned to California School for the Deaf in Riverside for dinner.



We posted some more pictures at Flickr. To see these pixs, go here:
http://www.flickr.com/photos/26322601@N03/