Students Meg Katter and Ben Polstra from Indiana School for the Deaf and Ameena Patterson from the Model Secondary School for the Deaf contributed to today’s blog.
Journey through San Jacinto ValleyThis morning we got on the bus and drove to San Jacinto Valley where Dr. Doug Morton and Dr. Michele Cooke told us about the San Jacinto Valley. They told us that the faults have certain shapes that are often not flat and that they can even curve. Another thing they taught us was there is a geological structure where the sediments and rocks are deposited in a called landslide. We also saw an alluvial fan where a river drops its sediments. Before we got back on the bus they reminded us that a fault can be segmented in different sections instead of one continuous fault. If the fault pulls apart it can cause a depression that usually fills in with water like Lost Lake, the sag pond we saw yesterday.
Hot Springs Fault
We then got back on the bus and headed off to the San Jacinto River near the town of San Jacinto to look at the man-made river levees. The river bed was dry because the water only flows in the winter and early spring. The students drew cross sections of the river to visualize the 3-D aspects of the river bed. Laura Dair, a graduate student from University of Massachusetts, explained how the river bed is higher within the walls of the levee than the base of the town. She told us that there was a difference in the levels because the sediments cannot escape outside the levee and it builds in higher and higher levels. Eventually the sediment level will become almost even with the levees and will cause the town to flood. Even now, if the river becomes very high during the rainy season, it could overflow the levees and flood the town.
Dr. Doug Morton then talked about why the alluvial fan on the San Jacinto fault got bigger every year. We learned the alluvial fan gets bigger due to erosion bringing more sediments to the bottom of the fan. Dr. Scott Marshall asked the group why we thought the San Jacinto River had no big rocks and then he explained the currents from the river were not very strong so the river could not carry big rocks. Instead, it only carries small rocks. Michele explained that the river flows on the mountain side of the valley because of the low area caused by the fault. The fault is lower, making the valley floor, so the river flows in the valley along the fault line hugging the base mountain instead of the typical position of running down the center of a valley
Dr. Cooke told us there are several hot springs located along the base of the mountain. The hot springs were trapped and created by a fault and the heat from magma. When the fault sides grind together, the force is so strong that the rock in between gets ground into fine powder, called gouge. Water heated deep in the Earth flows up through the gouge and comes out on the surface making hot springs.
Thousand Palms Oasis
We left the cool, breezy weather of the San Jacinto Valley and arrived in the dry heat of
Palm Springs Desert, a dry, sandy landscape with scrub bushes. We stopped to have our picnic lunch in the Thousand Palms Oasis, an amazing site of giant palm trees. We walked into the desert to view the oasis, which actually is a sag pond, created by water seeping into the cracks of a fault. Drs. Cooke and Marshall introduced us to the important geologist skill of plotting location on a topographical map and challenged us to find our present location on a topographical map of the Oasis area. We also had a contest to see who could draw the direction of two segments of the San Andreas Fault looked like in this area, then we walked further into the desert to another smaller oasis passing by some desert sand dune formations. It was hot and breezy. Everyone had to use sunscreen and drink plenty of water. We walked to another site with tall palm trees and were surprised to find a beautiful pond right in the middle of the desert! There were fish in the pond, bright orange dragonflies buzzed over the water, and one teacher was even surprised when a California King Snake crossed the trail in front of her.
Laura Dair, a graduate student from University of Massachusetts, told us that sand dunes have a shallow slope on one side and a steep slope on the other side. We learned that the reason was because the wind picks up sand one side and drops it on the other. When the sand is picked up it forms the shallow angle, but when it is dropped it forms a steep drop. She told us when a layer of sediments is solidified on top of a sand dune then another dune begins forming. This process continues over many years. She also told us about the Desert Pupfish. She told us that most geologists believe those are an ancient and endangered species that descended from fish living in the area after the Ice Age.
Mary D'Angelo, an Emergency Medical Technician, and Roy McCrory explained the procedures for preparing for and what to do after a severe earthquake. They told us if there was a severe earthquake, the important thing was to stay put and protect yourself. They told us it was important to have a supply kit with enough supplies for at least 72 hours. They also told us a disappointing fact was that less than 10% of the population has an emergency plan. Some people asked about standing under a doorway for safety, but Roy told us that it was a myth that was a safe thing to do.
Palm Springs Aerial Tram Ride
We took the tram ride up the San Jacinto Mountain to an elevation of almost 11,000 feet to a restaurant on the top of the mountain where patches of snow could be seen and the temperature dropped to around 50 degrees. The top of the mountain was awesome! After dinner we descended the mountain, dropped our California School for the Deaf Riverside guests back, and drove on to Long Beach on the coast in preparation for our next day’s travels.
# posted by Susan Flanigan @ 7:48 AM
