3D excavation across the San Andreas fault
Clay Stevens
CSU Northridge
claymichael@earthlink.net
Mentor: Doug Yule, CSU Northridge
My project will complement part of a larger
study that explores the earthquake history of the San Andreas
fault system near Banning, California. I hope to create a three-dimensional
fence diagram of the area using the information of previously
logged trenches and new trenches that will be opened this summer.
Once familiar with the site stratigraphy, I will build a fence
diagram using key structural and stratigraphic features, including
faults, folds, marker beds, and event horizons. The relative positions
of these features can be surveyed using a laser theodolite total
station. These data will then be plotted using GIS software (Arcview
or other equivalent software) to create the fence diagram. I will
also make hand drawn logs and photo mosaics to show the key relationships.
The fence diagram will provide a basis for approximating the shape
of event horizons. The geometry of the paleo-surface can be constrained
by extrapolating the event horizons between trenchcrops based
on the available structural and stratigraphic information. A 3D
approximation of each event horizon can show how the ground changed
relative to each earthquake event going back in time. Once this
is done we can estimate how much deformation occurred during the
paleo-seismic events. This information will help constrain the
magnitude of the earthquakes that rupture through the Burro Flats
site. I anticipate spending 5-6 weeks in the field mapping and
surveying the trenches, and ~5-6 weeks preparing the 3D fence
diagram. Computer labs at Caltech and CSUN will be used to prepare
the report and draft the diagrams.
Table of Contents
3D excavation across the San Andreas fault
Local Topographic relief and fault map
Locations of paleoseismic trenches along the San Andreas fault
History of earthquakes at each paleoseismic site
San Andreas fault, San Gorgonio Pass
Map of points along trench walls
Wall diagram based on surveyed points (contacts and faults)
3D image of bench and mapped features