Patricia Cashman

Determining Earthquake Recurrence Intervals from Trench Logs part of Rates and Time:GSA Activity Posters
Trench logs of the San Andreas Fault at Pallett Creek, CA are the data base for a lab or homework assignment that teaches about relative dating, radiometric dating, fault recurrence intervals and the reasons for uncertainty in predicting geologic phenomena. Students are given a trench log that includes several fault strands and dated stratigraphic horizons. They estimate the times of faulting based on bracketing ages of faulted and unfaulted strata. They compile a table with the faulting events from the trench log and additional events recognized in nearby trenches, then calculate maximum, minimum and average earthquake recurrence intervals for the San Andreas Fault in this area. They conclude by making their own prediction for the timing of the next earthquake.

Cause of the Mogul, Nevada, Earthquake Swarm, Spring 2008 part of Introductory Courses:Activities
Students examine data from fault- and magma- related earthquakes and determine distinguishing characteristics. They then apply these criteria to determine the cause of the Mogul earthquake sequence (that most of ...