Patricia Cashman

University of Nevada, Reno

Introductory course for non-majors; satisfies the college's core requirement for science.

None; the exercise stands alone.

This is one of four homework assignments in which students analyze and interpret real data. The students have several weeks to work on each.

The Mogul earthquake swarm generated a lot of attention locally. This was in part because its origin was not immediately clear, so no one could predict how long it would continue or how big the earthquakes might get. In this exercise, students learn to distinguish between fault-generated and magma-generated seismicity.

One theme throughout this course is distinguishing data from interpretations. Another is application of the scientific method, as demonstrated by collecting and interpreting real data, and writing up the results in the standard format for a scientific report. Students do this in four lab projects and four homework exercises; this is one of the latter.

Writing a scientific report

Students examine seismicity related to:
(1) a typical fault-generated earthquake sequence, the February, 2008 Wells earthquake, and
(2) a typical volcanic-generated earthquake sequence at Mt. St. Helens.

For each of these, students describe the distribution of earthquakes on the ground surface and at depth in the earth, and look for characteristics that are unique to each kind of earthquake. They also look for distinctive patterns in the size or depth of the earthquakes with time, again to establish criteria for determining the cause of seismicity.

Students then look at seismic records from the "Mogul earthquake swarm" in Spring 2008, and determine whether it looks like it was generated by faulting or by volcanic activity. They conclude with the reason(s) the Mogul earthquake swarm was unusual.

Student reports are graded using a rubric based on the specific questions in the homework handout. The report outline is the same for all lab reports and homework write-ups in the course.

M 6.0 Wells earthquake data from the Nevada Seismological Laboratory
3D animation of this event (AVI file, 4.7 MB)
Mogul-Somersett Earthquake Sequence; West Reno, Nevada from the Nevada Seismological Laboratory
Animation of 2008 Mogul sequence (AVI file, 23 MB)
USGS data from Mt. St. Helens