Cause of the Mogul, Nevada, Earthquake Swarm, Spring 2008

Patricia Cashman
University of Nevada, Reno
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Initial Publication Date: November 21, 2008


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 the students experienced) last spring.

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

Skills and concepts that students must have mastered

None; the exercise stands alone.

How the activity is situated in the course

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


Content/concepts goals for this activity

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.

Higher order thinking skills goals for this activity

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.

Other skills goals for this activity

Writing a scientific report

Description of the activity/assignment

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.

Determining whether students have met the goals

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.

More information about assessment tools and techniques.

Teaching materials and tips

Other Materials

Supporting references/URLs

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