Induced Seismicity: Are humans causing earthquakes?

John Taber, IRIS Consortium
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Summary

In this lab, students investigate a hotly debated topic relevant in the political, economic, and scientific arenas. They will examine the processes involved in unconventional oil and gas resource production, including hydraulic fracturing. In particular, they will examine nearby seismic activity and will be asked to determine if correlations can be established between fluid injection, related to hydrofracking or wastewater disposal, and earthquake activity. As an option, students can also investigate geothermal activity at the Geysers in California, to illustrate the difficulty in assessing natural versus induced seismicity in such a geologically complex region.

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Context

Audience

This lab is designed to be used in an intro or intermediate level geoscience course for majors, though it could also be adapted for a non-majors course.

Skills and concepts that students must have mastered

Before undertaking this activity students should know what earthquakes are and their basic mechanics, understand the earthquake cycle, and have been introduced to earthquake hazards. Some basic understanding of sedimentary rocks will also be helpful. It is recommended to show the short PowerPoint on hydraulic fracturing and wastewater injection before starting the activity.

How the activity is situated in the course

This activity is designed to follow a lecture on earthquakes, the earthquake cycle, and earthquake hazards,

Goals

Content/concepts goals for this activity

Students will be able to:
1. Describe the processes involved in unconventional oil and gas production.
2. Collect and analyze seismicity data for a region of interest using the IRIS Earthquake Browser.
3. Use data to either support or refute potential correlations between hydrofracking and/or disposal wells and earthquakes in Oklahoma.
4. Describe how other processes, such as geothermal energy might similarly induce seismicity.

Higher order thinking skills goals for this activity

Students will analyze several different real data sets and are asked to provide evidence and reasoning for claims based on the datasets. They are also asked to differentiate between correlation and causation.

Other skills goals for this activity

Description and Teaching Materials

In this lab, students first investigate the processes involved in unconventional oil and gas resource production, i.e. hydraulic fracturing, including examining the regions in the US where hydrofracking is being conducted. They then compare those regions to the geology and recent seismicity on a US scale. The next step is for the students to conduct a detailed comparison of hydrofracking wells, waste water disposal wells, and seismicity in Oklahoma. They are asked to decide if they can draw correlations between fluid injection related to hydrofracking or from wastewater disposal and earthquake activity, and to consider ways that we might establish a better understanding of correlations between the two. Finally they are asked to make a claim, backed up by evidence, as to whether there is a causal link between any of the correlations.

As an optional extension, students can also investigate geothermal activity at the Geysers in California, to illustrate the difficulty in assessing natural versus induced seismicity in such a geologically complex region.

Instructor guide for "Induced Seismicity: Are Humans causing earthquakes?" (Microsoft Word 2007 (.docx) 536kB Jun15 17)

Student worksheet KEY "Induced seismicity" (Microsoft Word 2007 (.docx) 4.7MB Jun15 17)

Student worksheet "Induced seismicity" (Microsoft Word 2007 (.docx) 993kB Jun15 17)

Induced seismicity figures (PowerPoint 2007 (.pptx) 6MB Jun5 17)

Earthquakes hydrofrac and injection wells (KMZ File 164kB Jun5 17)

Teaching Notes and Tips

Assessment

An activity key is provided which can be used to assess whether students have met the goals of the activity

References and Resources

Instructor Background:
Duggan-Haas, Robert M. Ross, and Warren D. Allmon (2013) The Science Beneath the Surface: A very short guide to the Marcellus shale,Paleontological Research Institution (Special Publication 43), Ithaca, New York, 252 pp.

Ellsworth, W. L. (2013), Injection-Induced earthquakes, Science, 341, 142-149.

Keranen, K. M., H. M. Savage, G. A. Abers, E. S. Cochran (2013), Potentially induced earthquakes in Oklahoma, USA Links between wastewater injection and the 2011 Mw5.7 earthquake sequence, Geology, doi:10.1130/G34045.1.

Langenbruch, C., and M. D. Zoback (2016), How will induced seismicity in Oklahoma respond to decreased saltwater injection rates?, Sci. Adv., 2(11), e1601542–e1601542, doi:10.1126/sciadv.1601542.

National Research Council (2013), Induced seismicity potential in energy technologies, Washington, D.C., The National Academies Press, 262 p., http://www.nap.edu/catalog.php?record_id=13355.

Rubinstein, J. L., and A. B. Mahani (2015), Myths and Facts on Wastewater Injection, Hydraulic Fracturing, Enhanced Oil Recovery, and Induced Seismicity, Seismo. Res. Lett., 86, no. 4, doi: 10.1785/0220150067.

Waste water:
http://energyblog.nationalgeographic.com/2013/10/04/fracking-water-its-just-so-hard-to-clean/