Unit 1: "If an earthquake happens in the desert and no one lives there, should we care about it?"
[How are human-made infrastructure lifelines affected by earthquakes?]
This unit initiates a discussion about the importance of recognizing faults in relation to modern societal infrastructure. Students consider the types of infrastructure necessary to support a modern lifestyle, especially for people living in population centers. Students also explore how key infrastructure such as aqueducts, power lines, or oil/gas pipelines, which traverse large distances, may also be susceptible to damage by earthquakes well away from the population centers. Additionally, earthquakes can occur in regions where none have occurred in recorded history. The ability to recognize and evaluate the potential for damage to key infrastructure that are near or cross a fault can be used, in turn, to classify and ultimately predict the most and least likely locations for damage, and to make suggestions for minimizing future impacts.
Unit 1 Learning Outcomes
- Students will assess the most vulnerable local and remote infrastructure components for a population center for damage from fault movement and the associated seismic waves that would be propagated.
- Students will identify and describe the spatial and temporal relationships that exist between the occurrence of an earthquake and the damage caused to infrastructure that may be either local and/or remote with respect to the population center. They will also include an explanation of which infrastructure type and location is easier/harder to access and what other information they would need to fully answer the question.
- Students will evaluate the relationship between earthquake hazards and the type and locations of faults, and provide a fault location error estimate for these faults as well as a statement of the probability that they have failed to recognize a fault.
Unit 1 Teaching Objectives
- Cognitive: Facilitate student consideration of infrastructure components necessary to support everyday life and synthesis of how the loss of these resources would impact society.
- Behavioral: Promote skills in reading and interpreting maps of infrastructure components or, in the absence of such maps, making reasonable inferences from Google Earth resources (satellite, road maps, street view, important local features).
- Encourage reflection about the various local and remote infrastructure failure points.
- Promote scenario building about the role the domino effect might have in complex and intertwined infrastructure systems and identification of the least and most robust infrastructure components.
- Support consideration and identification/description of alternative technologies, early warning systems, and re-engineering efforts to reduce and/or isolate failure problems.
Context for Use
The content in Unit 1 is appropriate for advanced geology/geoscience courses conducted at the junior and/or senior level in which geodesy data can be introduced in conjunction with traditional presentations of material on faults and faulting; this would typically be in a course on structural geology but could also be part of a course on tectonics, geomorphology, geophysics, or advanced geohazards. Unit 1 provides critical background on why hazards associated with earthquakes need to be considered in planning for location, engineering, construction, and maintenance of societal support infrastructure. Unit 1 provides the motivation for undertaking the other units, but this context may be provided in lectures and other instructional modes such as a PowerPoint presentation. Students should be able to conduct Internet searches; to read and understand a variety of maps including basic road maps, topographic maps, political maps, etc.; and to use Google Earth, Google Maps, or equivalent software. Unit 1 may be paired with just Unit 2: Identifying faulting styles, rates and histories through analysis of geomorphic characteristics (Lidar) to combine knowledge of societal support infrastructure with fault types and exact locations so students can make general predictions about earthquake hazards. If the entire module is used, then Unit 1 provides the motivation and context for Unit 5: How do earthquakes affect society?, the final project and summative assessment.
Description and Teaching Materials
In Unit 1 students learn what societal support infrastructure is at risk from earthquakes and rank the relative importance and vulnerability of various infrastructure components. This discussion can also be expanded to include considerations of secondary effects such as landslides and flooding that might be triggered by an earthquake. One approach is to break up the class into teams, assign each team to a different region of the country/world, and have them create a simple sketch map of an urban center with its associated infrastructure.
Infrastructure data (roads, power lines, dams, railroad, etc. as available) have been provided for six case study sites around the western United States: Cedar City, UT; Salt Lake City, UT; Fairfield, CA; Mojave, CA; Fillmore, CA; and Bakersfield, CA. Alternatively, you can assign groups to other cities/regions known to have a history of earthquake activity such as Los Angeles, Salt Lake, St. Louis, and Charleston (or globally: Mexico City, Kathmandu, Istanbul, and Tokyo). Students can be charged with finding or inferring the infrastructure data themselves. Students can conduct Internet searches for maps and descriptions of infrastructure that can provide details of the specific locations and pathways for linear infrastructure components such as road, subway or rail lines, pipelines/aqueducts, and electrical lines.
If students are using the provided case study sites, they can move fairly quickly into Part 4 after analyzing and interpreting the provided maps and possibly brainstorming or locating information about other types of infrastructure not included. If students are finding their own infrastructure data, they should work off of a base map of some sort. They should start by locating these features on a base map that might include geologic and topographic information. A common source for creating a base map is Google Earth. Another option is the UNAVCO Jules Vern Voyager . Unless you are teaching a course that includes GIS use, it will probably be easiest to have the students sketch maps by hand or work on top of a printed base map.
Finally, the students will create an earthquake scenario in which they discuss and rank all the potential disruptions that might occur as a result of an earthquake. Two points are critical to ensure that the students consider the entire range of possibilities. One is to consider both the immediate/short-term effects (minutes, hours days) as well as the medium/long-term effects (weeks, months, years). The other is the spatial distribution of disruption, including the immediate regions as well as distant regions that might experience an earthquake that would disrupt a service (e.g. electrical power, water) that crosses a fault at some distance from the urban center or cause a catastrophic failure of a dam/hydroelectric power plant.
Unit 1 Pre-exercise lecture on how earthquakes damage structures (PowerPoint 2007 (.pptx) 11.3MB Nov25 15)
Unit 1 Student exercise (Microsoft Word 2007 (.docx) 370kB Nov25 15)
Fault and infrastructure data in Google Earth (Zip Archive 11MB Dec4 15) contains critical infrastructure data for the six case study locations. It also includes the USGS Quaternary Faults in Google Earth, which contains all the known faults in the United States. The best subsets to use are "Historic" and "Holocene to Latest Pleistocene."
For instructors not planning to use Google Earth, poster files of the six case study locations are available in pdf or pptx formats that combine fault, LiDAR, and infrastructure data.
Fault-lidar-infrastructure data posters pdf format (Zip Archive 8.9MB Mar25 15)
Fault-lidar-infrastructure data posters pptx format (Zip Archive 119.2MB Mar25 15)
Case Study Sites
- Normal faults
- Cedar City, UT — Hurricane Fault
- Salt Lake City, UT — Wasatch Fault
- Strike-slip faults
- Fairfield, CA — Green Valley Fault
- Mojave, CA — San Andreas Fault
- Reverse faults
- Fillmore, CA — San Cayento Fault
- Bakersfield, CA — Wheeler Ridge
Teaching Notes and Tips
Before undertaking the lab, students should be familiar with basic map reading skills for both topographic and geologic maps. This most likely would have been covered in an earlier course at the introductory level or early in the semester of an advanced course. It is also assumed that students will have been introduced to the concept of earthquake hazards in a previous introductory class and have a general sense of the various direct and indirect consequences of an earthquake. Specific means of accessing and assessing data include:
- Viewing imagery and maps from various sources to begin to develop a sense of what data is available and how it is best displayed and analyzed. This would require basic Internet search experience and a sense of filtering out and using only valid, scientifically supported web sites that have some level of scientific review and quality assurance/control.
- Creating base maps from various sources to allow for the creation of a multi-layered data set that includes various features including the societal support infrastructure as well as geologic, topographic, and other relevant data sets in a combined fashion. Examples of means to accomplish this are:
- Exploring where earthquakes are occurring and developing a sense for the relative size, fault type, and repeat times for various regions of the country/world. The USGS Earthquake Hazards Program is a good tool for this. Students can explore regions of interest and query the data sets for various aspects of earthquake activity in various regions and also get plots of known active and recently inactive faults.
- The Google Earth and pdf map files provided in this exercise contain faults as mapped by the USGS Quaternary Fault Database. This database is very valuable for identifying potentially active faults; however you will want to caution students that many of the fault locations have not been updated since the acquisition of lidar data. Students may note that the faults are not in "the right place" based on where the fault is clearly visible in the high resolution lidar images. This is an opportunity to discuss with the students how scientific knowledge can be refined as methods improve. Using this newer data, students can "do better" than USGS scientists because they are using more recent technology.
Additional information that could be provided to students
Providing the students with additional geological information, such as Quaternary surface geological maps, may enable more nuanced discussions of infrastructure vulnerability. Detailed knowledge of the substrate type across the area of interest will enable the students to assess other possible causes of damage including liquefaction (water-saturated clays) and/or site amplification (unconsolidated/soft sediments). A preparatory lecture on the ways in which earthquakes can damage structures would be a useful accompaniment to this additional information.
Geological map overlay for Bakersfield (Zip Archive 97.4MB Nov16 15) - Geological map of the Bakersfield area, assembled from California Geological Survey map tiles
Geological map overlay for Fairfield (Zip Archive 6.6MB Nov16 15) - Liquefaction susceptibility map of the Fairfield area, derived from a USGS liquefaction map of the San Francisco Bay Area
Geological map overlay for Provo (Zip Archive 162MB Nov16 15) - Geological map of the Provo area, derived from a Utah Geological Survey map, plus a USGS report on liquefaction susceptibility
Earthquake preparedness extension
While they are learning about earthquakes, you could consider taking the opportunity to have the students do a basic earthquake drill of Drop-Cover-HoldOn. While they are learning about earthquakes effects, it is a prime time to make sure they know what to do to be safe. Earthquake Country Alliance have great resources on basic earthquake safety. More resources are available from The Great ShakeOut international earthquake drill, Redwood Coast Tsunami Workgroup for coast areas with tsunami threat, and of course FEMA and Red Cross
Example #1: Within the context of implementation of Parts 1, 2, and 3, a modified gallery walk might be considered. This would allow the various groups to see and discuss what additional considerations and data types were employed by the various groups that might reflect regional differences in both the geologic setting and the type of infrastructure at risk. There are several informal and formal methods that may be used to assess gallery walks available on the SERC website. Following the initial walk, the students are given time to modify their own maps and earthquake hazard assessment scenarios to either include additional considerations they learned about in looking at the other work or comment as to why such considerations are not necessary for their specific region. As an alternative, each group might create a PowerPoint presentation and make group presentations to the other groups.
Example #2: Faculty may collect student infrastructure risk assessment lists and evidence maps or PowerPoint files at the end of the class meeting, either one set from each student or one combined set of maps from each group before and after presentations and discussions and these can be evaluated.
For Part 4, assessment will take place via an evaluation of the student earthquake hazard assessment scenario. A set of grading rubrics will include a list of criteria for student responses to each of the segments (Parts 1, 2, 3, and 4) and the additional supporting graphics (maps) that are requested.
Example Unit 1 Assessment Rubric (Microsoft Word 2007 (.docx) 100kB Nov25 15)
References and Resources
- State Water Project (SWP) Facilities Map
- California Aqueduct: Evaluation of Groundwater Conditions and Land Subsidence Along the California Aqueduct
- UNAVCO Jules Vern Voyager
- The USGS Earthquake Hazards Program
- Earthquake and tsunami preparedness:
Earthquake Country Alliance
Redwood Coast Tsunami Workgroup