| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
|
| Initial Amendment Date: | June 14, 2019 |
| Latest Amendment Date: | August 26, 2022 |
| Award Number: | 1917048 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Colin A. Shaw
cshaw@nsf.gov (703)292-7944 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | August 15, 2019 |
| End Date: | December 31, 2023 (Estimated) |
| Total Intended Award Amount: | $81,707.00 |
| Total Awarded Amount to Date: | $81,707.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
1 N COLLEGE ST NORTHFIELD MN US 55057-4044 (507)222-4303 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
One North College Street Northfield MN US 55057-4001 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Tectonics |
| Primary Program Source: |
|
| Program Reference Code(s): | |
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The release of stored energy along large-scale faults, such as the San Andreas fault, can occur abruptly in an earthquake. But this stored energy can also be released via steady, periodic releases of energy known as "slow earthquakes", as well as through deformation in the regions around the fault. This project examines whether changes in how a fault moves or "slips" are linked to observable changes in the deformation of the regions around the fault. Physical experiments in a laboratory are used to replicate aspects of the San Andreas fault system to isolate individual factors controlling deformation and to understand the relationship between how a fault slips and where deformation occurs. Understanding how deformation is distributed between a fault itself and the surrounding regions is critical for forecasting regional earthquake hazards. This multi-institution project supports five students (high school, undergraduate, and graduate levels), and develops new computational tools for visualizing experimental results, along with curricular activities for middle school Earth Science courses.
The geological motivation for this project stems from observations from central California, flanking the San Andreas fault system, where slip behavior changes along the strike of the fault, and the style of off-fault deformation appears to change near the transition in slip behavior. However, naturally deforming systems are complicated, and it is difficult to show causation between slip behavior and borderland deformation. To simplify the problem, this project incorporates a series of physical experiments in the laboratory, where boundary conditions and material properties are controlled. This approach facilitates the evaluation of (1) patterns in off-fault deformation, (2) how geologic structures develop, (3) whether the system reaches a steady-state geometry, (4) whether the rate of slip impacts patterns of deformation, and (5) whether certain structures might be diagnostic of slip control. The model results may provide guidelines for characteristic structures to look for in the borderlands of lithospheric-scale faults to demonstrate slip control of off-fault deformation.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Faults are geologic structures that can have varying behavior along their lengths. Some portions may be "locked," meaning that they can slip suddenly and catastrophically in earthquakes, while other segments may "creep," meaning that the two sides move relative to each other all the time at a slow rate. This project focused on what happens when a fault shifts from locked behavior to creeping behavior, specifically looking at whether diagnostic features develop near this transition in the style of slip.
We used small-scale models to mimic a fault in the laboratory and compared the results to the San Andreas fault system in central California. Our laboratory models used silicone to represent the Earth's crust. By slicing through the silicone in a particular way, we recreated the transition in slip style. Our models demonstrated regions of extension and contraction on either side of the transition that match features in the GPS velocity field for the San Andreas fault. We also observed a domed hill that grew over time on one side of the transition. This feature grew in a position that correlates to the real-world location of the Gabilan mesa in central California, suggesting that the landform's growth may be related to the slip transition. We documented three other faults in the world with similar landforms near their slip transitions, making this domed hill a possible diagnostic feature of slip changes for faults.
As part of this project, we mentored one graduate student through her Ph.D. Two of her three papers in the publication pipeline and the third is being prepared for publication. We also involved four undergraduate students in various aspects of the research. Two conducted research at a university, which exposed them to opportunities not available at their own institution. Two used statistical tools for analyzing data, which provided them with valuable computational experience. Three of the four undergraduate students are in the process of applying to graduate school; one works as a data analyst. We also developed teaching materials about faults that were used in a public school in Iowa.
Last Modified: 02/23/2024
Modified by: Sarah J Titus
Please report errors in award information by writing to: awardsearch@nsf.gov.
