| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | August 17, 2016 |
| Latest Amendment Date: | August 2, 2018 |
| Award Number: | 1625069 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Russell Kelz
EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2016 |
| End Date: | August 31, 2019 (Estimated) |
| Total Intended Award Amount: | $840,000.00 |
| Total Awarded Amount to Date: | $840,000.00 |
| Funds Obligated to Date: |
FY 2017 = $276,022.00 FY 2018 = $311,852.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
8622 DISCOVERY WAY # 116 LA JOLLA CA US 92093-1500 (858)534-1293 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
CA US 92093-0225 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Major Research Instrumentation, Instrumentation & Facilities |
| Primary Program Source: |
01001718DB NSF RESEARCH & RELATED ACTIVIT 01001819DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The Scripps Institution of Oceanography of the University of California San Diego will prototype a new generation of sensitive motion detector of the earth. The fiber-optic-based sensors are deployed in deep boreholes and record movements as small as the width of a human hair over times that range from a fraction of a second to years. The new instrument package will record behavior from sudden earthquakes to slow movements that do not generate seismic waves. The instrument can be located where dangerous faults or volcanic hazards exist near human populations, as well as where induced earthquakes associated with fluid extraction or injection might occur. This project is aligned with NSF's mission of promoting the progress of science to advance the nation's health, prosperity, and welfare.
The Scripps Institution of Oceanography will develop a geodetic/seismometer package that can detect a range of earthquake-related phenomena from sudden slip to continuous slow slip and episodic tremor. The package will provide key data for understanding the physics of fault movement. The robust fiber-optic-based sensors will have a long instrument lifetime and be resistant to high downhole temperatures. The comprehensive instrument will measure vertical and horizontal ground velocities, gravity, tilt, and strain. The prototype instrument will be installed in an existing borehole at the Pinon Flat Observatory for testing and comparison with existing seismic and strain systems. The new package is expected to significantly expand the network of geodetic/seismic observations both on land and beneath the sea floor.
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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.
The goal of this project has been to develop and construct a borehole system that utilizes optical-fiber interferometry to provide in one package: (a) a broadband vertical seismometer/gravimeter, (b) a broadband two-component horizontal seismometer/tiltmeter, and (c) a low-noise vertical long baseline strainmeter. The combined system is able to measure vertical and horizontal ground velocities, gravity, tilt, and strain with sensitivities that compare favorably with any existing system. The downhole components are entirely passive, connected to the surface only with optical fibers, giving a long instrument lifetime.
The understanding of tectonic and earthquake processes depends upon observations of earth motions that span periods from years to fractions of a second and amplitudes from nanometers to meters. Up until now such observations came from a variety of instruments such as seismometers, geodetic-quality GPS receivers, gravimeters, and strain meters. Our new technology provides data equivalent to that from all of these sensors, combined into a single borehole unit.
Earthquakes account for only a fraction of plate tectonic movements. Slow slip events, continuous and episodic slip, and other earth movements are known to occur but generate no seismic waves. Many such movements are missed, yet they may contribute a large fraction of the total plate motions. Observing such motions is key to understanding the interior structure of the Earth and its processes of evolution and to addressing such fundamental questions as: what is the nature of the forces acting on the crust, what processes result in the large scale horizontal movements, what is the origin of the sources that produce metamorphic and igneous events? The proposed instrument, combining strain, gravity, and seismic measurements, will shine more light on the full spectrum of earth motions.
Locations in which both seismic and geodetic data are relevant to socially-important problems include volcanoes, areas of subsidence, oil fields, and CO2 sequestration The instrument we have developed will provide low noise and extremely broadband data in such settings, enhancing the ability to understand such processes as induced seismicity, reservoir dynamics, and pre-eruption behavior.
The instrument design and testing has been completed. Final assembly and installation in a borehole are the next and final step.
Last Modified: 01/15/2020
Modified by: Mark A Zumberge
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