| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
|
| Initial Amendment Date: | September 6, 2017 |
| Latest Amendment Date: | July 28, 2020 |
| Award Number: | 1736513 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Kandace Binkley
kbinkley@nsf.gov (703)292-7577 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | October 1, 2017 |
| End Date: | September 30, 2021 (Estimated) |
| Total Intended Award Amount: | $246,974.00 |
| Total Awarded Amount to Date: | $246,974.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
8622 DISCOVERY WAY # 116 LA JOLLA CA US 92093-1500 (858)534-1293 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
8602 La Jolla Shores Dr La Jolla CA US 92093-0210 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | OCEAN TECH & INTERDISC COORDIN |
| 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
Subduction Zones are geologic faults that begin offshore where one tectonic plate slides beneath another. Due to friction along the fault some of the down-going plate motion is slowly transferred to the upper plate which bends and contracts storing the motion. Occasionally, this built-up motion is rapidly released as an earthquake and displaces the sea floor causing a tsunami. The Cascadia subduction zone offshore northern California, Oregon and Washington and the Aleutian subduction zone offshore Alaska have generated large earthquakes and tsunami in the past and will do so again. Measuring where and how fast this slow build-up occurs can improve understanding of the potential hazard. This requires offshore seafloor sensors to collect data, and in the past, ships to access this data. In this project, new methods will be develop and tested that use fewer instruments and remotely-piloted, self-powered sea surface vehicles, rather than ships, to lower the cost of data collection.
This is a one-year project to implement acoustic upload of data from the sea floor to a wave- and solar-powered sea surface vehicle, and test a new lower cost method of collecting GPS-Acoustic data in shallow water (< 200 m) using a single seafloor transponder. An onboard computer will be programed to control the acoustic ranging system to operate in modem mode. A pressure sensor embedded with a transponder will be deployed offshore SIO to test the upload capability at varying ranges and depths. In addition, a transponder will be deployed offshore SIO and the sea surface vehicle will be operated remotely to circle the transponder for up to two weeks collecting GPS-Acoustic data. We will then evaluate if repeatability of positioning in shallow water is comparable to the existing GPS-Acoustic approach where data are collected from the center of an array comprised of three or more transponders.
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.
Two facts have limited scientists’ ability to track the deformation of Earth’s crust from plate tectonics and earthquakes: one, 70% of the planet is under the oceans, and two, signals from Global Navigation System Satellites cannot penetrate sea water. Consequently, most measurements of crustal deformation, which rely largely on precise GPS measurements, are limited to land. Developments over several decades beginning in the 1990s that advanced methods combining acoustic ranging to seafloor devices and GPS positioning of an ocean-surface platform have made it possible today to obtain cm-accuracy coordinates of seafloor positions. Until recently this required the use of expensive, large research vessels. In the work funded by this project, an unmanned self-powered ocean-surface vehicle known as a Wave Glider was fitted with the GPS antennas and acoustic ranging hardware to autonomously collect the data needed for geodetic quality surveys of permanent seafloor makers. This has revolutionized seafloor geodesy and made it possible to track the motions of the plates where they build up strain that can cause huge offshore earthquakes and tsunami. The technology developed has now been commercialized, making the equipment and technique available to researchers worldwide.
A key outcome of this technology development is the establishment of seafloor geodetic sites in both the Cascadia subduction zone (offshore Washington, Oregon, and northern California) and in the Alaska subduction zone offshore the Aleutian Island chain. Repeated measurements at those stations over many years will reveal where the subducted oceanic plate is locked to the overriding continental plate, building up strain that can lead to a large earthquake and/or a tsunami.
Last Modified: 06/29/2022
Modified by: C. David Chadwell
Please report errors in award information by writing to: awardsearch@nsf.gov.
