Millimeter-level precision in a seafloor geodesy experiment at the Discovery transform fault, East Pacific Rise

Thumbnail Image
Date
2013-10-07
Authors
McGuire, Jeffrey J.
Collins, John A.
Linked Authors
Alternative Title
Date Created
Location
DOI
10.1002/ggge.20225
Related Materials
Replaces
Replaced By
Keywords
Seafloor geodesy
Oceanic transform fault
Abstract
Direct-path acoustic ranging is a promising seafloor geodetic technique for continuous high-resolution monitoring of geodynamical process such as fault slip and magma intrusion. Here we report on a yearlong acoustic ranging experiment conducted across the discovery transform fault at ∼4°S on the East Pacific Rise. The ranging instruments utilized a novel acoustic signal designed to enhance precision. We find that, after correcting for variations in sound speed at the path end-points, the ranging measurements have a precision of ∼1 mm over baselines approaching 1 km in length. The primary difficulty in this particular experiment was with the physical stability of the benchmarks, which were deployed free fall from a ship. Despite the stability issues, it appears that the portion of the transform fault that the array covered was locked during the year of our survey. The primary obstacle to continuous, high sample rate, high-precision geodetic monitoring of oceanic ridges and transform faults is now limited to the construction of geodetic monuments that are well anchored into bedrock.
Description
Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 14 (2013): 4392–4402, doi:10.1002/ggge.20225.
Embargo Date
Citation
Geochemistry, Geophysics, Geosystems 14 (2013): 4392–4402
Cruises
Cruise ID
Cruise DOI
Vessel Name