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Lookup NU author(s): Dr Nigel Penna,
Professor Peter ClarkeORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Anelasticity may decrease the shear modulus of the asthenosphere by 8-10% at semi-diurnal tidal periods compared with the reference 1 s period of seismological Earth models. We show that such anelastic effects are likely to be significant for ocean tide loading displacement at the M2 tidal period around the East China Sea. By comparison with tide gauge observations, we establish that from nine selected ocean tide models (DTU10, EOT11a, FES2014b, GOT4.10c, HAMTIDE11a, NAO99b, NAO99Jb, OSU12, TPXO9-Atlas), the regional model NAO99Jb is the most accurate in this region, and that related errors in the predicted M2 vertical ocean tide loading displacements will be 0.2-0.5 mm. In contrast, GPS observations on the Ryukyu Islands (Japan), with uncertainty 0.2-0.3 mm, show 90th percentile discrepancies of 1.3 mm with respect to ocean tide loading displacements predicted using the purely elastic radial Preliminary Reference Earth Model. We show that the use of an anelastic PREM-based Earth model reduces these 90th percentile discrepancies to 0.9 mm. Use of an anelastic radial Earth model consisting of a regional average of the laterally-varying S362ANI model reduces the 90th percentile to 0.7 mm, which is of the same order as the sum of the remaining errors due to uncertainties in the ocean tide model and the GPS observations.
Author(s): Wang J, Penna NT, Clarke PJ, Bos MS
Publication type: Article
Publication status: Published
Journal: Solid Earth
Online publication date: 14/02/2020
Acceptance date: 09/01/2020
Date deposited: 14/02/2020
ISSN (print): 1869-9510
ISSN (electronic): 1869-9529
Publisher: Copernicus GmbH
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