Lookup NU author(s): Dr Nigel Penna
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
A combination of independent evidence (continuous GPS, repeat geodetic leveling, groundwater abstraction, satellite altimetry, and tide gauge (TG) records) shows that the long-recording Fremantle TG has been subsiding in a nonlinear way since the mid-1970s due to time-variable groundwater abstraction. The vertical land motion (VLM) rates vary from approximately -2 to -4 mm/yr (i.e., subsidence), thus producing a small apparent acceleration in mean sea level computed from the Fremantle TG records. We exemplify that GPS-derived VLM must be geodetically connected to the TG to eliminate the commonly used assumption that there is no differential VLM when the GPS is not colocated with the TG. In the Perth Basin, we show that groundwater abstraction can be used as a diagnostic tool for identifying nonlinear VLM that is not evident in GPS time series alone.
Author(s): Featherstone WE, Penna NT, Filmer MS, Williams SDP
Publication type: Article
Publication status: Published
Journal: Journal of Geophysical Research: Oceans
Print publication date: 01/10/2015
Online publication date: 09/10/2015
Acceptance date: 06/10/2015
Date deposited: 13/11/2015
ISSN (print): 2169-9275
ISSN (electronic): 2169-9291
Publisher: Wiley-Blackwell Publishing, Inc.
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