HR: 1340h
AN: G53A-0116    [Abstracts]
TI: Choosing Geodetic Monuments Based on Noise in New Zealand GPS Time Series
AU: * Beavan, J
EM: j.beavan@gns.cri.nz
AF: GNS, Gracefield Research Centre, P O Box 30-368, Lower Hutt, 6009 New Zealand
AB: Geodetic signals of tectonic or volcanological interest recorded by geodetic instrumentation may be degraded or obscured by the presence of noise in the geodetic data. Limiting the noise is therefore important for the detection and interpretation of such signals. One source of noise is random motion occurring within the connection of the geodetic instrument to the ground. In the case of surface instruments such as GPS, the connection to the ground is through a geodetic monument. The motion of this monument, with respect to a representative volume of the Earth's near surface in its vicinity, is termed monument noise. Monument noise results from processes such as soil swelling in response to rainfall, and general rock and soil weathering effects. In this paper we investigate the noise levels within time series of continuous GPS (CGPS) positions collected on concrete pillar monuments in New Zealand. We compare these noise levels with those from drilled, braced monuments in several U.S. CGPS networks. We investigate under what conditions monument noise is the limiting noise source in the CGPS data, and attempt to provide a basis for decisions on what type of monument to deploy under certain scenarios.
DE: 1206 Crustal movements--interplate (8155)
DE: 1208 Crustal movements--intraplate (8110)
DE: 1243 Space geodetic surveys
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting