sopac's instantaneous global plate motion model:
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SOPAC's Instantaneous Global Plate Motion Model:
Yehuda Bock, Linette Prawirodirdjo, Peng Fang, Paul Jamason, Shimon Wdowinski (TAU, UMiami)
Scripps Orbit and Permanent Array Center
Institute of Geophysics and Planetary Physics
Scripps Institution of Oceanography
University of California San Diego
La Jolla, California
2004 Joint AssemblyMontreal, CANADA
May 18, 2004
Contributions to a North America Fixed Reference Frame
SOPAC estimates monthly a global plate motion model (17 major and minor plates) based on its daily CGPS position time series.
Longest time series are 13 years old, beginning during the “GIG” experiment in January 1991. Shortest time series are about 4 years old.
Plate motion model is based on CGPS stations whose data are publicly available so that it can be easily used/replicated by other researchers.
Introduction
Entire daily time series have been re-estimated by SOPAC in a consistent manner after a reconciliation of all site metadata in the SOPAC archive.
Time series are from 24-hour GAMIT solutions of 20 sub-networks, including 4 global and 16 regional sub-networks with overlapping sites.
Sub-networks are combined daily with the GLOBK glorg module, aligned by a 7-parameter similarity transformation to ITRF2000 as realized by the IGS, thereby maintaining the No-Net-Rotation condition of ITRF2000 wrt to NNR-NUVEL-1A.
GPS Data Analysis
Modeled with linear rates (velocities), annual and semi-annual parameters, offsets (instrumental and coseismic), and postseismic decay.
Coefficients of a white noise plus flicker noise model are estimated by MLE approach, and propagated to uncertainties of time series parameters.
Time Series Analysis
PIN1 velocities:
N5.4±0.5;8.0±0.8
E-27.1±0.6;-27.0±0.8
U2.8±1.7;2.7±2.6
PIN2 velocities:
N5.4±0.5;7.5±0.7
E-27.4±0.7;-26.6±1.0
U2.6±1.3;4.1±1.9
RMS:
H 3-4mm;V 9mm
13-Year Daily (Unfiltered) Time Series at PIN1 & PIN2
Typical NA Time Series Used in PMM
NA Time Series Excluded from PMM
Stations that exhibit “anomalous” behavior are excluded (e.g., elastic and seismic deformation, significant vertical motion).
Estimate Euler poles by minimizing site velocities relative to ITRF2000.
Include in the rigid plate motion estimates only stations whose velocity residuals are less than the 2 velocity uncertainties.
This leaves us with about 110 global sites.
Plate Motion Model
Velocity differences between SOPAC and ITRF velocities and comparison of velocity error ellipses – 95% confidence).
Vertical Motions
SOPAC Plate Motion Model
Plate Lon. Lat. Error Ellipse (º)
2
N
(ºE) (ºN) º/Myr maj min Azim.
Anta -125.655 60.683 0.222±0.006
0.77 0.56
8 1.6 6
Aust 37.590 33.472 0.618±0.003
0.93 0.18 154 1.2 9
Eura -99.691 57.246 0.260±0.002 0.81 0.18
52 1.1 18
Indi -41.986 45.720 0.487±0.015 12.11 0.73 29 0.7 2
Noam -84.702 -3.583 0.200±0.003 0.87 0.25 101 1.3 22
Nubi -82.685 51.627 0.790±0.004
1.82 0.92 175 0.8 7
Pacf 110.161 -63.832 0.670±0.003 0.59 0.28
2 1.2 5
Soam -135.798 -21.086 0.108±0.003 6.33 1.80 171 0.4 5
Soma -106.378 51.305 0.326±0.017 3.87 1.40 36 1.6 3
North America Reference Frame
Examples of Use of Plate Motion Model
SOPAC Online Map Interface
Analysis of SCEC III Crustal Motion Model
Shen et al., 2003
Longitudinal Component LatitudinalComponent
Provide the necessary geodetic services to ensure the availability of accurate, consistent, and timely spatial referencing data.
Monitor temporal changes in geodetic coordinates due to tectonic motion, earthquakes, volcanic deformation and land subsidence.
Establish the legal spatial reference system for California (the “CSRS”).
California Spatial Reference Center (CSRC)
California Spatial Reference System
SECTOR and CSRS Epoch 2004.0
CSRS Epoch 2004.0 is defined as the coordinates (and velocities) computed by CSRC on 14 April 2004 using data up to an including 27 March 2004, and will not change.
SOPAC estimates monthly a global plate motion model (17 major and minor plates) to improve precision and reliability as new data become available.
Plate motion model is based on CGPS stations whose data are publicly available so that it can be easily used/replicated by other researchers.
The SOPAC PMM provides a baseline against which anomalous motions (tectonic or otherwise) can be detected.
Monthly SOPAC PMM Updates
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