:: Volume 3, Issue 3 (12-2015) ::
jgit 2015, 3(3): 39-52 Back to browse issues page
Three dimensional Lagrangian strain analysis using GPS time series without regularization (Case study: Washington)
Yashar Tode Zaeem, Vahab Nafisi *, Alireza Amiri Simkooii
University of Isfahan
Abstract:   (3181 Views)

Earth deformation is a three-dimensional phenomenon; therefore crust analysis also must be done in three-dimension. Analysis of deformation using two epochs can be replaced by analysis of time series, which is more effective for modeling of geodynamics phenomena. GPS permanent stations provide such observations. At the first part of this study, time series of 19 GPS permanent stations in Washington region have been used. With simultaneous analysis of common observations, displacements in three directions were obtained. According to the obtained results, estimation accuracy of horizontal displacements is nearly 3.5 times better than estimation accuracy of vertical displacements. In the next section, Lagrangian method has been used to analyze the deformation. Generally, by generalization of the mathematical model of this method, from two-dimensional to three-dimensional, there is a possibility of problem’s instability. The results of this study show that generalized three-dimensional model necessarily does not lead to instability of the problem. It seems that position of points relative to each other and topography of the region are more important elements which can make coefficients matrix ill-conditioned. As an important point, we can mention that deformation pattern obtained using two-dimensional and three-dimensional analysis are consistence. This consistency can be obviously found in most stations. But in terms of values, we can find serious differences between horizontal main values of strain tensors and compression values even up to two decimals. These differences may come from ignoring vertical component in analysis of two-dimensional deformation.  

Keywords: time series, condition number, ill-condition problem
Full-Text [PDF 1187 kb]   (1071 Downloads)    
Type of Study: Research |
Received: 2016/06/12 | Accepted: 2016/06/12 | Published: 2016/06/12



XML   Persian Abstract   Print



Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Volume 3, Issue 3 (12-2015) Back to browse issues page