Time filter

Source Type

Chang Z.,Capital Normal University | Liu X.,Capital Normal University | Luo Y.,Institute of Crust Dynamics | Ao Z.,Capital Normal University | And 3 more authors.
International Journal of Remote Sensing | Year: 2015

The problem of atmospheric phase effects is currently one of the most important limiting factors for widespread application of repeat-pass interferometric synthetic aperture radar (InSAR) measurements. Due to the extraordinary complexity of the atmospheric inhomogeneity and turbulence, it is generally difficult to obtain satisfactory mitigation of the atmospheric phase effects in repeat-pass InSAR measurements. In recent years, several methods have been developed for mitigating the atmospheric phase effects. An effective approach is interferogram stacking, which is based on stacking independent interferograms. However, as many as 2n images are required to generate n interferograms and the atmospheric delay errors of the stacked interferogram decrease only with the square root of the number of interferograms in the conventional interferogram stacking method, which is not very efficient. In order to efficiently mitigate the atmospheric phase effects on the stacked interferogram in repeat-pass InSAR measurements, we propose a relay-interferogram stacking method. Compared with the conventional method, this method not only can efficiently mitigate atmospheric phase effects on the stacked interferogram, but also greatly decreases the number of required synthetic aperture radar (SAR) images. The key element is that the first and the last SAR images are selected from the periods of similar meteorological conditions. In addition, we present an application of the approach to the study of ground subsidence in the area around Beijing, China. © 2015 Taylor & Francis. Source

Che Y.-T.,Institute of Geology | Liu Y.-W.,Institute of Crust Dynamics | He L.,Adaptec
Earthquake | Year: 2015

We first describe chemical and geochemical characteristics of hydrogen, as well as relations between hydrogen soil vapor concentrations and earthquake events. And then we discuses the possibility of using hydrogen soil vapor monitoring in the vicinity of fault zones to make short/immediate earthquake prediction. Hydrogen (H) is an element with the smallest particle size, the lightest weight, the fastest speed and the most powerful penetration ability. The concentration of hydrogen (H2) in the atmosphere is very low, only 0.5 ppm. But it is higher in the crust, approximately n~n×102 ppm, which is mainly located at a depth ranging from 5 to 8 km, especially in the fault zones. There are good correlations between Hydrogen concentrations and seismic activities. Noticeable changes of hydrogen concentrations can normally be observed several to tens of days before an earthquake, and the ratio of signal to noise is very high. Recently, the successful development of a new digital hydrogen detecting instrument (ATG-6118H) makes continuous monitoring of hydrogen possible. We present some experimental observation results and propose to establish a large scale hydrogen monitoring network along some fault zones. ©, 2015, Science Press. All right reserved. Source

Jing Z.-J.,Institute of Crust Dynamics | Xie F.-R.,Institute of Crust Dynamics | Cui X.-F.,Institute of Crust Dynamics | Zhang J.-F.,Institute of Crust Dynamics
Journal of Coal Science and Engineering | Year: 2013

By inverting fault slip data, the parameters of 12 tectonic stress tensors in the mine region can be determined. The following characteristics can be obtained for recent tectonic stress fields, which are found deep in the study region. The results show that the recent tectonic stress field mainly presents the characteristics of near NWW-SSE maximum compressional stress and near NE-SW minimum extensional stress, while the stress regimes are mainly of strike slip, part of the reverse-fault type. Recent tectonic stress field in the region is characterized by horizontal components. The maximum principal compression stress direction was from NEE to SEE, the average principal compression stress direction was near NWW-SSE maximum compressional stress and near NE-SW minimum extensional. The recent tectonic stress field of the studied area can be controlled by a large tectonic stress area. © 2013 The Editorial Office of Journal of Coal Science and Engineering (China) and Springer-Verlag Berlin Heidelberg. Source

Discover hidden collaborations