ROLE OF UNDERGROUND STRUCTURE DEFORMATION VELOCITY IN THE ANALYSIS OF BLAST-RESISTANT STRUCTURES

The structural deformation velocity plays a significant role in the dynamic calculation of underground blast-resistant structures. The motion differentiating equation of a structure system taking into account the role of deformation velocity of the structure will truthfully describe the actual situation of structural vibration. With the one-dimensional plane wave theory, the expression of load on the structural periphery is developed, and the generalized variation principle for the dynamic analysis of underground arched-bar structures is given. At the same time, the results of the numerical calculation are compared.

Present-day crustal deformation around Kalpin block,Xinjiang,China,observed by InSAR

Due to the effect of the collision between the Indian plate and Eurasian plate, Pamirs is constantly moving to the north. Under the interaction among multiple tectonic blocks, strong earthquakes often occurred around the Kalpin block which is located in western Tianshan of Chinese continent. In this paper, we used Intefferometric Synthetic Aperture Radar （InSAR） technique and adopted stacking algorithm to achieve the present-day crustal deformation field of the Kalpin block region based on 38 Envisat ASAR images. The results show that the deformation in radar line of sight around Kalpin block is mainly compressive between south and north with magnitude 1-1.5 mm/a. Displacement decreases gradually from northwest to southeast, which is consistent with the deformation characteristics shown in Tianshan, i.e. crust is gradually shortening from west to east detected by the GPS observations. Also, the Piqiang fault zone is uplifting. And there is an obvious displacement difference between the two sides of the Aozigeertawu fault.

Analysis of the Motion and Deformation Characteristics along the Zhangjiakou-Bohai Fault

We have collected GPS data in the period of 1999-2007 from the Crustal Motion Observation Network of China along the Zhangjiakou-Bohai fault and its adjacent regions to study the characteristics of present-day crustal horizontal motion velocities in the research zone.Strain rate components are computed in the spheric coordinate system by the least square collocation method.According to the spatial distribution of the principal strain rate,dilation rate and maximum shear strain rate derived from GPS measurements,this paper analyses the deformation of the subordinary faults of the Zhangjiakou-Bohai fault.The principal compression strain rates are apparently greater than the principal extension strain rates.The larger shear strain rate is mainly in and around the Xianghe,Wenan and Tangshan areas in Hebei Province.According to the profiles across different segments of the Zhangjiakou-Bohai fault,the three segments glong the Zhangjiakou-Bohai fault show an obviously left-lateal strike-slip and compression characteristics.By analysis of the motion characteristics of the blocks,e.g.the Yanshan block,North China Plain block,Ordos block,and Ludong-Huanghai block in and around the North China region,this paper speculates that the dynamics of the motion styles of Zhangjiakou-Bohai fault may directly come from the relative movement between the Yanshan block and the North China plain block,and the ultimate dynamics may be the results of the collison between Indian plate and Eurasian plate,and the persistent northeastward extrusion of the Indian plate.

Crustal deformation on the Chinese mainland during 1998—2004 based on GPS data

This study focuses on resolving moderate amounts of crustal motion at the continental scale based on a large volume of global positioning system（GPS） data during 1998e2014. A state-of-the-art GPS processing strategy was used to resolve position time series and velocities from carrier beat phases for all available data. Position time series were closely analyzed to estimate linear constant, coseismic displacements, postseismic motions, and other parameters. We present coseismic offsets inferred from the GPS data for the 2010 Yushu and 2014 Yutian earthquakes, and also illustrate transient postseismic motions following the 2001 Kokoxili, 2008 Wenchuan, and 2011 Tohoku-Oki earthquakes. Since not all GPS position time series dominated by postseismic motions can be modeled and corrected reasonably, we present contemporary horizontal velocities from 2009 to 2014 for campaign stations and from 1998 to 2014 for continuous stations, irrespective of postseismic deformations. Our study concludes that we need to accumulate observations over a greater duration and apply accurate postseismic modeling to correct for transient displacement in order to resolve reasonable interseismic velocity.