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981.
华北地区GPS监测网建设,地壳水平运动与应力场及地震活动性的关系 总被引:16,自引:1,他引:16
简要地介绍了华北地区、特别是首都圈GPS地震监测网的布设、观测、数据处理方法案和监测精度等,较详细地分析了地壳水平形变与构造运动、应力场变化以及地震活动的性的关系。 相似文献
982.
983.
滨海附近地区GPS和断层形变与地震关系研究 总被引:5,自引:0,他引:5
简要介绍了环勃海及华北部分地区跨断层形变资料的分析结果,同时介绍了1992年至1995年首都圈两期GPS测量资料处理分析的初步结果。通过比较,二者所显示的地壳活动趋势存在性质上的差异,主要是因观测时段的不一致而引起;在同时段资料的对比分析中,因测点和断层空间分布差异的存在,有44.8%的流动资料难以判定其与GPS资料的一致性,但在可判定的33项资料中,有89%是一致的,证明二者从不同的侧面反映了近 相似文献
984.
用GPS复测结果计算地应变 总被引:5,自引:0,他引:5
详细地叙述了用GPS和应变数据计算地壳水平速度和水平应变率的方法,这一方法满足变形协调性条件。用全国和大华北地区GPS网的多期观测数据进行了试算,获得了一系列地壳水平运动和应变率场分布的图像。根据这些计算结果,可以初步得出如下结论:(1)GPS能够有效地监测现今地壳运动和形变的信息;(2)所述的计算方法是有效的,其计算结果比直接测量结果提供了更多的有关现今地壳运动和形变的信息。 相似文献
985.
人工地震测深和天然地震流动观测兼用的轻便数字地震仪系统 总被引:7,自引:1,他引:7
本文介绍一种新的轻便数字地震仪DAS-1。其设计特点是:双微处理器硬件结构;过采样AD转换技术的运用;线性相位和最小相位FIR数字滤波的运用;大容量CMOS快闪存贮器作数据存储介质;GPS授时和内部高精度数字钟相结合的时间服务系统;采集器功耗低于0.65W。该仪器有3个信号输入通道,0 ̄40Hz的带宽和16位字长。它可方便地用于人工地震测深及天然地震流动观测。 相似文献
986.
Doñana National Park is an area of approximately 500 km2 located on the SW coast of Spain that shows one of the greatest geoid gradients on the entire Iberian Peninsula, due to its peculiar tectonic characteristics. So, it is necessary to elaborate an accurate geoid model that can be used with GPS for precise surveying, since the existing ones are insufficient, due to their poor resolution and their limited adaptation to a small area with such a strong gradient. The least squares prediction method was tested in order to obtain the undulation from GPS/orthometric points. The results obtained were unsatisfactory because of the strong geoid gradient. In order to improve accuracy the remove-restore technique was used. Global geopotential model EIGEN-CG01C and a Digital Elevation Model (DEM) with a 25 × 25 m resolution and an accuracy better than 3 m were used. Thus, the final geometrical geoid obtained reaches the precision required by other disciplines (3 cm in any point within the Park). Particularly, the geoid model has allowed for the acquisition of a precision DEM that is essential to formulate a hydrodynamic model for the Doñana marsh functions. 相似文献
987.
GPS observations in the Western Bohemia/Vogtland earthquake swarm region revealed indications of horizontal displacements
of low amplitude, and no clear long-term trend in 1993–2007. On the other hand, in 1998–2001 there was relatively significant
active movement along NNE-SSW oriented line that we called the “Cheb-Kraslice GPS Boundary” (ChKB), identical with an important
limitation of earthquake activity. The most impressive were dextral (right-lateral) movements in the 1998–1999 period followed
by reverse sinistral (left-lateral) movements in 1999–2000 that correlate with prevailing motion defined by fault plane solutions
of the Autumn 2000 earthquake swarm. Before the February 2004 micro-swarm, two points located on opposite sides of the Mariánské
Lázně fault showed extension in the order of about 7 mm in the same NNE-SSW direction of ChKB. The new NOKO permanent GPS
station in Novy Kostel showed the peak-to-peak vertical changes up to 10 mm before and during the February 2007 micro-swarm.
Annual precise levelling campaigns in the local network around Novy Kostel revealed regular vertical displacements during
the 1994, 1997 and 2000 earthquake swarms. The points around the Novy Kostel seismological station showed uplift during the
active periods, including the micro-swarm February 2004. However, no such indication was observed on levelling points in the
period of the February 2007 swarm. Long-term vertical displacements depend on the same direction NNE-SSW (ChKB) as the GPS
displacements. Both geodetic techniques have revealed oscillating displacements, GPS horizontal, and levelling vertical, rather
than any long-term trends in the study period 1993–2007. The displacements exhibited significant spatial and temporal relation
to tectonic activity (earthquake swarms) including their coincidence with the seismologically determined sense of motion along
the fault plane during earthquakes. 相似文献
988.
E. Yizengaw M.B. Moldwin D. Galvan B.A. Iijima A. Komjathy A.J. Mannucci 《Journal of Atmospheric and Solar》2008,70(11-12):1541-1548
The plasmaspheric electron content is directly estimated from the global positioning system (GPS) data onboard JASON-1 Satellite for the first time. Similarly, the ground-based GPS total electron content (TEC) is estimated using about 1000 GPS receivers distributed around the globe. The relative contribution of the plasmaspheric electron content to the ground-based GPS TEC is then estimated globally using these two independent simultaneous measurements; namely ground-based GPS TEC and JASON-1 GPS TEC. Results presented here include data from 3 months of different solar cycle conditions (October 2003, May 2005, and December 2006). The global comparison between the two independent measurements was performed by dividing the data into three different regions; equatorial, mid- and high-latitude regions. This division is essential as the GPS raypaths traverse different distances through the plasmasphere at different latitudes. The raypath length through the plasmasphere decreases as latitude increases. The relative contribution of the plasmaspheric electron content exhibits a diurnal variation that depends on latitude with minimum contribution (10%) during daytime and maximum (up to 60%) at night. The contribution is also maximum at the equatorial region where the GPS raypath traverses a long distance through the plasmasphere compared to its length in mid- and high-latitude regions. Finally, the solar cycle variation of plasmaspheric contribution is also reported globally. 相似文献
989.
Inflation along Kilauea's Southwest Rift Zone in 2006 总被引:1,自引:0,他引:1
David Myer David Sandwell Benjamin Brooks James Foster Masanobu Shimada 《Journal of Volcanology and Geothermal Research》2008
We report on InSAR and GPS results showing the first crustal inflation along the southwest rift zone at Kilauea volcano in over 20 years. Two independent interferograms (May 2–August 2, 2006 and June 22–Nov 7, 2006) from the ALOS PALSAR instrument reveal domal uplift located southwest of the main caldera. The uplift is bounded on the northeast by the caldera and follows the southwest rift zone for about 12 km. It is approximately 8 km wide. We use data derived from permanent GPS stations to calibrate the InSAR displacement data and estimate uplift of 7.7 cm during the first interferogram and 8.9 cm during the second with line-of-sight volumes of 2.8 × 106 m3 and 3.0 × 106 m3 respectively. The earthquake record for the periods before, during, and after inflation shows that a swarm of shallow earthquakes (z < 5 km) signaled the beginning of the uplift and that elevated levels of shallow seismicity along the rift zones occurred throughout the uplift period. GPS data indicate that the inflation occurred steadily over nine months between mid-January and mid-October, 2006 making injection of a sill unlikely. We attribute the inflation to recharge of a shallow ductile area under the SWRZ. 相似文献
990.
GPS观测得到的中国大陆地壳垂直运动 总被引:13,自引:1,他引:13
利用中国地壳运动观测网络基准站的GPS连续观测及基本站非连续GPS观测结果,分析了基准站垂直位移的年周期变化特点,讨论了获得中国大陆垂直位移长趋势速率的条件,说明由基本站(连同基准站)多期GPS观测得到的长趋势垂直位移速率是较为可靠的。由于不少GPS观测站有幅度达数cm的年周期变化及大部分区域站观测次数少,由1999年、2001年两期区域站GPS观测难以得到可靠的长趋势垂直构造运动速率。基本站的观测结果表明中国大陆长趋势垂直构造运动主要特点是,速率较低,北升,南降,东强,西弱,西部相对东部略有下降。 相似文献