子午线弧长的解析型幂级数确定

针对子午线弧长反解计算过于繁琐的问题,文中利用复合函数的求导法则 ,变换变量进行幂级数展开,在近似情况下给出了通项公式,并严密推导了幂级数展开式,又设定子午线弧长反解公式的形式,利用Ｈｅｒｍｉｔｅ插值原理得出各参数。用各方法得出的公式全部采用ｅ＾２的幂级数形式给出,可操作性,可重复性、唯一性都比较好,经试算其精度在千分之一秒以上,可提供实际使用。     

Digital photogrammetry and kinematic GPS applied to the monitoring of Vulcano Island, Aeolian Arc, Italy

Digital photogrammetry and kinematic global positioning system (GPS) techniques are investigated and compared over a volcanic area as operational approaches to map the topography and monitor surface displacements. The use of terrestrial and airborne GPS to support the photogrammetric survey allowed for operational and processing time reduction without loss of accuracy. A digital elevation model (DEM) is obtained from the processing of the high-resolution digital imagery survey, which provides detailed information over a large area. The internal accuracy of the derived DEM has been verified by the comparison of two sets of data obtained from imagery acquired in different epochs; the observed root-mean-square error of residuals ranges from a few centimetres to 15 cm depending on the morphological features. Kinematic and pseudo-kinematic GPS surveys are performed to derive accurate 3-D coordinates at monumented benchmarks and accurate elevation profiles along footpaths. The average repeatability of the GPS measurements on benchmarks is 1 cm for measurement durations of 2–3 min. The standard deviation of interpolated vertical coordinates obtained at the crossings of kinematic GPS profiles is 4.3 cm. The high quality of these GPS coordinates justifies their use also for the validation of the photogrammetric DEM. A comparison of 6000 common points provides a standard deviation of residuals of 18 cm. The results show that the deformation pattern of a volcanic area can be rapidly and accurately monitored even in the absence of geodetic benchmarks. The integration of aerial photogrammetry with GPS kinematic surveys may be considered as an optimal approach for deriving high-resolution mapping products to be used in support of studies of volcanic dynamics.     

Crustal deformation in the northern Andes – A new GPS velocity field

We present a velocity field for northwestern South America and the southwest Caribbean based on GPS Continuously Operating Reference Stations in Colombia, Panama, Ecuador and Venezuela. This paper presents the first comprehensive model of North Andean block (NAB) motion. We estimate that the NAB is moving to the northeast (060°) at a rate of 8.6 mm/yr relative to the South America plate. The NAB vector can be resolved into a margin-parallel (035°) component of 8.1 mm/yr rigid block motion and a margin-normal (125°) component of 4.3 mm/yr. This present-day margin-normal shortening rate across the Eastern Cordillera (EC) of Colombia is surprising in view of paleobotanical, fission-track, and seismic reflection data that suggest rapid uplift (7 km) and shortening (120 km) in the last 10 Ma. We propose a “broken indenter” model for the Panama-Choco arc, in which the Choco arc has been recently accreted to the NAB, resulting in a rapid decrease in shortening in the EC. The Panama arc is colliding eastward with the NAB at approximately 15–18 mm/yr, and the Panama-Choco collision may have been responsible for much of the uplift of the EC. The present on-going collision poses a major earthquake hazard in northwestern Colombia from the Panama border to Medellin area. Since the northeastward margin-parallel motion of the NAB is now greater than the rate of shortening in the EC, northeast trending right-lateral strike-slip faulting is the primary seismic hazard for the 8 million inhabitants of Bogota, the capital city of Colombia. There continues to be a high risk of a great megathrust earthquakes in southern Colombia along the Ecuador-Colombia trench. Trench earthquakes have only released a fraction of the energy accumulated in the Ecuador-Colombia trench since the 1906 Ecuador earthquake, and interseismic strain is accumulating rapidly at least as far north as Tumaco, the rupture area of the 1979 earthquake.     

Gravity changes before large earthquakes in China: 1998–2005

Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 2002, and 2005 at stations of the Crustal Movement Observation Network of China (CMONOC) and examined gravity changes be-fore the occurrence of nine large (Ms≥6.8) earthquakes that ruptured within or near mainland China and Taiwan from November 2001 to August 2008. Results from this analysis show that significant gravity changes occurred across a large region before each of these nine large earthquakes, and these changes were detected by repeated ground gravity surveys through CMONOC. Although these gravity changes were significant, more research is needed to investigate whether these gravity changes could be viewed as precursors of large earthquakes. Limitations and uncertainties in the data include sparseness of the gravity monitoring network, long time intervals between consecutive gravity surveys, inevitable measurement errors, hydrological effects on gravity, and effects of vertical crustal movements on gravity. Based on these observations, we make several recommendations about possible future direc-tions in earthquake-related research using gravity monitoring data.     

地球各圈层相互作用的大地测量研究和检测

大地测量资料，包括在球表面运动，地球引力场及地球整体自转运动的观测资料，是研究地球各圈层相互作用的重要地表约束，探讨了大地测量用于这一研究领域中的几个重要科学前沿问题。     

大地测量学基础课程教学与实践改革研究

大地测量学基础是测绘工程专业的骨干课程与专业基础课程之一,在学科体系中占有相当重要的地位。从测绘学科的教学与实践改革的实际出发,介绍了大地测量学基础教学与实践改革研究的主要内容,指出目前教学与实践中存在的问题,提出解决问题的对策。     

工程测量学发展的历史现状与展望

从工程测量学的定义出发,结合典型史料,阐述了工程测量学的发展历史,论述了工程测量学的发展现状与近半个多世纪以来科学飞速进步和工程建设巨大发展的关系,指出了工程测量学科发展的方向和特点,提出了对工程测量发展趋势的看法,展望工程测量将进一步向宏观和微观方面发展。