2002年上半年全球地震活动

2002年上半年，全球发生MW≥6．5地震16次，其中13次浅源地震，2次中源地震，1次深源地震；发生MW≥7．0地震6次。上半年MW≥7．0地震的地震矩释放是1976年以来的偏低水平。中国及邻区地震活动比较活跃：3月3日，在兴都库什地区发生了1次MW7．3中源地震；6月28日，在中国吉林汪清发生了1次MW7．3深源地震。统计检验表明，地震矩释放表现出持久性质。     

2003年5月22日阿尔及利亚6.9级地震概述

2003年5月22日阿尔及利亚发生6．9级地震，造成生命和财产的严重损失。这是阿尔及利亚近20年来遭遇最强烈的一次地震袭击。文章对该震的基本参数、震源机制、破坏伤亡、救援和发震背景等作了概述。     

Studies on seismic source

During the period of 1999-2002, the Chinese seismologists made a serious of developments in the study on seis-mic sources including observations, experiments and theory. In the field of observation, the methods of the accu-racy location of earthquake sources, the inversion of seismic moment tensor and the mechanism of earthquake source are improved and developed. A lot of important earthquake events are studied by using these methods. The rupture processes of these events are inverted and investigated combined with the local stress fields and the tec-tonic moment by using the measurements of surface deformation. In the fields of experiments and theory, many developments are obtained in cause of seismic formation, condition of stress and tectonics, dynamics of earthquake rupture, rock fracture and nucleation of strong earthquakes.     

Centroid Depth Versus Hypocentral Depth： Their Distribution and Depth／Mechanism Dependence

The Harvard Global CMT catalogue from 1977 to 1998 is analyzed to investigate the relation between the centroid depth and the hypocentral depth. It is observed that for shallow earthquakes, the hypocentral depth is systematically larger than the centroid depth, while for deep-focus earthquakes there is no statistically significant difference between the distributions of centroid and hypocentral depth. A detailed look at the result reveals that such a systematic difference is mainly from the contribution of thrust and normal earthquakes, while strike-slip earthquakes have no such regularity. It turns out that for shallow thrust and normal earthquakes, seismic rupture tends to initiate from the deeper part.     

成像光谱仪图像条带噪声去除的改进矩匹配方法

条带噪声是影响线阵CCD成像质量的一个重要因子。特别是对于CCD质量要求较高的高光谱成像往，往往由于硬件质量造成了许多通道中条带噪声的出现。分析了条带噪声形成的主要原因，比较了几种常用条带噪声去除方法及其局限性。在此基础上指出，标准的矩匹配方法改变了图像在成像行或列方向的均值分布，造成了一定的灰度畸变。这种情况对于在地物非均匀分布状况下成像的小幅图像尤其明显。着重提出和讨论了利用均值补偿法，傅里叶变换法，相关系数法结合矩匹配方法近似恢复由入射辐射强度产生的均值分布，从而达到保持图像质量并有效去除条带噪声的目的。并对条带噪声去除前后图像质量做了定性定量的比较，评价。     

2002年3月31日台湾M 7.5地震概述

2002年3月31日在台湾以东沿海附近发生里氏7.5级地震，造成生命和财产的较严重损失。文章概述了这次地震的情况，包括震源参数、震源机制解、破坏、伤亡和发震背景。     

Seismic moment tensor for intermediate depth earthquakes at regional distances in Southern Spain

A method has been developed to obtain the seismic moment tensor components by linear inversion of P waves recorded at regional distance for intermediate depth earthquakes. The seismic moment tensor is separated into double couple (DC) and compensated linear vector dipole (CLVD) parts. The method has been applied to four earthquakes (64<h<95 km) which occurred in the Malaga region (southern Spain). Solutions for the 1987 event show a percentage of CLVD of 20% with a short source time function and DC part corresponding to vertical motion. For the 1989, 1990 and 1992 earthquakes, percentages of CLVD between 0% and 6% have been found. Comparison with the results obtained in a previous study [Buforn et al., J. Seismol. 1 (1997) 113] by modelling of P waves using a DC model, shows that the use of a more general representation of the source (seismic moment tensor) gives a fit of data for the 1987 event.     

基于灭点的单片规则建筑物三维重建方法研究

为快速获取数字城市建设所需的三维信息,文中介绍了利用单张影像中规则几何建筑物在影像中的的灭点信息,在已知内方位元素的情况下,推导出在现有二维GIS数据的辅助下解求影像外方位元素公式,提出从单张影像上量测建筑物高程（或高度）数据的方法,并简要叙述了该方法的应用领域。