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关于城市地震

本文提出了一种新观点，即大城市的出现对地震有激发作用，列举了被认为是城市激发的震例，讨论了城市地震发生的机理，其中仅从重力荷载这一个方面的定量讨论中也可以得出：如果其它外力对地震有激发作用，那么城市激发地震的现象更值得重视，还讨论了涉及到城市激发地震的其它问题．     

信阳地区城乡聚落体系的分形几何特征

以信阳地区为研究区，探讨其城乡聚落体系的空间分布规律，证明乡镇聚落体系与城市体系遵循相同的分形模式，并借助分维，分析了系统的结构问题，指出其未来优化的方向。     

基于媒体事件的中亚、东盟区域对中国地缘关系判别研究

基于GDELT数据,通过构建语气指数、冲突语气均衡度、冲突事件集中度、事件时维记忆性等指标,定量分析2013—2020年中亚、东盟国家在有关中国的事件上的语气态度,辨识异常时段并追踪事件,从媒体事件角度识别和判断区域风险,进而揭示对中国的地缘关系。结论如下：中亚、东盟关于中国事件的语气态度以合作为主,语气指数表现出“尖峰肥尾”和对称性等特征,两区域存在冲突语气频繁波动的相同时段;相较东盟,中亚关于我国的冲突语气更不均衡、冲突事件高集中度时段更短少;以半月为单位,两地冲突事件的前时段会对后时段产生正向影响,以季度为单位,中亚仍为正向影响,而东盟则倾向产生逆向影响;中亚主要风险为公共卫生健康、恐怖袭击和民族宗教问题;东盟主要风险有公共卫生健康、领土主权受侵、境外犯罪、边境风险、空难、项目受阻、恐怖袭击等。研究建议,我国应加强对中亚、东盟的媒体舆论引导的影响力,对待中亚区域风险当以“重视阶段性”的防范方针,采取“积极平复和审慎对待”的策略,优化民族和宗教政策;对待东盟当以“重视长时距”的合作布局,在法律完善、防暴防恐、打击犯罪、提升公民文明行为等方面强化地缘合作,优化地缘关系。     

Effects of ionospheric disturbances on GPS observation in low latitude area

In this paper, ionospheric disturbance data from a local GPS network in Hong Kong (low latitude region) are studied in the solar maximum period (2001–2003). The spatial and temporal distributions of the disturbances in Hong Kong are investigated. It is found that strong ionospheric disturbances occur frequently during the solar maximum period, particularly around March and September, and concentrate at the region around geographic latitude 22°N (geomagnetic latitude 12°N). The effects of the disturbances on GPS geodetic receivers, such as loss of lock and measurement noise level, are also analyzed for the 3-year period. It shows that the measurement noise level and the number of losses of lock in GPS data increase dramatically during ionospheric disturbance periods. The behaviors of different types of GPS receivers during the disturbances are also compared.     

北京早白垩世东狼沟组非海相腹足类化石

本文所描述的腹足类化石采自北京西山早白垩世东狼沟组，共８属１３种，赋存于火山岩沉积夹层中，以Ｌｉｏｐｌａｃｏｄｅｓ，Ｂｉｔｈｙｎｉａ，Ｇａｌｂａ三属分子最为发育。与腹足类共生的有早白垩世的双壳类、介形虫类及鱼类化石。     

Detailed seafloor geomorphology of the western region of the North Yellow Sea,China: The result of Holocene erosional and depositional processes sculpting the offshore continental shelf

High-resolution multi-beam/single-beam bathymetric data and seismic profiling data from the latest surveys are used to map and interpret the detailed seafloor geomorphology of the western region of the North Yellow Sea (NYS), China. The mapping area covers 156 410 km2, and incorporates a flat shelf plain, subaqueous accumulation shoals, tidal scouring troughs, and tidal sand ridge groups. Offshore areas with water depths less than 50 m in the western region of the NYS are mainly covered by thick, loose sediments, forming wide spread accumulation geomorphological features; these include the Liaodong Peninsula subaqueous accumulation system containing shoals and rugged scouring troughs, and the large mud wedge of the Shandong Peninsula. In the central part of the NYS, there is a relatively flat residual shelf plain with coarser sediment deposits. This flat shelf plain has a water depth larger than 50 m and a thin layer of sediment, on which there is a large pockmark field caused by seafloor seepage. These geomorphological structures indicate that modern sedimentary processes are the main driving force controlling the sculpture of the current seafloor surface landform. Extensive strong tidal current systems and abundant sediment sources provide the critical external forces and essential conditions for the formation of seafloor geomorphology. The tectonic basement controls the macroscopic morphological shape of the NYS, but is reflected very little in the seafloor geomorphic elements. Our results provide a detailed seafloor geomorphological map of the western region of the NYS, an area that has not previously mapped and also provide a scientific framework for further research into offshore seafloor geomorphology, shelf sedimentary processes, and submarine engineering construction in this region.     

Relation of ice conditions to climate change in the Bohai Sea of China

1NTRODUcrIONThe bohai As is a seasonally ice-covered sea and is located in the lowest latitudes (37' -4l'N), where sea ice occurs. The bohai ffea is nearly enclosed by land in the south, the northand the west, and only connects to the Huanghai ffea through the bohai Strait in the east.The width of the strait is abeut l06 km. The boai ffea is very shallow basin with the meandepth of l8 m and the maximum depth of 78 m. The topography of the sea bottom and thecoastal regions has an importan…     

大地电场观测地震前兆异常提取技术研究

首都圈地区布设的11个地电场观测台于2001年9月已正式投入观测,现已积累了近7年的资料．使用大地电场观测系统中同一测向的长、短极距测值的比值方法,对其中的10个台和邻区2个台的资料进行了处理,发现该方法能够较好地排除来自大地电场及自然电场远场的变化信息,突出了可识别的地震前兆异常信息．研究结果表明,2006年7月4日河北文安MS5.1震前,多数台站的地电场观测资料出现比值异常变化,从而证明了这次地震前地电场观测存在着短临异常前兆变化信息,只是由于这些信息混杂于正常大地电场变化的背景中,使用常规的分析方法无法识别和提取．研究结果还表明,地电场观测的台址条件和台址到震中区的距离与震前地电场比值异常出现的时间和幅度有关．     

Extraction of seismic precursory information from gravity tide at Kunming station based on HHT

Hilbert-Huang Transformation(HHT)is a recently-developed method for non-linear signal processing (Huang et al,1998).By performing empirical mode decomposition(EMD)with HHT,various frequency compo-