Research on seismic intensity zonation by use of the response intensity of historical earth－quakes───with the central part of Shanxi Province as an example

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西藏东南部嘉黎断裂新知

野外调查表明 ,西藏东南部的嘉黎断裂带从那曲到嘉黎由三段呈雁行排列 ,大致沿N60°W方向延伸 ,其东南段在波密附近向南转折 ,沿贡日嘎布曲向南南东过上察隅和下察隅后转为近南北向延入缅甸境内与什阶断裂相连。嘉黎断层全新世以来活动性不强 ,其第四纪以来的平均滑动速率约为 4mm/a。一个有趣的现象是 ,虽然总体上嘉黎断裂的新活动不强 ,但在局部与张性盆地相邻的地段表现出较强的活动性 ,在这些段上沿断裂发育晚第四纪地表破裂 ,横跨断层的冲沟和河流被错断 ,其晚第四纪以来的平均滑动速率达到 15mm/a。但是这种现象的存在只局限在盆地中 ,盆地以外则截然终止 ,不复存在。从上述事实看 ,嘉黎断裂的走滑活动似乎是伴随张性活动而产生的 ,在断层几何和活动特征上类似于横切大洋中脊的转换断     

Synthesis of accelerations of the 1976 Tangshan earthquake(M_S 7.8)in near-and far-field by using semi-empirical method

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地震预报实验场:科学问题与科学目标

本文简要回顾了以往地震预报实验场的经验教训,讨论了新一代地震预报实验场的实施策略。汲取汶川地震的经验启示,本文提出"地震博弈"策略,即考虑中长期地震预测的可用性与不确定性,在监测与实验系统设计中考虑地震活动和地震构造相依的区域模型。对于特定的活动断裂或活动地块边界带的潜在强震段落,设置适应多种孕震模型的"想定地震破裂",针对地震孕育的"想定模式"设计观测项目和监测系统。这一系统以地震成因和孕震模型的有效约束、"预期"前兆的有效监测、预测/预报效能的有效检验为导向。从技术角度,本文提出将地震预报实验场作为一个"大科学工程",强调复杂的多层次、多组分技术系统性能的稳健性,以及为确保与地震有效的"近距离接触"的系统可持续性。     

Burst strain disturbance—A new test study on fracture precursor

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成组中强震前后动态小震的时空活动特征

分析了进入活跃时段以来,新疆及邻近地区自１９９５年３月１９日和硕Ｍｓ５．０地震后,相继发生的１２次Ｍｓ≥４．７地震前后调制小震和动态小震的时空活动特征,据此提出了孕系统失稳模式;     

Evaluation model of landslide hazards induced by the 2008 Wenchuan earthquake using strong motion data

Landslides induced by the 2008 Wenchuan earthquake in the Longmenshan area were relatively well instrumented,which makes it possible to investigate the landslides using ground motion records.Firstly,this paper analyzes the data from Wenchuan earthquake on both regional and local site scale.The analyses show that the Newmark accumulative displacement calculated from the ground motion recorded in a particular geological hazard zone corresponds to the hazard intensity in that zone;the larger the displacemen...     

Estimated Green’s function extracted from superconducting gravimeters and seismometers

Estimated Green’s function (EGF) between stations has been extracted from ambient seismic noise, direct surface wave and coda waves. It is also confirmed by laboratory experiments on ultrasonics and theoretical derivations assuming diffusive wave field, equi-partition of modes or random sources on an enclosed surface. This method provides a new approach to study the crust and mantle structure at regional scale, continental scale and global scale. Following the achievements with seismometer records, the reco...     

Changes in biodiversity of the extremely polluted Golden Horn Estuary following the improvements in water quality

Long-term biological data supported by physicochemical parameters were evaluated to investigate the biodiversity of the Golden Horn Estuary from the past to the present. Limited observations dating back to 60 years ago indicated the existence of a diverse community in this small estuary. Unfortunately, in parallel with the increase in unplanned settlements and industry around the Golden Horn, pollution stress increased since the 1960s. Preliminary studies in the 1990s indicated survival of only a couple of pollution-resistant species, in the relatively cleaner lower estuary. Following the intensification of rehabilitation studies in 1998 and particularly after the opening of the floating bridge at the mid estuary; a remarkable day-by-day recovery in marine life has begun with the improving water quality. Nutrient concentrations decreased markedly; while water clarity significantly increased. Fecal coliform values decreased 10(3) fold. Phytoplankton composition changed and dense blooms of eukaryotic phytoplankters frequently occurred. Hydrogen sulfide almost completely disappeared even during the warmest periods of the year and dissolved oxygen concentrations increased. All results clearly depicted that the Golden Horn ecosystem shifted to eutrophic conditions from an anoxic environment. SCUBA dives in 2002, documented the level of diversification of life in the Golden Horn. All appropriate substratums were intensely covered by macrobenthic forms until the Halic Bridge and filter feeders dominated the plankton-rich ecosystem. Achieving the diversity of 1940s is not possible since the Black and Marmara seas, influencing water quality of the Golden Horn, are also suffering from anthropogenic impacts and are far less diverse than their rich diversity in 1940s. However, the Golden Horn is a good example that even the most polluted ecosystems can recover when appropriate measures are taken.     

Features and mechanism of neotectonic deformation of the Xishan fault system west of Urumqi

We have made careful field investigation and trench exploration to the Xishan fault system in west of Urumqi,and an integrated analysis in conjunction with data of deep seismic sounding.Our result suggests that under the SN-oriented compressive stress,the Xishan block moves steadily toward the Tianshan Mountains in south,resulting in southward thrust-slip and crustal shortening,particularly the southward thrust of the Xishan fault which serves as the main boundary in south.North of the Xishan fault are the ...