利用跨断层形变资料研究近期唐山断裂活动性

采用1999年1月～2012年9月唐山台跨断层基线和水准数据资料,计算出唐山断裂水平和垂直形变及断层活动速率.并求解了唐山台站的应变特征和主应变方向,研究了唐山断裂的活动特征,并探讨了唐山断裂活动与地震活动的关系.结果表明,较远区域的大震和本地区中强地震对唐山断裂的水平向张压运动和垂向运动都可能有一定的影响.2003年可能是唐山断裂周边应力场发生较大改变的一年.     

河源台地电专用电源和外线路故障查修方法

对C-ATS地电仪专用观测电源的原理和特点进行了简要介绍,并对其供电电源和外线路故障的查修方法作了较详细的阐述,列举故障实例,逐一说明检查维修过程.最后指出地电台站工作人员掌握一定的故障排查维护经验非常必要,对仪器的安全运行,及其产出数据的可靠性和连续性都有积极意义.     

前兆远程子台CDMA传输故障诊断及排除

本文简要介绍了CDMA传输技术及其在地震前兆远程子台的应用,之后以天津市地震局宝坻地震台的远程子台为实例,对地震前兆远程子台CDMA传输中的故障原因进行了研究,指出导致CDMA传输故障的原因主要有:仪器通讯部分故障、资费余额不足、路由器"假死"、路由器死机、路由器内部故障(特别是SIM卡接触不良)、CDMA信号强度不够、交换机故障、传输硬件连接断路等。在此基础上提出了一套行之有效的故障诊断流程,并对常见故障原因的判定和排除方法做了归纳整理。本文对使用CDMA传输方式或其他无线传输方式的地震前兆远程子台的维护管理人员有一定的参考意义。     

Synoptic Classification of Snowfall Events in the Great Smoky Mountains,USA

Mean annual snowfall in the Great Smoky Mountains National Park (GSMNP) exhibits considerable spatial variability, ranging from 30 cm in the valleys to 254 cm at higher elevations. Snowfall can be tied to a variety of synoptic classes (e.g., Miller A or B cyclones, 500 hPa cutoff lows), but the frequency and significance of different synoptic classes have not been fully assessed, particularly at higher elevations. In this paper, we manually classify all snowfall events during the period 1991 to 2004 according to a synoptic classification scheme, calculate mean annual snowfall by 850 hPa wind direction and synoptic class, and develop composite plots of various synoptic fields. Hourly observations from nearby first-order stations and 24 hr snowfall totals from five sites within the GSMNP are used to define snowfall events. NCEP/NCAR reanalysis data are used to develop composite plots of various synoptic fields for cyclones passing south and then east of the area (e.g., Miller A cyclones). Results indicate that over 50% of the mean annual snowfall at higher elevations occurs in association with low-level northwest flow, and that Miller A cyclones contribute the greatest amount to mean annual snowfall at all elevations.     

Identifying spatial concentrations of surnames

Surnames (family names) have been overlooked as a valuable source of spatially referenced population data. Presented here is a methodology, based on kernel density estimation, which is used to identify the areas of Great Britain where any surname is most concentrated. This not only indicates a surname's geographic origin in the country but also its current spatial extent and spatial relationship with other surnames and place names. We argue that such analysis can provide baseline and change measures, and an empirical basis to change forecasting. Such analysis offers valuable insights into national, regional and local changes in population structure, and testimony to the relevance of GIScience to population genetics, historical geography and genealogy.     

Changing Properties of Snowpack in the Great Salt Lake Basin,Western United States,from a 26-Year SNOTEL Record

Daily observations from automated snowpack telemetry (SNOTEL) stations from within the drainage basin of the Great Salt Lake over the period from 1982 to 2007 are analyzed. The major finding is a shift toward an earlier date of peak snow water equivalent (SWE) by around fifteen days. Less robust findings are reductions in the amounts of peak SWE and 1 April SWE. This suggests increased chances of late-summer water shortages, especially when combined with rapid recent population growth. Less freshwater is likely to be available to flow into the Great Salt Lake, increasing its salinity and potentially affecting its ecology.     

Thermal infrared remote-sensing detection of thermal information associated with faults: A case study in Western Sichuan Basin, China

Using enhanced land surface temperatures (LSTs) image retrieved from Landsat ETM+, this article shows that thermal information associated with faults have been detected. These anomalies may be provided by geothermal natural convection through faults and partially influence the ground surface thermal environment. The study area in southern segment of Longmen Mountains thrust belt of Western Sichuan Basin contains complex faults and folds with recent earthquake activity. In order to study the faults for future oil exploration, we use LST data retrieved from Landsat thermal infrared band to detect the thermal information associated with faults. The LSTs are enhanced by filtering out anthropogenic activity and influence land cover classes, and interpolating to contour map. The spatial patterns of the enhanced images revealed the spatial correspondence between the thermal information and the dip planes of faults when compared with the explanation profiles and geologic features obtained from the 3D-seismic geophysical data. The thermal-affected ranges calculated and the statistically significant of regression model also indicate the result that the thermal information located near the faults are consistent with the faults’ dip planes.     

云南澜沧勐佛铅多金属矿成矿特征

勐佛铅多金属矿的成因类型为破碎带热液充填交代型。沿断裂分布方铅矿化、黄铜矿化、黄铁矿化、斑铜矿化、方铅矿化及相应的次生矿化蚀变。     

独山子背斜的几何学运动学数字模拟

独山子背斜位于准噶尔盆地南缘西段,是北天山逆冲推覆带在前陆盆地山前形成的断层相关褶皱。本文以横跨背斜的过井地震剖面为蓝本,用钻井数据、相邻地震剖面和地表形态为约束,运用断层相关褶皱模型对独山子背斜进行几何学定量分析,以建立合理的与实际接近的构造模型; 提取构造特征参数进行基于Trishear模型的运动学定量模拟,选取与实际数据吻合度最高的构造形态为独山子背斜的最佳几何模型。模拟数据表明:独山子背斜为前翼呈三角剪切的断层传播褶皱; 背斜变形从喜马拉雅山晚期更新统(Q_1-3)沉积期间开始形成并生长,平均推覆速率为0.18 mm/a; 全新统沉积期间(Q₄)推覆活动强度达到最大值,平均推覆速率为 4.64 mm/a。形成独山子背斜所需的总推覆位移量为5 600 m左右,第四纪期间的平均推覆速率约为0.19 mm/a。