用河北张家口台速度与位移记录测定近震震级的对比

对河北张家口台FBS-3宽频带大动态范围的数字化速度地震仪和DD—2短周期模拟位移地震仪所记录的河北张北地区的地震，利用速度和位移数据分别测定了近震震级并进行了对比分析。结果显示，在一定的震级范围内，这两种资料测定的震级基本一致，没有发现二者之间存在系统误差，标准误差也较小。可以认为，无论从其物理意义还是具体做法上，用速度测定的震级与由位移测定的震级之间能够保持较好的一致性和连续性。     

The Gubbio normal fault (Central Italy): geometry, displacement distribution and tectonic evolution

Normal faults within orogenic belts can be pre-, syn- or post-orogenic features. We studied the Gubbio normal fault (central Italy), which is an example of a pre-orogenic fault reactivated in a post-orogenic stage. The Gubbio Fault is a 22-km-long fault bordering a Quaternary basin and part of an active faults system in the Umbria–Marche region (Central Italy). The interpretation of a set of seismic profiles enables us to reconstruct the fault geometry in detail and to measure displacement and throw distributions along the fault strike. Seismic data indicate that the Gubbio Fault represents an example of multiple reactivation: at least a portion of the fault was active in the Miocene and only a part of the total displacement was achieved in the Quaternary. The reconstruction of the fault geometry at depth shows that the fault is characterised by listric geometry. The fault is also characterised by a bend along strike and structure contours show that this geometry is maintained at depth. As the fault is commonly addressed as presently active, the maximum fault dimensions are correlated to the maximum expected earthquake, and the presence of the fault bend is discussed as a possible barrier to seismic ruptures propagation.     

Mechanical stratigraphy as a factor controlling the development of a sandbox transfer zone: a three-dimensional analysis

In thrust belts, fold–fault terminations are common features of the structural architecture and can pose complicated problems to unravel, in particular when two or more terminations are in close proximity. Such terminations usually reflect pre-existing attributes. Amongst the many factors, lateral variations in the mechanical stratigraphy can control along-strike geometry and kinematics of fault-related folds.A displacement transfer zone was produced in a compressional sandbox model by means of two adjacent, mechanically different stratigraphic domains. The experiment allowed two discrete chains to develop in the different domains, so that a complex structural setting occurred in the connecting area. Periclinal folds, oblique thrust fronts and oblique ramps developed in the resulting transfer zone. The interaction between periclines in the transfer zone produced lateral culminations in the folded structures. The analysis of displacement across the structural domains revealed that a significant loss of slip along the faults occurred in the relay zone. In this area, imbricate faulting was partially replaced by layer-parallel shortening. A linear relationship appears to exist between the bed length of the thrust sheet and the related fault slip.     

Displacement behavior of CH4 adsorbed on coals by injecting pure CO2, N2, and CO2–N2 mixture

Gas adsorption isotherms of Akabira coals were established for pure carbon dioxide (CO₂), methane (CH₄), and nitrogen (N₂). Experimental data fit well into the Langmuir model. The ratio of sorption capacity of CO₂, CH₄, and N₂ is 8.5:3.5:1 at a lower pressure (1.2 MPa) regime and becomes 5.5:2:1 when gas pressure increases to 6.0 MPa. The difference in sorption capacity of these three gases is explained by differences in the density of the three gases with increasing pressure. A coal–methane system partially saturated with CH₄ at 2.4 MPa adsorption pressure was experimentally studied. Desorption behavior of CH₄ by injecting pure CO₂ (at 3.0, 4.0, 5.0, and 6.0 MPa), and by injecting the CO₂–N₂ mixture and pure N₂ (at 3.0 and 6.0 MPa) were evaluated. Results indicate that the preferential sorption property of coal for CO₂ is significantly higher than that for CH₄ or N₂. CO₂ injection can displace almost all of the CH₄ adsorbed on coal. When modeling the CH₄–CO₂ binary and CH₂–CO₂–N₂ ternary adsorption system by using the extended Langmuir (EL) equation, the EL model always over-predicted the sorbed CO₂ value with a lower error, while under-predicting the sorbed CH₄ with a higher error. A part of CO₂ may dissolve into the solid organic structure of coal, besides its competitive adsorption with other gases. According to this explanation, the EL coefficients of CO₂ in EL equation were revised. The revised EL model proved to be very accurate in predicting sorbed ratio of multi-component gases on coals.     

金川露天矿边坡岩体移动和变形的光弹性软材料模拟实验研究

通过对边坡岩体破坏机理的光弹性力学模拟实验研究, 岩体在地应力作用和自重体积力作用下, 对露天矿边坡的力学状态具有明显地影响。实验采用了明胶软材料, 模型比例1:1100。实验模拟了在自重应力和构造应力作用下, 边坡岩体的位移和变形。     

关系处理中要素重叠的自动判别

关系处理一直是自动制图综合中解决起来困难比较多的一个问题,而解决关系处理的前提则是要素重叠位置的自动识别。本文着重讨论数据库条件下进行要素重叠自动识别的方法及其在编图实践中的应用。     

岩体结构效应的综合反演分析

本文根据多点位移计现场测量的位移值，结合洞室开挖时一般性的变形规律和基本地质知识，探讨了反演推断洞室周围岩体结构的理论和方法，并且利用某一实际工程进行了验证。     

Double-parameter threshold and its formation mechanism of the colluvial landslide: Xintan landslide, China

Data compiled from monitoring the displacement resulting from the Xintan landslide in China was analyzed. The stability of the demonstrated colluvial slope has a close correlation with two parameters, the velocity of the displacement and the angle of the surface vector. The stability trend can be described and evaluated by both the velocity of the displacement and the vector angles. The displacement vector angle, for which there is no substitute, serves as an explicit criterion for the stability of the slope, hence it is significant in the prediction of the catastrophic movement of landslides. A systematic analysis of the features of the vector angles of the surface displacement space and time was performed. The evolving mechanism of space-time and the characteristics of the displacement vector angles were deduced. On the basis of these deductions and by using principles of statistics, the double-parameter threshold for forecasting the stability of the colluvial slopes was established. According to the double-parameter threshold, a calculation and evaluation of stability was completed in terms of the monitoring data of the F-series of points on the Xintan slope. The forecast results coincided with the destabilized timetable, thus demonstrating that the double-parameter criterion has, to a certain extent, precision and practical application for forecasting of landslides.     

Normal faulting on Europa: implications for ice shell properties

We identify two likely normal faults on Europa, of lengths ≈30 and 11 km. A simple flexural model of fault-related topography gives effective elastic thicknesses of 1.2 and 0.15 km, respectively, and the resulting inferred fault strength is of order 1 MPa. The maximum fault displacement: length ratio for each fault is ≈0.02, comparable with values on silicate planets. We combine this observation with a modified linear elastic fracture mechanics model to conclude that the shear modulus of the Europan surface must be significantly less than that for unfractured ice. The low value of the modulus is probably due to near-surface fracturing or porosity, which will affect the material's radar properties and seismic velocities. For a likely reduction in shear modulus of an order of magnitude, the driving stresses inferred are about 6–8 MPa, much higher than present-day diurnal tidal stresses. However, stresses approaching these values can be generated by non-synchronous rotation or polar wander, while stresses exceeding these values arise during ice shell freezing. If the entire larger fault breaks, it will generate an event of seismic magnitude M_s≈5.3.     

共沸蒸馏置换干燥法制备纳米氧化镁粉体的研究

以六水氯化镁和尿素为原料,采用均匀沉淀法制备出氢氧化镁沉淀,利用不同共沸蒸馏置换干燥法除去沉淀中的湿分,再将干燥的氢氧化镁粉体经马弗炉煅烧得到纳米氧化镁粉体;通过透射电子显微镜和X射线衍射仪的表征与分析,研究不同共沸蒸馏置换干燥法对纳米氧化镁粉体形貌、颗粒尺寸和团聚情况的影响;探讨了共沸蒸馏置换干燥的基本原理、操作方法和置换剂的选择原则。