2022年1月中国大陆地区MS≥4.0地震震源机制解测定

本文利用中国地震台网记录的宽频带波形资料,采用近震全波形反演方法得到2022年1月1—31日发生在中国大陆地区的M_S≥4.0共13次地震的震源机制解。结果显示逆断型1次,走滑型9次,未知型3次。      

XRF半定量分析技术在矿石光片鉴定中的应用

偏光显微镜反光镜下鉴定金属矿物是最常用、最快捷有效的方法,然而鉴定结果容易受到鉴定者主观因素或磨片情况的影响。为了更快速、准确地在反光镜下鉴定矿物,利用XRF半定量分析技术快速、无损、前处理简单等特点,以及磨平抛光的矿石矿物在半定量分析过程中能较好地避免楔入效应和阴影效应的有利因素,采取了先用XRF半定量分析测得的结果去反推矿物,再在显微镜下鉴定矿物的方法。以多金属硫化物矿石、含铀多金属矿石及含微量铀的矿石样品为例进行鉴定,结果表明,在鉴定前知道光片上的元素及其质量分数,通过地球化学方法和经验法反推矿物,结合显微镜观察需要鉴定的矿物,可有效避免忽略掉透明/半透明矿物（锡石）、小粒径矿物（沥青铀矿）、易混淆矿物（铀黑）,提高光片鉴定工作的效率和准确性。     

Review and Prospect of the Study on Soil Wind Erosion Process

Soil wind erosion processes include mechanical process and dynamic changes of the factors affecting soil wind erosion, as well as the corresponding changes of wind erosion rate. The former is rich in experimental and theoretical researches that have clearly defined the process of particle starting, transporting and settling. The latter focuses on the dynamic changes of various wind erosion factors and the response of soil wind erosion rate to the change of the factors, of which systematic research of which is very limited. The difficulties in research of soil wind erosion process include: ①Dynamic parameterization of wind erosion factors; ②Observation and quantitative expression of the dynamic changes of wind erosion factors; ③Scaling problem of wind erosion process; ④Prediction ability of wind erosion models. At present, it is urgent to carry out the following work on soil wind erosion. The first is to establish standard wind erosion observation field in typical regions to obtain continuous and complete data of wind erosion in the field; the second is to study the saturation path of wind sand flow to solve scale problem; and the third is to construct a wind erosion model with solid theoretical foundation and fully consider both mechanical process of soil wind erosion and dynamic changes of the factors.     

地质建模中的二维数据模型

地质图用于记录和显示研究区的地质特征,二维地质图通常借助于地理信息系统（GIS）编制而成。随着计算机GIS技术的发展,可以对点、定点、线和区（多边形）等地质特征做抽象处理,以联系地质图与传统地质模型。然而,GIS的传统数据结构不能通过地质图来解释复杂的概念地质模型。阐述了使用信息技术表达地质图的若干关键问题,提出了面向对象的地质数据模型GeoFeature,并构建了支持存储和管理计算机数据结构的二维圆弧拓扑结构。最后,在Minesoft软件中集成了此功能。     

The influence of materials on the breaching process of natural dams

In this study, a series of natural dam overtopping laboratory tests are reported. In these tests, the effect of seven different sediment mixtures on the breaching process was investigated. According to the test results, three stages of the breaching process of natural dams made of different materials were observed. Backward erosion was the primary cause for the incising slopes. The effects of backward erosion became stronger with the larger fines contents of the materials. With an increase in the median diameter (d ₅₀) of particles, the breaching time became longer. However, the peak discharge became smaller. With an increase in the fines contents (p), the median diameter of the particles and the void ratio were changed, which resulted in a decrease in the breaching time and an increase in the peak discharge. The breaching time and peak discharge were more sensitive to the median diameter than to the fines contents. The relation between breach width and depth was found to follow a logistic function \( W\kern0.5em =\kern0.5em \frac{\zeta }{1\kern0.5em +\kern0.5em {e}^{\left(-k\left(D\kern0.5em -\kern0.5em {D}_0\right)\right)}} \). The parameters ζ, k, and D ₀ are defined by a linear relationship with the median diameter and fines content. A breach of the side slope occurred as a tensile failure when the fines contents of the materials were large; otherwise, shear failure occurred. Furthermore, when the materials had fewer fines contents, the volume of the collapsed breach side slope became larger.     

Three-dimensional analyses of the sliding surface distribution in the Huangtupo No. 1 riverside sliding mass in the Three Gorges Reservoir area of China

The Huangtupo landslide is one of the largest and most destructive landslides still deforming in the Three Gorges area of China. In recent years, most studies on this landslide have been based on the data obtained from an investigation conducted in 2001. To further elucidate the geological structure and evolution of the landslide, we began building a field test site in the area of the sliding mass with the fastest deformation velocity in 2009. A group of tunnels with a total length of 1.1 km has been excavated, and nine boreholes with depths between 76.8 and 127.1 m have been drilled into the sliding body. Additionally, relative monitoring devices, such as borehole inclinometers and crack meters, have been installed. Based on the findings of the previous investigation and the latest tunneling, drilling, and monitoring data, a spatial distribution model of the sliding surfaces of the Huangtupo No. 1 riverside sliding mass has been established using the discrete smooth interpolation (DSI) method. Significant differences are revealed between the previous proposed sliding surface and the latest monitoring data. We propose that the Huangtupo No. 1 sliding mass has two sliding surfaces. Thus, the sliding mass can be further divided into two secondary sliding bodies, which are named the No. 1-1 (east) and No. 1-2 (west) sliding masses. The No. 1-1 sliding mass slid first, and the material along the western boundary slid later, producing the No. 1-2 sliding body, which has a smaller volume and shallower depth. The areas, volumes, and thicknesses of each sliding body have been calculated using a digital 3D model.