四川攀枝花小河流域地质灾害发育分布规律浅析     

李石桥  许俊豪  刘磊  曹亚廷  刘多林  计扬  叶小林  马启科 《地质灾害与环境保护》2016,(3):45-48

小河流域地处四川省攀枝花仁和区境内,地势南高北低,山脉走向近南北,岭谷相间。总体为中-大起伏中山地貌,较复杂的地形为滑坡、崩塌、泥石流的发生提供了空间,流域内地质灾害的发生一定程度影响了当地经济的发展。本文通过对区内23处地质灾害点的分析,讨论了流域地质灾害的主控因素及发育、分布规律,为科学合理地评价预测地质灾害的发展趋势与可能造成的危害提供参考资料。  相似文献   

单自由度陀螺寻北仪的运动规律分析     

郭金运  李成尧 《四川测绘》1995,18(2):57-61

根据傅科第一类回转仪的设想模型，本文用分析力学的方法研究了单自由度陀螺寻北仪的定向原理，分析了陀螺轴的运动规律，建立了多种因素如陀螺力矩，常阻尼力矩和空气阻尼等影响下的运动微分方程，分别求出对应解，并用小扰动理论研究了稳定性。  相似文献   

Implications of principal stress axes and eigenvalue ratios on critical orientation of fractures. Application to two tectonic regions in Alaska     

C. Caldentey  X. Lana 《Pure and Applied Geophysics》1990,133(1):87-102

The principal stress axes and eigenvalue ratios of the stress tensors from two active seismic regions in Alaska (eastern Aleutian Arc and eastern Gulf of Alaska) are computed. These results are obtained using focal mechanisms of earthquakes with magnitudes ranging from 5.5 to 8.2 and show for both regions slightly different compressional states with an orientation of the pressure axis of N26°W for the eastern Gulf of Alaska and N27°W for the east Aleutian Arc. The eigenvalue ratios for the eastern Gulf of Alaska and east Aleutian Arc are 0.84 and 0.99, respectively. The algorithm used in computations allows us to detect some focal mechanisms which are incoherent with respect to the obtained stress tensors. These incoherences are explained in terms of some tectonic features of the region. The orientations of possible pre-existing fractures which would need an unrealistically high maximum shear stress to start a slip on their fault planes are also investigated. These critical orientations depend on a constitutive frictional law as well as on eigenvalue ratios and eigenvectors of the stress tensors. The orientation, which is given in our case by the angle between the normal vector to a fracture and the regional tensional axis, is approximately 59° for the eastern Aleutian Arc. This angle ranges from 49° to 59° for the eastern Gulf of Alaska. It must be pointed out that fractures which need unrealistically high shear stress to start slip on their fault planes are defined by a very narrow band of possible angles between tensional direction and the normal vector to fault plane.  相似文献   

新疆铜镍硫化物矿床的基本地质特点   总被引：5，自引：1，他引：5  

王有标 《新疆地质》1990,(4)

作者从矿化岩带、含矿岩体和矿床特点三个层次,概括地阐述了新疆铜镍硫化物矿床成生的地质条件、基本特点,成因及矿模式;用归纳对比法,突出地探讨了新疆槽区铜镍硫化物矿床的分布规律.  相似文献   

震源构造发震概率的初步研究     

潘善德 《地震研究》1991,14(2):152-164

“入”字型构造是一种发震构造几何类型。它亦即是一种重要的震源构造。本文用“入”型为造为例,以它的力学模拟计算数据为基础给出了一个计算震源构造发震概率的粗算方法。 本文取Poisson分布为震源构造处发震概率对有关物理量分布的原型。按我们的数据,一个具体构造的发震概率与震源处应变能密度最大值(e_max),最大破裂值(F_max)和泊松比倒数(1/v)的各自增减有关。为确定一个震源构造的发震概率,可先计算它在不同参数下的典型力学情况,然后以e_max,F_max和1/v作独立变量分别算出单位增量的发震概率。最后,再按公式P(e_max,F_max,v)=Ak(e_max-e°_max)(F_max-F°_amx)(1/v-1/v°)×exp{-(100η_1(e_max一e°_max)+100η_2(F_max-F°_max)+η_3(1/v-1/v°))} 计算该震源处的发震概率,其中e°_max,F_max和v°分别为它们的标准值,A与e_max,F_max和1/v单位增量发震概率有关,而放大系数k则与震源区断层本构律、其它有关物性和震源规模有关。 本文为从力学的数学实验计算数据提供了一个寻求震源处发震概率的初步方法。为此,本文已对本方法做过某些理论上的论证。从实际结果看,我们认为本方法有某种合理性,且结合实际可把它使用于其它几何构造类型。  相似文献   

Alkyl nitrates and bifunctional nitrates of atmospheric interest: Henry's law constants and their temperature dependencies     

Jost Kames  Ulrich Schurath 《Journal of Atmospheric Chemistry》1992,15(1):79-95

Henry's law coefficients of 15 alkyl nitrates, keto-, hydroxy-, and dinitrates of atmospheric interest have been measured, mostly over the temperature range 1–25°C. The compounds are stable in aqueous solution. Where literature data were available, Henry's law coefficients are in very good agreement. It is concluded that dissolution in cloud and rain water is not an important loss process for alkyl mononitrates in the atmosphere. The residence times of the more soluble bifunctional organic nitrates, however, are significantly affected or even controlled by washout and rainout. Gas chromatographic analysis of bifunctional nitrates in preconcentrated atmospheric samples may be adversely affected by the adsorptive properties of these compounds.  相似文献   

大地震前的“震情三分律”   总被引：9，自引：1，他引：9  

王泽皋  郭妍 《内陆地震》1989,3(3):220-229

本文主要根据地震学理论和六十年代中期以来我国多震区Ms≥6.0级大震前小震活动频度增高异常的震兆图象,分析研究了其涨落峰、谷间的时间分布特点与大震发生时间的关系,提出了大震前的“震情三分律”方法。并进行了回顾性预报应用检验,同时还指出“前兆三分律”现象。  相似文献   

长江下游上河口段北岸无凝聚性砂岸的变形破坏规律     

Kuang Youwei Chen Rong 《地球科学》1989,(2)

长江下游上河口段北岸,属南通市城港口范围,岸线在平面上是反“S” 型,大部分处于凹岸的顶冲区,尽管江岸的演变受诸如河型,迳流、潮汐、科氏力等主要因素的影响,但其变形破坏规律恰受以细粉砂层为主体的这一江岸介质条件的制约。文中分析了发生于近数十年来江岸的各种变形破坏形式和规律。对是否存在砂体的渗透变形问题,据水位观测,室内渗透变形试验和现场调查所得,亦作了较详细的分析。  相似文献   

A study of rupture length vs. moment for synthetic earthquakes     

Jeen-Hwa Wang 《Pure and Applied Geophysics》1995,144(2):211-228

From the events synthesized from the one-dimensional dynamical mass-spring model proposed byBurridge andKnopoff (1967), the relation between rupture length and earthquake momentM is studied for various model parameters. The earthquake moment is defined to be the total displacement of a connected set of mass elements which slide during an event. A parameter stiffness ratios is defined as the ratio of the spring constant between the two mass elements to that between one mass element and the moving plate. The velocity-dependent friction law (including weakening and hardening processes) is taken to control the sliding of a mass element. The distribution of the breaking strengths over the system is considered to be a fractal function. The cases for severals values and different velocity-dependent friction laws with different decreasing ratesr _w of the frictional force with sliding velocity are studied numerically. The weakening process of the frictional force from the static one to the dynamic one obviously affects theM– relation. Meanwhile, a rapid weakening process rather than a slow weakening process can result in aM– relation, which is comparable to the observed one. Although an increase in thes value can yield an increase in the upper bound of the value and the number of events with largeM and values, the scaling of theM– relation is not affected by the change of thes value. For the cases in this study, the theoretical –M relations for small events withM<1 are almost in the form: M ^1/2, while those for large events withM>1 have a scaling exponent less than but close to 1. In addition, the fractal dimension, the friction drop ratio and the roughness of the distribution of the breaking strengths over the fault surface are the minor parameters influencing the –M relation. A comparison between the theoreticalM– relation and the observed one for strike-slip earthquakes shows that for large events the theoreticalM– relation is quite consistent with the observed one, while for small events there is a one-order difference in the two relations. For the one-dimensional model, the decreasing rate of the dynamic frictional force with velocity is the main factor in affecting the characteristic value of the earthquake moment, at which the scaling of theM– relation changes.  相似文献   

地震工作中的国家计量法规     

肖承邺  冯义钧 《地震地磁观测与研究》1995,16(1):71-77

在综述现行有效的国家计量法规和计量技术法规的同时,重点介绍了１９９４年７月１月开始施行的最新版《量和单位》国家标准的特点,以及从事地震工作的科技人员和管理人员正确认识与使用这一强制性国家标准的重要性。  相似文献