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211.
An appreciation of the physical mechanisms which cause observed seismicity complexity is fundamental to the understanding
of the temporal behaviour of faults and single slip events. Numerical simulation of fault slip can provide insights into fault
processes by allowing exploration of parameter spaces which influence microscopic and macroscopic physics of processes which
may lead towards an answer to those questions. Particle-based models such as the Lattice Solid Model have been used previously
for the simulation of stick-slip dynamics of faults, although mainly in two dimensions. Recent increases in the power of computers
and the ability to use the power of parallel computer systems have made it possible to extend particle-based fault simulations
to three dimensions. In this paper a particle-based numerical model of a rough planar fault embedded between two elastic blocks
in three dimensions is presented. A very simple friction law without any rate dependency and no spatial heterogeneity in the
intrinsic coefficient of friction is used in the model. To simulate earthquake dynamics the model is sheared in a direction
parallel to the fault plane with a constant velocity at the driving edges. Spontaneous slip occurs on the fault when the shear
stress is large enough to overcome the frictional forces on the fault. Slip events with a wide range of event sizes are observed.
Investigation of the temporal evolution and spatial distribution of slip during each event shows a high degree of variability
between the events. In some of the larger events highly complex slip patterns are observed. 相似文献
212.
地质复杂度与成矿预测之间的关系--以兰坪盆地为例 总被引:1,自引:0,他引:1
地质复杂度是由赵鹏大院士提出的地质异常圈定方法之一。它综合了地质、遥感等各种有利的成矿因素,充分发挥其定量化和综合性分析的特点,对各种控矿因子进行加权得分,进而圈定了6个成矿远景区。 相似文献
213.
214.
MAO Jianhua GUO Qingsheng WANG Tao lecturer Ph.D candidate School of Resource Environment Science Wuhan University Luoyu Road Wuhan China. 《地球空间信息科学学报》2002,5(3):53-57
1 IntroductionThedirectionalinformationisakindofimportantspatialinfor mationinGIS ,andplaysimportantrolesintheproblemsdealingwithvisualizationofspatialinformation,patternrecognitionandspatialinformationinquiringetc.Therearesuccessfulresearch esonthecomp… 相似文献
215.
216.
The conservation of biological diversity is recognized as a fundamental component of sustainable development, and forests contribute greatly to its preservation. Structural complexity increases the potential biological diversity of a forest by creating multiple niches that can host a wide variety of species. To facilitate greater understanding of the contributions of forest structure to forest biological diversity, we modeled relationships between 14 forest structure variables and airborne laser scanning (ALS) data for two Italian study areas representing two common Mediterranean forests, conifer plantations and coppice oaks subjected to irregular intervals of unplanned and non-standard silvicultural interventions. The objectives were twofold: (i) to compare model prediction accuracies when using two types of ALS metrics, echo-based metrics and canopy height model (CHM)-based metrics, and (ii) to construct inferences in the form of confidence intervals for large area structural complexity parameters.Our results showed that the effects of the two study areas on accuracies were greater than the effects of the two types of ALS metrics. In particular, accuracies were less for the more complex study area in terms of species composition and forest structure. However, accuracies achieved using the echo-based metrics were only slightly greater than when using the CHM-based metrics, thus demonstrating that both options yield reliable and comparable results. Accuracies were greatest for dominant height (Hd) (R2 = 0.91; RMSE% = 8.2%) and mean height weighted by basal area (R2 = 0.83; RMSE% = 10.5%) when using the echo-based metrics, 99th percentile of the echo height distribution and interquantile distance. For the forested area, the generalized regression (GREG) estimate of mean Hd was similar to the simple random sampling (SRS) estimate, 15.5 m for GREG and 16.2 m SRS. Further, the GREG estimator with standard error of 0.10 m was considerable more precise than the SRS estimator with standard error of 0.69 m. 相似文献
217.
近年来大规模图分析问题在网络大数据领域发挥着重要作用.经典的图分析问题包括求图的直径、半径、围长、聚类系数、紧密中心度和介数中心度等.集中式算法求解这些图计算问题一般都需要问题规模的平方甚至立方以上复杂度,显然不适用于大规模图.本文旨在从分布式算法角度介绍对这些基本图计算问题具有最坏性能保证的低复杂度(线性时间)算法.此外,本文还将介绍如何通过通信复杂性理论证明分布式图计算问题的下界. 相似文献
218.
Juan Emilio Sánchez-Moyano Isabel García-Asencio & José Carlos García-Gómez 《Marine Ecology》2007,28(2):324-337
The aim of this study was to establish the effect of temporal variation of the alga Caulerpa prolifera cover on the composition and stability of the associated crustacean community. Forty‐five crustacean species were found, amphipods and tanaidaceans being the most abundant groups. The stations were grouped mainly based on the gradient of algal cover, independently of location or sampling period (MDS analyses). Considering separately epifaunal and infaunal species, the epifauna occurred mainly at high cover (HC) and medium–low cover (MLC) stations, while the infauna occurred at MLC and unvegetated (UV) stations. Infaunal species were predominant in all stations and sampling periods, and the abundance and numbers of epifaunal species showed a clear dependence of algal cover. To quantify the loss of biodiversity due to the plant cover variations, we applied the average and variation in taxonomic distinctness (Δ+ and Λ+, respectively). The HC stations, especially those with fewer algal cover variations along the study period, showed few fluctuations of Δ+,and Λ+ was usually located near mean; however, UV stations tended to fall in the area where the statistical power of the test is reduced and showed more oscillations of Λ+. The ability of these indices to test the fauna composition in function of the alga presence is discussed. 相似文献
219.
Fishery systems and linkages: from clockworks to soft watches 总被引:2,自引:0,他引:2
220.
This commentary response reflects on the thoughts offered by Solem, Mohan, Rawling, and Lambert regarding Larsen and Harrington's article titled “Developing a Learning Progression for Place” (2018). 相似文献