山西太原郝庄ML5.0地震应急工作的思考

随着城市化进程的加快，城市的致灾形态愈发复杂多样，城市的承灾能力亦显脆弱。回顾了2002年9月3日发生在山西太原郝庄ML5．0地震的应急工作，剖析了这次震感十分强烈的城市直下型地震发生后政府及社会的应急措施及经验教训，分析了太原市这座地震重点防御城市的承灾能力。认为，这次地震的应急工作是高效、有序的，但亦存在潜在的危险因素。     

山西洪洞县ML5.0地震波及区的应急反应

2003年11月25日山西省临汾市洪洞县甘亭镇发生ML5.0地震，此次地震波及面广，对这次地震波及区——运城市地震局的地震应急工作进行了回顾，认为在平时工作中扎实地做好应急预案的演练工作是十分重要的。     

Toward Optimal Calibration of the SLEUTH Land Use Change Model

SLEUTH is a computational simulation model that uses adaptive cellular automata to simulate the way cities grow and change their surrounding land uses. It has long been known that models are of most value when calibrated, and that using back‐casting (testing against known prior data) is an effective calibration method. SLEUTH's calibration uses the brute force method: every possible combination and permutation of its control parameters is tried, and the outcomes tested for their success at replicating prior data. Of the SLEUTH calibration approaches tried so far, there have been several suggested rules to follow during the brute force procedure to deal with problems of tractability, most of which leave out many of the possible parameter combinations. In this research, we instead attempt to create the complete set of possible outcomes with the goal of examining them to select the optimum from among the millions of possibilities. The self‐organizing map (SOM) was used as a data reduction method to pursue the isolation of the best parameter sets, and to indicate which of the existing 13 calibration metrics used in SLEUTH are necessary to arrive at the optimum. As a result, a new metric is proposed that will be of value in future SLEUTH applications. The new measure combines seven of the current measures, eight if land use is modeled, and is recommended as a way to make SLEUTH applications more directly comparable, and to give superior modeling and forecasting results.     

云南省地质灾害预报预警系统

基于云南省地质灾害综合研究成果，架构云南省地质灾害预报预警模型方法，认为：影响地质灾害活动是多种因素叠加，地质灾害系统是一个开放、复杂的灾害系统。在对影响地质灾害发生因素分析的基础上，可以利用相应的预测模型，对给定区域内发生地质灾害的危险度作预测，由此创建概念模型和数学模型，运用VB语言在MapGIS平台上进行二次开发，建立了云南省地质灾害预报预警系统。     

Seismicity, deformation and seismic hazard in the western rift of Corinth: New insights from the Corinth Rift Laboratory (CRL)

This paper presents the main recent results obtained by the seismological and geophysical monitoring arrays in operation in the rift of Corinth, Greece. The Corinth Rift Laboratory (CRL) is set up near the western end of the rift, where instrumental seismicity and strain rate is highest. The seismicity is clustered between 5 and 10 km, defining an active layer, gently dipping north, on which the main normal faults, mostly dipping north, are rooting. It may be interpreted as a detachment zone, possibly related to the Phyllade thrust nappe. Young, active normal faults connecting the Aigion to the Psathopyrgos faults seem to control the spatial distribution of the microseismicity. This seismic activity is interpreted as a seismic creep from GPS measurements, which shows evidence for fast continuous slip on the deepest part on the detachment zone. Offshore, either the shallowest part of the faults is creeping, or the strain is relaxed in the shallow sediments, as inferred from the large NS strain gradient reported by GPS. The predicted subsidence of the central part of the rift is well fitted by the new continuous GPS measurements. The location of shallow earthquakes (between 5 and 3.5 km in depth) recorded on the on-shore Helike and Aigion faults are compatible with 50° and 60° mean dip angles, respectively. The offshore faults also show indirect evidence for high dip angles. This strongly differs from the low dip values reported for active faults more to the east of the rift, suggesting a significant structural or rheological change, possibly related to the hypothetical presence of the Phyllade nappe. Large seismic swarms, lasting weeks to months, seem to activate recent synrift as well as pre-rift faults. Most of the faults of the investigated area are in their latest part of cycle, so that the probability of at least one moderate to large earthquake (M = 6 to 6.7) is very high within a few decades. Furthermore, the region west to Aigion is likely to be in an accelerated state of extension, possibly 2 to 3 times its mean interseismic value. High resolution strain measurement, with a borehole dilatometer and long base hydrostatic tiltmeters, started end of 2002. A transient strain has been recorded by the dilatometer, lasting one hour, coincident with a local magnitude 3.7 earthquake. It is most probably associated with a slow slip event of magnitude around 5 ± 0.5. The pore pressure data from the 1 km deep AIG10 borehole, crossing the Aigion fault at depth, shows a 1 MPa overpressure and a large sensitivity to crustal strain changes.     

利用SPOT-5卫星遥感影像更新1∶10 000地形图初探

通过利用SPOT-5(2.5 m)卫星遥感影像更新山地1∶10000地形图试验研究,总结了利用SPOT-5(2.5 m)卫星影像更新1∶10000地形图的工艺方法。成功地用于重庆市部分无航片山区的1∶10000地形图更新。     

The influence correction of boreal forest vegetation on SRTM data

The digital elevation model based on SRTM is very convenient for a wide range of studies but requires correction due to the influence of forest vegetation. The present study was conducted to analyse the effect of boreal forests on altitudes, aspects and slopes calculated from the SRTM. A DEM based on topographic maps at 1:100 000 scale was used as a reference. The linear regression analysis showed low data correlation in forested areas. The presence of different types of forests and felling in the woods leads to a complex distribution of deviations from the SRTM. A simple correction method was proposed, using a forest mask, built according to Landsat, and forest heights indicated on the topographic maps. After correction, the correlation coefficient between the altitudes increased by 0.05–0.14, the share of matching aspects by 1–4% and the share of matching slopes by 2–8%.     

生态地质调查工程进展与主要成果

为全面支撑山水林田湖草整体保护、系统修复和综合治理,中国地质调查局部署了“生态地质调查工程”。该工程自2019年以来,以地球系统科学理论为指导,重点开展了我国北方林草湿分布区1∶50万生态地质调查以及黄河源区、大凉山区等重点生态功能区1∶5万生态地质调查,采用“空-天-地”一体化调查技术,获取了不同尺度森林、草原、湿地等生态类型分布与变化,成土母岩、水文地质要素、土壤、地形地貌等生态地质条件,以及荒漠化、湖泊萎缩等生态问题分布数据,分析了生态-地质之间相互制约影响关系,剖析了主要生态问题的成因机理,划分了生态地质单元,建立了生态地质图谱,提出了基于地球系统科学的国土空间生态保护修复对策建议,为我国北方地区生态保护与系统修复工作提供了基础数据与技术支撑。     

利用MEMapGIS快速绘制地质图件方法探讨

以往地质工作中野外工作和图件编制往往脱节,大大降低了报告编制的效率。近些年涌现的快速绘制图件的方法均不具备普遍适用性。该文利用MEMapGIS软件实现由地质人员在野外快速绘制槽探素描图和钻孔柱状图等图件。该方法大大提高了图件绘制效率,同时减少了人为因素造成的误差,降低了人员成本。     

An IO-efficient parallel implementation of an R2 viewshed algorithm for large terrain maps on a CUDA GPU

A rapid and flexible parallel approach for viewshed computation on large digital elevation models is presented. Our work is focused on the implementation of a derivate of the R2 viewshed algorithm. Emphasis has been placed on input/output (IO) efficiency that can be achieved by memory segmentation and coalesced memory access. An implementation of the parallel viewshed algorithm on the Compute Unified Device Architecture (CUDA), which exploits the high parallelism of the graphics processing unit, is presented. This version is referred to as r.cuda.visibility. The accuracy of our algorithm is compared to the r.los R3 algorithm (integrated into the open-source Geographic Resources Analysis Support System geographic information system environment) and other IO-efficient algorithms. Our results demonstrate that the proposed implementation of the R2 algorithm is faster and more IO efficient than previously presented IO-efficient algorithms, and that it achieves moderate calculation precision compared to the R3 algorithm. Thus, to the best of our knowledge, the algorithm presented here is the most efficient viewshed approach, in terms of computational speed, for large data sets.