Empirical prediction of the ground shaking scenario for the Catania area

Simplified approaches for prediction of strong ground shaking, that can be efficiently implemented through a Geographical Information System (GIS), are applied to constructing earthquake scenarios for the Catania municipal area. Ground shaking maps in terms of peak ground acceleration and response spectral ordinates are developed both for a repetition of the catastrophic 1693 earthquake (M7.3), and for a lower energy event, like that which occurred in 1818 (M6.2). The maps account for amplification due to local site conditions. According to the commonly used attenuation relations, the local amplification is taken into account either in a simpler way or in a more detailed approach, derived from an extensive geotechnical zonation. The approximation introduced by the simpler methodology, to be used whenever accurate data are not available, is estimated by a comparison with damage distribution.     

Seismic imaging of lithospheric discontinuities and continental evolution

Discontinuities in physical properties within the continental lithosphere reflect a range of processes that have contributed to craton stabilization and evolution. A survey of recent seismological studies concerning lithospheric discontinuities is made in an attempt to document their essential characteristics. Results from long-period seismology are inconsistent with the presence of continuous, laterally invariant, isotropic boundaries within the upper mantle at the global scale. At regional scales, two well-defined interfaces termed H (60 km depth) and L (200 km depth) of continental affinity are identified, with the latter boundary generally exhibiting an anisotropic character. Long-range refraction profiles are frequently characterized by subcontinental mantle that exhibits a complex stratification within the top 200 km. The shallow layering of this package can behave as an imperfect waveguide giving rise to the so-called teleseismic Pn phase, while the L-discontinuity may define its lower base as the culmination of a low velocity zone. High-resolution, seismic reflection profiling provides sufficient detail in a number of cases to document the merging of mantle interfaces into lower continental crust below former collisional sutures and magmatic arcs, thus unambiguously identifying some lithospheric discontinuities with thrust faults and subducted oceanic lithosphere. Collectively, these and other seismic observations point to a continental lithosphere whose internal structure is dominated by a laterally variable, subhorizontal layering. This stratigraphy appears to be more pronounced at shallower lithospheric levels, includes dense, anisotropic layers of order 10 km in thickness, and exhibits horizontal correlation lengths comparable to the lateral dimensions of overlying crustal blocks. A model of craton evolution which relies on shallow subduction as a principal agent of craton stabilization is shown to be broadly compatible with these characteristics.     

乔木的斜向支撑效能及其坡面稳定意义

以滇中地区的松林为例,初步定量探讨了乔木对顺坡有的浅层土壤的斜向支撑作用。研究,树根可能提供的锚固力可达０．６９ｋＮ;在有效的锚固作用下,单株树干的支撑力（抗滑力）最高为０．４２ｋＮ,平均为０．１７ｋＮ;受斜向支撑作用的影响,本来不稳定的浅层松散物质的稳定性系数Ｆ值,由０．５４提高到１．１０,使坡面成为稳定斜坡。如果在特定条件下,树根的锚固力全部转化为支撑力,坡面的Ｆ值可以达到２．８２。     

带状态滞后及控制滞后的一阶线性系统预测镇定

研究状态变量及控制变量均带滞后的一阶线性系统的预测镇定问题。通过按无滞后系统设计控制规律,预测物理上不可实现的超前状态变量的方法,得到了预测镇定控制规律。该控制规律可保证闭环系统的无穷个极点都位于根平面上希望极点的左边。     

Ocean governance in a competitive world. The BRIC countries as emerging maritime powers—building new geopolitical scenarios

Owing to their style and economic impact, Brazil, Russia, India and China (the BRIC countries) are destined to become relevant actors in the new ocean governance. The following working hypothesis is sustained: the BRIC countries, due to the potential of their maritime territories, can be considered to be emerging maritime powers capable of displacing some of the historical maritime powers. This would also entail a shift of strategic maritime space towards the southern hemisphere. Other emerging maritime scenarios associated with the BRIC countries include the Russian Arctic, and the Indo-Pacific ocean belt, or “string of pearls”, as it is known. Factors such as competitiveness, maritime leadership and ocean governance are thus placed in a new economic and political context where they might be redefined and adapted to the circumstances of the BRIC block and other emerging countries, the majority of which are subject to demographic pressure and a high degree of poverty. The most relevant conclusions point to the emergence of a new type of neo-navalism, on the one hand—a BRIC version of traditional sea power and, on the other, a possible threat to the EU's Integrated Maritime Policy under pressure from strong competitiveness in a highly internationalised environment, forcing changes in its original approach with its distinct social profiles and commitment to latest generation rights.     

Hydrothermal Origin of Early Permian Chert Nodules in theCentral North China Craton Linked to Northern MarginCratonic Activation

Sedimentary chert phases from the Archean to the present are widely used to trace sedimentary environments and tectonic settings. Recently,chert nodules occurring within carbonates have been the subject of possible hydrothermal or biogenic origin,in lieu of a diagenetic origin.However,chert nodules from a vast cratonic basin represent extremely rich silica accumulations but less noted is how they respond to submarine hydrothermal activity (and/or surface siliceous organism productivity). The links between the cratonic-type chert depositions and environmental changes regarding cratonic evolution need to be revisited at a large temporal-spatial scale. The chert nodules are widespread throughout the Lower Permian Taiyuan Formation in the North China Craton (NCC).Several Taiyuan chert-rich successions across the NCC have been selected to study possible links between chert deposition and cratonic evolution in scenario of partial cratonic activation of the northern NCC margin during the Late Paleozoic.Based on stratigraphic correlation,the chert nodules are ubiquitously,evenly distributed throughout the Taiyuan Formation at a large craton-basin scale from the northern to southern interior NCC.Petrological results,elemental abundances,together with silicon and oxygen isotopic compositions of chert samples infer significant hydrothermal contributions for the silica accumulations. Therefore, the cratonic-scale chert depositions of hydrothermal origin infer a giant and remote silica reservoir,linking to the large igneous province and magmatism in the NCC northern margins.The Taiyuan chert nodules could be unique marine sedimentary archives recording the Late Paleozoic NCC partial activation,which also generated continental records of igneous rocks,bauxites and tuffs.The strong tectonics of the northern margin,south-dipping topography and northward transgression of the Early Permian NCC facilitated the chert deposition on the shallow marine platform in the cratonic interior.     

线下和线上场景社区零售可达性及公平性研究

随着数字化转型深入居民日常生活,线上服务对社区资源配置的效率和公平产生了深远影响。论文以南京零售业为例,基于线下和线上零售特征,采用WMS (Web Map Service)方法和SAG (Scenarios Accessibility Gap)测度线下、线上和综合场景下社区零售可达性格局及其场景差异,采用SLM (Spatial Lag Model)、基尼系数,逐一讨论多场景下不同收入群体的社区零售可达性的公平差异程度。结果表明：(1)不同场景下,南京市社区零售可达性均呈现“城郊两极化”区域差异,随中心城区、主城区、郊区逐次下降。(2)线上服务能有效提高96.76%社区的零售可达性,降低线下场景中64.23%的盲点社区,显著优化了传统线下的社区零售可达性。(3)线下场景,零售可达性随着房价区间升高而先升后降;线上场景,零售可达性随着房价区间升高呈现线性递增,说明线上服务改变了线下场景社区经济属性与零售可达性的关系,放大了不同经济属性社区之间的机会不平等。(4)线下场景,南京市不同收入群体所享有的社区零售资源差距相对较小,而线上场景则差距较大,不公平性更高;由于尺度效应,相比于线下场景...     

Vulnerability of natural ecosystem in China under regional climate scenarios:An analysis based on eco-geographical regions简

Assessment of vulnerability for natural ecosystem to climate change is a hot topic in climate change and ecology, and will support adapting and mitigating climate change. In this study, LPJ model modified according to features of China＇s natural ecosystems was em- ployed to simulate ecosystem dynamics under A2, B2 and A1B scenarios. Vulnerability of natural ecosystem to climate change was assessed according to the vulnerability assessment model. Based on eco-geographical regions, vulnerability of natural ecosystem to climate change was analyzed. Results suggest that vulnerability for China＇s natural ecosystems would strengthen in the east and weaken in the west, but the pattern of ecosystem vulner- ability would not be altered by climate change, which rises from southeast to northeast gradually. Increase in ecosystem vulnerable degree would mainly concentrate in temperate humid/sub-humid region and warm temperate humid/sub-humid region. Decrease in eco- system vulnerable degree may emerge in northwestern arid region and Qinghai-Tibet Plateau region. In the near-term scale, natural ecosystem in China would be slightly affected by cli- mate change. However, in mid-term and long-term scales, there would be severely adverse effect, particularly in the east with better water and thermal condition.     

基于CLUE-S和Markov复合模型的土地利用情景模拟研究——以江苏省环太湖地区为例

基于江苏省环太湖地区1990、2000年TM影像和2005年中巴卫星遥感影像,综合集成区域DEM、交通图和居民点分布图等,充分利用CIUE-S模型空间模拟特长和Markov模型数量预测优势,应用CLUE-S和Markov复合模型及GIS分析技术分别对现有土地转移速率发展和根据规划约束对转移概率进行调整的严格保护耕地的土地利用变化情景进行时空模拟,揭示不同情景下的土地利用格局变化.通过模拟得知,江苏省环太湖地区今后确需控制建设用地总量,提高节约集约用地水平,最严格地保护水田等优质耕地.     

中国北方未来土地利用变化情景模拟

利用系统动力学 (SD) 的原理和方法,发展了区域土地利用情景变化SD模型。在不同系统状态下,模拟了中国北方13省未来50年不同社会经济情景下的区域土地利用结构变化,并初步评价了这些变化的可能生态影响。1990~2001年的模型结果表明该SD模型具有一定的可靠性,能在一定程度上为当前理解土地利用系统的复杂驱动行为,评估脆弱生态区土地系统变化的潜在生态效应提供帮助。2000~2050年的情景仿真结果表明,经济、人口、市场和技术等因素对中国北方13省未来土地利用变化的影响非常明显。