The Natural Hazards Theme of the International Year of Planet Earth

The United Nations has declared 2008 to be the International Year of Planet Earth. It is being organised under the auspices of the International Union of Geological Sciences and UNESCO. Planning for the International Year of Planet Earth has consisted of establishing 10 major science themes including Hazards. The Hazards Theme is centred around the following key questions: (1) How have humans altered the geosphere, the biosphere and the landscape, thereby creating long-term changes detrimental to life and the environment and triggering certain hazards, while increasing societal vulnerability to geophysical (geological and hydrometeorological) hazards? (2) What technologies and methodologies are required to assess the vulnerability of people and places to hazards and how might these be used at a variety of spatial scales? (3) How do geophysical hazards compare relative to each other regarding current capabilities for monitoring, prediction and mitigation and what can be done in the short-term to improve these capabilities (4) What barriers exist to the utilisation of risk and vulnerability information by governments (and other entities) for risk and vulnerability reduction policies and planning (including mitigation) from each of the geophysical hazards? Following the 26 December 2004 Indian Ocean Tsunami and the UN World Conference on Disaster Reduction held in Kobe, Japan in January 2005, the International Council for Science (ICSU) decided to establish a major research programme and initiative on Natural and Human Induced Environmental Hazards and Disasters that will co-operate with the Hazards theme of the International Year and continue through to 2011.     

Interannual variability of summer monsoon rainfall over Myanmar

Observed summer (May–October) rainfall in Myanmar for the period 1981–2010 was used to investigate the interannual variability of summer monsoon rainfall over Myanmar. Empirical orthogonal function, the sequential Mann-Kendall test, power spectrum analysis, and singular value decomposition (SVD) were deployed in the study. Results from spectral analysis showed that the variability of rainfall over Myanmar exhibits a 2- to 6-year cycle. An abrupt change in rainfall over the country was noted in 1992. There was a notable increasing rainfall trend from 1989. After the sudden change, the mean rainfall increased by 36.1 mm, compared with the mean rainfall before the sudden change, and was associated with a rise in temperature of about 0.2 °C. An increase in heavy rainfall days was observed from the early 1990s to 2010. IOD and ENSO play an important role in the interannual variability of the summer rainfall over Myanmar. The covariability between rainfall over Myanmar and Indian Ocean SST generally suggests that a positive IOD mode is associated with suppressed rainfall in the central and northern parts of Myanmar. During a negative IOD mode, nearly the whole Myanmar experiences enhanced rainfall, which is associated with devastating socioeconomic impacts. The covariability between the rainfall over Myanmar and the sea surface temperature in the Pacific Ocean in the first and second SVD modes was dominated by warming in the east and central Pacific—an El Niño-like pattern—resulting in dry conditions in central Myanmar.     

First-order regional seismotectonic model for South Africa

A first-order seismotectonic model was created for South Africa. This was done using four logical steps: geoscientific data collection, characterisation, assimilation and zonation. Through the definition of subunits of concentrations of earthquake foci and large neotectonic and structural domains, seismotectonic structures, systems and domains were created. Relatively larger controls of seismicity exist between the Great Escarpment and the coast. In the south, this region is characterised by large aeromagnetic anomalies and large EW trending faults. In the west, it is characterised by the NW–SE trending Wegener stress anomaly, radial-trending dykes and earthquake clusters. In the east, it is characterised by a large neotectonic domain where several large historical earthquakes occurred. In the centre of South Africa, several clusters of earthquake activity are found, often related to mining activity. Further north, seismicity is related to both mining activity and neotectonic deformation. This work contributes to the development of a seismotectonic model for South Africa by (1) bringing together, digitally, several data sets in a common GIS platform (geology, geophysics, stress, seismicity, neotectonics, topography, crustal and mantle structure and anisotropy), (2) understanding the significance of data sets for seismotectonic zonation and limitations thereof and (3) obtaining a reasonable regional model for use in seismic hazard assessments.     

Optimal seismic retrofit model for steel moment resisting frames with brittle connections

Based on performance-based seismic engineering, this paper proposes an optimal seismic retrofit model for steel moment resisting frames (SMRFs) to generate a retrofit scheme at minimal cost. To satisfy the acceptance criteria for the Basic Safety Objective (BSO) specified in FEMA 356, the minimum number of upgraded connections and their locations in an SMRF with brittle connections are determined by evolutionary computation. The performance of the proposed optimal retrofitting model is evaluated on the basis of the energy dissipation capacities, peak roof drift ratios, and maximum interstory drift ratios of structures before and after retrofitting. In addition, a retrofit efficiency index, which is defined as the ratio of the increment in seismic performance to the required retrofitting cost, is proposed to examine the efficiencies of the retrofit schemes derived from the model. The optimal seismic retrofit model is applied to the SAC benchmark examples for threestory and nine-story SMRFs with brittle connections. Using the retrofit efficiency index proposed in this study, the optimal retrofit schemes obtained from the model are found to be efficient for both examples in terms of energy dissipation capacity, roof drift ratio, and maximum inter-story drift ratio.     

CATASTROPHIC ECO-ENVIRONMENTAL CHANGE IN THE SONGNEN PLAIN, NORTHEASTERN CHINA SINCE 1900S

Although the Songnen Plain in the northeastern China was developed relatively late in the temperate zone of the world, its eco-environment has changed greatly. This paper analyzes the changes of land cover and the rates and trends ofdesertification during the past 100 years in the Songnen Plain. According to the macroscopic analysis, we find that the eco-environment in the plain has reached to the threshold of catastrophic change since the 1950s. The Thorn Needle Catastrophic Model was used to determine and validate this conclusion. Human activities, including large-scale construction projects, such as huge dams and dikes, and excessive grazing were the primary factors contributing to regional eco-environmental catastrophe. And irrational reclamation of the wilderness also affected the eco-environmental change. The results reveal the complex human-land interactions.     

江西银山多金属矿床伊利石的形成与流体成矿作用的初步研究

江西银山多金属矿床的热液蚀变粘土矿物主要由伊利石组成,伊利石主要由流体作用过程中长石的伊利石化形成,其结晶度与成矿流体作用密切相关.银山第1期铅锌银成矿作用,水/岩比相对较低,成矿流体以孔隙渗透为主,溶质迁移慢,形成含有少量膨胀层的伊利石;第2期铜金成矿作用,水/岩比相对较高,流体的运移方式以通道式或裂隙式为主,溶质迁移的速度快,形成不含膨胀层的伊利石.研究表明成矿作用过程中的伊利石化主要与铅锌银矿化有关,而绿泥石化与铜金矿化有关.     

The first field-based descriptions of pumping-induced saltwater intrusion and upconing

Development of the ideas about the equilibrium between freshwater and saline water has received considerable attention in the literature, but little has been written so far about the earliest scientific works about well salinization. Based on a review of the literature from the second half of the 19th century and the early 20th century, this historical note explores how insights into groundwater abstraction and saltwater intrusion developed, and examples of the earliest field studies are provided. Fundamental research was driven by the need for increasing water supply, but the progress of science did not lead to sustainable management practices everywhere. Research outcomes were shared between scientists of different countries, marking the beginning of coastal hydrogeology as a scientific specialization in the first decade of the 20th century.     

Hydraulic and flood-loss modeling of levee,floodplain, and river management strategies,Middle Mississippi River,USA

In this investigation, four scenarios were used to quantify the balance between the benefits of levees for flood protection and their potential to increase flood risk using Hazards U.S. Multi-Hazard flood-loss software and hydraulic modeling of the Middle Mississippi River (MMR). The goals of this study were (1) to quantify the flood exposure under different flood-control configurations and (2) to assess the relative contributions of various engineered structures and flood-loss strategies to potential flood losses. Removing all the flood-control structures along the MMR, without buyouts or other mitigation, reduced the average flood stages between 2.3 m (100-year flood) and 2.5 m (500-year), but increased the potential flood losses by $4.3–6.7 billion. Removing the agricultural levees downstream of St. Louis decreased the flood stages through the metro region by ~1.0 m for the 100- and 500-year events; flood losses, without buyouts or other mitigation, were increased by $4.3–6.7 billion. Removing the agricultural levees downstream of St. Louis decreased the flood stages through the metro region by ~1.0 m for the 100- and 500-year events; flood losses, without buyouts or other mitigation, were increased by 155 million for the 100-year flood, but were decreased by $109 million for the 500-year flood. Thus, agricultural levees along the MMR protect against small- to medium-size floods (up to the ~100-year flood level) but cause more damage than they prevent during large floods such as the 500-year flood. Buyout costs for the all the buildings within the 500-year floodplain downstream of urban flood-control structures near St. Louis are ~40% less than the cost of repairing the buildings damaged by the 500-year flood. This suggests large-scale buyouts could be the most cost-effective option for flood loss mitigation for properties currently protected by agricultural levees.     

用MapInfo软件实现地震震中县乡一级地名的快速检索

在大震地震速报时 ,通常不仅需要迅速确定地震的三要素 ,各级政府和有关部门还需要尽快知道震中的地名 ,以迅速采取相应的措施。另外 ,各省地震局上报中国地震局的快报和月报也要求给出乡 (镇 )一级的地名。目前 ,多数省的地震部门在确定地震震中地名时 ,采用的是根据所定位地震的经纬度在地图上查找地名的方法 ,既繁琐费时 ,又容易出错。本文介绍的是利用目前最流行的地理信息系统 ( GIS)软件 Map Info及开发工具 Map Basic,快速精确的确定出地震震中到县和乡 (镇 )一级地名的方法。1　GIS软件 Map Info及开发工具 Map BasicMap Inf…