塔里木盆地遥感区域地质研究   总被引：5，自引：0，他引：5  

管海晏  王学佑 《遥感学报》1998,2(1):57-62

本文着重阐述将塔里木盆地（地块）划分出“内、中、外三环体（带）”的构造新格局;提出该区存在着巨大的“环式弧形构造系统”及其相应的“环式弧形成矿带”与“环式弧形地质环境带”的新论点与新概念,揭示该区矿产资源的成矿、控矿规律,建立行之有效“多位一体”的遥感地质找矿模式;发现环绕塔里木盆地油气、钾盐、煤、铀、金属、建材及宝玉石等５个环状成矿带和罗布泊特大型钾盐矿产基地;以及塔克拉玛干大沙漠区内４大富水区,并提出塔里木地壳具“稳定之中不稳定,不稳定中有稳定”等新的认识。  相似文献   

Determination of depths to centroids of three-dimensional sources of potential-field anomalies with examples from environmental and geologic applications     

D. Ravat  Patrick T. Taylor   《Journal of Applied Geophysics》1998,39(4):191-208

A method is developed for determining the depth to the centroid (the geometric center) of ‘semi-compact' sources. The method, called the anomaly attenuation rate (AAR) method, involves computing radial averages of AARs with increasing distances from a range of assumed source centers. For well-isolated magnetic anomalies from ‘semi-compact' sources, the theoretical AARs range from 2 (close to the sources) to 3 (in the far-field region); the corresponding theoretical range of AARs for gravity anomalies is 1 to 2. When the estimated source centroid is incorrect, the AARs either exceed or fall short of the theoretical values. The levelling-off of the far-field AARs near their theoretical maximum values indicates the upper (deeper) bound of the centroid location. Similarly, near-field AARs lower than the theoretical minimum indicate the lower (shallower) bound of the centroid location. It is not always possible to determine usable upper and lower bounds of the centroids because the method depends on characteristics of sources/anomalies and the noise level of the data. For the environmental magnetic examples considered in this study, the determined deeper bounds were within 4% of the true centroid-to-observation distance. For the case of the gravity anomaly from the Bloomfield Pluton, Missouri, USA, determination of only the shallower bound of the centroid location (7 km) was possible. This estimate agrees closely with the centroid of a previously determined three-dimensional model of the Bloomfield Pluton. For satellite magnetic anomalies, the method is appropriate only for high-amplitude, near-circular anomalies due to the inherent low signal-to-noise ratio of satellite magnetic anomalies. Model studies indicate that the AAR method is able to place depths within ±20–30 km of actual center locations from a 400-km observation altitude. Thus, the method may be able to discriminate between upper crustal, lower crustal, and mantle magnetic sources. The results from the prominent Kentucky anomaly are relatively well-resolved (centroid depth 30 km below the Earth's surface). For the Kiruna Magsat anomaly, the deleterious effects from neighboring anomalies make a determination difficult (possible depth could be between 20 and 30 km). The centroid depths are deeper for the Kursk anomaly (40–50 km). These depths may indicate that magnetic anomalies from the near-surface Kursk iron formations (a known contributor) and deep crustal magnetic sources could combine to form the Kursk Magsat anomaly.  相似文献   

海陵岛及邻区地质环境与灾害初步探讨   总被引：3，自引：0，他引：3  

詹文欢 《华南地震》1998,18(3):58-63

海陵岛及邻区是华南沿海地质环境与灾害较集中和类型较齐全的地区之一。根据野外调查资料,简要地分析了该区地质环境因素中的活动断裂,地震活动、地震裂纹、第四纪沉积与沙土液化、滑坡与崩塌、海面上升与地面沉降、风沙灾害等,这些因素多分布在洋边海周缘和海陵岛南部海岸。这些地区的构造活动性较强,同时也是多组活动断裂相互交切的地方,另外在基岩海岛的岸边,还见有崩塌, 在工程建设中应加以重视。  相似文献   

江苏省重要气象灾害综合评估方法的研究   总被引：13，自引：6，他引：7  

姜爱军  王冰梅 《气象科学》1998,18(2):196-202

本文首先提出影响江苏省的七种重要气象灾害的定量指标,考虑其共同影响和受灾区域的社会经济状况,建立了气象灾害综合评估模型,可以分季节对重要气象灾害的严重程度及综合经济影响作出客观的评估。  相似文献   

湘西花垣—张家界逆冲断裂带地质特征及其控矿意义   总被引：4，自引：0，他引：4  

杨绍祥 《湖南地质》1998,17(2):96-99,104

湘西花垣－张家界断裂带显逆冲压扭性、与其分枝断裂古丈－张家界断裂带关系密切,平面上在张家界市后坪复合、具有类似的地质特征。形成时代较古丈－张家界断裂带晚,时间上有先后及生成关系,向上呈叠瓦状、深部收敛在一起。具有明显的控矿作用。  相似文献   

浅谈错视及其纠正与地质制图     

黄德纯 《湖南地质》1998,17(3):197-200

本文侧重论述了错视,错视的表现及其利用与纠正,同时举例论述了正确运用错视对提高地质制图质量的重要性。  相似文献   

云南红土型金矿床地质特征及成矿条件研究   总被引：12，自引：0，他引：12  

李志群 《矿产与地质》1998,12(3):160-166

红土型金矿是云南找金工作的主攻类型之一。云南新构造期运动是红土型金矿的主成矿期,地壳的快速抬升,古气候与古地貌的变化,表现出红土型风化壳剖面发育不全,成熟度低,厚度不大,对基岩含金性依存度高等特点。云南红土型金矿成矿作用为红土化作用的初、中期阶段,其金矿类型有岩控型、层控型和构控型三种。  相似文献   

Social differentiation and the long-term origin of disasters     

Lars Clausen 《Natural Hazards》1992,6(2):181-190

To explain both origin and outcome of disasters (natural, technical, and war-borne), as well as social action during disasters proper, a macrosociological model of internal causation is introduced (PERDUE). It consists of six stages of possible, and of most likely paths of social change between these six (Peace is founded, Everyday routine, Rising class struggle, Disasters strike, Unconditional surrender of collective defence, and Evaporation of common values). The stages are developed by making use of three dimensions of social change (rapidity, radicality, and rituality), and described.  相似文献   

Experiences of vulnerable households in low-attention disasters: Marshalltown,Iowa (United States) after the EF3 Tornado     

《Global Environmental Change》2022

Tornados are among natural hazards that many towns in the Midwest region of the United States (US) experience frequently, sometimes with relatively overwhelming impacts and little attention and resources from media or government entities. Low-attention disasters that affect vulnerable populations create unique recovery challenges that are rarely addressed in the disaster literature. This paper presents a qualitative case study of impacts and recovery of housing in Marshalltown, Iowa, US after an EF3 Tornado in 2018 which affected a large portion of the town, in particular neighborhoods with high concentration of immigrant, low-income households in old and poorly maintained housing. Our analyses highlight the long-term challenges created by delayed and unsuccessful recovery of housing as a result of the intersection of pre-disaster social and physical vulnerability and inadequate housing recovery policy.  相似文献   

Flirting with Disaster: Impacts of natural disasters on public support for environmental spending     

《Global Environmental Change》2022

Policymakers must understand public opinion to craft effective policies, particularly in highly polarized areas such as environmental policy. However, the literature investigating the factors that drive public opinion on environmental spending largely ignores the role of exogenous events. This article investigates the role that natural disasters, as a form of exogenous shock, play in shaping public opinion. We construct a dataset using the General Social Survey (GSS) and National Oceanic and Atmospheric Administration’s (NOAA) natural disaster data from 1980 to 2018 and use generalized ordered logistic models to analyze the relationship between disasters and environmental opinions in the US. Our findings reveal that the number of disasters that occur significantly drives public support for environmental spending and that different types of disaster have heterogeneous impacts with wildfires and severe winter weather events being the most impactful. These results shed light on the impact of environmental events on public opinion on the environment, helping both researchers and policymakers make sense of dynamic public opinions.  相似文献