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近几年来,在辽南地区开展深部地球物理探测的基础上,通过对深地震测深、大地电磁测深、重力、航磁、大地热流等综合地球物理资料对辽南地区地壳与上地幔介质进行不同物性的正、反演计算与研究,获得了辽南地区地壳与上地幔介质的速度结构、电性结构、密度结构和温度结构,揭示了该区介质的横向不均匀性及其重要特征.发现在海城地震区一带,存在壳内低速、高导、低密度、高热流等一系列重大地球物理异常,在空间上与震源区存在相当好的一致关系,对分析大震的震源物理过程提供了重要实际依据. 相似文献
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中国辽南地区地壳与上地幔介质的横向不均匀性与海城7.3级地震 总被引：7，自引：1，他引：7
近几年来,在辽南地区开展深部地球物理探测的基础上,通过对深地震测深、大地电磁测深、重力、航磁、大地热流等综合地球物理资料对辽南地区地壳与上地幔介质进行不同物性的正、反演计算与研究,获得了辽南地区地壳与上地幔介质的速度结构、电性结构、密度结构和温度结构,揭示了该区介质的横向不均匀性及其重要特征.发现在海城地震区一带,存在壳内低速、高导、低密度、高热流等一系列重大地球物理异常,在空间上与震源区存在相当好的一致关系,对分析大震的震源物理过程提供了重要实际依据. 相似文献
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为了取得邢台地震区地壳细结构,对该区进行了综合地球物理方法探测,其中电磁阵列剖面法（EMAP）测量在我国尚属首次．EMAP剖面穿过邢台7．2级地震区,经过EMAP阻抗求取、空间滤波处理和二维反演解释,剖面显示出清晰的地壳电性细结构特征：4km以上电性简单,4-20km深度电性复杂;震源区电性复杂,非源区简单;发震深度变化复杂;震源区电性突变,显示隐伏高角度断裂,高寻层不连续部位为发震部位．其观测结果对于了解该区的构造背景、发震构造和深部构造的关系有重要意义． 相似文献
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为了取得邢台地震区地壳细结构,对该区进行了综合地球物理方法探测,其中电磁阵列剖面法（EMAP）测量在我国尚属首次．EMAP剖面穿过邢台7．2级地震区,经过EMAP阻抗求取、空间滤波处理和二维反演解释,剖面显示出清晰的地壳电性细结构特征：4km以上电性简单,4—20km深度电性复杂;震源区电性复杂,非源区简单;发震深度变化复杂;震源区电性突变,显示隐伏高角度断裂,高寻层不连续部位为发震部位．其观测结果对于了解该区的构造背景、发震构造和深部构造的关系有重要意义． 相似文献
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本文从4个方面综述了长乐-诏安断裂带深部地质-地球物理探测研究的概况和新进展:岩浆岩活动与分布特征;地壳上地幔速度结构、Q 值结构和电性结构;地球物理场分布特征;矿产资源远景预测、开发和利用。根据在该带发现文象、晶洞花岗岩,地壳中存在低速-低 Q-高导层,低速层隆起区与莫霍面隆起区、居里面隆起区基本吻合,地球物理场显著变异,大地热流值明显偏高,存在深断裂等地壳深部构造背景等,笔者等认为地壳内可能存在着半熔融态的高温透镜体软物质,预测在长乐-诏安断裂带能够找到高温热水田。 相似文献
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本文扼要地阐述了在东北南部地区开展综合地球物理探测与研究的内容与思路:介绍了综合地球物理方法在确定潜在震源区过程中的作用及其效果;提出了6级以上潜在震源区的地球物理场及深部构造标志。 相似文献
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繁峙—太仆寺旗剖面S波资料解释及深部构造特征与地震相关性分析 总被引：10，自引：0，他引：10
通过对繁峙－怀安－太仆寺旗三分向深地震测深宽角反射／折射剖面的Ｓ波资料进行处理、结合Ｐ波处理结果，给出了地壳上地幔的Ｓ波速度ＶＳ及介质物性参数泊松比σ的二维结构；综合地质及其它的地球物理资料，参照国内外岩石物理参数的实验结果，对地壳深部结构，构造及岩性进行了解释和推测。 相似文献
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为查明滇西三江构造带及邻区复杂的构造特征,并揭示该区深部电性结构,沿福贡—巧家布设了一条长约410 km的大地电磁剖面.共观测到61个物理点,其中宽频大地电磁测点41个,长周期大地电磁测点20个.通过对采集到的数据进行一系列的处理、反演,得到了沿剖面的壳幔电性结构模型.并结合研究区内区域地质资料及其他地球物理资料,对剖面所经过的各个主要地质构造单元及主要断裂带进行了综合解释.电性结构模型揭示沿剖面地壳电性层次复杂,深部电性结构由西往东呈分块展布,横向变化大,壳内广泛发育低阻异常.在中甸构造带(香格里拉地块)和盐源—永胜构造带深部壳幔存在大规模低阻异常,这可能与地下局部熔融体和地热流有关;康滇构造带壳幔存在大规模高阻异常,表明地壳中曾经有地幔物质侵入;在大凉山构造带地下10~50 km深处存在一呈横向“半月形”展布的低阻体,电阻率值不满10Ωm,结合地质资料与前人的研究成果,推测该低阻体成因应与青藏高原东南缘“地壳管道流”有一定关联. 相似文献
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佳木斯地块及东缘是中国东北地区的重要地质构造单元. 为探测该地区地壳深部结构与构造关系，沿桦南—饶河实施了240 km的大地电磁测深的探测研究. 采用光滑模型二维反演方法对桦南—饶河大地电磁剖面的探测数据进行了二维反演和综合地球物理解释. 研究结果揭示了研究区断面域的电性结构：(1)剖面西段具有稳定的高阻特征且具有稳定的岩石圈厚度（约90km），在十几公里深度范围存在壳内高导层，该区段对应佳木斯地块. (2)剖面中部具有明显的电性梯度带，该梯度带反映了佳木斯地块的东界位置及其深部的结构形态. (3)剖面东段电性特征揭示了佳木斯地块以东区段浅部为逆冲推覆体，深部为多个高阻块体和低阻条带相间的电性结构，这些高阻块体可能为早期俯冲的岩石圈残片. 相似文献
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Gtz Schroth Luciana Ferreira Da Silva Marc‐Andree Wolf Wenceslau Geraldes Teixeira Wolfgang Zech 《水文研究》1999,13(10):1423-1436
The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi‐strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open‐area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for palmito, respectively, 0·5% in the cupuaçu monoculture and 3·1% in the fallow. With more than 20% of the open‐area rainfall, the highest stemflow contributions to the water input into the soil were measured in the palm monocultures and in the fallow. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
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M. A. Kahn 《洁净——土壤、空气、水》2000,28(2):95-101
Red tide, a recurrent phenomenon has become conspicuous in several Kashmir lake ecosystems since 1991. The responsible organism (Euglena pedunculata), a rare flagellate rediscovered in the Kashmir Himalaya (Khan 1993) caused first and unprecedented red tide outbreak, constituting a maximum of 96% of resident numerical phytoplankton density in Dal Lake. At present, conflicting hypotheses exist on the generation of causal assemblage(s) imparting redness to waters: Jeeji Bai (1991) linked its origin to acid precipitation – a fallout of burning oil‐fields during the Gulf War – whilst Khan (1993) holds local factor(s) responsible. Field/experimental studies support the latter contention that the influx of untreated sewage, in unison with warm temperatures, high levels of PhAR, iron and interruption to hydrological flow‐pattern together with absence/or reduction in grazing activity created conducive environmental milieu for red tide outbreak. Dal Lake “red tide” drifted the bloom‐inoculum to other waters, including Lake Wular, where additional ecological niches were carved out, threatening the aesthetic value and biological diversity of Kashmir lakes. Ecological monitoring indicates frequent seasonal red tide occurrence in Dal Lake (including summer‐autumn event of 1998) which testifies its unabated eutrophication status. Further studies are needed on ecological adaptability and biogeographic distribution of this rare and unique red tide‐causing flagellate. 相似文献