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全球对比同类大地构造单元的壳幔结构,根据壳幔结构的差异和大地构造作用发生的时代把它们按演化阶段排序,可以找寻这类大地构造单元岩石圈演化的规律性。笔者在文中根据全球地学界实施的COCORP、BIRPS、DEKORP、LITHOPROBE、ICDP、ECORS和SINOPROBE等计划取得的成果,扩充了板块构造学中的威尔逊循回,即把原先主要描述大洋板块起源、发展和封闭的威尔逊循回,扩展到同时包括大陆和大洋板块演化的大循回中去。文中概述了扩充的威尔逊循回的内容,除经典的威尔逊循回的组元之外,扩充的组元包括洋陆转换、大陆汇聚拼合和大陆裂解等,为大陆岩石圈生成和演化作用提供了细节。根据扩充的威尔逊循回的大陆岩石圈演化规律,可以对中国地质学家已经发展的大陆构造演化的序列进行进一步的阐释,使构造演化的序列的属性和轨迹更加准确清晰。从寒武纪古亚洲洋扩张和冈瓦纳大陆裂解,到新生代印度次大陆与亚欧大陆碰撞拼合,中国大陆的大地构造事件序列说明扩充的威尔逊循回的是大陆岩石圈演化轨迹的大概率规律。 相似文献
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水箱模型在北方寒冷湿润半湿润地区的应用探讨 总被引：6，自引：0，他引：6
依据北方寒冷地区水文特性，将水箱模型功能进行了扩充，通过在几个流域验证显示这种扩充是有效的，能够用于北方湿润半湿润地区的多年连续径流模拟，也为春汛的径流预报提供了一条途径。 相似文献
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介绍了用PC—1500计算机与内扩充模块及磁带录音机相配合,建立小型多样钻孔资料数据库的作法,并举例说明。 相似文献
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近年来国内在水系沉积物区域化探资料解释中出现了一些不可忽视的趋向。这些包括对旧参数术语的涵义的扩充和新参数术语的使用。下面几个是这些新旧参数术语的典型代表。 相似文献
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随着城市建设的发展,土地资源日益稀缺,对城市地下空间的使用也变得日益频繁。地下空间开发利用是提高城市土地利用效率、缓解城市中心密度、人车立体分流、扩充基础设施容量、减少环境污染、改善城市生态最为有效的途径。 相似文献
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介绍一种为Ｃ语言扩充矩阵运算功能的方法,其特点是利用编码与解码传递矩阵运算所必须的参数,以简化应用程序的编写。 相似文献
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脆云母热水综合试验的初步结果 总被引：1，自引：0，他引：1
长久以来地质学家对定向压力(stress)在矿物形成过程中的作用有着不同的看法。如哈克尔把云母、绿泥石和脆云母都算作所谓定向压力矿物(stress mineral),即它们的稳定范围(主要对压力和温度而言)因有了定向压力的参加而得以扩充。拉尔 相似文献
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The Azores Islands are located in the mid-Atlantic region near the triple junction where the Euro-Asiatic-African-American plates join together. Seismic activity in the area is very high, as can be observed either from historical events since the fifteenth century, from present day microseismicity, and from direct and indirect measurements of recent tectonic deformation. Volcanic activity is also present throughout the region. All available information, even data exhibiting low quality, was used to develop hazard models of São Miguel Island. Source zones were established based on both the global tectonic behaviour of the region and on the local active fault structures. Recurrence laws for São Miguel Island, for which historical information seemed quite incomplete, were obtained from the large events in the entire archipelago and from their remarkable pattern of time and space dependence, and complimented by information on long-term fault deformation (for the longer recurrence periods) and on high precision instrumental network (for the very short recurrence periods). Attenuation laws were derived from data on events felt and/or recorded in the Island. Hazard maps were obtained through a modified version of McGuire's algorithm for several geometries of source areas and results compared with the maximum observed intensity of historical events. 相似文献
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The Azores Islands are located in the mid-Atlantic region near the triple junction where the Euro-Asiatic-African-American plates join together. Seismic activity in the area is very high, as can be observed either from historical events since the fifteenth century, from present day microseismicity, and from direct and indirect measurements of recent tectonic deformation. Volcanic activity is also present throughout the region.All available information, even data exhibiting low quality, was used to develop hazard models of São Miguel Island. Source zones were established based on both the global tectonic behaviour of the region and on the local active fault structures. Recurrence laws for São Miguel Island, for which historical information seemed quite incomplete, were obtained from the large events in the entire archipelago and from their remarkable pattern of time and space dependence, and complimented by information on long-term fault deformation (for the longer recurrence periods) and on high precision instrumental network (for the very short recurrence periods).Attenuation laws were derived from data on events felt and/or recorded in the Island.Hazard maps were obtained through a modified version of McGuire's algorithm for several geometries of source areas and results compared with the maximum observed intensity of historical events.Abstract presented at the 21st General Assembly of the European Seismological Commission held in Sofia, 1988. 相似文献
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This paper presents a Straightforward Inversion Scheme (SIS) for interpreting one-dimensional magnetotelluric sounding data.
The basic steps of SIS are (i) parameterization of the layered model such that the layer thickness, expressed in units of
its skin depth, is a constant (α); (ii) expansion of the reflection function at each interface as a power series in parameter
u = exp(-2(1 +j)α√f);(iii) development of a recurrence relation between the coefficients of the same powers ofu in the power series of reflection functions of any two successive layers; (iv) estimation of the impedance power series coefficients
using regressed minimum norm estimator; and (v) evaluation of layer resistivities and thicknesses using the inverse recurrence
relation. The power of SIS is established by inverting four synthetic data sets and two field data sets. The effect of noise
is extensively studied on a synthetic data set, deliberately corrupted with increasing levels of Gaussian random noise up
to 25%. It is found that the scheme can retrieve broad features of the true model even with noise levels as high as 25%. On
the basis of findings of different experiments conducted on SIS, it is concluded that SIS is an efficient, robust algorithm
with high resolving power. Further, being linear, it is non-iterative and it dispenses with the requirement of having to choose
an initial guess model. 相似文献
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伽马测井曲线包含了储层的粒度信息,采用二进制小波变换对伽马测井曲线处理可以提取粒度参数。通过分析不同粒度区间单位体积含量(以Udden-Wentworth方案为标准)与伽马测井曲线变换后信号的幅度、频率之间关系,考虑测井仪器探头测量速率造成的采样间隔的影响,建立求解不同粒度区间体积含量的递归方程组。将获得不同粒度区间的绝对体积转化为相对体积含量,按照Trask或Folk-Ward公式,计算粒度中值、平均粒度、分选系数、偏度、峰度。选择塔里木盆地大北地区DB101等4口井51个取样点进行方法适用性和可靠性验证,此方法的计算结果与筛选法相比,各项参数误差均在允许接受范围内。与国内外同类方法相比,此方法在信息来源、耗时、成本方面的要求均有所降低。 相似文献
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Jesse L. Morris Andrea Brunelle R. Justin DeRose Heikki Seppä Mitchell J. Power Vachel Carter Ryan Bares 《Quaternary Research》2013,79(1):24-36
Paleoenvironmental reconstructions are important for understanding the influence of long-term climate variability on ecosystems and landscape disturbance dynamics. In this paper we explore the linkages among past climate, vegetation, and fire regimes using a high-resolution pollen and charcoal reconstruction from Morris Pond located on the Markagunt Plateau in southwestern Utah, USA. A regime shift detection algorithm was applied to background charcoal accumulation to define where statistically significant shifts in fire regimes occurred. The early Holocene was characterized by greater amounts of summer precipitation and less winter precipitation than modern. Ample forest fuel and warm summer temperatures allowed for large fires to occur. The middle Holocene was a transitional period between vegetation conditions and fire disturbance. The late Holocene climate is characterized as cool and wet reflecting an increase in snow cover, which reduced opportunities for fire despite increased availability of fuels. Similarities between modern forest fuel availability and those of the early Holocene suggest that warmer summers projected for the 21st century may yield substantial increases in the recurrence and ecological impacts of fire when compared to the fire regime of the last millennium. 相似文献
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Lalliana Mualchin 《Engineering Geology》1996,42(4):217-222
Caltrans has developed a deterministic fault and earthquake hazard map for California for use in engineering. The deterministic method avoids the problem of long recurrence in the probabilistic approach. Relating earthquake recurrence or probability to the design/economic/useful lifetime of a structure is not always a sound approach for safety considerations because earthquake cycles are largely unknown and lifetimes are conceptual and not fixed. Experience in California shows that the recurrence and temporal sequence of earthquakes are not related. The deterministic approach avoids these problems. 相似文献
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《Quaternary International》2006,142(1):110-121
The frequency of debris flows and rockfalls was estimated by temporal distribution of these events during the last 50 years. This parameter was expressed by annual probability of occurrence and mean interval of recurrence of historical events. More recurrent events in this sector of the Central Andes are associated with the Guido locality and tunnels situated along International road No. 7. Furthermore, these events are more frequent in Cordillera Frontal where the mean recurrence interval was lower than in Precordillera. The maximum interval of recurrence is rarely greater than 20 years, showing the activity of these events on human lives and infrastructure in this region. The accuracy of the determined recurrence frequency is discussed. A future scenario indicates that landslides will be probably more frequent under global climate change. As a consequence, those most vulnerable elements in the region, the international access routes, may be severely damaged in the future, implying an adverse impact in our regional economy. 相似文献
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在实际沉降监测中,由于不确定性因素的影响,导致基于实测沉降数据的工后沉降预测误差较大。采用递归图和递归定量分析方法对沉降时间序列的可预测性进行分析,选择出预测效果好的沉降时间序列,进行准确的工后沉降预测。通过对无砟轨道整体道床的沉降时间序列进行可预测性分析得出:（1）沉降时间序列具有混沌特性;（2）沉降时间序列的递归图颜色分布越规律、色彩深浅变化越均匀,沿着主对角线出现的白色区域越小,沉降时间序列的可预测性越强;（3）通过提取递归定量指标随时间变化的曲线,可以直接确定预测时间起点;（4）利用递归图求取二阶任意熵作为沉降时间序列的可预测步长因子,可推算出预测效果最佳的沉降时间序列。 相似文献