R/S分析及其在地震磁效应研究中的应用

将重标极差法（R／S，Rescaled range analysis）这一时间序列分析方法引入到地震地磁前兆观测资料的处理和分析当中，并应用该方法对陕西关中地区3个地磁台站在1996～1998年间Z分量观测数据进行处理。分析了地磁Z分量赫斯特指数变化与1998年1月5日泾阳肘。4．8地震的关系，发现地震前2～4个月地磁Z分量出现明显小于0．5的异常变化，背离了地磁场正常的长程相关趋势性增强的变化规律，预示了此次地震的发生。这些结果表明该方法能够挖掘出丰富的地磁前兆信息，在地震前兆观测资料的非线性处理中具有良好的应用前景。     

基于R/S分析黄河及黄土高原主要河流水资源的变化

河流水资源观测资料反映河流随时间变化,它表现为一时间系列。作为非线性分析的工具,R/S可以有效地分析这些资料的时间系列。将R/S 这一时间序列分析方法引入到水资源观测资料的处理和分析中,并应用该方法对黄河及黄土高原地区主要河流在1956—2004年间水资源观测数据进行处理,预测了今后黄土高原地区水资源的变化情况。分析结果表明,黄河及黄土高原地区主要河流径流量赫斯特指数在0.2771～0.3305之间,均小于0.5,背离了正常的长程相关趋势性增强的变化规律,预测了径流量逐步增大的趋势。     

1960-2009年汉中市气候变化特征及未来趋势

运用一元回归分析、Mann-Kendall和R/S方法,对1960-2009年汉中市气温、降水量和日照时数变化特征及未来趋势进行分析。结果表明：近50 a来,汉中市年平均气温以0.14℃/10 a的速率升高,并在1997年发生增温突变,其Hurst值为0.94,表明未来气温的变化与过去50 a有较强的持续性,仍将呈现上...     

Hydrological effects of within-catchment heterogeneity of drainage density

Local drainage density (dd) has been traditionally defined as the inverse of twice the distance one has to walk before encountering a channel. This formalization easily allows to derive raster-based maps of dd extracted straight off from digital elevation model data. Maps of local dd, which are continuous in space, are able to reveal the appearance of strong heterogeneities in the geological and geomorphological properties of natural landscapes across different scales. In this work we employ the information provided by these spatial maps to study the potential effects of the within-catchment variability of dd on the hydrologic response. A simple power law relationship between runoff yield at the local scale and the value of dd has been adopted; the hypothesis is supported by a large number of past empirical observations and modeling. The novel framework proposed (ddRWF) embeds this spatially variable runoff weight in the well-known Rescaled Width Function (RWF) framework, based on the more general geomorphological theory of the hydrologic response. The model is applied to four sub-basins in the Cascade Range Region (Oregon, USA) where strong contrasts in dissection patterns due the underlain geology have been broadly addressed in previous literature. The ddRWF approach is compared with the classic RWF in terms of shape, moments and peak of the simulated hydrograph response. Results hint that the variability of runoff yield due to the heterogeneity of dd (i.e. of hillslope lengths) determines a more rapid concentration of runoff, which implies shorter lag times, larger skewness and higher peak floods, especially in the case hillslope velocity is much smaller than channel velocity. The potential of the proposed framework relies on accounting for spatially variable losses related to geomorphologic heterogeneity in lumped rainfall–runoff models, still keeping the simple and robust structure of the IUH approach.     

Time varying seismicity in Greece: Hurst's analysis and Monte Carlo simulation applied to a new earthquake catalogue for Greece

Hurst's rescaled range analysis is a useful tool in the examination of a time series and is designed to measure memory content and determine its fractal texture. This study applies the Hurst method to a new earthquake catalogue for Greece. The study also adopts Monte Carlo simulations to provide a statistical test underpinning the Hurst analyses. Together these reveal basic temporal fractal characteristics in the earthquake occurrence time-histories' memory. Three regions are considered, approximately: all of Greece and some surrounding areas, and the sub-zones of the Hellenic Arc and the Gulf of Corinth. Three temporal textures are considered: elapsed time between earthquakes, strain energy release, and earthquake frequency. The elapsed temporal textures for the zone whole Greece indicate distinct characteristics in chronological order and possess long memory. These belong to the class non-random pattern. However, these characteristics generally disappear when the sub-zones are considered and become random patterns. The Monte Carlo simulations support this. Therefore, memoryless statistical seismic hazard estimates may not be suitable for whole Greece but could be useful for the sub-zones. The strain energy release temporal textures for whole Greece and for the sub-zones, no matter that these seem to possess long memory at first analysis, are all random patterns. In other words, the Monte Carlo simulations demonstrate that these patterns are much more likely to happen by chance. The seismic frequency textures for whole Greece and for the sub-zones suggest long memory, however, only the texture for the Hellenic Arc zone (M_S ≥ 5.0) and that for whole Greece (M_S ≥ 4.0) approach demonstrable non-random patterns. Except for these, other patterns happen by chance.     

Spatial distribution of inter-layer shear zones at Gaobazhou dam site, Qingjiang River, China

The spatial distribution of inter-layer shear zones is studied, based on the fully mapped inter-layer shear zones at the Gaobazhou dam site on the Qingjiang River in Hubei province, China. The field observations revealed that two types of inter-layer shear zone, under-developed and well-developed, are distributed differently. The former are associated with the incompetent rock layers, and the latter are controlled by the inter-bed folds and lithological properties of the strata. To represent their lithological properties geomechanically, data on strength by the Schmidt hammer test and thickness of each field-identified rock layer were collected to form strength sequences and thickness sequences. The adjacent rock layers of similar strength are then grouped, and two grouped sequences are combined into a single sequence, whose individual term is the strength weighted by the exponential function value of the centralized thickness (SCT). The rescaled range (R/S) analysis results of SCT (SCT-R/S), taking into account the presence of inter-bed folds, are in good agreement with R/S analysis results of the spacing sequence of the well-developed inter-layer shear zones. Thus the SCT-R/S model has the potential to predict their spatial distributions.     

R／S分析及矿井瓦斯涌出量的分形预测

介绍了分形理论中的时间序列（R／S）分析方法，讨论了赫斯特指数的理论意义和实际计算方法，并将其应用于矿井瓦斯涌出量预测。通过对矿井瓦斯涌出量时间序列的分形处理，根据极差、标准差的结构分维值的大小，对矿井瓦斯涌出量的增量趋势做了分形预测。     

地震活动性参数的变尺度（Rem>/Sem>）分析

将改变时间标度的方法应用于地震活动性分析中，选择具有不同空间尺度范围、时间范围和地震活动背景的现代仪器地震目录作为研究对象，分析了几个地震活动性参数——地震频度和地震发生时间间隔与时间标度的关系．这些地震活动性参数的极差和均方差之比与时间标度呈现出幂指数变化方式，且幂指数都大于0.5，表明地震的发生并非无记忆的泊松过程，而是具有随机和规律的双重特性．犎指数偏离0.5的程度可以衡量随机与规律成分所占比重，偏离越大，该序列的规律性成分越多，反之则越少．通过时间标度变换，可以较短时间的观测为基础，对变量未来的发生情况做出保守的估计．      

1960—2009年汉中市气候变化特征及未来趋势

运用一元回归分析、Mann-Kendall和R/S方法,对1960—2009年汉中市气温、降水量和日照时数变化特征及未来趋势进行分析。结果表明：近50 a来,汉中市年平均气温以0.14℃/10 a的速率升高,并在1997年发生增温突变,其Hurst值为0.94,表明未来气温的变化与过去50 a有较强的持续性,仍将呈现上升趋势。汉中市年降水量以-28.45 mm/10 a的速率显著减少,呈波动变化,突变不显著,其Hurst值为0.75,说明汉中市降水量减少的趋势还将继续;日照时数在过去50 a呈减少趋势,减少率为-56.42 h/10 a,并在1979—1980年发生突变,其Hurst值为0.91,说明汉中市未来日照时数变化趋势与过去一致,仍将持续减少。