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一些研究表明中强以上地震的发生可能与水平引潮力极值状态有关。如1966年邢台、1967年河间和1976年唐山等几次强地震的发震时间都在朔、望的半日潮水平引潮力极大值时刻附近。而当处于朔、望大潮时,半日潮水平引潮力的极大值时刻即总的水平引潮力极大值时刻。有学者对上世纪全球的7级强震统计也表明许多大震都发生在日、月对震中区水平引潮力的极值附近。 相似文献
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初步分析了2004年印尼苏门答腊岛西海岸Mw9.0大地震的地质构造环境,回顾性研究了震前NCEP增温异常和天体引潮力附加构造应力变化。结果表明:主震临震期间NCEP全球分析温度资料(1 000 hPa)沿岛弧地震构造带具有明显增温异常和清晰的初始增温→加强→高峰→衰减→发震的时空演变规律;地震序列活动与增温异常起伏变化对应良好;主震和强余震皆发生在发震断裂带上的天体引潮力附加应力绝对值最大时段。此典型大震再次说明:NCEP温度资料与天体引潮力结合是地震短临预测的一个有希望的新思路。 相似文献
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基于地震对应概率谱的多参数综合异常空间特征研究 总被引：2，自引：0，他引：2
本文应用基于地震对应概率谱的多参数滑动极值概率方法对新疆南天山西段多种地震学参数资料进行定量化的异常识别提取, 通过对该区中强地震前多参数滑动极值概率的空间演化过程进行全时空扫描, 定量识别了该区中强地震的前兆综合异常时空异常特征。 研究结果表明, 南天山西段1980年以来发生的10次(组)中强地震前1～2年, 震区附近区域多参数滑动极值概率均出现了高值异常变化过程, 震后1年左右高值异常区逐步分散、 缩小乃至消失, 而中强地震平静时段滑动极值概率普遍无高值异常区域出现。 相似文献
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天体的引潮力能否触发地震的问题早已引起人们的关注,许多学者作了大量的研究和分析,得到一些有说服力的统计结果.但这些都是从单一角度进行地震发震研究,任振球等将天体应力与地应力结合研究地震预报.地震发震前后卫星热红外图像异常增温已经得到广泛的认可,如何将红外异常增温为主导与天体引力为诱导的方法相结合,对地震时空强三要素预报,是一个有价值的研究课题. 相似文献
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利用美国国家环境预测中心NCEP全球再分析资料的温度图像结合天体引潮力附加构造应力,对2003年5月以来的国内MS≥6.0、国外MS≥7.0的地震作了统计分析。以2004年7月12日—2004年8月25日间西藏地区3次地震为例得出如下认识:NCEP温度异常图像可以较好地反映短临地震构造活动时空演变过程;天体引潮力附加构造应力对地应力处于临界状态的活动断层具有明显的诱发作用;利用NCEP温度异常图像与天体引潮力附加构造应力结合进行地震短临预测是具有良好应用前景的新思路;西藏的3次地震均发生在天体引潮力附加构造应力周期相同的相位上,即天体引潮力附加构造应力变化达到相对稳定的峰值的末端,而不是发生在天体引潮力附加构造应力最大时刻,同时2003—2004年在西藏发生的其它震例中,地震发生在上述周期相同的相位,因此认为应当对其它区域更长时间更多的震例作这方面的进一步研究 相似文献
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应用基于地震对应相关谱的多参数滑动极值相关度方法对山西地震带及邻区进行时间和空间扫描计算,定量识别和提取该区中强地震前的综合异常时空特征。时间扫描结果显示绝大多数目标地震前均有高值异常出现;空间扫描结果表明中强地震前1年左右震区及其附近区域多参数滑动极值平均概率出现高值异常现象,且异常区域逐渐扩大增强,地震多发生在异常区域内或者附近。中强地震发生后高值异常区逐渐缩小,震后1~2年异常区域基本消失;若高值异常区仍持续发展,可能是后续中强地震的异常反映。 相似文献
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为探寻太阳系天体位置的变化对大地震发生的影响,作者分析了1900-1996年发生在中国7级以上大地震的天体位置特征和引潮力．分析结果表明,太阳系天体的特殊位置的确对地震的爆发起到了一定作用,太阳系10个天体中,又以月亮影响最大,本世纪71％的大地震发生于赤白交角从极大变为极小时期,对引潮力的分析表明,其水平分力更易触发大震,这与大震时10个天体天顶距集中分布于40°─140°之间是一致的,文中对此作了初步讨论,认为天体引潮加速度触发地震不在于某一量值,而在于其变化量的大小． 相似文献
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日月引潮力触发地震的一个证据——论邢台、河间和唐山地震的时间特性 总被引：8，自引：0，他引：8
研究表明,中国河北省是引潮力与强震相关区: 1966年邢台地震、1967年河间地震和1976年唐山地震即均为引潮力触发的地震．本研究对这些地震发震时刻共同特性的研究也证明了这一点．通过对日月半日潮水平引潮力极值时刻的计算发现,上述地震时刻与朔望大潮半日潮水平引潮力极大值时刻极为接近,隆尧6.8级、宁晋7.2级、河间6.3级地震滞后日月半日潮水平引潮力极大值时刻均仅几十分钟,而唐山7.8级大地震仅超前16 min(力的方向均为向西,与太平洋板块对华北块体挤压力方向一致),这就是它们的时间特性．这种地震的时间特性体现了这些地震的发生不是随机的,而是受日月引潮力控制、受引潮力所激发的．这是符合引潮力触发机制的,因而是引潮力触发地震的一个证据． 相似文献
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本文讨论了在构造应力水平达到岩石破裂临界值时引潮力、潮汐附加应力的动态变化与地震序列之间的关系，选用了中国大陆1970年以来7级以上地震序列资料，分析了引潮力水平分量动态变化与强震发震时间之间的关系，结果显示在一定时空范围内前震、主震及余震序列发震时刻的引潮力存在优势方向，多数地震发震时刻与选取时段引潮力水平分量的方位角相位比平均值仅为35%；对于构造复杂地区，结果显示引潮力水平分量的方位角不仅存在一个优势方向，还明显存在其他优势方向，可能与发震构造有关.根据1966～1976年中国九大地震震源机制解计算潮汐正应力和滑动方向的剪应力及其变化率，结果显示多数地震发震时刻潮汐剪应力接近最大值. 相似文献
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A Bayesian hierarchical spatio-temporal model for extreme rainfall in Extremadura (Spain) 总被引：1，自引：1，他引：0
A statistical study was made of the temporal trend in extreme rainfall in the region of Extremadura (Spain) during the period 1961–2009. A hierarchical spatio-temporal Bayesian model with a GEV parameterization of the extreme data was employed. The Bayesian model was implemented in a Markov chain Monte Carlo framework that allows the posterior distribution of the parameters that intervene in the model to be estimated. The results show a decrease of extreme rainfall in winter and spring and a slight increase in autumn. The uncertainty in the trend parameters obtained with the hierarchical approach is much smaller than the uncertainties obtained from the GEV model applied locally. Also found was a negative relationship between the NAO index and the extreme rainfall in Extremadura during winter. An increase was observed in the intensity of the NAO index in winter and spring, and a slight decrease in autumn. 相似文献
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Francisco Javier Acero Sylvie Parey Thi Thu Huong Hoang Didier Dacunha-Castelle José Agustín García María Cruz Gallego 《水文科学杂志》2017,62(9):1394-1411
Based on a previous study for temperature, a new method for the calculation of non-stationary return levels for extreme rainfall is described and applied to Extremadura, a region of southwestern Spain, using the peaks-over-threshold approach. Both all-days and rainy-days-only datasets were considered and the 20-year return levels expected in 2020 were estimated taking different trends into account: first, for all days, considering a time-dependent threshold and the trend in the scale parameter of the generalized Pareto distribution; and second, for rainy days only, considering how the mean, variance, and number of rainy days evolve. Generally, the changes in mean, variance and number of rainy days can explain the observed trends in extremes, and their extrapolation gives more robust estimations. The results point to a decrease of future return levels in 2020 for spring and winter, but an increase for autumn. 相似文献
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Larissa A. Naylor Tom Spencer Stuart N. Lane Stephen E. Darby Francis J. Magilligan Mark G. Macklin Iris Möller 《地球表面变化过程与地形》2017,42(1):166-190
The increasing frequency and/or severity of extreme climate events are becoming increasingly apparent over multi‐decadal timescales at the global scale, albeit with relatively low scientific confidence. At the regional scale, scientific confidence in the future trends of extreme event likelihood is stronger, although the trends are spatially variable. Confidence in these extreme climate risks is muddied by the confounding effects of internal landscape system dynamics and external forcing factors such as changes in land use and river and coastal engineering. Geomorphology is a critical discipline in disentangling climate change impacts from other controlling factors, thereby contributing to debates over societal adaptation to extreme events. We review four main geomorphic contributions to flood and storm science. First, we show how palaeogeomorphological and current process studies can extend the historical flood record while also unraveling the complex interactions between internal geomorphic dynamics, human impacts and changes in climate regimes. A key outcome will be improved quantification of flood probabilities and the hazard dimension of flood risk. Second, we present evidence showing how antecedent geomorphological and climate parameters can alter the risk and magnitude of landscape change caused by extreme events. Third, we show that geomorphic processes can both mediate and increase the geomorphological impacts of extreme events, influencing societal risk. Fourthly, we show the potential of managing flood and storm risk through the geomorphic system, both near‐term (next 50 years) and longer‐term. We recommend that key methods of managing flooding and erosion will be more effective if risk assessments include palaeodata, if geomorphological science is used to underpin nature‐based management approaches, and if land‐use management addresses changes in geomorphic process regimes that extreme events can trigger. We argue that adopting geomorphologically‐grounded adaptation strategies will enable society to develop more resilient, less vulnerable socio‐geomorphological systems fit for an age of climate extremes. © 2016 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
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Variations and statistical probability characteristic analysis of extreme precipitation events under climate change in Haihe River Basin,China 
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下载免费PDF全文 The magnitude and frequency of regional extreme precipitation events may have variability under climate change. This study investigates the time–space variability and statistical probability characteristics of extreme precipitation under climate change in the Haihe River Basin. Hydrological alteration diagnosis methods are implemented to detect the occurrence time, style and degree of alteration such as trend and jump in the extreme precipitation series, and stationarity and serial independence are tested prior to frequency analysis. Then, the historical extreme precipitation frequency and spatio‐temporal variations analyses are conducted via generalized extreme value and generalized Pareto distributions. Furthermore, the occurrence frequency of extreme precipitation events in future is analysed on the basis of the Fourth Assessment Report of the Intergovermental Panel on Climate Change multi‐mode climate models under different greenhouse gases emission scenarios (SRES‐A2, A1B and B1). Results indicate that (1) in the past, alteration of extreme precipitation mainly occurred in the area north of 38°N. Decreasing trends of extreme precipitation are detected at most stations, whereas jump alteration is not obvious at most stations. (2) Spatial variation of estimated extreme precipitation under different return periods shows similarity. Bounded by the Taihang Mountain–Yan Mountain, extreme rainfall in the Haihe River Basin gradually reduces from the southeast to the northwest, which is consistent with the geographical features of the Haihe River Basin. (3) In the future, extreme precipitation with return period 5–20 years accounts for a significant portion of the total occurrence times. The frequency of extreme precipitation events has an increase trend under A1B and A2 scenarios. The total occurrence times of extreme precipitation under A1B senario are not more than that under B1 senario until the 2030s. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Generalized extreme value shape parameter and its nature for extreme precipitation using long time series and the Bayesian approach 总被引：2，自引：2，他引：0
Assessing the probability of extreme precipitation events is consequential in civil planning. This requires an understanding of how return values change with return periods, which is essentially described by the generalized extreme value (GEV) shape parameter. Some works in the field suggest a constant shape parameter, while our analysis indicates a non-universal value. We re-analysed an older precipitation dataset (169 stations) extended by Norwegian data (71 stations). We showed that while each set seems to have a constant shape parameter, it differs between the two datasets, indicating regional differences. For a more comprehensive analysis of spatial effects, we examined a global dataset (1495 stations). We provided shape parameter maps for two models and found clear evidence that the shape parameter depends on elevation, while the effect of latitude remains uncertain. Our results confirm an explanation in terms of dominating precipitation systems based on a proxy derived from the Köppen-Geiger climate classification.
EDITOR D. KoutsoyiannisASSOCIATE EDITOR not assigned 相似文献
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The issue of selecting appropriate model input parameters is addressed using a peak and low flow criterion (PLC). The optimal artificial neural network (ANN) models selected using the PLC significantly outperform those identified with the classical root‐mean‐square error (RMSE) or the conventional Nash–Sutcliffe coefficient (NSC) statistics. The comparative forecast results indicate that the PLC can help to design an appropriate ANN model to improve extreme hydrologic events (peak and low flow) forecast accuracy. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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选取2010—2020年呼和浩特基准地震台记录的195个6.0级以上极远震事件波形,分析震相特征。按照震中距由小到大的顺序,挑选出9个典型极远震事件作为研究对象,依据AK135走时表,分析波形记录特征,以期提高地震台站的震相分析水平及资料产出质量。 相似文献
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本研究系统地对低硬度橡胶隔震支座的材料及力学性能进行了试验研究。研究用低硬度橡胶天然及铅芯橡胶隔震支座18种规格总计近30个大直径隔震支座。研究内容涉及低硬度橡胶隔震支座的基本力学性能，温度、压力、剪切变形、老化及徐变等相关性能，压缩界限、拉伸界限、极限剪切变形等界限性能和屈曲特性，以及橡胶材料性能和隔震工程应用等方面。本文主要介绍低硬度橡胶天然及铅芯隔震支座的压缩、拉伸、剪切等界限性能和屈曲应力与剪切应变的相关特性，文中提出了基于刚度因子建立的橡胶支座的界限压缩和界限拉伸应力评价方程，同时还给出了剪切变形状态下的屈曲应力评价方法。 相似文献
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分析了盐池台不同震中距极远震震相特征,提出了单台分析中应该注意的一些问题,这将有助于提高极远震的分析水平,对台站日常资料产出将起到积极作用。 相似文献