b值在地震预测中的三类应用及其物理基础与须注意的问题

将b值在地震预测中的直接应用归为三类：1）根据b值的动态变化预测地震。2）根据G－R律求出各级地震平均复发周期或年均发生率，推测未来一定时段如50年或100年内发生各级地震的危险性。3）根据G－R直线在横轴的截距，预测强余震的震级。讨论了这三种用法的物理基础及现有工作中容易出现的问题。     

最大熵原理与地震频度-震级关系

地震是一种随机事件 ,它的发生具有极大的不确定性 ,因而可以用熵来进行描述。地震以最无序的方式在各地发生 ,意味着地震熵达到了极大值。古登堡 (Gutenberg)和里克特 (Richter)根据资料和经验得出的地震频度 -震级关系式实际上是在给定的约束条件下 ,当地震熵取极大值时得到的一种负指数分布。文中从最大熵原理得出了同一形式的地震频度 -震级关系 ,使它的来源从理论上得到了解释     

新疆于田地区地震活动趋势分析

2008年和2014年,新疆和田地区于田县先后发生一次MS 7.3地震.2020年6月26日,该区再次发生MS 6.4地震,震源深度10 km,震中位于(35.73°N,82.33°E).通过地震活动性和构造背景,探讨该区域未来地震孕育特征和地震活动危险性. (1)发震构造背景.新疆于田地区位于西昆仑断裂带康西瓦断裂、...     

关于2001年11月14日昆仑山口西地震震级的调查

2001年昆仑山口西地震之后,相当多的研究文章使用了震级8.1的数据,但也有人对该震级表示怀疑.为了澄清数据来源,本文整理了国内外主要的地震目录网站,以及已有文章对该地震震级的使用情况,给出了不同的结果.最终表明,震级8.1的说法来自于国内大震速报目录.     

Fingerprinting the 8.2 ka event climate response in a coupled climate model

Using results from coupled climate model simulations of the 8.2 ka climate event that produced a cold period over Greenland in agreement with the reconstructed cooling from ice cores, we investigate the typical pattern of climate anomalies (fingerprint) to provide a framework for the interpretation of global proxy data for the 8.2 ka climate event. For this purpose we developed an analysis method that isolates the forced temperature response and provides information on spatial variations in magnitude, timing and duration that characterise the detectable climate event in proxy archives. Our analysis shows that delays in the temperature response to the freshwater forcing are present, mostly in the order of decades (30 a over central Greenland). The North Atlantic Ocean initially cools in response to the freshwater perturbation, followed in certain parts by a warm response. This delay, occurring more than 200 a after the freshwater pulse, hints at an overshoot in the recovery from the freshwater perturbation. The South Atlantic and the Southern Ocean show a warm response reflecting the bipolar seesaw effect. The duration of the simulated event varies for different areas, and the highest probability of recording the event in proxy archives is in the North Atlantic Ocean area north of 40° N. Our results may facilitate the interpretation of proxy archives recording the 8.2 ka event, as they show that timing and duration cannot be assumed to correspond with the timing and duration of the event as recorded in Greenland ice cores. Copyright © 2011 John Wiley & Sons, Ltd.     

A STATISTICAL FRAMEWORK FOR TREE‐RING RECONSTRUCTION OF HIGH‐MAGNITUDE MASS MOVEMENTS: CASE STUDY OF SNOW AVALANCHES IN EASTERN CANADA

This paper investigates the application of the peaks‐over‐threshold method in combination with fitting of the generalized Pareto distribution for estimating the frequency of high‐magnitude geomorphic events, on the basis of tree‐ring data. In particular, attention is focused on extreme value distribution of tree‐ring responses and in the minimum threshold or index number required to assure the past occurrence of high‐magnitude events. The objective is to set a threshold, adapted to the sample distribution, which will make the distinction between high‐magnitude years and remaining years, where the response of sampled trees is too weak to be attributed to a high‐magnitude geomorphic event. The statistical framework proposed is based on the statistics of extremes. Through the use of simple, strong and effective mathematics, this model should strengthen the position of dendrogeomorphology in the evaluation and management of natural hazards.     

Magnitude-Intensity Relationships in the Ibero-Magrebhian Region

In this paper we present magnitude (Ms) – magnitude(mb) and magnitude-intensity relationships which areconsidered the most adequate in the Ibero-Maghrebianregion. This work is based on selected samples ofrecently revised events with magnitude mb assigned bythe Instituto Geográfico Nacional (I.G.N.) and Msassigned by I.S.C and N.E.I.C., and isoseismal mapsfrom 142 events. Using these data, we have obtainedone magnitude (Ms) – magnitude (mb) relationship, twomagnitude (mb and Ms) assignment relationships viaepicentral intensity (I₀), and ten magnitude (mb andMs) assignments relationships via macroseismicinformation: four using Ambraseys' methodology (1985)and six using the isoseismal area of degree III, IV and VI.According to the obtained results it could be concluded that historical magnitude assignment with lesser uncertainties are those obtained via macroseismic information using magnitude-intensity relationships with Ambraseys' methodology (1985). The magnitude-isoseismal area assignment relationships have, in most cases, great differences depending on the degree of the isoseismal area used. Magnitude assignments via epicentral intensity have the highest uncertainties. Geographic regionalization of the relationshipshas been studied but the highest correlations and statistical significance are obtained when we fit all the Ibero-Maghrebian region data.Finally we have used the results obtained in this workto assign magnitude to some important historicalearthquakes in the Ibero-Maghrebian region: the 1755Lisbon earthquake, the 1680 Málaga earthquake, the1829 Torrevieja earthquake and the 1884 Arenas del Reyearthquake. According to our relationships andmethodology we have assigned an Ms value of 9.3 ±0.6 to the 1755 Lisbon earthquake (its mb magnitudecannot be estimated due to the saturation of the mbscale), an mb value of 6.3 ±0.4 and an Ms valueof 6.9 ± 0.6 to the 1829 Torrevieja earthquake, anmb value of 6.2 ± 0.4 and an Ms value of 6.4 ±0.6 to the 1680 Málaga earthquake and an mb valueof 6.1 ± 0.4 and an Ms value of 6.5 ± 0.6 tothe 1884 Arenas del Rey earthquake.     

黄河小浪底水库诱发地震预测

黄河小浪底水库库区地质构造复杂 ,库区及周边存在着十几条活动断层 ,它们是可能诱震断层。本文首先对库区断裂分布规律、相互关系进行分析 ,并探讨其断裂活动性 ,然后在综合地质条件分析、地震地质与工程地质类比的基础上 ,应用概率预测法分析得知小浪底水库有诱发地震的可能 ,并采用水库综合影响参数法、断层破裂长度法、聚类分析法估算了水库诱发地震震级 ,结果表明其震级以 5级为上限 ,随后简单估计了其震中位置与时间。