概率方法应用于地震短期预测的探索

根据爆发地震平静两项活动性前兆的统计结果,对地震发生的背景概率、条件概率和概率增益进行了估计,给和北地震发生前发震概率逐步增加时间过程,由背景概率Ｐ（Ｅ）增至中期前兆Ａ出现后的条件概率Ｐ（Ｅ／Ａ）,再增至短期前铛Ｂ（平静）出现后的联合条件概率Ｐ（Ｅ／Ａ）。结果表明,在１９９７年１２月１７日后的一个月内,华北地区发生６级以上的条件这３８％,概率增益超过２０,对概率预测结果的使用进行了探讨,提出应充分     

四川九寨沟7.0级地震中长期预测的回顾认识

回顾了2013年郭增建提出的基于地震活动性的"静中动"和后期与作者共同发展的"准静中动"方法,以1987年1月8日在甘肃南部迭部县发生的5.9级地震作为标志性的"准静中动"地震,结合国家地震局在1989年综合划定的1990—2000年南北地震带10年地震危险区,用中长期预测的时间尺度,指出了南北地震带北段三个未来可能发生6~7级地震的地区,其中一个就是四川省九寨沟地区。回顾分析中对"静中动"方法预测效能、存在的问题及一些中长期预测的问题进行讨论,得到两点认识:一是通过这次地震的再次验证,证明"静中动"方法是一种可行的预测地震的独立指标方法,在验证的基础上对该方法进行了优化认识;二是基于"静中动"方法与南北地震带北段10年地震危险区对应地震较为准确的启发,初步认为前兆可以划分为平静期的前兆与活跃期的前兆,而前者可能对于地震的预测意义更大,未来可以沿这一思路开展进一步的论证和研究。     

试用累积求和方法研究地震活动平静现象及大震概率预报

以表征区域地震活动强度背景的震级期望值作为单个地震事件的目标值,利用震级累积和C值随时间的变化分析地震活动相对平静现象,并给出其显著性检验. 文中还定量分析了平静异常与大震的关系,提出了利用核函数对大震发生时间进行概率外推的方法. 用上述方法对华北区的山西、张家口-渤海地震带的部分地区及新疆区域进行计算,显示该方法能够描述地震活动平静现象,并可合理地对未来大震发生时间进行概率外推估计.     

Precursory seismic quiescence: Past,present, and future

Precursory seismic quiescence has played a major role in most of the succesful earthquake predictions made to date. In addition to these successes, the number of detailed post-mainshock documentations of precursory quiescence is steadily growing. These facts suggest that precursory quiescence will play an important role in earthquake prediction programs of the future. For this reason it is important to critically evaluate the present state of knowledge concerning this phenomenon. The history of observations of precursory seismic quiescence includes work on seismic gaps and seismic preconditions as well as actual studies of temporal quiescence. These papers demonstrated the importance of quantitative evaluation of seismicity rates and the benefits of systematic analysis. During the early 1980's the impact of man-made effects on seismicity rates was demonstrated for the first time. Despite progress in catalog understanding, the identification and correction of man-made seismicity changes remains as the major barrier to earthquake prediction using these data. Effects of man-made changes are apparent in many past studies of seismicity patterns, making the results difficult to evaluate. Recent experience with real-time anomalies has demonstrated the necessity of determining the false alarm rates associated with quiescence precursors. Determination of false alarm rates depends on quantitative definitions of anomalies and statistical evaluations of their significance. A number of successful predictions, which have been made on the basis of seismic quiescence, provide important lessons for present and future work. There are many presently unanswered questions regarding seismic quiescence which must be answered before we can determine the reliability of this phenomena as a precursor.     

一种评估地震前兆可信度的方法

本文提出了一种可以对地震前兆的可信度进行评估的方法. 通过对前兆信息的抽取、各类非地震干扰的识别、前兆与地震事件在时间和空间的相关性分析以及前兆的随机检验等一系列手段来评估前兆信息的真伪,提高地震前兆信息的显著性和可信度. 该方法及思路也可为其他非地震前兆的可信度评估所借鉴. 作为一个具体的例子,本文利用日本气象厅的地震目录以及能定量描述地震活动的时、空、强信息演化特征的RTL(Region_Time_Length)方法对2000年10月6日在日本鸟取县西部发生的73级地震前周围地区近26年的地震活动进行了系统的研究,得到了可能的地震活动前兆信息,并采用本文提出的方法对该前兆进行了评估,证实了上述前兆的显著性和可信性.     

A sequence of seismic activity in the Kanto area precursory to the 1923 Kanto earthquake

The Kanto earthquake (M=7.9) that occurred along the Sagami Trough in the Sagami Bay on 1 September 1923 was one of the most disastrous earthquakes in Japanese history. The Kanto area includes Metropolitan Tokyo and Yokohama which are densely populated, and hence it has been a matter of great concern, from the viewpoints of earthquake prediction and disaster prevention, whether or not the 1923 Kanto earthquake was preceded by precursory seismicity. A study using the most complete lists of earthquakes catalogued recently by Utsu and the Japan Meteorological Agency reveals that seismic activity in the Kanto area was appreciably higher before and after the Kanto earthquake, and that the Kanto earthquake was preceded by a sequence of anomalous seismic activity, quiescence, and foreshocks. Such higher activity before and after the Kanto earthquake is contrasted with low seismicity during the recent 30-year period. A model is proposed to explain the precursory seismic activity, subsequent quiescence, and foreshocks for the Kanto earthquake. In the model, the transition from precursory seismic activity to quiescence is ascribed to time-dependent fracture due to stress-aided corrosion. Foreshocks are related to an acceleration of premonitory slip shortly before the mainshock slip.     

汶川8.0级与昆仑山口西8.1级地震前地震活动异常特征与启示

两次特大地震前在不同时段、 不同范围出现了多项相似的地震活动性异常, 它们对预测特大地震具有一定意义: ① 两次大震前10余年, 青藏块体同期出现了两个规模巨大的中强以上地震增强区, 两次大地震发生在增强区内的空区里; ② 两次巨大地震前数年, 形成规模巨大的中强地震活动带, 地震发生在两个条带间的平静区里; 同期形成中等以上地震活动环, 其内部的地震频度、 加卸载响应比及非均匀度等参数甚高, 且随时间而变化, 这可作为孕震进入中期的信号; ③ 两次大震前的震群、 震丛均很显著, 昆仑山口西地震前四个显著震丛环绕震中四周分布, 汶川地震前震群在震中周围形成包围圈, 它们应视为大震孕育进入后期的显示; ④ 大震前数月, 靠近发震断裂带发生少量中小地震或少见的震群。 汶川地震前10个月, 龙门山断裂带北部发生两次青川4级多地震和松潘4.3级地震, 南部康定附近发生3次4级以上地震。 紫坪铺水库区小震群于震前3个月活动十分强烈。 昆仑山口西地震前约1年青海兴海发生6.6级地震, 昆仑山口西发生5.1级地震, 该地震距离8.1级地震约30 km。这些特征给我们的重要启示是: ① 特大地震前出现的前兆时空特征与常见的中强地震差异很大, 现行的监测预报体制(分省分片负责)与特大地震前兆不相适应; ② 特大地震的预测预报不能单纯依靠地震前兆, 必须与地质构造及深部探测紧密结合起来; ③ 特大地震的预测预报应有新的预报战略、 观测系统与组织机构相适应。     

Progress in Earthquake Science and Technology in China: Review and Prospects (I)

ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｋｎｏｗｎｔｈａｔＣｈｉｎａｉｓａｎｅａｒｔｈｑｕａｋｅ ｐｒｏｎｅｃｏｕｎｔｒｙｉｎｔｈｅｗｏｒｌｄａｎｄｉｓａｌｓｏａｃｏｕｎｔｒｙｓｕｆｆｅｒｉｎｇｍｏｓｔｓｅｖｅｒｅｓｅｉｓｍｉｃｃａｌａｍｉｔｉｅｓｉｎｔｈｅｗｏｒｌｄ .Ｃｈｉｎａ’ｓｔｅｒｒｉｔｏｒｙｏｃｃｕｐｉｅｓａｂｏｕｔ 1 1 4ｏｆｔｈｅｇｌｏｂａｌｃｏｎｔｉ ｎｅｎｔａｌａｒｅａ ,ｗｈｉｌｅａｂｏｕｔ 1 3ｏｆｇｌｏｂａｌＭ≥ 7.0ｃｏｎｔｉｎｅｎｔａｌｅａｒｔｈｑｕａｋｅｓｏｃｃｕｒｒｅｄｉｎＣｈ…     

前兆性地震平静研究

作为一种重要的强震前兆现象, 地震平静有可能提供关于地震位置、时间和大小的有用信息,在地震预测中将具有重要作用.为全面了解地震平静这一极具希望的前兆现象,本文将详细地阐述地震平静的定义、研究方法、存在规律、模型及其可能的物理机制,并对存在的问题与未来的发展提出初步的设想.     

地震前兆含义,科学问题与研究途径的研讨

地震前兆的研究已经取得了很大的进展,地震前兆的复杂性引起了广泛的关注,对地震预报、有关科学问题和探索途径的研究现状及其前景有各种评价。文章认为由于一些科学问题没有解决,尽管对中缅边境１９９５年７月连７．３级地震作出了成功预报,经验性预报有一定的局限性,文中讨论了广义地震前兆和狭义地震前兆,广义地震前兆包含二类前兆：场兆和源兆;而狭义前兆仅指后者。大陆震例前兆的系统研究证实了广义地震前兆的存在,然而     

2010年太康ML5.0级地震前地震活动特征

通过对2010年10月24日太康ML5.0级地震前的资料进行回顾研究,认为在这次地震前,存在区域中等地震活动增强、ML≥2.0级弱震空区、弱震条带、地震平静及霍山地震后窗口高频次异常等异常图象.它又一次为该区对中等地震的监测预报积累了资料.     

Precursory seismic quiescence: A preliminary assessment of the hypothesis

Numerous cases of precursory seismic quiescence have been reported in recent years. Some investigators have interpreted these observations as evidence that seismic quiescence is a somewhat reliable precursor to moderate or large earthquakes. However, because failures of the pattern to predict earthquakes may not, in general, be reported, and because numerous earthquakes are not preceded by quiescence, the validity and reliability of the quiescence precursor have not been established.We have analyzed the seismicity rate prior to, and in the source region of, 37 shallow earthquakes (M 5.3–7.0) in central California and Japan for patterns of rate fluctuation, especially precursory quiescence. Nonuniformity in rate for these pre-mainshock sequences is relatively high, and numerous intervals with significant (p<0.10) extrema in rate are observed in some of the sequences. In other sequences, however, the rate remains within normal limits up to the time of the mainshock. Overall, in terms of an observational basis for intermediate-term earthquake prediction, no evidence is found in the cases studied for a systematic, widespread or reliable pattern of quiescence prior to the mainshocks.In earthquake sequences comprising full seismic cycles for 5 sets of (M 3.7–5.1) repeat earthquakes on the San Andreas fault near Bear Valley, California, the seismicity rates are found to be uniform. A composite of the estimated rate fluctuations for the sequences, normalized to the length of the seismic cycle, reveals a weak pattern of a low rate in the first third of the cycle, and a high rate in the last few months. While these observations are qualitative, they may represent weak expressions of physical processes occurring in the source region over the seismic cycle.Re-examination of seismicity rate fluctuations in volumes along the creeping section of the San Andreas fault specified by Wyss and Burford (1985) qualitatively confirms the existence of low-rate intervals in volumes 361, 386, 382, 372 and 401. However, only the quiescence in volume 386 is found by the present study to be statistically significant.     

震兆平静的再认识--海城地震30周年有感于经验性地震预报的议论

从对海城地震时期所关注的平静震兆的再认识中,阐明了经验性地震预报在探索地震预报从无到有的历程中所能发挥的作用。     

我国地震预报研究近十年的发展与展望

简要回顾了我国地震预报的发展过程，并着重对最近10年（尤其是90年代以来）的地震预报研究进展作了较系统的阐述．主要分为：（1）大地震震源区地壳细结构和介质物性的探测研究；（2）地震和前兆数字化观测技术的研制；（3）地震短临预报方法及其判据、指标的研究；（4）地震序列类型和震后趋势早期应用判断方法及其指标的研究；（5）华北北部地震短临预报方法、前兆综合解释模型与短临预报综合判别系统的研究；（6）地震预报新技术、新方法的探索；（7）地震中长期预报研究及我国近期（10年左右尺度）地震重点监视防御区的确定；（8）板内地震孕育发生的物理模型及前兆场物理解释的探索研究．最后还对我国地震预报的未来发展进行了展望．     

地震震相分析与测量的进展

地震震相分析是地震学研究中最基本、也是最基础的工作。本文就震相分析与测量方面的一些重要进展进行了概述,主要包括初动到时和极性的测量,震相中其他参数的测量,以及其他震相的识别与测量等。本文还着重介绍了《IASPEI标准地震震相表》,该震相表的完成与公布是地震震相分析工作的重要进展。     

Prediction of the largest events in the sandpile model based on the earthquake precursors

Earthquake precursors used for earthquake prediction in the M8 algorithm [Keilis-Borok and Kossobokov, 1990a] are adapted to the sandpile grid model close to the Manna [1991] model. It is established that the adapted precursors are efficient for predicting the largest model earthquakes. However, as distinct from real seismicity, where activity outbursts often precede a large earthquake, the prediction of the model dynamics, is characterized by a certain quiescence.     

Seismological evidence for the nucleation of two strong earthquakes

The structure of seismicity before the Kronotskii (1997) and Simushir (2006) earthquakes off Russian shores is studied. Different algorithms are applied to the identification of seismic quiescence, seismicity activation, and clustering of seismic events. It is established that the seismic process developed according to the same scenario in both cases. Seismic quiescence arose a few years before an earthquake near the epicenter in an area ～200 km in size. A 100-km area of subsequent activation included the epicenter. The activation stage ended more than one year before an earthquake. An abrupt rise in the number of clusters of seismic events was observed a few days before an earthquake near its epicenter.     

山东聊古一井水化学组分地震异常的场源兆特征及其机制讨论

从山东聊古一井构造地质和水文地质条件的分析入手，以实际观测的水化学组分地震前兆异常变化实例为基础，讨论了该井水化学组分震前异常变化的场源兆特征．利用断层位错理论和岩石力学实验获得的认识探讨了聊古一井水化学组分变化场源兆异常形成的物理力学机制及预报意义．所获成果丰富了对场源兆地震前兆的认识，同时对地震预测预报也有一定的意义．     

大震前地震活动图像演变及中期向短期过渡的地震活动性标志

通过多震例分析，表明大震前地震活动图像具有类似的演变形式，即空段－背景空区－增强活动－条带－平静，地震平静可以看作是中期短期过渡的地震活动性标志，从图像演变角有助于识别异常平静，并有可能把震前平静的时间尺度缩短至几个月量级。     

唐山地震前华北地区的构造活动信息

本文综合分析了华北地区18幅630张不同时相、不同波段的卫星图象,发现唐山地震前,卫星图象上显示出了压扭性的构造活动信息及张性的构造活动信息。这些信息出现在唐山地震前13—16个月之间,是一种地震中期前兆信息。运用我国地面站卫星图象,监测京津及敏感点上的构造活动信息,捕捉未来大地震的中期前兆信息,对地震减灾是十分必要