“Strike suddenly and without obvious warning”

“突然袭击而无明显的警告。”

In the Introduction of this debate Ian Main stated:

在这场辩论的引言中，Ian Main 宣称∶ 

“Despite the significent global effort that has gone into the investigation of the nucleation process of earthquakes, such events still seem to strike suddenly and without obvious warning.” 

“无论对地震‘成核’〔necleation〕过程的调查研究投入了多么大的全球努力，这种事件仍然似乎突然袭击而无明显的警告。”

He also admits:

但是，他也承认∶ 

“Not all natural catastrophes are so apparently unpredictable, however.” 

“然而，并非所有的自然灾难这样即将完成无法预测。”

In contrary, Max Wyss points out :

与此相反，Max Wyss指出33∶ 

“...’earthquakes ... appear to strike suddenly,’ is a phrase used by people who wish to argue that earthquake prediction is impossible, however, it does not reflect the facts correctly.” 

“……‘地震……似乎突然袭击，’是某些人的习惯用语，他们企望争辩地震预测是不可能的，然而，这并不真实地反映事实。” 

“The fact is that many main shocks do not occur "suddenly": 10-30% of them are preceded by foreshocks during the week before their occurrence; some are preceded by year-long pre-activity9 ; some are preceded by increased moment release during the years before them10-14 , and some are preceded by seismic quiescence15-17 . On the basis of these seismicity patterns, some earthquakes have been predicted correctly18-24 and one case has been predicted, but with incorrect parameters25-27 .” 

“事实是，许多主震并非‘突然’发生∶主震中的10-30%之前在发震之前的一周有前震；有的主震前有长达一年的震前活动性34；有的在震前有数年的加大的瞬间释放35 36 37 38 39，有的则在震前出现地震活动性的静止40 41 42。在这些地震活动性模式的基础上，对有的地震预测正确43 44 45 46 47 48 49，还有一次情况进行了预测，但预测的某些指标不正确50 51 52。”

“Time intervals show no periodic nature”

“时间间隔显示没有周期性性质”

Leon Knopoff pointed out :

Leon Knopoff指出53∶ 

“For a prediction to be successful, the probability of occurrence in a time interval and a space domain must be specified in advance, as must the lower magnitude. There are two important additional constraints: a utilitarian constraint demands that the lower magnitude bound be appropriate to societal needs; in other words, we are especially interested in strong destructive earthquakes.” 

“一项预测称之为成功，发生的概率，包括时间的间隔、位置的范围，以及最低量级，均必须事先明确。还有两项重要的额外约束∶实利性的约束要求最低的量级下限须适合于社会需要；换句话说，我们特别注重于强烈破坏性地震。” 

“Despite our assertions about the desirability of probabilistic estimates the problem is not statistical. There have been too few large enough events in any small sufficiently area in the past century to be able to define probabilities of the largest events sufficiently accurately.” 

“尽管我们对预计的几率提出希求，预测的问题仍然不是统计学性的。过去一个世纪里，在任何足够较小的区域里均发生过太少足够大的地震，使我们无法对较大地震判断出足够准确的可能性。 

“Cyclic inferences推论” 

“循环推论” 

“There are two ways in which to proceed. One is to study the time intervals between earthquakes in the region in this magnitude scale. If earthquakes are periodic, the problem is solved. Current estimates of interval times through measurements by global positioning by satellite (GPS) of rates of slip, coupledwith geological estimates of slips in great earthquakes, give only average values of interval times. However, from palaeoseismicity, we find that the interval times for the strongest earthquakes at one site on the San Andreas fault have large variability1 . The statistical distribution of these interval times is poorly identified even in this, the best of cases. And a long duration since the last occurrence is no guarantee that the next event is imminent; the next event could be farther in the future2 , as Ian Main has also noted. The conclusion depends on the actual interval time distribution, which is unknown.” 

“有两种继续进行的途经。一种途径是研究区域中该震级标度的地震之间的时间间隔。如果地震是周期性的，问题获得了解决。通过GPS〔全球卫星定位系统〕对滑移率进行测量，结合考虑大地震期间从地质学角度对滑移量的预计，从而获得目前对上述间隔时间进行的估计，仅能给出间隔时间的平均值。然而，从原始地震，我们发现San Andreas断层某个地点最强烈的地震的间隔时间有很大的可变性54。这些间隔时间的分布，即便在这种最好的例子中，其识别也较差。上次地震以来很长的期间亦不能保证下次地震即将来临；或下一次地震可能再更遥远的未来55，如Ian Main说明的那样。这方面的结论取决于实际的时间间隔分布，我们对此未知。” 

“The failure of the Parkfield prediction is a case in point: extrapolationfrom a brief set of interval times was insufficient to provide adequate information about the distribution of interval times. The variability of interval times is due to the influence of earthquakes on nearby faults; the earthquakes on a given fault cannot be taken as occurring as though they were independent of the activity on the other faults in the neighbourhood. Without information about the distribution of interval times, an earthquake prediction programme based only on GPS and short runs of palaeoseismicity must fail; the average values of slips and slip rates alone are not sufficient to solve the problem, but they comprise one of several pieces of information important to the prediction problem. Indeed, it is only on some faults that we have information about the date of the most recent sizable earthquake. What is lacking in this version of the programme is a theoretical effort to understand the distribution of interval times in one subareadue to earthquakes on an inhomogeneousnetwork of inhomogeneous faults and subfaults, a modelling problem of considerable difficulty.” 

“对Parkfield地震预测的失败是一个典型事例∶基于粗略的一组间隔时间的推论，不足以推导出间隔时间分布的足够信息。间隔时间的变化受到附近断层地震的影响；已知断层上的地震的发生，不能认为是独立于附近区域断层地震活动性之外。若缺乏有关间隔时间分布的信息，仅建立在GPS〔全球卫星定位系统〕和短期原始地震研究基础上的地震预测计划肯定会失败；单独的滑动和滑动率的平均值不足以解决这个问题，但是它们包括了对地震预测很重要的几项信息之一。确实，仅对于某些断层我们具有最近有一定大小的地震的信息。这样一项地震预测计划中所缺的是一种理论上的努力，以理解地震在由不均一的断层和分断层构成的网络上所造成的一个分区上间隔时间的分布情况。建立这种情况的数学模型相当困难。”

“We do not yet have a definitive theory of the seismic source”

“我们至今没有对地震成因的一个确定的理论”

Robert J. Geller pointed out11:

Robert J. Geller 指出11∶ 

“Why is prediction so difficult? This question cannot be answered conclusively, as we do not yet have a definitive theory of the seismic source. The Earth's crust (where almost all earthquakes occur) is highly heterogeneous, as is the distribution of strength and stored elastic strain energy. The earthquake source process seems to be extremely sensitive to small variations in the initial conditions (as are fracture and failure processes in general). ” 

“为什么地震预测那么困难？对这个问题不能做出最后的答复，因为我们至今没有对地震成因的一个确定的理论。地球的外壳〔几乎所有的地震均在那里发生〕是高度不一致性的，强度和储存的弹性应变能量的分布也如此。地震成因过程看来对原始状态中较小变化非常敏感〔破碎和失效过程总的来说亦如此〕。” 

“There is complex and highly nonlinear interactionbetween faults in the crust, making prediction yet more difficult. In short, there is no good reason to think that earthquakes ought to be predictable in the first place. A few laboratory failure experiments might seem to suggest otherwise, but they are conducted on a limited scale and do not replicatethe complex and heterogeneous conditions of the problem in situ.” 

“地壳中的断层之间有一种复杂的高度非线性的交互作用，这使地震预测更加困难。一句话，至今本来就没有好的理由认为地震是有可能预测的。少数几项实验室失败的实验可能看来建议另外的意见，但是他们仅在很有限的标度上进行，根本没有将地震预测问题实际存在的场所的复杂和不致性的状况复制出来。”

“The SOC theory -- Earthquakes of any size can occur randomly anywhere at any time” And “an earthquake cannot ‘know’ how big it will become because that depends entirely on initial conditions (local state of stress and strength of the fault)”.

“自组成临界性理论 – 任何大小的地震能够随意地在任何地方在任何时间发生”，以及“一个地震不‘知道’它能够发展为多大，因为这完全取决于其原始状态〔应力的局部状态以及断层的强度〕”

Addressing such arguments, Christopher Scholz explained3:

针对这项争论，Christopher Scholz解释3∶ 

“The current debate has taken the matter further, with the assertion, based on two arguments论据, that such prediction is intrinsically impossible.” 

“目前的争论已将这个问题进一步引伸，依据两项论据，断言地震预测从内在原因上讲是不可能的。” 

“The first argument is that the Earth is in a state of self-organized criticality (SOC), everywhere near the rupture point, so that earthquakes of any size can occur randomly anywhere at any time.” 

“第一项论据基于，认为‘地球’处于一种‘自组成临界性’〔SOC〕，所有处临近即将破裂点，使任何大小的地震能够随意地在任何地方在任何时间发生。” 

“SOC refers to a global state, such as that of the whole Earth or a large portion of it containing many earthquake generating faults with uncorrelated states.” 

“SOC〔译注∶‘自组成临界性’〕指的是一种全球状态，即整个‘地球’或其很大一部分，包含着许多易产生地震的断层，它们之间为不相关状态。” 

“Their second argument is based on the conjecture that an earthquake cannot 'know' how big it will become because that depends entirely on initial conditions (local state of stress and strength of the fault). This will prevent the earthquake magnitude from being predicted even if one could sense its nucleation (which friction theory predicts might be detectable days or weeks before the earthquake instability不稳定性5 ).” 

“第二项论据基于，推测一个地震不‘知道’它能够发展为多大，因为这完全取决于其原始状态〔应力的局部状态以及断层的强度〕。这阻止对地震的大小进行预测，即便有人能够感知其‘成核’〔nucleation〕〔依据摩擦理论应可能在地震不稳定性发生之前数天或数周56〕。”

On this topic, Leon Knopoff also pointed out53:

在这个议题上，Leion Knopoff也指出53∶ 

“However, there are several important arguments against the applicability of SOC to the earthquake problem.” 

“然而，针对SOC〔译注∶‘自组成临界性’〕应用于地震问题有几项对其进行批驳的论据。” 

“Faults and fault systems are inhomogeneous: we have already noted the presence of several scale sizes.” 

“断层和断层系统是不同种类非一致性的∶我们已经注意到存在着标度不同的断层和断层系统。” 

“Seismicity at almost all scales is absent from most faults, before any large earthquake on that fault; the San Andreas Fault in Southern California is remarkably somnolent at all magnitudes on the section that tore in the 1857 earthquake.” 

“大地震在某个断层发生之前，几乎所有标度的地震活动性都存在于大部分断层之外；地震活动性在南加利福尼亚州San Andreas断层上1857年被扯断的那一段前处于一种引人注目的催眠状态。” 

“There is no evidence for long-range correlations of the stress field before large earthquakes.” 

“没有证据说明大地震之前存在着应力场的长期相关性。” 

“I do not see that the salient properties of SOC that are requisites for its application are reproduced in the earthquake data.” 

“我从地震资料数据中看不出SOC〔译注∶‘自组成临界性’〕的显著性质对其应用是必不可少的。”

David Bowman & Charles Sammis also stated6:

David Bowman和Charles Sammis也指出6∶ 

“... forecasting on the year-to-decade scale ... In recent years there has been the suggestion that even this goal might be inherently impossible. Central to this argument is the claim by many authors that the crust is in a continuous state of self-organized criticality22,6 (and Per Bak's contribution to this debate). In the context of earthquakes, 'criticality' is defined as a system in which the stress field is correlated at all scales, meaning that at any time there is an equal probability that an event will grow to any size. If the system exhibits self-organized criticality, it will spontaneously evolve to criticality and will remain there through dissipative feedback mechanisms, relying on a constant driving stress to keep the system at the critical state. The implication of this model is that, at any time, an earthquake has a finite probability of growing into a large event, suggesting that earthquakes are inherently unpredictable.” 

“……在一年至十年标度上进行预测……最近几年有人建议即便这样一个目标也从内在上来讲也可能是不可能的。这样一个争论的核心是，许多作者认为地壳处于一种连续的‘自组成临界性’2 57〔以及Per Bak对该场辩论提交的文章〕。在与地震有关的上下文中，‘临界性’被定义为这样一个系统，在其中，应力场在所有量级相互有关，这意味着一次孕震在任何时间具有发展为任何规模的相同的概率。如果该系统显示为‘自组成临界性’，它将自然起进化为‘临界性’，并通过一种消耗性的反馈机制保持这种临危险状态，依赖于一种恒定的驱动应力使系统保持处于临界状态。这样一个数学模型的含义为，在任何时间，一个地震都具有一种有限的发展为大地震的可能性，从而建议地震从内在上讲是不可预测的。”

“Unsuccessful to find precursory phenomena that could be used to make reliable and accurate predictions of earthquakes”

“未能找到能够用于做可靠和准确地震预测的前兆现象”

Robert J. Geller stressed11:

Robert J. Geller强调11∶ 

“Because large earthquakes release huge amounts of energy, many researchers have thought that there ought to be some precursory phenomena that could be consistently observed and identified, and used as the basis for making reliable and accurate predictions. Over the past 100 years, and particularly since 1960, great efforts, all unsuccessful, have been made to find such hypothetical假定的 precursors.” 

“由于大地震释放大量的能量，许多研究者认为应当有一些能够始终观察到和识别到的前兆现象，可以作为做出可靠准确预测的基础。过去100年期间，而且特别从1960年以来，做出了重大努力，全部失败了，来找到这种假定的前兆。”

David Bowman & Charles Sammis also pointed out6:

David Bowman和Charles Sammis也指出6∶ 

“But as some of the participants in this debate have pointed out18,22 current efforts to identify reliable short-term precursors to large earthquakes have been largely unsuccessful, suggesting that earthquakes are such a complicated process that reliable (and observable) precursors might not exist. That is not to say that earthquakes do not have some 'preparatory phase', but rather that this phase might be not be consistently observable by geophysicists on the surface.” 

“但是，如同这场辩论的某些参加者指出的那样8 2，识别大地震的可靠的短期前兆的目前努力基本上是不成功，从而建议地震是一个更复杂的过程，可靠的〔和可观察到的〕前兆可能根本不存在。这并不是说地震没有一定的‘准备阶段’，但是说这个阶段有可能不能由地震学家从地壳表面上始终能观察到。”

Can not “distiguish a ‘precursor-type’ from a ‘non-precursor-type’ anomaly”

不能“将一种‘前兆型’和一种‘非前兆型’异常区别开来”

Pascal Bernard pointed out :

Pascal Bernard指出58∶ 

“M1: Processes reported in O1 to O4, and their subsequent effects (such as ground deformation and electromagnetic effects) can sometimes be recognized (retrospectively) as being precursors to large earthquakes3 ,9 . This is the basis for the preparation-zone paradigm in seismogenesis.” 

“M1∶所报告的O1和O4的过程，及其而后的效果〔如地形变和电磁效应〕，有时可被认识〔回顾性的〕为大地震的前兆59 60。这就是地震因学说中准备区范例的基础。” 

“Many authors have convincingly shown that proponents of M1 have not been very successful — if at all — in providing statistical evidence for such correlations between anomalies and earthquakes, nor for stating what would distinguish a 'precursor-type' from a 'non-precursor-type' anomaly122. Furthermore, it is difficult to explain how the size of the preparation zone, which is expected to be relatively small, can scale with the final size of large earthquake.” 

“许多作者令人信服的表明，M1的支持者在提供异常与地震之间相关性方面的统计数字证据方面，以及说明如何区别‘前兆型’异常和‘非前兆型’异常方面是不太成功的2。此外，在解释预计应相对小的准备区的大小如何能够以比例决定大地震最后的规模方面，亦存在着困难。

“The precursor strategy will not work because earthquakes are too complicated and too infrequent” and “lack of rigour in Earth sciences”.

“前兆战略无法工作，因为地震太复杂和太罕见”以及“地球科学缺乏严格性”。

David D. Jackson stressed13:

David D. Jackson强调13∶ 

“In principle, earthquakes might be predicted by one of two strategies: detecting precursors, or detailed modelling of earthquake physics. For precursors, confidence would come from empirical observations; understanding mechanisms would be desirable but not necessary. Earthquake physics involves modelling strain, stress and strength, for example, in some detail.” 

“从原则上，地震有可能通过两种战略之一进行预测∶探测前兆，或对地震物理学建立详细的数学模型。对前兆来讲，信心来自经验主义的观察；理解机制是期求的，但并非必要。地震物理学涉及，例如对应变、应力和强度，建立详细的数学模型。 

“The precursor strategy will not work because earthquakes are too complicated and too infrequent. Even if precursors existed, a few observations would not lead to prediction, because their signature would vary with place and time. This problem cannot be overcome simply by monitoring more phenomena such as electric, magnetic or gravity fields, or geochemical concentrations. Each phenomenon has its own non-seismic natural variations. Monitoring these phenomena without complete understanding is courting trouble. Monitoring them properly is a huge effort with only a remote connection to earthquakes. Such studies would certainly unearth more examples of anomalies that might be interpreted as precursors, but establishing a precursory connection would require observations of many earthquakes in the same place.” 

“前兆战略无法工作，因为地震过于复杂、过于罕见。前兆即便存在的话，少量的观察无法导致预测，因为其特征将因地因时而异。这个问题不能通过监督更多的现象而克服，例如电的、磁的，或重力场，或某些地球化学浓度。每种现象均有其自己的非地震性的变异。在没有完全理解的条件下监督这些现象将导致问题。对这些现象进行适当的监督则又花力极大，而仅与地震有较遥远的联系。这样的研究将肯定地揭示更多异常的例子，有可能解释为前兆，但是建立一种前兆联系将要求在同一地点观察许多次地震。 

“Earthquake physics is an interesting and worthwhile study in its own right, but short-term earthquake prediction is not a reasonable expectation. One idea is that high stresses throughout the impending rupture area might induce recognizable inelastic processes, such as creep or stress weakening. Even if these phenomena occur they will not lead to earthquake prediction, for several reasons. Earthquakes start small, becoming big ones by dynamic rupture. The critically high stress needed to start rupture is not required to keep it going. The telltale signs, if they were to exist, need affect only the nucleation point (several kilometres deep), not the eventual rupture area. Even very large earthquakes cluster8 , indicating that seismogenic areas are almost always ready. Earthquakes clearly respond to stress changes from past earthquakes9 , but the response is complex. For example, most aftershocks occur on planes for which the shear stress should have been reduced by the main shock. Monitoring strain accumulation and deducing the boundary conditions and mechanical properties of the crust will tell a lot about earthquakes and perhaps allow us to predict some properties. To forecast better than purely statistical approaches would be in itself a solid accomplishment, which must come long before deterministic prediction.” 

“地震物理学是很有趣并值得单独研究的课题，但是短期地震预测并非一种合理的期望。有一种想法，临近破裂区域的高应力有可能激发可识别的无弹性过程，如蠕变或应力衰减。这种现象即便发生，由于几项理由，它们也不会导致地震预测。地震开始时较小，通过动态破裂而变成大地震。造成破裂开始的临危险状态高应力，对于使其继续发展并非需要〔译注∶同样高的应力〕。现象表明，如果这种高应力存在话，只需要它们影响达到‘成核’〔nucleation〕点〔几公里深〕，而不是影响最终破裂区域。即便特别大的地震群61，也显示地震活动区几乎总是准备好〔译注∶发生地震〕地震清楚地对过去地震的应力变化做出响应62，但是这种响应是复杂的。举例来讲，大部分余震发生在剪切应力应被主震减少的平面上。监督应变值的增长情况，以及对分界状况和地壳的机械性质进行推论，有可能使我们能够对某些性质进行预测。比纯粹统计学途径能够做出更好的预测本身就是一项具体的成就，应当能够在实现‘确定性预测’前很早首先实现。” 

“Part of our difficulty is a lack of rigour in Earth sciences. We examine past data for patterns (as we should) but we pay very little attention to validating these patterns. Many of the patterns conflict: some contend that seismicity increases before large earthquakes10 , others that it generally decreases11 . We generally explain exceptions retrospectively rather than describe the patterns, rules and limitations precisely enough to test hypotheses.” 

“我们困难的一部分是在地球科学中缺乏严格性。我们审查了过去的数据以找出某些模式〔如我们应当的那样〕，但是我们对确认这些模式且不够注意。许多这样的模式有矛盾∶有的主张地震活动性在大地震增加63，其它的则主张它一般减少64。我们总的来讲趋于对于特殊情况进行回顾性的解释，而对这样的模式、规则和限制进行足够准确的描述来测试这些假定。”

“Large enough earthquakes with no precursors in the geophysical and geochemical parameters of a network”, “a type of precursor could appear before some earthquakes and not before others”, “different premonitory anomaly forms both at different sites of a network for the same earthquake and at the same site for different earthquakes”

“有足够大的地震，但监测网指标中且没有地球物理和地球化学方面的前兆”，“某种类型的前兆可能在某些地震发生前出现，但在另一些地震发生前却不出现”，“同一个监测网不同位置对同一个地震反映出不同预兆性的异常，亦在同位置对不同地震反映出不同预兆性的异常”。

Based on their observation, Francesco Biagi stated30:

根据他们观察的情况，Francesco Biagi宣称30∶ 

“Since 1974 our group has been performing research on empirical precursors. Tilts, hydrogeochemicals, electromagnetic emissions and radiowave disturbances have been investigated. We have reported results for the Friuli earthquake4 (1976), the Umbria earthquake5 (1979), the Irpinia earthquake6 (1980), the Spitak earthquake7 ,8 (1988) and the largest earthquakes that occurred in southern Kamchatka9 ,10 during the past decade.” 

“从1974年起，我们的小组一直对经验主义的前兆开展研究。对倾斜、水地球化学、电磁发射和无线电波干扰均进行调查研究。我们曾对Friuli地震65〔1976〕、Umbria地震66〔1979〕、Irpinia地震67〔1980〕、Spitak地震68 69〔1988〕，以及过去十年期间发生在Kamchatka南部的最大地震70 71报告过调查研究的结果。 

“Our field measurement and empirical data led us to suppose that there is an extremely small possibility that the precursors detected occurred randomly and are unrelated to the earthquakes. But it seems that the relationship linking earthquakes and premonitory anomalies is very complex and might be different in relation to seismogenetic zones. Consequently no general rules can be assumed. The following main aspects can be emphasized:” 

“我们现场测量的数据∑经验数据使我们认为，我们监测到的这些前兆仅有非常小的可能性是随意发生的和与地震无关。但是，看来将地震和这些有预兆性的异常联系在一起的关系非常复杂，并对不同的地震活动区域之间又有不同的关系。因此无法假定任何总的规则。其主要方面可以强调如下∶ 

“there are earthquakes that will produce no precursors in the geophysical and geochemical parameters of a network, even if the earthquakes are large enough to be considered as potential sources of precursors;” 

“有一些地震，即便大到可认为是前兆的潜在源，它们不产生〔监测〕网的地球物理和地球化学指标方面的前兆；” 

“there are network sites in which one type of precursor will appear before some earthquakes and not before others, although these earthquakes could be potential sources of precursors;” 

“在〔监测〕网中有一些现场，在此某种前兆将在某些地震前出现，而在其它地震前则不出现，虽然这些地震可以认为是前兆的潜在源；” 

“there are different premonitory anomaly forms both at different sites of a network for the same earthquake and at the same site for different earthquakes.” 

“有一些不同的有预兆性的异常，对同一个地震在〔监测〕网不同地点出现，又在同一地点对不同地震出现。” 

“These and other features are related to the anisotropy of the natural processes and it might therefore not be possible to eliminate them.” 

“这些和其它一些特点，与自然过程的各向异常有关，从而不可能排除它们。” 

“The main problem in using precursors in earthquake prediction is to discover whether in a seismogenetic area these features are totally random or whether there are significant recurrences. In the first case the prediction of earthquakes is a null hypothesis; in the second case the prediction of some earthquakes might be possible.” 

“在地震预测中使用前兆的主要问题，是发现在一个地震活动区中这些特点是完全随意的，还是它们有意义的重现。在头一种情况下，预测地震是无价值的假定；在后一种情况下，对某些地震进行预测是有可能的。”

“Invalid assumption using the prediction of small earthquakes as a proxy for the prediction of large ones”

“使用对小地震的预测依据作为对大地震的预测是无效的假定”

Leon Knopoff pointed out53:

Leon Knopoff指出53∶ 

“De novo prediction” 

“重新预测” 

“The second and more attractive approach is to search for the immediate precursors of strong earthquakes. Here there have been many culs-de-sac: searches for foreshocks, tilts, radon, electrical precursors and variations in velocity ratios of P-waves to S-waves have either failed or are at best unproven. In general, these efforts (a) failed to restrict the problem to the study of large earthquakes and (b) failed to evaluate seriously the success in units of poissonian behaviour. In many cases the invalid assumption was made that one could use the prediction of small earthquakes as a proxy for the prediction of large ones.” 

“第二种和更有吸引力的途径是探寻强烈地震的地震前兆。在这方面曾走进许多死胡同∶寻找前震、地倾斜、氡、电学的前兆，以及P-波或S-波速率的变化。但是，这些努力或者失败，或者在最好的情况下未能获得验证。总的来说，这些努力(a)未能将问题限于对大地震的研究，而且(b)未能对poissonian〔泊松式〕行为单位的成功进行认真的评估。在许多事例中，做出无效假定时，将小地震的预测前兆代替用来对大地震进行预测。” 

“Part of the blame for the use of the assumption can be put at a misinterpretation of the Gutenberg-Richter magnitude frequency distribution. The illusion of the G-R distribution is that there are no characteristic scale sizes except for the largest-magnitude events that a region can support. We now know that there are at least three subscales in the Southern California distribution: the central trapped-mode core of the fracture in the largest earthquakes has a dimension of the order of 100-200 m (ref. 3 ); the dimension of the zone of aftershocks astride a large fracture is of the order of 1-3 km; and the thickness of the brittle seismogenic layer is of the order of 15 km. (Space limitations do not allow me to discuss the cause of the apparent log-linearity of the G-R distribution in the presence of characteristic length scales4 .) ” 

“采用这种假定，可以部分地怪罪于对Gutenberg-Richter定律震级频率分布的曲解。G- R 分布的幻想是没有具有特征的标度决定大小的分布，唯一的例外是对于一个区域可以支承的最大震级地震。我们现在知道在加利福尼亚南部的分布中至少有三种标度的分布∶最大的地震发生时中心部困住方式的破裂核心部分，其尺寸约100-200米〔参看文献72〕；余震跨越的大破裂区域的尺寸为1-3公里；易脆的地震活动性层的厚度为15公里〔文章长度的限制不允许我在此讨论造成存在于具有特征的长度比例决定分布时明显G-R分布的log-线性关系的原因73。〕”

“Large variability of the faulting environment from region to region”, “The size of an individual earthquake is contingent upon minor variations of the actual configurations构造 of the crust of the Earth”

“一个地区到另一个地区的很大不同断裂层环境”，“一次地震的规模与地球地壳实际构造的某些次要不同有关”

Leon Knopoff pointed out53:

Leon Knopoff指出53∶ 

“Because of the wealth of scales, the 'prediction' of earthquakes at a smaller scale to understand larger ones cannot be valid. The assumption that we can amplify our data set by a study of large earthquakes worldwide is also not tenable, because of the large variability of the faulting environment for the largest earthquakes from region to region.” 

“由于大量丰富的标度，以对于较小标度地震的‘预测’来理解大的地震并非有效。认为我们可以通过对世界范围大地震的研究来放大我们的数据组的假定是无法保持的，因为一个地区到另一个地区的很大不同断裂层环境。”

Per Bak also pointed out :

Per Bak也指出74∶ 

“Assuming that we are dealing with an SOC phenomenon, what can this tell us about the prospects of going on from statistical prediction towards the level 5 of individual prediction? Unfortunately, the size of an individual earthquake is contingent upon minor variations of the actual configuration of the crust of the Earth8 , as discussed in Main's introduction. Thus, any precursor state of a large event is essentially identical to a precursor state of a small event. The earthquake does not "know how large it will become", as eloquently stated by Scholz. Thus, if the crust of the earth is in a SOC state, there is a bleak future for individual earthquake prediction. On the other hand, the consequences of the spatio-temporal correlation function for time-dependent hazard calculations have so far not been fully exploited!” 

“假定我们正在对付一种SOC〔自组成临界性〕现象，这可以就从统计学预测进一步向对个别5级地震预测的前景告诉我们什么？遗憾的是，一次地震的规模与地球地壳实际构造的某些次要的不同有关75，如Main对这次辩论的引言中讨论的那样。因而，任何大地震的前兆状态实质上与小地震的前兆状态类似。地震‘不知道它将成为多大’，如Scholz善辩所说的那样。因而，如果地壳处于SOC〔自组成临界性〕状态，对个别地震进行预测的前景就相当黯淡。另一方面，对于依赖于时间的危险计算的时空相关性的推论，至今则尚没有进行充分的开拓。”

“No one has been able to identify which earthquakes are foreshocks”

“没有人能够识别哪些是地震，哪些是前震。”

Andrew Michael pointed out :

Andrew Michael指出76∶ 

“Recognizing foreshocks would allow us to predict these more important events. But no one has been able to identify which earthquakes are foreshocks. This has limited us to statistical analyses in which we probabilistically estimate the odds that an earthqyuake is a foreshcok3 or treat each earthquake as a main shock and allow for the possibility that one of its aftershocks might be larger1 ,2 . In both cases, the probabilities that any earthquake will be followed by a larger even are only a few per cent over the first several days.” 

“识别前震能够允许我们预测这些重要的事件。但是，没有人能够识别哪些是地震，哪些是前震。这就限制了我们进行统学分析，对一次地震是一个前震的或然率进行预计77，或者将每次地震先当作主震并允许其一个余震可能更大的可能性78 79。在两种情况下，任何一个地震后可能跟随着一个更大的地震的或然率在头几天中仅为百分之几。”

“Prediction far more earthquakes than were later observed”

“预测到地震比我们事后观察到的地震多的多”

David Jackson pointed out13:

David Jackson指出13∶ 

“.... our test of the gap theory ....Unfortunately the new gap model also failed5 because it predicted far more earthquakes than observed in the following five-year period. Now 10 years have elapsed with the same result.” 

“……在我们对间隙的试验中……遗憾的是新的间隙数学模型也失败了80，因为它所预测到地震比我们事后五年期间观察到的地震多的多。现在过去了十年，结果仍相同。”

接续后篇∶

——>4.Main problems plaguing earthquake prediction research

对地震预测研究增添麻烦的主要问题

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