陈一文 （cheniwan@263.net）　2007.01

In the debate, Robert J. Geller made unusual severe attack on “case studies” as follows7:

在这场辩论中，Robert J. Geller对“地震案例研究”超乎寻常的攻击如下7∶ 

“Needed: objective testing, not case studies” 

“需要∶有目标的试验，不是地震案例研究” 

“What is wrong with present prediction research? Wyss cites scientifically weak work and scientifically unqualified publicity seekers as problems. I agree5 , but I do not think these are the main problems. The principal problem appears to be the use of the anecdotal 'case study' approach by prediction researchers. At an early stage this approach can be valuable, but there are now literally thousands of published claims of precursors18. The value of further additions to this list is questionable.” 

“目前的预测研究错在哪里？Wyss指出科学上薄弱的工作和科学上不合格的寻求宣传者为问题所在。我同意89，但是我不认为这些是主要的问题。最基本的问题看来是预测研究者们采用的轶事一样的‘地震事例研究’的研究途径。在早期阶段，这种途径可能是有价值的，但是到目前为止已经有数千篇声称找到前兆的书面文章8。对这清单增加新的内容的价值是令人怀疑的。” 

“Wyss's contribution to this debate cites both "increased moment release" (more small earthquakes than usual) and "seismic quiescence" (fewer small earthquakes than usual) as precursors. Thus it appears that any variability whatsoever in background seismicity can be claimed, after the fact, to have been a precursor. To determine whether these variations in seismicity levels are random fluctuations or real physical phenomena, objective testing of unambiguously stated hypotheses is required6 .” 

“Wyss对这次辩论提交的文章将‘增加的瞬间释放’〔比通常多的小地震〕以及‘地震活动静止’〔比通常少的小地震〕均列为前兆。这样看来，可以将背景地震活动性中的任何变化，在地震发生之后，认为是一种前兆。为确定地震活动性中的这些变化是否是随机偶然的波动，还是真实的物理学现象，对不含糊指明的假说有必要进行有目标的试验90。” 

“It is regrettable that the other contributors to the first two weeks of this debate have not sufficiently acknowledged the importance of objective statistical testing in resolving the prediction debate. Researchers looking for precursors could greatly benefit from the experience of pharmaceutical research, where new drugs are routinely evaluated by randomized double-blind testing using placebos7 .” 

“遗憾的是，这场辩论头两个星期中提交文章的研究者们，并没有足够认识到有目标的统计学试验对于解决预测方面辩论的重要性。寻找前兆的研究者们可以从医学研究的经验中受益，该领域中通过随机采用安慰剂的双盲试验法对新药进行评估91。” 

“We should instead be searching for reliable statistical methods for quantifying the probability of earthquake occurrence as a function of space, time, earthquake size, and previous seismicity. The case study approach to earthquake prediction research should be abandoned in favour of the objective testing of unambiguously formulated hypotheses.” 

“我们应改为寻找可靠的统计学方法对地震作为方位、时间、地震大小，以及过去地震活动性的函数关系概率进行定量分析。对地震预测研究的案例研究途经应当被抛弃，代之以对较明白建立起来的假定进行有目标的试验。”

With strong disagreement with the above views, Max Wyss points out32:

“对上述观点强烈反对，Max Wyss指出32∶ 

“Case histories are often all we have” 

“地震案例历史是我们仅有的一切” 

“Very large earthquakes occur too infrequently to test hypotheses on how to predict them with the statistical rigor one would like (for example L. Knopoff's contribution to this debate ), and potential data sets for testing are further reduced by the need to separate different tectonic settings (see Z. Wu's contribution to this debate ). In addition, most earthquakes occur far from existing dense instrumentation networks, making it impossible to gather data pertinent to most hypotheses.” 

“特别大的地震很少发生，不足于对假说进行试验，即如何利用人们希望那样严格的统计数字〔如L. Knopoff对该辩论提交的论文描述的那样〕对地震进行预测；为不同板块的不同设置值〔参看Z. Wu对这次辩论提交的论文〕，使用于进行这种试验的潜在数据组进一步减少。此外，大部分地震又发生在远离现在密集布置的仪器网，更使研究者们无法收集与大部分假定有关的数据。” 

“Thus sets of case histories in which the individual cases may number about a dozen will be all we will have for years to come, whether we like it or not. However, I do not see this as a reason to give up prediction research or rupture initiation studies altogether, as long as we have not exhausted the data available. As it is, we have hardly scratched the surface, because of lack of funding.” 

“因而，对于不同地震的大约一打地震案例的历史，可能是数年之内我们仅有的一切，无论我们喜欢不喜欢。然而，只要我们尚没有将对我们有的数据用到尽头，我认为就不能将这种情况看为我们应当完全放弃预测研究或破裂起始研究的一种理由。从实际情况看，我们仅仅接触到问题表面的皮毛，因为没有足够的研究经费。”

Zhong-liang Wu pointed out :

吴中良指出92∶ 

“An extreme example is Geller's claim10 that time and effort need not be wasted on evaluating prediction schemes that cannot outperform Kagan's 'automatic alarm' strategy11 . If earthquakes were all the same, then this claim would be absolutely reasonable. However, from the perspective of the classification of earthquakes, such a stance might lead to the loss of some useful information.” 

“一个极端的例子是Geller的要求93，即不应在性能上未能超越Kagan的‘自动报警’战略94的预测计划的评估上花费时间和努力。如果所有的地震都一样，那么这样一种要求可能是完全合理的。然而，从地震分类的观点来看，这样一种姿态可能导致丧失掉许多有益的信息。” 

“Geller et al.122 proposed that the question of precursor test can be addressed using a Bayesian approach where each failed attempt at prediction lowers the a priori probability for the next attempt. In this case, if all earthquakes are treated as the same and no difference is made between failures-to-predict and false-alarms, the 'game rule' will be extremely harsh, and many potential precursors will be rejected by this 'razor'.” 

“Geller的文献2提议，关于前兆试验的问题可以采用一种Bayesian方法来处理，即，预测方面的每一次努力的失败将降低对进行下一努力的先验的概率。在这种情况下，如果所有的地震均以同样的方式对待，并对漏报和误报不做任何区别，‘游戏规则’将非常粗糙，许多潜在的前兆则将被这个‘刮脸刀’排除。” 

“From this point of view, it is too early to accept the conclusions that the search for earthquake precusors has proved fruitless and earthquakes cannot be predicted1194,122.” 

“从这样的观点来看，做出寻找地震前兆已证实为没有结果和地震无法预测的结论着实过早94 2。”

In the Conclusion Remarks of the debate, Ian Main summarized as follows:

在这次辩论的总结中，Ian Main归纳如下∶

2. Precursors

前兆 

“Perhaps the greatest degree of controversy lingers in the possibility of making probabilistic forecasts of future earthquakes based on the observation of precursory phenomena. The reason for this continuing controversy is two-fold: 

“或许，最大量论战在如下话题上，即，在对前兆现象的进行观察的基础上对未来地震进行或然率预测的可能性。对此话题继续论战的理由基于两个方面∶ 1.

The plain practical difficulty of objectively identifying any precursory phenomena with sufficient clarity and repeatability to convince the sceptical of their general existence. Some believe that this problem will be overcome in time (Wyss, week 1; Knopoff, week 3; Biagi, week 4), although at least one feels that the effort needed will require resources comparable with those currently spent on astronomical research (Wyss, week 3). Many contributors to the debate, while acknowledging the problems, argue nevertheless that we should not rule out a priori the possibility of a level of prediction above that of earthquake clustering (Bernard, week 1; Michael, week 2; Scholz, week 2; Knopoff, week 3; Bowman & Sammis, week 4, Wu, week 5).

“1、 这个问题的实际困难在于，能够有目标的识别任何这样的前兆现象，并在这样做时有足够的清楚度和重复性，从而消除对其存在的怀疑。有些人相信这个问题经过一段时期将能够克服〔Wyss，第1周；Knopoff，第3周；Biagi，第4周〕；至少一个人感到所需的努力将需要与目前花费在天文研究上可比的资源〔Wyss，第3周〕。对这次辩论提交论文的研究者们，在承认存在的问题的同时，争辩说我们不应当否认进行超过地震‘丛集性’〔clustering〕水平以上的预测可能性的先前经验〔Bernard，第1周；Michael，第2周；Scholz，第2周；Knopoff，第3周；Bowman & Sammis，第4周；Wu，第5周〕。

“Geller (week 4) argued that a massive investment of new resources specifically targeted at earthquake prediction would be an unwise investment without more obvious success, and Bernard (week 1) that any increase in resources should be targeted first at a better fundamental understanding of earthquakes and crustal transients themselves. Geller (week 6) criticised the 'case study' approach inherent in the investigation of precursory phenomena, on the grounds that sample bias can lead to apparent statistical significance - the 'gambler's fallacy'. Wyss (week 6) responded by saying that this may be all we have for the foreseeable future, but this does not of itself refute Geller's argument.”

“Geller〔第4周〕争辩讲，没有更多的明显的成功，用新的资源大量投资于地震预测将是轻率的投资；Bernard〔第1周〕则强调增加这方面任何资源应首先着重于对地震和地壳瞬间变化本身获得更好的实质性理解。Geller〔第6周〕批评了对前兆现象进行调查研究时的‘地震案例研究’固有方法，其批评基于偏见性的取样可导致显然的统计学重要性 – ‘赌棍’的谬误。Wyss〔第6周〕做出答复，强调在可预见的未来这是我们所具有的一切，但是这种说法本身并没有驳倒Geller的争辩。” 2.

The lack of a universally-agreed physical model for the complicated and non-linear process of seismogenesis. We may all agree that the local physics of fracture or friction play a strong role, but how do these scale from the controlled conditions of the laboratory to the field case, how do we account for changes in the boundary conditions, and how do we take into account the strong interactions between faults during earthquakes?”

“对于地震成因的复杂非线性过程缺乏一种普遍同意的物理模型。我们可能都同意破裂或摩擦的局部物理性发挥重要的作用，但是如何将基于实验室控制状况获得的这种信息用来标度现场地震事例的情况，我们如何去计算考虑边际状况中的变化，我们又如何计算考虑地震期间断层之间强烈的交互作用？”

接续后篇∶

——>7.Arguments against “earthquakes can not be predicted”

对于“地震无法预测”的争论

参考文献

1 Geller, R.J. Predictable publicity. Astron. Geophys Quart. J.R. Astr. Soc. 38(1), 16-18 (1997).

2 Jackson, D.D. Hypothesis testing and earthquake prediction. Proc. Natl Acad. Sci. USA 93, 3772-3775 (1996).

3 Shapiro, A.K. & Shapiro, E. The powerful placebo (Johns Hopkins University Press, Baltimore, MD, 1997).

4 Zhong-liang Wu, Email contribution, 25 March, Nature debate on earthquake prediction (1999).

5 Geller, R. J. Earthquake prediction: a critical review. Geophys. J. Int. 131-425-450 (1997).

6 Kaan, Y.Y. VAN earthquake predictions – an attempt at statisical evaluation. Geophys. Res. Lett. 23, 1315-1318 (1996).

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