华北地区地震短临异常综合标志及预报指标的研究

本文对华北１６次中强以上地震前多兆短临异常进行了分析，归纳出短临异常的综合变化特征。依据短临异常的综合特征，提出在中期异常背景上孕震过程由中期向短期过渡的两个定量化综合标志。研究了孕震后期在观测到较多数量短临异常情况下，能否发布５级以上地震预报意见的预报指标。作为本文结果的检验，计算了８次地震丧的综合标志和预报指标。本研究工作在短临预报中具有一定的实用价值。     

地震决策过程的一些思路

将翁文波（１９８４）信息预测过程的理论应用于地震的决策过程，用四个圆的交叉和重叠表示不同组合，共可分出１３个区，从决策结论是有震的情况可区分出７种不同性质的决策结果，剩下６处种都是在无决策情况下。决策有震且正确的有４种性质，决策有震且错误的有３种性质，当前，有关地震预报的理论尚很不完善，决策有震的符合比率相当低，通过决策过程的系统分析有利于理解漏报、虚报、伪报、假正确等情况的产生原因，有利于改善地     

The Chemical Composition of Global Subducting Sediments and Its Geological Significance

Subducted sediments play an important role in crust-mantle interaction and deep mantle processes, especially for subduction zone magmatism and mantle geochemistry. The current rate of Global Subducting Sediments (GLOSS) is 0.5~0.7 km³/a. The GLOSS are composed of terrigenous material(76 wt.%), calcium carbonate(7 wt.%), opal(10 wt.%) and mineral-bound H₂O⁺(7 wt.%). The chemical compositions of GLOSS are similar to those of upper continental crust which is mainly controlled by the terrigenous materials, and yet the materials formed by marine processes will dilute the terrigenous materials. The components of subducted sediments are different among trenches. In the accretionary margin, the components of subducted sediments are similar to those of the upper crust, while in the non-accretionary margin the components are terrigenous materials plus those produced by marine processes. During subduction, subducted sediments will released fluids, melt or supercritical fluid to affect island arc/back-arc basin magmatism by means of aqueous fluid or sediment melt. In addition, a part of subducted sediments, together with underlying altered oceanic crust/lithosphere, recycle into the mantle and contribute to the mantle heterogeneity. Geochemical tracers indicate that subducted sediments play variable contributions to the magmatic processes in different tectonic setting. Thus, subducted sediments play an important role in two relatively independent dynamics systems (plate tectonics and mantle plume), as well as related mantle evolution models. As a result, by accurately calculating the compositions of subduction sediments and using various geochemical indicators, we can further limit the input and output fluxes of various elements or isotopes, and then obtain more accurately residual subducted components, which can provide us some important clues for geodynamic process.     

逆断裂在浅部松散层中的破裂传播方式

根据实际资料分析研究，逆断裂破裂位错向上传播至松散层中有４种消减形式：端部分叉、从断裂向褶皱转换、破裂在松散层中的吸收与尖灭及逆断层前方碎砾物质的扰动变形等。端部分叉与扰动变形的消减可能与突发性位错相关；上覆层的褶皱及位错在松散层中的尖灭则多属弹－塑转换型的消减方式     

中长期地震预测方案综合信度评价的层次分析法

由于存在各种复杂的不确定因素的影响，正确合理地评价地震观测结果的可信度，具有一定的难度。本文首先引入具有广泛应用途的层次分析法，并以华北北部为例，结合Ｄｅｌｐｈｉ专家咨询结果，给出了反映各个预测方案结果的可信度及具有满意一致性的相对重要性权系数。其结果可作为综合各种预测方案，确定该地区中长期地震危险区的参考依据。     

Geomorphological study on a clastic accretionary prism: The Nankai Trough

Abstract The Nankai Trough, off southwest Japan, is one of the best sites for the study of geomorphic characteristics of a clastic accretionary prism. A recent multibeam survey over the central and eastern parts of the Nankai accretionary prism has revealed a large variation of the topography along the trough axis. Analysis of the bathymetric data suggests the existence of prism deformational features of different scales, such as depressions, embayment structures and cusps. These structures are the results of slope instability caused by basement relief of subducted oceanic plate. Unstable slopes recover by new accretion and development of a low angle thrust. Small-scale deformation due to the subduction of a small isolated seamount is then adjusted to the regional trend. By contrast, a 30 km indentation of the wedge observed in the eastern part of the Nankai Trough, the Tenryu Cusp, has seemed to retain its geometry. The subducted Philippine Sea plate has deformed greatly near the eastern end of the Nankai Trough, because of the collision between the Izu-Ogasawara (Bonin) arc and central Japan. Therefore, the indentation may be the result of the continuous subduction of a basement high, such as the Zenisu Ridge, which has been formed under north-south compression due to the arc-arc collision.     

闽东南大陆边缘构造特征及泉州海外大震构造环境分析

闽东南大陆边缘构造活动，自晚更新世以来，断裂活动以继承性差异升降作为主要特点，本文分析了１６０４年１２月２９日泉州海外８级大震与该区断裂活动的关系，并对该次大震震源断层面错动方式进行了讨论。     

Hypotheses for earthquake occurrences

Very little work has been done in generating alternatives to the Poisson process model. The work reported here deals with alternatives to the Poisson process model for the earthquakes and checks them using empirical data and the statistical hypothesis testing apparatus. The strategy used here for generating hypotheses is to compound the Poisson process. The parameter of the Poisson process is replaced by a random variable having prescribed density function. The density functions used are gamma, chi and extended (gamma/chi). The original distribution is then averaged out with respect to these density functions. For the compound Poisson processes the waiting time distributions for the future events are derived. As the parameters for the various statistical models for earthquake occurrences are not known, the problem is basically of composite hypothesis testing. One way of designing a test is to estimate these parameters and use them as true values. Momentmatching is used here to estimate the parameters. The results of hypothesis testing using data from Hindukush and North East India are presented.     

A three‐component end‐member analysis of streamwater hydrochemistry in a small Japanese forested headwater catchment

Intensive water sampling in conjunction with hydrological observations was conducted during three different rainstorms in order to understand the effects of rainfall events on the temporal variation of streamwater chemistry in a small headwater forest catchment. Concentrations of Na⁺ and SO₄^2? decreased as the discharge rate increased. Hydrograph separation of the components was made using the three‐component model based on the end‐members mixing analysis (EMMA). The three end‐members were:

• 1 the groundwater in the saturated zone that prescribes the chemistry of the baseflow;
• 2 the throughfall that dilutes the streamwater;
• 3 the groundwater in the transient saturated zone prescribed, which was dependent on the groundwater level.

When the groundwater level was lower, only the two components, groundwater in the saturated zone and throughfall, affected the streamwater chemistry. When the groundwater level rose and the saturated zone spread, the groundwater in the transient saturated zone became the third component. When the groundwater in the transient saturated zone contributed to the discharge, this component became the dominant source and the streamwater chemistry was affected by the groundwater chemistry in the transient saturated zone. When this component was discharged as the saturation overland flow, the streamwater chemistry was greatly affected by this component. Copyright © 2001 John Wiley & Sons, Ltd.