用地下水位异常对1998年1月10日张北-尚义MS6.2地震的检验性预测

分析了１９９８ 年１ 月１０ 日张北尚义 Ｍ Ｓ６ ．２ 地震前后晋冀蒙交界地区前兆台网地下水位异常特征．用多层次跟踪预报法对该次地震进行了检验性预测,探讨了地下水位高值异常与该次地震的关系．检验预测结果表明,这些异常就是该次地震的前兆反映     

诱发地震与诱发性前兆

本文以１９６９年以来中国大陆９对ＭＳ≥５．９级地震为例，引出诱发性前兆的概念。诱发性前兆是指远区强震（Ａ）发生后３个月内产生于未来后续地震（Ｂ）附近（△≤２００ｋｍ）的，并与该地震有某种成因联系的继发性异常和新异常。诱发地震与诱发性前兆是反映强震间耦合作用的同因异象。１９８８年以来南北带强震组（１９８８年耿马、澜沧７．６级地震──１９９０年天祝、景泰６．２级地震）诱发地震和诱发性前兆显著，并呈连锁式分布，表明该地震组各强震之间具有较强的耦合作用。     

前兆场稳定度Dk在中强地震前兆资料分析中的应用

提出了前兆场稳定度的概念,利用前兆场稳定度的方法对中强地震前豫鲁冀交界区不同台站和不同手段的前兆观测数据进行分析。结果表明,在１９８３年１１月７日山东菏泽Ｍs５ ．９级和１９８５年１１月３０日河北任县Ｍs５．０级地震前１４个月内,前兆场稳定度有低值异常显示,并且异常幅度越来越大,地震后恢复到正常值。     

张北6.2级地震前宝昌地震台的前兆异常研究

１９９８年１月１０日河北省张北６．２级地震前,距震中１００ｋｍ的内蒙古宝昌地震台石英倾斜仪ＮＳ分量自１９９６年７月出现向南倾斜的趋势异常,ＥＷ分量１９９７年８月向西倾斜的短期异常,并在地震发生前６天之内,倾斜仪固体潮曲线上出现多次阶跃式畸变,可能是张北６．２级地震的临震前兆。与此同时,该台站的地电阻率也在震前２．５个月出现短期异常。     

地震前兆信息量的研究：（三）地震前兆信息量（S值）方法在大同地震研 …

本文采取统一分析模式,系统地研究了１９８９年大同５．８级地震前河北省及其邻近地区各种前兆观测手段所出现的异常变化,并计算了这些异常所提供的前兆信息量,在此基础上,得到了大同地震之前前兆信息场的时,空动态图像,发现１９８９年大同５．８级地震前,河北省及邻近地区前兆信息场,先在震源附近及外围出现,尔后向震源区边缘迁移集中,在保持震源区边缘较强信息的同时,前兆信息又向外围扩展,不久即发生地震。     

地震前兆信息量的研究(三)地震前兆信息量(S值)方法在大同地震研究中的应用

本文采取统一分析模式,系统地研究了１９８９ 年大同５．８ 级地震前河北省及其邻近地区各种前兆观测手段所出现的异常变化,并计算了这些异常所提供的前兆信息量,在此基础上,得到了大同地震之前前兆信息场的时、空动态图像,发现１９８９ 年大同５．８ 级地震前,河北省及其邻近地区前兆信息场,先在震源附近及外围出现,尔后向震源区边缘迁移集中,在保持震源区边缘较强信息的同时,前兆信息又向外围扩展,不久即发生地震。     

多前兆出现时间综合概率法在地震预报中的应用研究

四川、滇江地区２０多种曾在的Ｍ≥６级地震前出现过异常的前兆项目的１００多个数据，初步建立起三期异常持续时间Ｔ＿ｐ的概率分布模型。以此为基础，应用宇津等人发展的综合概率方法对１９８９年巴塘６．７级地震和１９８９年小金６．６级地震作了回顾性预报检验。结果表明这种以各学科观测异常资料为基础的综合概率方法，可能是一种对强震进行异常势态跟踪和预报的较好途径。     

云南水汞的远震和近震前兆异常特征分析

本通过对云南西部７个水汞观测站,１９９０年￣１９９６年９月省内及邻区２６次Ｍ≥５．０级地震的水汞资料进行异常时空强及其形态的分析研究,总结出云南水汞在远震和近震前的前兆异常特征,用这些前兆异常特征对１９９６年９月后１年内各观测站的水汞异常与所发生的地震进行检验,结果很好。此项研究,有助于对未来发震区的判定。     

灰色系统GM模型在地下水动态异常识别中的应用

本应用灰色系统理论的ＧＭ模型对地下水动态资料进行了异常识别，发现在１９８１年河北宁晋ＭＳ５．８级地震、１９８３年荷泽ＭＳ５．９级地震、１９８５年河北任县ＭＳ５．０级地震前，有明显的异常显示，通过选择不同建模数据个数及外推个数，发现对豫０１井五日均值资料建模处理，选择２个月的数据１０天滑动逐次建模识别的异常较清楚。同时对所建模型的精度进行了分析，证明该方法在本区豫０１井、鲁０５井资料处理及前兆异常     

鲁南地区地震活动性异常与苍山ML5.6级地震

利用《地震学分析预报方法程式指南》中的方法分析一鲁南地区的地震活动性异常，发现在苍山ＭＬ５．６级地震前，鲁南地区２３个月无ＭＬ≥２．５级地震；在１９８５年６月新泰ＭＬ４．１级地震以后，ＭＬ≥３．０级地震主要集中在新泰－苍山－莒县之间的三角地带。１９７４年以后沿苍尼断裂的ＭＬ≥３．０级地震都发生在５．６级地震震中附近。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Information for authors

正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research.     

INTERNATIONAL RESEARCH AND TRAINING CENTER ON EROSION AND SEDIMENTATION(IRTCES)

正Director:Shangfu Kuang,China Vice-directors:Chunhong Hu,China Duihu Ning,China Guangquan Liu,China The International Research and Training Center on Erosion and Sedimentation(IRTCES)was jointly set up by the Government of China and UNESCO on July 21,1984.It aims at the promotion of international exchange of knowledge and cooperation in the studies of erosion and     

Calendar of events

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Dynamic process-response model of river channel development

Feedback mechanisms, which operate upstream through drawdown and backwater effects and downstream through sediment discharge are responsible for channel evolution. By combining these mechanisms with channel processes it euables a dynamic process-response model to be developed to simulate the initial evolution of straight gravel-bed channels. When erosion commences on a land surface, sediment entrained in the headwater reach by hydraulic action is selectively transported, deposited and reworked. This produces a damped oscillation between degradation and aggradation as the channel and valley respond to spatial and temporal variations in sediment calibre and hydraulic conditions. The initial cut and fill phases are responsible for valley incision and floodplain development while secondary and subsequent activity can produce river terraces. Eventually sediment entrainment in the headwaters declines as slopes are reduced. Subsequent channel evolution is relatively insignificant because it is dependent on local weathering activity producing material that can be transported on declining slopes. Therefore landforms produced during the initial phase of development, when local weathering was non-limiting, dominate the landscape.