依据近年来我国南北地震带部分地区强震、大震与华北地区中等地震活动的某些相关性特征,结合华北地区地震活动演化特点,以及对异常信度较高的区域异常项目对比与分析,山东地震台测震学与综合预报学科对研究区近期发生的一次中等地震,即2022年10月30日渤海海域ML 4.1地震作出预测,并指出:近年来南北地震带中南段中部大震发生前后,华北地区中等以上地震多出现长时间平静现象,且平静打破后,其后续ML 4地震分布也有一定规律可循;莱州湾及附近海域存在小震调制比高值异常;渤海海域及附近部分地区ML 3地震较活跃,同时,ML 3地震能量释放呈逐渐增强态势.希望通过对2022年渤海海域ML 4.1地震预测过程的分析与总结,为今后地震研究相关工作提供借鉴.

大量研究认为,日本地区强震活动与华北地区的中强地震活动之间存在一定相关关系.通过梳理太平洋板块西北缘俯冲带的大震活动,在搜集历史资料的基础上,结合构造背景,重新对日本与华北地区强震活动的相关性进行了分析,最终认为:日本地区8级以上大震与华北地区6级强震之间不存在一一对应的直接相关关系;日本和华北地区大的地震活动期和稳定期具有某种对应性,华北地区活动期的强释放阶段与东西两个构造边界活动存在联系;2011年日本"311"9.0级地震的余震活动基本结束,日本地区可能已经恢复背景的活动节律;当前华北地区可能仍处于活动期末尾的调整期,未来几年,华北地区仍存在进入剩余释放阶段最后一个活跃幕的可能.

1 研究方法 地震活动性是表征某地区地震活动强弱的重要指标,具有地域性和时域性的特点.为将地震活动定量化,引入一个新的模糊量S,该参数是对地震活动性时、空、强诸因素的综合表征,将各隶属函数归一化并以加权组合的方式给出,基本公式为S=1/ n∑n i=1W(Xi)μ～A(X i) (1)式中,Xi是隶属函数的参数,μA～(为隶属函数,W为权因子.

基于时间相依的地震复发间隔混合概率模型,开展山东地区中、短期尺度上的中小地震的概率预测实践,1年的检验结果显示,3、4级中小地震基本发生在此前给出的地震危险性高概率区.研究认为,该方法在日常地震会商中应用效果较好,并有望为破坏性地震的概率预测提供参考.

Through the investigation about the present situation of Shandong Zhucheng dwellings,it was found its seismic performance is poor.The problems of Shandong rural dwellings in the seismic fortification are analyzed and put forward the countermeasures.

On basis of mechanical background analysis of increased seismic activity in southern North China and architectonic relevance between southern North China and the northeast edge of the Tibetan Plateau,significant change of cross-fault short leveling on Gaofengtou,Wusheng,Ganlin and et al.in middle southern segment of the Tanlu fault zone during 2007-2008 is analyzed.The result shows that the significant change may be related to the 2008 Wenchuan M8.0 great earthquake.

对苏、鲁、皖、豫交界地区地震活动进行研究,指出该区2006年10月-2010年10月出现一个长轴约230 km的3级地震空区.该空区及附近地区存在多项中期异常,即ML≥3地震活动具有频度高、能量强,中等地震震中空间分布相对集中及低b值等.讨论认为,苏、鲁、皖、豫交界地区存在多项中期异常,与2004年10月24日太康4.7级地震的强度不匹配,未来具有发生中强以上地震的危险.

In this paper,the group anomalies of seismic activity parameters appeared before sixteen earthquakes of ML≥4.7 in eastern Shandong and its offshore areas since 1970 are studied.The results show that seismic activity parameters related to seismic intensity and frequency are more sensitive to moderate earthquake.Generally,the values of Et,Qp and η are in low level or drop from high level before moderate earthquake,while the values of the other seismic parameters are in high level.Fourteen seismic activity parameters sensitive to moderate earthquake are selected from twenties,and the group abnormal indexes of which are determined.If more than ten parameters of the fourteens show abnormal,the area may be at the risk of occurring earthquake of ML≥5.0.

The paper analyzes the historical materials of Yanzhou earthquake with the earth cracking and springs gushing on August 17,462 A.D.,focusing on the Yanzhou and Lujun legacy during this earthquake.We come to the conclusion that(1) the state government of Yanzhou was in Hulu at that time,presently known as the Shaoyang lake of Weishan county,Shandong Province,but not in Juancheng(now east of Juancheng county) or Xiaqiu(now northeast of Yanzhou) as previously believed;and(2) the county government of Lujun was in Zouxian(now south of Yishan,Zoucheng),but not in Luxian(now Qufu).On this bases,the epicenter is revised(35.0°N,117.0°E,with the reference place names in the junction area of Weishan and Tengzhou of Shandong Province and Class Ⅲ positioning accuracy) in terms of historical earthquake basic parameters and earthquake damages,feeling area,and aftershocks activities.

In this paper,the wave velocity ratio in the Puyang and its surrounding area(35.1°～36.0°N,115.1°～115.7°E) is calculated and tested with T-test. The results show that the Vp/Vs ratio of this area calculated on basis of 41 ML≥2.6 earthquakes is normal in the period of 2001-2008.The focal depth of ML≥3 earthquakes occurred in Heze-Puyang and its surrounding area(35.1°～36.0°N,115.1°～115.7°E) from 1970 to 2008 is analyzed.The result indicates that focal depth(average of 19km) of the earthquakes occurred before Heze 1983 Ms5.9 earthquake are deeper than that(average of 13 km) of earthquakes occurred after the Heze 1983 Ms5.9 earthquake.

On the assumption that current state of earthquake activities in North China will go on,based on Benioff strain released series of different tectonic belts since 1970,many types of non-linear functions have been adopted to fit the strain cumulative release trend.By the proximal and optimal fitting model,the author gives the forecasts of Benioff strain release in the coming 1 to 3 years.According to the linear magnitude frequency law,the author also gives estimation of corresponding max magnitude for each tectonic belt.

Using travel-time equation of direct wave,the average velocity of direct P-wave and direct S-wave(ν-p-=6.13 km/s,ν-s-=3.52 km/s) in Juxian-Tancheng area are calculated based on 23 Multiple screened earthquakes and 130 sets of high-precision seismic parameters.Then,the crustal thickness(HP11,HS11) of the study area are calculated using the reflection P-wave,reflection S-wave.The results indicate that the average crustal thickness in Junan-Tancheng area is about 34.8 km.

Applying Acceleration Index(AI)algorithm,this paper makes statistical retrospective tests for earthquakes with MS≥5.0 in eastern China since 1970.The results show that AI can quantitatively indicate activity strengthen or weaken level of micro earthquakes before moderate-to-strong shocks.If earthquake catalog is completed,activity of micro earthquakes 1 year before moderate-to-strong shocks near epicenters will 'accelerate' or 'decelerate' compared to the 3-year background.

<正>将一定范围内的地震活动视为随机时间序列,则可以用线性回归的方法对未来的地震活动情况进行预测(Vere-Jones,1995)。在地震活动的研究中常采用自回归模型。