千岛群岛大地震与中国东北地区地震相关性的探讨

在分析3次千岛群岛大地震对应东北地区地震的基础上,讨论了在地质构造背景下千岛群岛大地震引起板块俯冲与我国东北地区地震的相关性.结果表明,千岛群岛发生7级以上地震对应东北地区地震有较强相关性;千岛群岛在大地震破裂过程中产生的俯冲作用自东向西对东北板块产生挤压作用,东北地震区相继发生了浅源地震;千岛群岛地区发生地震时,东北...     

西北地区中强震前固体潮调制比时空特征分析

基于1900—2015年中国大陆地区浅源地震阴历目录,依据地震活跃特征确定固体潮调制阴历日期和调制比阈值,并利用固体潮调制比时空扫描方法回顾性地研究近年来西北地区发生的3次中强地震,即2013年甘肃岷县漳县M_S6.6、2015年内蒙古阿拉善M_S5.8和2016年青海门源M_S6.4地震前, 区域小震的固体潮调制比时空演化过程.研究结果显示:岷县漳县M_S6.6和阿拉善M_S5.8地震前震中区域出现固体潮调制比异常,门源M_S6.4地震前震中附近的固体潮调制比异常演化时间较长; 西北地区3次中强震均发生在固体潮调制比时空扫描的高值异常集中地区及周围区域,扫描时间窗长度和固体潮调制比异常区域的大小可能与中强震的强度有一定的相关性.      

中国东北地区地震活动特征及其与日本海板块俯冲的关系

分析中国东北地区深震 (mb≥ 6 .0 )及浅震 (MS≥ 5 .0 )的成组性活动特征 ,研究了深震“强震组”与浅震“强震组”的时、空相关性。着重探讨了西太平洋板块与欧亚板块碰撞带的地震分布特征及其与西太平洋俯冲带形态的关系 ,并着重分析了西太平洋板块对欧亚板块地震活动的影响。结果表明 :西太平洋板块俯冲倾角小的地区 ,板块碰撞带地震活动强烈 ,板块俯冲对欧亚大陆的影响也较强 ,俯冲带处于较强的挤压应力状态 ;西太平洋板块俯冲倾角大的地区 ,板块碰撞带地震活动较弱 ,板块俯冲对欧亚大陆的影响也较弱 ,深部俯冲带引张应力增强。分析认为 ,未来 10年中国东北地区将进入浅震“强震组”活动时段 ,期间可能发生MS≥ 5 .0地震 6次左右 ,应加强东北地区的地震监测预报工作     

青海昆仑山口西8.1级地震时空强有序特征探讨

通过对2001年11月14日昆仑山口西8.1级地震的时间、空间、强度和触发特征的分析和初步研究认为，昆仑山口西8.1级地震在时间上具备时间节律的特征，符合8级地震24年左右和7级以上地震7年左右的时间节律关系；在空间上存在地震活动等间距、地震集中活动、共轭条带等特征；在强度上符合节律特征，并存在明显地受地球自转，以及月亮、太阳的调制和触发作用. 最后，对巨大地震孕震和发震的条件进行了讨论．      

新一代地震预报专家系统NGESEP预报效能的初步研究

利用４０个地震震例对新一代地震预报专家系统ＮＧＥＳＥＰ的预报效果进行了检验。比较了使用信度分布图和信度等值线图两种方法未来发震地点的效能，分析了系统对地震三要素的预报结果，表明该系统具有较高的预报效能。     

Calculation of Calibration Functions and Explosive Aftershock Magnitudes in the Near Field

The current calibration function used in calculating the magnitude of natural earthquakes within 5km is a constant; a fact that causes several serious difficulties for the calculation of the magnitude of small and shallow-focus earthquakes. According to the attenuation law of explosions and the propagation theory of elastic waves, the calibration function is calculated for near field quakes from 0kin to 5kin. Magnitudes of two aftershock sequences are calculated. The magnitudes of most explosion earthquakes are small, ranging mainly from magnitude -0.5 to 1.0. The M-t chart of the explosive aftershocks is completely different from that of strong earthquake aftershocks. It not only shows positive columnar lines indieatJng large magnitudes but also short negative columnar lines indicating small magnitudes.     

震级频度与古登堡-里克特关系式偏离的前兆意义

地震震级频度的古登堡-里克特关系式(简称G-R关系式)一直是许多地震学问题研究的重要前提之一, 然而实际分布常常与这一关系式有一定的偏离。 文中利用已有的对含有凹凸体、 挤压雁列破裂及Ⅲ型剪切破裂等三种类型的岩石实验结果, 对接收到的声发射事件序列分别进行了分段地震震级频度的G-R关系式拟合, 重点考察了每一时间窗内表征实际地震震级频度与这一关系式偏离程度的线性拟合系数r值的变化。 研究结果表明, 含有凹凸体、 挤压雁列破裂的岩石声发射序列在加压－破裂过程中, 分段扫描分别计算得出的r值在标本失稳前出现数字下降的现象, 表明临近岩石失稳, 实际地震震级频度与G-R关系式偏离程度有加大的趋势; 而含Ⅲ型剪切破裂的岩石在标本失稳前, 声发射序列r值数字下降的现象不明显。 部分实际震例也表明, 在一些中强地震前也存在着这种偏离。 研究结果可能对利用区域地震活动资料探求部分类型的中强地震前可能存在的前兆信息具有一定的参考意义。     

A Review of Earthquake Statistics: Fault and Seismicity-Based Models, ETAS and BASS

There are two fundamentally different approaches to assessing the probabilistic risk of earthquake occurrence. The first is fault based. The statistical occurrence of earthquakes is determined for mapped faults. The applicable models are renewal models in that a tectonic loading of faults is included. The second approach is seismicity based. The risk of future earthquakes is based on the past seismicity in the region. These are also known as cluster models. An example of a cluster model is the epidemic type aftershock sequence (ETAS) model. In this paper we discuss an alternative branching aftershock sequence (BASS) model. In the BASS model an initial, or seed, earthquake is specified. The subsequent earthquakes are obtained from statistical distributions of magnitude, time, and location. The magnitude scaling is based on a combination of the Gutenberg-Richter scaling relation and the modified Båth’s law for the scaling relation of aftershock magnitudes relative to the magnitude of the main earthquake. Omori’s law specifies the distribution of earthquake times, and a modified form of Omori’s law specifies the distribution of earthquake locations. Unlike the ETAS model, the BASS model is fully self-similar, and is not sensitive to the low magnitude cutoff.     

地震活动图像特征与强震危险区经验性预测依据的初步研究

在研究近期（10年）强震危险性判定和总结四川地区1972--2002年强震预测经验的基础上，清理了中国大陆1920--2002年47次浅源大震事件前地震活动图像特征（M≥4．7），提炼出10个方面12项经验性预测依据：主体活动区、多发时段、关联序列、大陆及地区地震异常图像、地区（带）-地段（震源区）地震增强图像（含信号震、诱发地震、地震条带）、相关地震、窗口地震、复发间隔、大陆及地区缺震、地段缺震与地段强震一缺震转折等。它们在47次震例中的综合出现率≥0．58（即依据比7／12以上）占42例；≥0．66（即8／12以上）占34例。因此，强震（M≥4．7）活动图像经验性预测依据可以作为预测有较大可能发生大地震危险区的依据之一。     

关于速报深远震问题的探讨

通过分析云南数字地震台网1998~2006年的地震记录资料,给出了该台网的深远地震震相记录特征,避免了常规分析方法中将深远地震误作浅源地震而带来的定位误差;利用1978年1月~2005年8月的深远地震记录资料,绘制了全球深远地震震中分布图,以作为地震速报的参考。     

日本海板块俯冲与中国东北地震

利用日本海区丰富的震史资料,研究了该区强震活动时—空变化的某些特征,并以此为据,将1900年以来的地震活动划分了三个地震轮回,同时还分析了各轮回的强震地区分布及其持续时间。分析了中国东北地区深震(mb≥6.0)及浅震(MS≥5.0)的成组性活动特征,研究了日本海西部深震与中国东北地区浅震的相关性。这些结果可作为研究日本海区强震高潮到来和结束的标志以及为判断未来主体活动区等强震预测问题提供线索。     

MDCB-5型临震信息监测仪模拟未来震级大小计算初探

根据MDCB－5型临震信息监测仪记录到的某一地震临震异常幅度（电压值）、持续时间（天数）与岩石破裂、地震发生、地震波能量释放的相关性，从地震发生的物理基础出发，推导出了2个计算未来震级大小的理论公式。使用44天的监测数据对该期间发生的5次6级以上地震的震级进行了计算，在相应的震中距范围内计算的震级与实际发生的震级误差小于0．5级，初步说明了该方法应用于实际地震预报具有一定的参考价值。     

Discussion on the feature of strong earthquake: Orderly distribution in time, space and intensity before the Western Kunlun Mountain Pass M=8.1 earthquake

Introduction The Western Kunlun Mountain Pass M=8.1 earthquake occurred on November 14, 2001 is the other M=8 earthquake occurred 50 years after Dangxiong, Tibet M=8.0 earthquake in Chinese mainland. The earthquake has caused the attention of the seismologists in the following aspects: 1) The fracture length is more than 400 km, which is far away from the estimated length by the statistic empirical function between the magnitude and the fracture length (WANG, et al, 2002); 2) The aftersh…     

地震形势的模糊综合评判

由中国大陆板块内部地震活动与其周缘地震活动的相关性,可以确定我国大陆未来地震活动的主体和地震活动高潮时间[1].在此基础上,本文进一步探讨用长时间、大面积的地震活动信息,对重点监测区未来地震作出时、空、强综合评判.全文分为三部分:1.地震强度的预报.对于确定的能有效地估计未来地震强度的5项地震活动性指标,选择加权平均型的模糊综合评判方法,对监测区未来地震的震级给出明确的结果.2.发震地点预报.对于扫描单元定义了反映b值时空变化的二项指标:b值异常次数A_yi;和b值异常均值b_yi.通过对二项指标空间分布的综合分析,可以估计未来地震发生的地点.3.发震时间预报.把缺震时间T_l与b值回升时间T_bu,作为描述大震前平静过程的二项定量指标.在对未来地震强度作出模糊综合评判后,可用T_l,T_bu二项指标综合推断监测区未来地震发生的时间.总结的九个震例结果表明,该方法可使地震预报定量化、实用化,可以用于地震形势的预测和中、短期地震预报.      

Earthquake magnitude or seismic moment in seismic hazard evaluation?

Seismic hazard analysis requires the estimation of the probabilities that earthquakes will take place within a region of interest, and the expected level of ground motion which will be received at a site during the nextt years. The earthquake magnitude has been used as a basic parameter, because it is available, under the assumption that the earthquake occurrence is a compound Poisson process with exponential or multinomial distribution of magnitude.For improving the hazard prediction, we used the seismic moment as a basic parameter to estimate the mean rate, , of occurrence of earthquakes in a function of seismic moment rate and slip rate released in a seismogenic region.As an illustration of the model, the seismic hazard analysis at different sites in and around the Gulf of Corinth, central Greece, is presented on the basis of the earthquake magnitude and the seismic moment. Comparison of the results shows that determination of the mean rate of earthquake occurrence, using the conventional Gutenberg-Richter recurrence model, underestimates the seismic hazard at a site.     

Research on determining the annual earthquake occurrence rates of potential seismic source areas

To actually reflect the seismic temporal-spatial inhomogeneity of intra continental strong earthquakes of North China in seismic hazard analysis, several seismological and geological characteristics have been selected and quantized to describe the seismicity features in time and space of every magnitude interval with the thought of dividing the interesting magnitude range into several intervals and using of spatial probability distribution function. A component analysis method with orthogonal transformation is introduced to avoid the repeated use of the same element and the subjective effects in determining the annual earthquake occurrence rates of earthquake. By passing synthetic fuzzy judgement on the nonintercorrelated new characteristics, the annual occurrence rates of every magnitude interval of each potential source area are obtained associated with the adjustments of earthquake reducing process after the occurrence ofM>7 quake. An intensity map of the Beijing-Tianjin-Zhangjiakou area is calculated as an example which shows a close coincidence with the seismic temporal-spatial inhomogeneity of North China. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 496–504, 1991.     

中国大陆东部地区中强震水位异常的统计特征

中国大陆东部地区的地震活动以中强震为主。本文在前人工作的基础上用统计学的方法系统分析了该区中强震前地下水位动态异常的形态,时间与空间分布特征及其与地震三要素的关系,由此建立了地震预报的指标,并用1989年10月大同-阳高6.1级地震的实例进行了其信度与预报效能的检验     

Focal depth,magnitude, and frequency distribution of earthquakes along oceanic trenches

The occurrence of earthquakes in oceanic trenches can pose a tsunami threat to lives and properties in active seismic zones. Therefore, the knowledge of focal depth, magnitude, and time distribution of earthquakes along the trenches is needed to investigate the future occurrence of earthquakes in the zones. The oceanic trenches studied, were located from the seismicity map on: latitude +51° to +53°and longitude-160° to 176°(Aleutian Trench), latitude+40° to +53° and longitude +148° to +165°(Japan Trench), and latitude-75° to-64° and longitude –15° to+30°(Peru–Chile Trench). The following features of seismic events were considered: magnitude distribution, focal depth distribution, and time distribution of earthquake. The results obtained in each trench revealed that the earthquakes increased with time in all the regions. This implies that the lithospheric layer is becoming more unstable. Thus, tectonic stress accumulation is increasing with time. The rate of increase in earthquakes at the Peru–Chile Trench is higher than that of the Japan Trench and the Aleutian Trench. This implies that the convergence of lithospheric plates is higher in the Peru–Chile Trench. Deep earthquakes were observed across all the trenches. The shallow earthquakes were more prominent than intermediate and deep earthquakes in all thetrenches. The seismic events in the trenches are mostly of magnitude range 3.0–4.9. This magnitude range may indicate the genesis of mild to moderate tsunamis in the trench zone in near future once sufficient slip would occur with displacement of water column.     

Discussion on the feature of strong earthquake: Orderly distribution in time,space and intensity before the Western Kunlun Mountain Pass <Emphasis Type="Italic">M</Emphasis>=8.1 earthquake

In the paper, the feature of strong earthquake orderly distribution in time, space and intensity before the Western Kunlun Mountain Pass M=8.1 earthquake is preliminarily studied. The modulation and triggering factors such as the earth rotation, earth tides are analyzed. The results show that: the giant earthquakes with the magnitude more than 8 occurred about every 24 years and the earthquakes with the magnitude more than 7 about every 7 years in Chinese mainland. The Western Kunlun Mountain M=8.1 earthquake exactly occurred at the expected time; The spatial distance show approximately the same distances between each two swarms. The earth rotation, earth tide, sun tide and sun magnetic field have played a role of modulation and triggering in the intensity. At last, the conditions for earthquake generation and occurrence are also discussed.     

A Simplified Approach to Earthquake Risk in Mainland China

There are limitations in conventional earthquake loss procedures if attempts are made to apply these to assess the social and economic impacts of recent disastrous earthquakes. This paper addresses the need to develop an applicable model for estimating the significant increases of earthquake loss in mainland China. The casualties of earthquakes were studied first. The casualties of earthquakes are strongly related to earthquake strength, occurrence time (day or night) and the distribution of population in the affected area. Using data on earthquake casualties in mainland China from 1980 to 2000, we suggest a relationship between average losses of life and the magnitude of earthquakes. Combined with information on population density and earthquake occurrence times, we use these data to give a further relationship between the loss of life and factors like population density, intensity and occurrence time of the earthquake. Earthquakes that occurred from 2001 to 2003 were tested for the given relationships. This paper also explores the possibility of using a macroeconomic indicator, here GDP (Gross Domestic Product), to roughly estimate earthquake exposure in situations where no detailed insurance or similar inventories exist, thus bypassing some problems of the conventional method.