对1954年民勤7级地震的初步研究

较系统地研究了１９５４年民勤７级地震的宏观震中、震区烈度分布及地质构造背景等问题,并圈定了极震区范围,根据调查结果认为,该次地震是由于红崖山－四道山断裂在ＮＥ向或ＮＮＥ向主压应力作用下,发生左旋斜冲向东端扩张破裂的结果,与ＮＮＷ向构造带的复合也有一定的关系。     

Earthquake swarms preceding the 2000 eruption of Miyakejima volcano, Japan

The first sign of magma accumulating beneath Miyakejima, an island volcano in the northern Izu islands, Japan, came at around 18:00 on 26 June 2000, when a swarm of earthquakes was detected by a volcano seismic network on the island. Earthquakes occurred initially beneath the southwest flank near the summit and gradually migrated west of the island, where a submarine eruption occurred the next morning. Earthquakes then migrated further to the northwest between Miyakejima and Kozushima, another volcanic island and developed to the most intense earthquake swarm ever observed in and around Japanese archipelago. To better image how the initial magma intrusion occurred, we relocated hypocenters by using a station-correction method and a double-difference method. The relocated epicenters are generally concentrated near the upper bound of dyke intrusions inferred from geodetic studies throughout the initial stages of the 2000 eruption at Miyakejima from 26 to 27 June 2000. As for seismic activity westward off Miyakejima in the morning on 27 June, hypocenters from both a nationwide seismic network that were relocated by the double-difference method, and those from the volcano seismic network relocated by the station-correction method, formed a very shallow cluster that ascended slowly with time as it propagated northwestward from Miyakejima. This suggests that the dykes have both a radial and upward component of movement.Editorial responsibility: S. Nakada, T. Druitt     

青海地区地震序列参数的早期特征研究

采用时间序列的"传染型余震序列"(ETAS)模型系统估算了青海地区地震序列参数,并对地震序列的震后早期特征进行分析。采用"自然边界法"选取了2009年以来青海地区9个地震序列,利用"震级-序号"法确定了每个地震序列的完整性震级M_c,并对每个地震序列进行估算。研究表明,截止震级选取对地震序列参数的影响很大,在应用中需谨慎。α值和p值的稳定时间与序列的主震震级间没有明显的关系,主震震级较大的地震序列,序列参数的稳定时间可能较短;主震震级较小的地震序列,序列参数的稳定时间也可能较长。同一个地震序列,α值和p值的稳定时间与不同截止震级间也没有明显的对应关系。最后给出了研究区域地震序列参数的最长稳定时间和最短稳定时间。     

青藏块体东北缘跨断层形变典型震例总结与预测判据指标分析

针对青藏块体东北缘跨断层监测区及周边发生的5.8级以上地震, 结合以往研究结果, 对跨断层资料进行了重新梳理, 重点分析了1995年永登5.8级、 2000年景泰5.9级、 2003年民乐—山丹6.1级和2013年岷县漳县6.6级地震前出现的跨断层形变异常。 结果表明: 这4次典型地震前出现的跨断层异常数量较多, 为13~23项不等; 分布范围较广, 震中距在600 km范围内, 相对集中出现在300 km左右范围内, 也有近震区异常; 异常特征以逆断加速、 趋势转折、 活动加剧、 突跳、 大幅变化等为主; 震前2~3年或稍长时间开始出现异常, 震前半年至1年半时段异常集中出现, 具有中期背景或短期前兆意义, 异常空间分布有向震中区汇聚迁移的特征。     

从断裂强度到临界点──重整化群理论在地震预报中的应用述评

介绍了临界自组织现象和重整化群方法的基本原理，对地震的自组织临界行为作了较为深入的讨论，并就这一领域中的一些概念和观点发表了作者自己的见解。     

浅谈地震灾害符号体系构建的理论框架

地震灾害符号的研究已经成为地震应急工作的一项重要内容,本文借助于符号学及传播学的方法论,在分析地震灾害符号的符号学内涵、使用人群和传播内容的基础上,探讨了地震灾害符号体系的特点及构建原则。地震本身的特殊性和破坏性决定了地震灾害符号体系的特殊性和时间性,本文在遵循实用性、主次性及概括性三个原则的前提下,提出了一套地震灾害符号体系构建的理论框架,可为地震灾害符号体系的构建和深入研究提供参考。     

江苏省盐城地区地震活动特征及震灾分析

对盐城地区地震活动概况进行了背景性分析,从该地区地震地质构造背景人手,阐述了影响盐城地区地震活动的主要断裂构造．对研究区域内的地震活动空间、时问分布特征进行了探讨,并分析了盐城地区的地震灾害特点。     

Progress in the Application of Ground Gravity Observation Data in Earthquake Prediction

The mechanism of earthquake inoculation and the process of earthquake occurrence are very complicated. Additionally, earthquakes do not happen very often, and we lack enough cognition to the earth’s interior structure, activity regularity and other key elements. As a result, research progress about the theory of earthquake precursors has been greatly restricted. Ground gravity observation has become one of the main ways to study earthquake precursor information in many countries and regions. This paper briefly summarized the surface gravity observation technology and observation network in China: the surface gravity measurement instrument developed from Huygens physical pendulum in seventeenth Century to today’s high-precision absolute gravimeter, and its accuracy reached to ±1×10^-8 m/s². China has successively established the National Gravity Network, Digital Earthquake Observation Network of China,the Crustal Movement Observation Network of China Ⅰ and the Crustal Movement Observation Network of China, to provide a public platform for monitoring non tidal gravity change, seismic gravity and tectonic movement. The use of specific examples illustrated the role of gravity observation data in earthquake prediction. The gravity observation data of ground gravity can be used to capture the information of gravity change in the process of strong earthquake inoculation, and to provide an important basis for the long-term prediction of strong earthquakes. The temporal and spatial variation characteristics of the regional gravity field and its relation to strong earthquakes were analyzed: Before the earthquake whose magnitude is higher than M_S 5, generally there will be a large amplitude and range of gravity anomaly zones. Strong earthquakes occur mainly in areas where the gravity field changes violently. The dynamic change images of gravity field can clearly reflect the precursory information of large earthquakes during the inoculation and occurrence. Finally, the existing problems of surface gravity technology in earthquake precursor observation were put forward and the use of gravity measurement data in earthquake prediction research was prospected.     

Morphological characteristics of the earthquake surface ruptures on Awaji Island, associated with the 1995 Southern Hyogo Prefecture Earthquake

Abstract The earthquake surface ruptures on the northern side of Awaji Island accompanying the 1995 Southern Hyogo Prefecture Earthquake in Japan consist of three earthquake surface rupture zones called the Nojima, Matsuho, and Kusumoto Earthquake Surface Rupture Zones. The Nojima Earthquake Surface Rupture Zone is - 18 km long and was formed from Awaji-cho at the northern end of Awaji Island to Ichinomiya-cho. It occurred along the pre-existing Nojima geological fault in the northern segment and as a new fault in the southern segment. The northern segment of the Nojima Earthquake Surface Rupture Zone is composed of some subparallel shear faults showing a right-step en echelon form and many extensional cracks showing a left-step en echelon form. The southern segment consists of some discontinuous surface ruptures which are concentrated in a narrow zone a few tens of meters in width. This surface rupture zone shows a general trend striking north 30°-60° east, and dipping 75°-85° east. The deformational topographies and striations on the fault plane generated during the co-seismic displacement show that the Nojima Earthquake Surface Rupture Zone is a right-lateral strike-slip fault with some reverse component. Displacements measured at many of the outcrops are generally 100-200 em horizontally and 50-100 em vertically in the northern segment and a few em to 20 em both horizontally and vertically in the southern segment. The largest displacements are 180 em horizontally, 130 em vertically, and 215 em in netslip measured at the Hirabayashi fault scarp. The Matsuho Earthquake Surface Rupture Zone striking north 40°-60° west was also found along the coastline trending northwest-southeast in Awaji-cho for ～1 km at the northern end of Awaji Island. The Kusumoto Earthquake Surface Rupture Zone occurred along the pre-existing Kusumoto geological fault for ～ 1.5 km near the northeastern coastline, generally striking north 35°-60° east, dipping 60°-70° west. From the morphological and geomorphological characteristics, the Nojima Earthquake Surface Rupture Zone can be divided into four segments which form a right-step en echelon formation. The geological and geomorphological evidence and the aftershock epicenter distributions show clearly that the distributions and geometry of these four segments are controlled by the pre-existing geological structures.     

2003年青海德令哈6.6级地震前地震活动和前兆异常特征

2003年4月17日青海省德令哈市西北发生6.6级地震。该地震发生在具有强烈活动特征的大柴旦—宗务隆山断裂带上,震前地震活动表现出明显的大面积ML4级地震平静,而震中附近则同时出现了高频次、高GL值异常以及ML3级地震平静—活跃、ML4级地震平静等异常现象。对省内及甘肃省前兆观测资料进行追踪分析,认为震前有4项前兆测项呈现出中期和短期异常特征。