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Generalized Rydelek-Sacks test for distinguishing between periodic and randompatterns in seismicity 被引量:2
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作者 吴忠良 《Acta Seismologica Sinica(English Edition)》 CSCD 1999年第5期534-541,共8页
For distinguishing the periodicity of strong earthquakes on the time scale of decades, we generalized the Rydelek-Sacks test (R) delek. Sacks. 1989) to explore whether a time series is modulated by a periodic process ... For distinguishing the periodicity of strong earthquakes on the time scale of decades, we generalized the Rydelek-Sacks test (R) delek. Sacks. 1989) to explore whether a time series is modulated by a periodic process or not. Thetest is conducted by comparing the total phasor of seismicity with that produced by a random Brownian motion.The phdse angle is defined by the origin time of earthquakes relative to a reference time scale. Using this methodwe tested two hypotheses in geodynamics and earthquake prediction study. One is the hypothesis of Romanowicz( 1993 ) who proposed that the great earthquakes alternate in a predictable fashion between strike-slip and thrustingmechanisms oil a 20~30 years cycle. The other hypothesis is that the strong earthquakes in and around China havean active period of about ten years. The test obtains a negative conclusion for the former hypothesis and a positiveconclusion for the latter at the 93% confidence level. 展开更多
关键词 seismicITY Rydelek-Sacks test periodICITY earthquake prediction
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Influence of long period seismic waves induced by the Taiwan large earthquake on Shanghai area
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作者 庄昆元 徐永林 +1 位作者 沈建文 丁伟国 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第6期87-94,共8页
In this paper a group of long period seismic waves in Shanghai area induced by Taiwan large earthquake is presented by using the method of semi empirical Green function, the period is up to 20 s. Such seismic waves c... In this paper a group of long period seismic waves in Shanghai area induced by Taiwan large earthquake is presented by using the method of semi empirical Green function, the period is up to 20 s. Such seismic waves can be used as a reference curve to test the strength of long period structures and their aseismic design. The long period part of seismic influence curve presented in 'Architecture Aseismic Design Code'(GBJ11 89) is less than 3 s, and uncertainties exist in the effects of earthquake safety evaluation. This research will be able to eliminate these shortages. 展开更多
关键词 fault rupture length rupture velocity semi empirical Green function long period seismic wave
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Simulation of the active and quiet periods of seismicity
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作者 黄忠贤 《Acta Seismologica Sinica(English Edition)》 CSCD 1996年第2期245-253,共9页
In this paper we simulate the repeated occurrence of strong earthquakes along a strike-slip fault by using a finite element model. The fault valve mechanism is included in the model in order to take into account the e... In this paper we simulate the repeated occurrence of strong earthquakes along a strike-slip fault by using a finite element model. The fault valve mechanism is included in the model in order to take into account the effeCt of POre fluid pressure variation. Five parameters are used to characterize the rheology of the fault, POre pressure variation, and fracture criteria. By Systematically varying these parameters and calculating a large number of models we carried out a preliminary investigation on the alternatively quiet and active periods of seismicity and their relation to model Parameters and loading conditions. Under the action of a constant-rate boundary movement, in the case of intermediate stress and pore pressure, the models display a regular quiescence-activity phenomenon with a cycle length of 1/3-1 of the recurrence pened. When the model is under high stress or high pore pressure, this phenomenon becomes irregular or inexplicit. When the model is subject to periedic boundary forces and the amplitude of force variation is not too small, it results in an alternatively quiet and active seismicity Pattern with the same Period Of the force variation. 展开更多
关键词 earthquake model finite element method seismicITY active period quiet period.
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Correlation of Structural Seismic Damage with Fundamental Period of RC Buildings
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作者 Anastasia K. Eleftheriadou Athanasios I. Karabinis 《Open Journal of Civil Engineering》 2013年第1期45-67,共23页
The sufficient estimation of the natural period of vibration constitutes an essential step in earthquake design and assessment and its role in the development of seismic damage is investigated in the current research.... The sufficient estimation of the natural period of vibration constitutes an essential step in earthquake design and assessment and its role in the development of seismic damage is investigated in the current research. The fundamental period is estimated for typical reinforced concrete building types, representative of the building stock of Southern Europe, according to existing relationships. The building typologies also represent groups of 180,945 existing damaged buildings of an observational database created after the Athens (7-9-1999) near field earthquake. The estimated fundamental periods are correlated to several degrees of the recorded damage. Important conclusions are drawn on the parameters (height, structural type, etc.) that influence the seismic response and the development of damage based on the wide database. After conducting a correlation analysis, noticeable is the difference between the seismic demand of the elastic spectrum of the first (1959), the contemporary (2003) Greek Seismic Code and the values of peak ground accelerations of several Athens earthquake records. Moreover, PGAs in most records are often between the lower and the upper bound of the estimated fundamental periods for RC buildings with regular infills (n-normal) and with ground levels without infill panels (p-pilotis) regardless the height. A disparity is noticed when the estimated fundamental period is based on EC8 provisions for the considered as “high” buildings in S. Europe regarding the referring earthquake. The majority of buildings that developed several degree, type and extent of damage are considered of “low” height with estimated fundamental periods close to the PGA values of Athens earthquake ground motions. However, the developed damage was the result of the combination of parameters based on geological, tectonic and morphological characteristics of the affected area. In addition, a damage scale for the measurable recording, beyond the qualitative characterization of seismic damage in Greek post-earthquake surveys, is presented wherein the performance levels are defined according to the physical description of the seismic damage and, as well, in terms of structural and economic damage index. 展开更多
关键词 seismic DAMAGE period of Vibration FUNDAMENTAL period DAMAGE Scale OBSERVATIONAL DAMAGE Database ATHENS Earthquake
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Seismic pounding and collapse behavior of neighboring buildings with different natural periods
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作者 Daigoro Isobe Tokiharu Ohta +1 位作者 Tomohiro Inoue Fujio Matsueda 《Natural Science》 2012年第8期686-693,共8页
Seismic pounding phenomena, particularly the collision of neighboring buildings under long-period ground motion, are becoming a significant issue in Japan. We focused on a specific apartment structure called the Nuevo... Seismic pounding phenomena, particularly the collision of neighboring buildings under long-period ground motion, are becoming a significant issue in Japan. We focused on a specific apartment structure called the Nuevo Leon buildings in the Tlatelolco district of Mexico City, which consisted of three similar buildings built consecutively with narrow expansion joints between the buildings. Two out of the three buildings collapsed completely in the 1985 Mexican earthquake. Using a finite element code based on the adaptively shifted integration (ASI)-Gauss technique, a seismic pounding analysis is performed on a simulated model of the Nuevo Leon buildings to understand the impact and collapse behavior of structures built near each other. The numerical code used in the analysis provides a higher computational efficiency than the conventional code for this type of problem and enables us to address dynamic behavior with strong nonlinearities, including phenomena such as member fracture and elemental contact. Contact release and recontact algorithms are developed and implemented in the code to understand the complex behaviors of structural members during seismic pounding and the collapse sequence. According to the numerical results, the collision of the buildings may be a result of the difference of natural periods between the neighboring buildings. This difference was detected in similar buildings from the damages caused by previous earthquakes. By setting the natural period of the north building to be 25% longer than the other periods, the ground motion, which hada relatively long period of 2 s, first caused the collision between the north and the center buildings. This collision eventually led to the collapse of the centerbuilding, followed by the destruction of the north building. 展开更多
关键词 seismic POUNDING Collapse Behavior Neighboring BUILDINGS NATURAL period Asi-Gauss Technique
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Joint observation of long period tremor signals with broadband seismometer,tiltmeter and gravimeter 被引量:25
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作者 张雁滨 蒋骏 +2 位作者 廖盈春 李胜乐 钟铁涛 《地震学报》 CSCD 北大核心 2008年第6期626-633,共8页
We report here the observation result of joint observation of long period tremor signals with broadband seismome-ter,tiltmeter and gravimeter at the HUST(Huazhong University of Science and Technology)station.The obser... We report here the observation result of joint observation of long period tremor signals with broadband seismome-ter,tiltmeter and gravimeter at the HUST(Huazhong University of Science and Technology)station.The observed data were compared and analyzed.Since 2005,the several tens of abnormal tremor signals which are weak,com-plex and duration of 2 to 3 days have been synchronously recorded by the different instruments.The tremor signals have the periodic domain in the range of 3 to 5 minutes,20 to 30 minutes and even more than 1 hour.The observa-tion shows such tremors are a physical existence.The analysis indicates that a part of the tremors caused by the typhoon from the western Pacific Ocean.These tremors have a close relationship with wind velocity of typhoon and distance between the typhoon center and the station.Except these,the cause of others is still unclear. 展开更多
关键词 宽频地震观测 重力观测 倾斜观测 长周期信号 震颤 台风
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The seismicity research in the sub-regions of Chinese mainland using strain accumula-ting and releasing model 被引量:2
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作者 马宏生 刘杰 +1 位作者 张国民 李丽 《Acta Seismologica Sinica(English Edition)》 CSCD 2002年第6期595-606,共12页
The sub-regions are divided for the seismicity of the Chinese mainland based on the hypothesis of the active crustal blocks and the division of the active boundaries. On this result, the seismicity of each active crus... The sub-regions are divided for the seismicity of the Chinese mainland based on the hypothesis of the active crustal blocks and the division of the active boundaries. On this result, the seismicity of each active crustal blocks are studied by calculating the accumulated and released strain of the earthquakes based on strain accumulating and releasing model, and the different seismicity stages of the sub-regions are discussed basically. Finally we have discussed the premise of the model application and the potential problems of the model results. 展开更多
关键词 strain accumulation and release active crustal block seismicITY seismic active period +
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A new seismic isolation system and its feasibility study 被引量:8
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作者 Jia Gaofeng~+ and Shi Zhifei~(++) School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China Graduated Student ++ Professor 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第1期75-82,共8页
This paper introduces a new seismic isolation system called a periodic foundation (PF), where inclusions are periodically arranged. The PF is different from traditional base isolation in that it causes a fundamental... This paper introduces a new seismic isolation system called a periodic foundation (PF), where inclusions are periodically arranged. The PF is different from traditional base isolation in that it causes a fundamental frequency shift in the structure, thus reducing its response and generating a frequency gap. If the frequency contents of a seismic wave fall into the gap, it can not propagate in the foundation. Thus, it will exert no influence on the structure above. A systematic study of the band of frequency gap for a 2D PF is conducted. The influence of physical and geometrical parameters such as density and elastic modulus as well as filling fraction of the PF and its materials on the band of frequency gap are investigated, and a design with a frequency gap as low as 2.49-3.72 Hz is achieved. This band of frequency gap corresponds well to the design spectra in earthquake engineering. Numerical simulations of a six-story frame structure with different foundations demonstrate that a proposed PF can greatly reduce the seismic response of an isolated structure. This investigation shows that PFs have great potential in future applications of seismic isolation technology. 展开更多
关键词 seismic isolation periodic foundation band of frequency gap
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Study of characteristics of long-period ground motion response spectra by using broad-band records of the Chinese Digital Seismograph Network 被引量:1
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作者 汪素云 俞言祥 吕红山 《Acta Seismologica Sinica(English Edition)》 EI CSCD 1998年第5期41-48,共8页
Broad band and very broad band (BB and VBB) records of Chinese Digital Seismograph Network (CDSN) from 65 earthquakes are used to calculate the horizontal relative displacement, relative velocity and absolute accelera... Broad band and very broad band (BB and VBB) records of Chinese Digital Seismograph Network (CDSN) from 65 earthquakes are used to calculate the horizontal relative displacement, relative velocity and absolute acceleration response spectra with critical damping ratio ζ =0.005, 0.01, 0.02, 0.05 and 0.10, respectively. The results show that it is insufficient to obtain the credible characteristics of long-period ground motion response spectra only with the common ground acceleration records in engineering, while the broad band records of CDSN, as an important supplementary to ground acceleration records, can be used to study the characteristics of long-period ground motion response spectra. 展开更多
关键词 CDSN broad band digital seismic record long-period response spectrum
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Effect of site amplification on inelastic seismic response 被引量:4
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作者 Adhikary S Singh Y 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第3期535-554,共20页
The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility ... The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility demand, on the eff ective periods, is investigated, and inelastic site amplifi cation is shown to be strongly correlated to the normalized eff ective period. Two non-dimensional parameters, analogous to the conventional site amplifi cation factors in codes, are defi ned to quantify the inelastic site amplifi cation. It is shown that the inelastic site amplifi cation factor (i.e. ratio of constant ductility spectral ordinates at soil site to those at rock outcrop) is able to represent the site eff ects more clearly, as compared to the inelastic site amplifi cation ratio (i.e. ratio of inelastic spectral ordinates at soil site to the corresponding elastic spectral ordinates at rock outcrop). Further, the peak in the amplifi cation factor corresponding to the eff ective site period diminishes rapidly with increasing ductility demand. 展开更多
关键词 SITE amplifi CATION normalized RESPONSE SPECTRA eff ective period INELASTIC seismic RESPONSE INELASTIC SITE amplifi CATION factor
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A Computer Model for Cyclic Activity of Strong Earthquakes in Continental Seismic Zones
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作者 Zhang Guomin,Geng Lumin,and Shi YaolinCenter for Analysis and Prediction,Beijing 100036,China,’Graduate School,Academia Sinica,Beijing 100039,China 《Earthquake Research in China》 1995年第1期20-34,共15页
Based on the study of activity of earthquakes with M**********】7.0 in China's Mainland,we have found a dynamic pattern,i.e.,the cyclic characteristics in time and migration from one seismic zone to another in spa... Based on the study of activity of earthquakes with M**********】7.0 in China's Mainland,we have found a dynamic pattern,i.e.,the cyclic characteristics in time and migration from one seismic zone to another in space.In order to understand the physical mechanism of this pattern,we use a nonlinear dynamic model to simulate the seismic activity in fault zones under a unified tectonic stress field.The basic elements in our model consist of a Maxwell body and a rigid sliding block.Basic elements in a column represent a fault,and coupling elements connecting different columns simulate the interaction among faults and fault segments.The results provide insights to the cyclic activity of strong earthquakes and to the feature of mutual influence between strong earthquakes in groups in the climax of seismic activity. 展开更多
关键词 seismic period Physical model seismicITY ZONE seismicITY feature
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四川康定—磨西断裂强震危险背景研究 被引量:1
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作者 环文林 张萌 潘华 《地震科学进展》 2024年第10期671-679,共9页
本文对四川西部鲜水河断裂带上的康定—磨西断裂的强震危险性作了分析探讨。该断裂位于川西—滇东第Ⅲ弧形挤出构造带的弧顶转折部位,这里应力高度集中,块体左旋大幅度滑移,断裂两侧垂直差异运动幅度达1000~2000 m,为大陆板块内部断裂... 本文对四川西部鲜水河断裂带上的康定—磨西断裂的强震危险性作了分析探讨。该断裂位于川西—滇东第Ⅲ弧形挤出构造带的弧顶转折部位,这里应力高度集中,块体左旋大幅度滑移,断裂两侧垂直差异运动幅度达1000~2000 m,为大陆板块内部断裂活动性较高的地震区。鲜水河断裂带是我国地震活动性和重复性都很高的一条左旋走滑断裂带,自1725年至今接近300年的时间里,鲜水河断裂带上重复出现了2期地震活动,地震重复周期为100~200年。康定—磨西断裂于1786年发生过7¾级大地震,此地震发生迄今已237年,断裂一直处于能量积累的相对平静期。近期地震活跃起来,2022年9月6.8级四川沪定磨西地震以后5.6级以下的中小震频繁发生,并沿着磨西断裂成带分布,是否预示着该断裂又重新活动起来,进入新的地震活动期?这些特征表明康定—磨西断裂具有大地震孕育发生的背景条件。 展开更多
关键词 康定—摩西断裂 鲜水河断裂带 鲜水河-滇东挤出构造 地震活动重复周期 大地震危险性
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A preliminary study on seismic design criteria of offshore platforms in Bohai Sea of China
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作者 Peng Yanju1,Lu Yuejun1,Yan Jiaquan2,Tang Rongyu1,Wang Junqin3 and Li Jiagang3 1. Institute of Crustal Dynamics,China Earthquake Administration,Beijing 100085,China 2. Institute of Geophysics,China Earthquake Administration,Beijing 100081,China 3. Beijing Research Center of China National Offshore Oil Corp.,Beijing 100027,China 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第2期223-231,共9页
This paper analyzes the seismicity in Bohai Sea,introducing a shape factor K to characterize the seismic risk distribution in sub-regions of the sea. Based on the seismic design ground motions for 46 platforms located... This paper analyzes the seismicity in Bohai Sea,introducing a shape factor K to characterize the seismic risk distribution in sub-regions of the sea. Based on the seismic design ground motions for 46 platforms located in the Bohai Sea,a statistical analysis was performed for different peak ground acceleration (PGA) ratios at two different probability levels. In accordance with the two-stage design method,a scheme of two seismic design levels is proposed,and two seismic design objectives are established respectively for the strength level earthquake and the ductility level earthquake. By analogy with and comparison to the Chinese seismic design code for buildings,it is proposed that the probability level for the strength level earthquake and ductility level earthquake have a return period of 200 and 1000 - 2500 years,respectively. The validity of these proposed values is discussed. Finally,the PGAs corresponding to these two probability levels are calculated for different sub-regions of the Bohai Sea. 展开更多
关键词 fixed offshore platform seismic design level seismic design objective return period Bohai Sea
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New national seismic zoning map of China 被引量:1
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作者 GAO Meng-tan(高孟潭) 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第6期639-645,共7页
A new set of seismic zoning maps were published in August 1, 2001. It includes two maps, one is the seismic zon-ing map of peak acceleration, and the other is the zoning map of the characteristic period of the respons... A new set of seismic zoning maps were published in August 1, 2001. It includes two maps, one is the seismic zon-ing map of peak acceleration, and the other is the zoning map of the characteristic period of the response spectrum. The exceeding probability of the map is 10% within 50 years. The scale of the map is 1:4 000 000. These maps serve as the national standard. The background of this project, technical approach and key scientific measures, the basic feature and the application of the maps are introduced in this paper. 展开更多
关键词 seismic hazard seismic zoning earthquake design response spectrum INTENSITY characteristic period
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装配式轻钢框架-轻钢骨架轻混凝土墙板结构抗震性能 被引量:5
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作者 曹万林 杨兆源 《北京工业大学学报》 CAS CSCD 北大核心 2024年第2期165-179,共15页
为研究装配式轻钢框架-轻钢骨架轻混凝土墙板结构抗震性能,对1个足尺轻钢框架结构试件和3个足尺轻钢框架-轻钢骨架轻混凝土墙板结构试件进行了低周反复荷载下的抗震性能试验及理论分析,试件变量包括:2种装配构造,即内嵌式装配墙板、外... 为研究装配式轻钢框架-轻钢骨架轻混凝土墙板结构抗震性能,对1个足尺轻钢框架结构试件和3个足尺轻钢框架-轻钢骨架轻混凝土墙板结构试件进行了低周反复荷载下的抗震性能试验及理论分析,试件变量包括:2种装配构造,即内嵌式装配墙板、外贴式装配墙板;2种轻钢骨架轻混凝土墙板,即框架式轻钢骨架轻混凝土墙板、桁架式轻钢骨架轻混凝土墙板。研究了各试件的破坏特征和损伤演化过程,分析了结构滞回特性、承载力、变形能力、刚度退化、耗能性能和应变。结果表明:装配式轻钢框架-轻钢骨架轻混凝土墙板结构共同工作性能良好,其水平承载力相比轻钢框架提高了204.7%~210.4%,抗侧刚度提高了257.3%~512.5%,结构变形及耗能能力有显著提高;内嵌墙板的自攻钉连接构造以及外贴墙板的螺栓连接构造传力性能可靠,结构具备2道抗震防线的受力特征;基于简化塑性分析模型以及拉压杆软化桁架模型,对试件承载力进行了计算,计算结果与试验符合较好。 展开更多
关键词 装配式组合结构 轻钢框架 轻钢骨架轻混凝土墙板 抗震性能 低周反复荷载试验 承载力计算
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2022年泸定M_(s) 6.8级地震发震构造与鲜水河断裂带强震迁移规律
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作者 钟永生 李敬波 +6 位作者 王国洪 颜照坤 周吉谦 王多福 郑良忠 张聚源 吴明亮 《地质论评》 CAS CSCD 北大核心 2024年第3期975-995,共21页
2022年9月5日12时52分在四川甘孜州泸定县发生Ms6.8级地震,震源深度16 km。这是继2014年康定地震后,发生在鲜水河断裂带上的又一次强震。笔者等通过已有文献资料,结合鲜水河断裂带南段野外地质调查,统计了滑动速率及历史地震资料,并总... 2022年9月5日12时52分在四川甘孜州泸定县发生Ms6.8级地震,震源深度16 km。这是继2014年康定地震后,发生在鲜水河断裂带上的又一次强震。笔者等通过已有文献资料,结合鲜水河断裂带南段野外地质调查,统计了滑动速率及历史地震资料,并总结了近代鲜水河断裂带强震迁移规律,对认识鲜水河断裂带活动特征及未来地震危险性具有重要意义。主要得出以下几点认识:①鲜水河断裂带各段滑动速率差异较大,以乾宁为界,从NW至SE段整体上呈现出“先减速后加速”的滑动特点;②泸定地震发震构造磨西断裂,为一次左旋走滑事件;③川滇地区近代历史强震活跃期具有“跳跃性”迁移的特点。自1981年道孚地震后,鲜水河断裂带断进入相对平静期,持续了33 a。自2014年康定地震发生,鲜水河断裂带再次进入地震活跃期;④鲜水河断裂带的强震破裂并非单次地震的“贯通型”模式,而是多次地震的渐进式。断层间相互作用尤其是大地震的发生对断裂带强震复发间隔具有重大影响,相同断裂带的强震也会对后续地震的发生概率产生变化。 展开更多
关键词 鲜水河断裂带 泸定地震 复发间隔 强震迁移规律 地震活跃期
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鲁东—黄海地块西部中强地震活动特征及周边地震对该地区的影响
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作者 黎明晓 刘杰 +4 位作者 薛艳 姜祥华 苑争一 闫伟 于磊 《地震学报》 CSCD 北大核心 2024年第3期377-393,共17页
鲁东—黄海地块西部为华北地块东侧的次级地块,其地震活动具有显著的周期特征,地块内部的中强地震活动特征和周边大震对该地区的影响对研究该地区地震活动状态有重要意义。采用小波分析方法定量计算了鲁东—黄海地块西部历史地震的活动... 鲁东—黄海地块西部为华北地块东侧的次级地块,其地震活动具有显著的周期特征,地块内部的中强地震活动特征和周边大震对该地区的影响对研究该地区地震活动状态有重要意义。采用小波分析方法定量计算了鲁东—黄海地块西部历史地震的活动周期,并结合中强地震活动的定性分析、时空演化、能量释放及周边大震等资料,探讨了该地区的地震活动特征。结果显示:(1)鲁东—黄海地块西部M5.0以上地震活动存在着60.6—78.6 a的长周期,该周期反映了地震活跃—平静的韵律特征,据此M≥5.0地震可划分为活跃时段Ⅰ(1844—1879年)、活跃时段Ⅱ(1905—1949年)和活跃时段Ⅲ(1974年至今)。1997年以来,该地区处于活跃时段末期的弱释放阶段;(2)在三个活跃时段,地震活动的主体地区不同,活跃时段Ⅰ,Ⅱ以海域地震活动为主,并且地震活动水平海域强、陆域弱。活跃时段Ⅲ陆域、海域均有M≥6.0地震活动;(3) 1815年以来,鲁东—黄海地块西部M≥5.0地震与华北M≥6.0地震活动大致同步,当鲁东—黄海地块西部中强地震恰好处于较强活跃时段时,华北地块M6.0地震显著平静后,M≥6.0地震先从鲁东—黄海地块西部开始活动,然后向华北地块中西部地区活动;(4)当太平洋板块西侧的俯冲带上M_(W)≥5.0中深源地震活跃,并发生M_(W)≥7.0地震时,鲁东—黄海地块西部易于发生M_(S)≥6.0地震,这可能是太平洋板块西侧深部俯冲构造动力作用增强导致的结果。 展开更多
关键词 鲁东—黄海地块 地震活动 Morlet小波变换 地震周期特征
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Rediscussion on the seismic regime network
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作者 王泽皋 孙佩卿 +3 位作者 高景春 李淑莲 张雪 郭妍 《Acta Seismologica Sinica(English Edition)》 CSCD 1994年第3期369-377,共9页
On the basis of the past research and utilization on the windows and belts of seismic regime, the seismic regime network which has been supposed and proved in the past is set up by using the monthly frequency data of ... On the basis of the past research and utilization on the windows and belts of seismic regime, the seismic regime network which has been supposed and proved in the past is set up by using the monthly frequency data of small earthquakes from 1970 to 1991 over the whole country. Through checking its function in practice, it is found that the spatial distribution of precursor information is not an isolate window or belt, but a broad precursor information field before the Ms≥7. 0 earthquakes in China and its nearby regions. According to the windows and belts in the field, synchronism and generality of initial time and place of prediction, the comprehensive prediction of activity time periods of groups of strong earthquakes and the detail method of correspondence of groups are proposed. After restrict mathematical test, 10 prediction methods for references are set forth, in which two best methods are selected as references for the whole case prediction in one to three years. Some related problems are discussed at the end of this paper. 展开更多
关键词 seismic regime network seismic precursor information field comprehensive prediction period of activity time
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A Seismic Facies Analysis to Determine the Relative Age and History of the Al Idrissi Mud Volcano from Offshore Larache Located in the NW Moroccan Atlantic Margin
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作者 Asher Hategekamungu Nadia Mhammdi +1 位作者 Mohamed Amine Manar Asmae Bernachid 《Open Journal of Geology》 CAS 2023年第3期203-220,共18页
Formed on top of the Gulf of Cadiz, the Al Idrissi mud volcano is the shallowest and largest mud volcano in the El Arraiche mud volcano field of the northwestern Moroccan margin. The development and morphology of mud ... Formed on top of the Gulf of Cadiz, the Al Idrissi mud volcano is the shallowest and largest mud volcano in the El Arraiche mud volcano field of the northwestern Moroccan margin. The development and morphology of mud volcanoes from the El Arraiche mud volcanoes group have been studied at a large scale. However, the time interval related to their formation period still needs to be better understood. In this regard, we interpreted and analyzed the seismic facies from the 2D reflection data of the GEOMARGEN-1 campaign, which took place in 2011. The aim was to identify the seismic sequences and draw the Al Idrissi mud volcano system to determine the formation period of the Al Idriss mud volcano. And as a result, the Al Idrissi mud volcano system is made of both buried and superficial bicone and was identified along with the Upper Tortonian to Messinian-Upper Pliocene facies. As the initial mud volcano extrusive edifice, the buried bicone was formed in the Late-Messinian to Early-Pliocene period. However, the superficial bicone, as the final extrusive edifice, was included in the Late Pliocene. In this case, the timing interval between the buried and superficial bicone is equivalent to the Late-Messinian to Upper-Pliocene period. Therefore, the latter corresponds to the Al Idrissi mud volcano formation period. 展开更多
关键词 Northwestern Moroccan Margin Al Idrissi Mud Volcano 2D Reflection Data from the GEOMARGEN-1 Campaign seismic Signatures Analysis Formation period
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Seismic risk analysis of coastal area of Pakistan 被引量:1
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作者 Shahid A.Khan M.AliShah M.Qaisar 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第4期382-394,共13页
Estimation of seismic hazard for the fast developing coastal area of Pakistan is carried out using deterministic and probabilistic approaches. On the basis of seismotectonics and geology, eleven faults are recognized ... Estimation of seismic hazard for the fast developing coastal area of Pakistan is carried out using deterministic and probabilistic approaches. On the basis of seismotectonics and geology, eleven faults are recognized in five seismic provinces as potential hazard sources. Maximum magnitude potential for each of these sources is calculated. Peak ground acceleration (PGA) values at the seven coastal cities due to the maximum credible earthquake on the relevant source are also obtained. Cities of Gwadar and Ormara with acceleration values of 0.21g and 0.25g respectively fall in the high seismic risk area. Cities of Turbat and Karachi lie in low seismic risk area with acceleration values of less than 0.1g. The Probabilistic PGA maps with contour interval of 0.05g for 50 and 100 years return period with 90% probability of non-exceedance are also compiled. 展开更多
关键词 seismic risk analysis deterministic and probabilistic approaches maximum credible earthquake recurrence period
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