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High-resolution seismicity imaging and early aftershock migration of the 2023 Kahramanmara?(SE Türkiye)M_W7.9&7.8 earthquake doublet 被引量:7
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作者 Hongyang Ding Yijian Zhou +5 位作者 Zengxi Ge Tuncay Taymaz Abhijit Ghosh Haoyu Xu Tahir Serkan Irmak Xiaodong Song 《Earthquake Science》 2023年第6期417-432,共16页
We build a high-resolution early aftershock catalog for the 2023 SE Türkiye seismic sequence with PALM,a seamless workflow that sequentially performs phase picking,association,location,and matched filter for cont... We build a high-resolution early aftershock catalog for the 2023 SE Türkiye seismic sequence with PALM,a seamless workflow that sequentially performs phase picking,association,location,and matched filter for continuous data.The catalog contains 29,519 well-located events in the two mainshocks rupture region during 2023-02-01–2023-02-28,which significantly improves the detection completeness and relocation precision compared to the public routine catalog.Employing the new PALM catalog,we analyze the structure of the seismogenic fault system.We find that the Eastern Anatolian Fault(EAF)that generated the first M_(W)7.9 mainshock is overall near-vertical,whereas complexities are revealed in a small-scale,such as subparallel subfaults,unmapped branches,and stepovers.The seismicity on EAF is shallow(<15 km)and concentrated in depth distribution,indicating a clear lock-creep transition.In contrast,the SürgüFault(SF)that is responsible for the second M_(W)7.8 mainshock is shovel-shaped for the nucleation segment and has overall low dip angles(~40°–80°).Aftershocks on the SF distribute in a broad range of depth,extending down to~35 km.We also analyze the temporal behavior of seismicity,discovering no immediate foreshocks within~5 days preceding the first mainshock,and no seismic activity on the SF before the second mainshock. 展开更多
关键词 2023 Türkiye Earthquake Doublet aftershock catalog PALM fault imaging aftershock migration
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Development of an aftershock occurrence model calibrated for Turkey and the resulting likelihoods 被引量:3
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作者 Ziya Muderrisoglu Ufuk Yazgan 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2020年第1期149-160,共12页
This paper presents the calibration of Omori’s aftershock occurrence rate model for Turkey and the resulting likelihoods. Aftershock occurrence rate models are used for estimating the probability of an aftershock tha... This paper presents the calibration of Omori’s aftershock occurrence rate model for Turkey and the resulting likelihoods. Aftershock occurrence rate models are used for estimating the probability of an aftershock that exceeds a specific magnitude threshold within a time interval after the mainshock. Critical decisions on the post-earthquake safety of structures directly depend on the aftershock hazard estimated using the occurrence model. It is customary to calibrate models in a region-specific manner. These models depend on rate parameters(a, b, c and p) related to the seismicity characteristics of the investigated region. In this study, the available well-recorded aftershock sequences for a set of Mw ≥ 5.9 mainshock events that were observed in Turkey until 2012 are considered to develop the aftershock occurrence model. Mean estimates of the model parameters identified for Turkey are a =-1.90, b = 1.11, c = 0.05 and p = 1.20. Based on the developed model, aftershock likelihoods are computed for a range of different time intervals and mainshock magnitudes. Also, the sensitivity of aftershock probabilities to the model parameters is investigated. Aftershock occurrence probabilities estimated using the model are expected to be useful for post-earthquake safety evaluations in Turkey. 展开更多
关键词 aftershock occurrence model aftershock likelihoods rate parameters aftershock hazard
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Study of the correlations between main shocks and aftershocks and aftershock synthesis method 被引量:5
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作者 Zhang Yingnan Zhi Xudong Fan Feng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第4期759-775,共17页
To consider the infl uence of aftershocks in engineering design, the correlations between main shocks and aftershocks should be examined, and an aftershock simulation method with main shock ground motions needs to be ... To consider the infl uence of aftershocks in engineering design, the correlations between main shocks and aftershocks should be examined, and an aftershock simulation method with main shock ground motions needs to be developed. In this study, the data on the sequences of main shock–aftershock ground motions and other related parameters were collected. Using these data, correlations between the magnitude, frequency, duration and energy of the main shock–aftershock ground motions were investigated. The results showed that the magnitude of the aftershock can be larger than that of the main shock. The shapes of the Fourier amplitude spectra of main shocks and aftershocks were similar;however, the predominant frequency and high-frequency components of the aftershock tended to be larger. Considering the magnitude diff erence between the main shock and the aftershock, the correlation of durations was explored. Additionally, a new concept, the duration ratio, was defi ned to describe the concentration of seismic energy release, and main shock energy was strongly positively correlated with the energy attenuated during the main shock–aftershock sequence. Finally, based on these results regarding correlation, an aftershock synthesis using recorded main shock ground motions was constructed with the trigonometric series method for seismic design, and some examples are given to analyze the rationality of this synthetic method. 展开更多
关键词 MAIN shock-aftershock SEQUENCE CORRELATION aftershock synthesis SEISMIC design
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Spatio-temporal characteristics of strong aftershocks of the M_S8.0 Wenchuan earthquake 被引量:5
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作者 Jisheng Zhao Yanqiong Liu +1 位作者 Zhenghua Zhou Chenggang Zhao 《Earthquake Science》 CSCD 2010年第3期215-221,共7页
Based on Gutenberg-Richter's relation,Bath's law,Omori's law and Well's relation of rupture scale,this paper forecasts the temporal decay,total number,possible area and greatest magnitude of strong aftershocks(gr... Based on Gutenberg-Richter's relation,Bath's law,Omori's law and Well's relation of rupture scale,this paper forecasts the temporal decay,total number,possible area and greatest magnitude of strong aftershocks(greater than or equal to M6.0) of the MS8.0 Wenchuan earthquake by using the magnitude and statistical parameters of earthquakes in California area of USA.The number of strong aftershocks,the parameters of Gutenberg-Richter's relation and the modified form of Omori's law are validated based on the relocation data of aftershock sequence of the MS8.0 Wenchuan earthquake.Moreover,the spatio-temporal characteristics and wave energy release of the strong aftershocks(M≥6.0) are analyzed.The result shows that strong aftershocks may occur at the end of local drop and sharp drop on the wave energy release curve. 展开更多
关键词 Wenchuan earthquake strong aftershock wave energy release statistic of aftershocks
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Statistical features of aftershock distribution size for moderate and large earthquakes in Chinese mainland 被引量:3
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作者 蒋海昆 郑建常 +3 位作者 吴琼 曲延军 李永莉 代磊 《Acta Seismologica Sinica(English Edition)》 CSCD 2007年第2期158-171,共14页
Based on data of earthquake sequences with Ms≥5.0 in Chinese mainland from 1970 to 2004, for different sequence types and different rupture modes of the main shock, the relationship between aftershock distribution si... Based on data of earthquake sequences with Ms≥5.0 in Chinese mainland from 1970 to 2004, for different sequence types and different rupture modes of the main shock, the relationship between aftershock distribution size R and the magnitude of the main shock Mo has been studied statistically. Considering the rupture mode of the main shock, we give the quantitative statistical relationships between R and Mo under 95% confidence level for different sequence typos. Qualitatively, lgR, the logarithm of the aftershock distribution size, is positively correlative to the M0, but the data distribution is dispersed. Viewing from different sequence typos, the correlation between R and M0 is very weak for isolated earthquake type (lET) sequence, R distributes in the range from 5 to 60 km; For mainshock-aftershock type (MAT), lgR is positively correlative to M0; For multiple main shock type (MMT), the corelation between lgR and M0 is not very obvious when M0≤6.2 and R distributes in the range from 5 to 70 km, while it shows a linear correlation when M0≥6.3. The statistical results also show that the occupational ratios of different sequence types for strike-slip and oblique slip are almost the same. But for dip-slip (mostly are thrust mechanisms), the ratio of MAT is higher than that of IET and MMT. Comparing with previous results, it indicates that, when M0 is large enough, R is mainly determined by M0 and there is almost no relationship with the rupture mode of the main shock. 展开更多
关键词 Chinese mainland aftershock distribution size types of aftershock sequences rupture mode ofthe main shock
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Preliminary study on aftershock decay rate of the 2013 Ms 7.0 Lushan earthquake 被引量:2
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作者 Zhe Jia Weiwen Chen Risheng Chu 《Earthquake Science》 2013年第3期185-190,共6页
We obtained a catalog of early aftershocks of the 2013 Lushan earthquake by examining waveform from a nearby station MDS which is 30.2 km far away from the epicenter, and then we analyzed the relation between aftersho... We obtained a catalog of early aftershocks of the 2013 Lushan earthquake by examining waveform from a nearby station MDS which is 30.2 km far away from the epicenter, and then we analyzed the relation between aftershock rate and time. We used time-window ratio method to identify aftershocks from continuous waveform data and compare the result with the catalog provided by China Earthquake Networks Center (CENC). As expected, a significant amount of earthquakes is missing in CENC catalog in the 24 h after the main shock. Moreover, we observed a steady seismicity rate of aftershocks nearly in the first 10,000 s before an obvious power-law decay of aftershock activity. We consider this distinct early stage which does not fit the Omori law with a constant p (p - 1) value as early aftershock deficiency (EAD), as proposed by previous studies. Our study suggests that the main shock rupture process is different from aftershocks' processes, and EAD can vary in different cases as compared to earthquakes of strike-slip mechanism in California. 展开更多
关键词 aftershock rate Early aftershock deficiencyOmori law Earthquake rupture
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Numerical simulation of dynamic Coulomb stress changes induced by M6.5 earthquake in Wuding, Yunnan and its relationship with aftershocks 被引量:6
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作者 虎雄林 吴小平 +3 位作者 杨润海 付虹 胡家富 黄雍 《地震学报》 CSCD 北大核心 2008年第1期26-35,共10页
Based on the discrete wavenumber method, we calculate the fields of dynamic Coulomb rupture stress changes and static stress changes caused by M6.5 earthquake in Wuding, and study their relationship with the subsequen... Based on the discrete wavenumber method, we calculate the fields of dynamic Coulomb rupture stress changes and static stress changes caused by M6.5 earthquake in Wuding, and study their relationship with the subsequent after- shocks. The results show that the spatial distribution patterns of the positive region of dynamic stress peak value and static stress peak value are similarly asymmetric, which are basically identical with distribution features of aftershock. The dynamic stress peak value and the static stress in the positive region are more than 0.1 MPa and 0.01 MPa of the triggering threshold, respectively, which indicates that the dynamic and static stresses are helpful for the occurrence of aftershock. This suggests that both influences of dynamic and static stresses should be con- sidered other than only either of them when studying aftershock triggering in near field. 展开更多
关键词 武定地震 动态库仑破裂应力变化 余震 动态应力触发
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Magnitude and distance distribution of strong aftershocks in Sichuan-Yunnan region 被引量:4
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作者 吕晓健 高孟潭 +1 位作者 高战武 米素婷 《地震学报》 CSCD 北大核心 2008年第4期397-404,共8页
研究了川滇地区1966年以来12次主震震级Ms≥6.5的地震序列中,主震与强余震(本文定义为所有Ms≥5的余震)震级差分布特征和强余震与主震距离的分布特征。结果表明,强余震与主震震级差服从截断的指数分布,据此推导出了强余震与主震震... 研究了川滇地区1966年以来12次主震震级Ms≥6.5的地震序列中,主震与强余震(本文定义为所有Ms≥5的余震)震级差分布特征和强余震与主震距离的分布特征。结果表明,强余震与主震震级差服从截断的指数分布,据此推导出了强余震与主震震级差的概率密度函数;强余震距离分布的优势范围是距主震10-39km,且强余震与主震震中的距离服从正态分布。 展开更多
关键词 川滇地区 强余震 概率分布 空间分布
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Improved HVSR site classification method for free-field strong motion stations validated with Wenchuan aftershock recordings 被引量:16
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作者 Wen Ruizhi Ren Yefei Shi Dacheng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2011年第3期325-337,共13页
Local site conditions play an important role in the effective application of strong motion recordings.In the China National Strong Motion Observation Network System(NSMONS),some of the stations do not provide boreho... Local site conditions play an important role in the effective application of strong motion recordings.In the China National Strong Motion Observation Network System(NSMONS),some of the stations do not provide borehole information,and correspondingly,do not assign the site classes yet.In this paper,site classification methodologies for free-field strong motion stations are reviewed and the limitations and uncertainties of the horizontal-to-vertical spectral ratio(HVSR) methods are discussed.Then,a new method for site classification based on the entropy weight theory is proposed.The proposed method avoids the head or tail joggle phenomenon by providing the objective and subjective weights.The method was applied to aftershock recordings from the 2008 Wenchuan earthquake,and 54 free-field NSMONS stations were selected for site classification and the mean HVSRs were calculated.The results show that the improved HVSR method proposed in this paper has a higher success rate and could be adopted in NSMONS. 展开更多
关键词 site classification strong motion recording entropy weight theory horizontal-to-vertical spectrum ratio Wenchuan earthquake aftershock head-tail joggle
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High-precision relocation of the aftershock sequence of the January 8,2022,M_(S)6.9 Menyuan earthquake 被引量:21
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作者 Liping Fan Boren Li +2 位作者 Shirong Liao Ce Jiang Lihua Fang 《Earthquake Science》 2022年第2期138-145,共8页
The 2022 Menyuan M_(S)6.9 earthquake,which occurred on January 8,is the most destructive earthquake to occur near the Lenglongling(LLL)fault since the 2016 Menyuan M_(S)6.4 earthquake.We relocated the mainshock and af... The 2022 Menyuan M_(S)6.9 earthquake,which occurred on January 8,is the most destructive earthquake to occur near the Lenglongling(LLL)fault since the 2016 Menyuan M_(S)6.4 earthquake.We relocated the mainshock and aftershocks with phase arrival time observations for three days after the mainshock from the Qinghai Seismic Network using the double-difference method.The total length and width of the aftershock sequence are approximately 32 km and 5 km,respectively,and the aftershocks are mainly concentrated at a depth of 7-12 km.The relocated sequence can be divided into 18 km west and 13 km east segments with a boundary approximately 5 km east of the mainshock,where aftershocks are sparse.The east and west fault structures revealed by aftershock locations differ significantly.The west fault strikes EW and inclines to the south at a 71°-90°angle,whereas the east fault strikes 133°and has a smaller dip angle.Elastic strain accumulates at conjunctions of faults with different slip rates where it is prone to large earthquakes.Based on surface traces of faults,the distribution of relocated earthquake sequence and surface ruptures,the mainshock was determined to have occurred at the conjunction of the Tuolaishan(TLS)fault and LLL fault,and the west and east segments of the aftershock sequence were on the TLS fault and LLL fault,respectively.Aftershocks migrate in the early and late stages of the earthquake sequence.In the first 1.5 h after the mainshock,aftershocks expand westward from the mainshock.In the late stage,seismicity on the northeast side of the east fault is higher than that in other regions.The migration rate of the west segment of the aftershock sequence is approximately 4.5 km/decade and the afterslip may exist in the source region. 展开更多
关键词 Menyuan earthquake aftershock sequence double-difference relocation Lenglongling fault Tuolaishan fault
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The 20 April 2013 Lushan, Sichuan, mainshock, and its aftershock sequence: tectonic implications 被引量:22
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作者 Jianshe Lei Guangwei Zhang Furen Xie 《Earthquake Science》 2014年第1期15-25,共11页
Using the double-difference relocation algo- rithm, we relocated the 20 April 2013 Lushan, Sichuan, earthquake (Ms 7.0), and its 4,567 aftershocks recorded during the period between 20 April and May 3, 2013. Our res... Using the double-difference relocation algo- rithm, we relocated the 20 April 2013 Lushan, Sichuan, earthquake (Ms 7.0), and its 4,567 aftershocks recorded during the period between 20 April and May 3, 2013. Our results showed that most aftershocks are relocated between 10 and 20 km depths, but some large aftershocks were relocated around 30 krn depth and small events extended upward near the surface. Vertical cross sections illustrate a shovel-shaped fault plane with a variable dip angle from the southwest to northeast along the fault. Furthermore, the dip angle of the fault plane is smaller around the mainshock than that in the surrounding areas along the fault. These results suggest that it may be easy to generate the strong earthquake in the place having a small dip angle of the fault, which is somewhat similar to the genesis of the 2008 Wenchuan earthquake. The Lushan mainshock is underlain by the seismically anomalous layers with low-Vp, low-Vs, and high-Poisson's ratio anomalies, possibly suggesting that the fluid-filled fractured rock matrices might signifi- cantly reduce the effective normal stress on the fault plane to bring the brittle failure. The seismic gap between Lushan and Wenchuan aftershocks is suspected to be vulnerable to future seismic risks at greater depths, if any. 展开更多
关键词 Lushan mainshock aftershock sequence Double-difference algorithm - Shovel-shaped structure Variable dip angle
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Slope Seismic Response Monitoring on the Aftershocks of the Wenchuan Earthquake in the Mianzhu Section 被引量:6
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作者 WANG Yunsheng LUO Yonghong +4 位作者 WANG Fuhai WANG Dong MA Xiao LI Shun DENG Xi 《Journal of Mountain Science》 SCIE CSCD 2012年第4期523-528,共6页
Previous investigations have shown that the seismic response of slopes during the Wenchuan earthquake was highly variable. The present study tries to give an answer to the question: Which are the main factors affecti... Previous investigations have shown that the seismic response of slopes during the Wenchuan earthquake was highly variable. The present study tries to give an answer to the question: Which are the main factors affecting the seismic response degree of slopes? With the support of the China Geological Survey Bureau, we set 3 monitoring sections in Jiulong slope, Mianzhu city, China with the aim to record the site response of the slope during the affershoeks of the Wenehuan earthquake. After the Wenchuan earthquake, which happened on 12 May 2008, 30 aftershocks have been recorded in these monitoring points. We analyzed 11 records, with magnitudes ranging from ML = 4.6 to ML = 3.1. The amplification factors of the horizontal compound PGA and 3D compound PGA have been determined for the 3 points at different elevations on the slope. Results showed that the dynamic response of the slope on the earthquake was controlled by factors such as topography and the thickness of the Quaternary overburden. 展开更多
关键词 Seismic response SLOPE MONITORING Longmen Mountains aftershockS Wenchuanearthquake
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Long aftershock sequences in North China and Central US: implications for hazard assessment in mid-continents 被引量:4
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作者 Mian Liu Gang Luo +1 位作者 Hui Wang Seth Stein 《Earthquake Science》 2014年第1期27-35,共9页
Because seismic activity within mid-continents is usually much lower than that along plate boundary zones, even small earthquakes can cause widespread con- cerns, especially when these events occur in the source regio... Because seismic activity within mid-continents is usually much lower than that along plate boundary zones, even small earthquakes can cause widespread con- cerns, especially when these events occur in the source regions of previous large earthquakes. However, these small earthquakes may be just aftershocks that continue for decades or even longer. The recent seismicity in the Tangshan region in North China is likely aftershocks of the 1976 Great Tangshan earthquake. The current earthquake sequence in the New Madrid seismic zone in central United States, which includes a cluster of M- 7.0 events in 1811-1812 and a number of similar events in the past millennium, is believed to result from recent fault reactivation that releases pre-stored strain energy in the crust. If so, this earthquake sequence is similar to aftershocks in that the rates of energy release should decay with time and the sequence of earthquakes will eventually end. We use simple physical analysis and numerical simulations to show that the current sequence of large earthquakes in the New Madrid fault zone is likely ending or has ended. Recognizing that mid-continental earthquakes have long aftershock sequences and complex spatiotemporal occur- rences are critical to improve hazard assessments. 展开更多
关键词 aftershock EARTHQUAKE Intraplateseismicity Earthquake hazard
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Variations in shear wave splitting during aftershocks of the Luquan earthquake in Yunnan Province 被引量:4
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作者 李白基 《Acta Seismologica Sinica(English Edition)》 CSCD 1996年第2期289-297,共9页
Shear wave splitting has been measured from analyzing the three-component digital seismograms recorded at Guiquan station after the 1985 Ms6 1 Luquan earthquake in Yunnan Province. The variations in parameters ofshear... Shear wave splitting has been measured from analyzing the three-component digital seismograms recorded at Guiquan station after the 1985 Ms6 1 Luquan earthquake in Yunnan Province. The variations in parameters ofshear wave splitting with time for over 100 aftershocks have two periods, the local stress Period and the regionalstress period. In the local stress period, there exist two vertical, paralell crack sets intersecting at about (50-60°), both affect on the propagation of S-waves, and the local stress is slightly stronger than the regional stress.With the activity of aftershock going down and the local stress dying away, it is returned to the state of the regional stress in the focal area. The polarizations of the fast split S-wave and their period variations are identicalwith the azimuths and changes of the principal compressive stress axis of focal stress field inferred independentlyfrom earthquake mechanisms, hense, it is interpreted that the shear wave splitting is the effects of anisotropy ofEDA cracks controlled by stress field. The time delay of the slow split S-wave, except the difference betweenthe two periods shows in some examples that it increases in a few hours before an event and decreases in a fewdays after an event on the individual background of period. 展开更多
关键词 aftershockS shear wave splitting stress field Luquan earthquake.
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Spatio-temporal characteristics of aftershocks and seismogenic structure of the 2011 Mw9.0 Tohoku earthquake,Japan 被引量:2
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作者 Farah Lazzali 《Earthquake Science》 CSCD 2012年第3期219-227,共9页
The Tohoku megathrust earthquake, which occurred on March 11, 2011 and had an epicenter that was 70 km east of Tohoku, Japan, resulted in an estimated ten′s of billions of dollars in damage and a death toll of more t... The Tohoku megathrust earthquake, which occurred on March 11, 2011 and had an epicenter that was 70 km east of Tohoku, Japan, resulted in an estimated ten′s of billions of dollars in damage and a death toll of more than 15 thousand lives, yet few studies have documented key spatio-temporal seismogenic characteristics. Specifically, the temporal decay of aftershock activity, the number of strong aftershocks (with magnitudes greater than or equal to 7.0), the magnitude of the greatest aftershock, and area of possible aftershocks. Forecasted results from this study are based on Gutenberg-Richter’s relation, Bath’s law, Omori’s law, and Well’s relation of rupture scale utilizing the magnitude and statistical parameters of earthquakes in USA and China (Landers, Northridge, Hector Mine, San Simeon and Wenchuan earthquakes). The number of strong aftershocks, the parameters of Gutenberg-Richter’s relation, and the modified form of Omori’s law are confirmed based on the aftershock sequence data from the Mw9.0 Tohoku earthquake. Moreover, for a large earthquake, the seismogenic structure could be a fault, a fault system, or an intersection of several faults. The seismogenic structure of the earthquake suggests that the event occurred on a thrust fault near the Japan trench within the overriding plate that subsequently triggered three or more active faults producing large aftershocks. 展开更多
关键词 2011MW9.0 Tohoku earthquake aftershock seismogenic structure
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Study on displacement field generated by aftershocks in Landers earthquake fault zone and its adjacent areas 被引量:1
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作者 万永革 沈正康 兰从欣 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2005年第2期147-153,共7页
The displacement field generated by aftershocks in Landers earthquake fault zone and its adjacent areas is calculated in this study. The result is compared with the displacement field of the main shock calculated by c... The displacement field generated by aftershocks in Landers earthquake fault zone and its adjacent areas is calculated in this study. The result is compared with the displacement field of the main shock calculated by co-seismic slip model of Wald and Heaton (1994). The result shows that the direction of displacement generated by aftershocks in Landers seismic fault plane and its adjacent areas is consistent with that generated by main shock. The rupture of aftershock is generally inherited from main shock. The displacement generated by aftershocks is up to an order of centimeter and can be measured by GPS sites nearby. So when we use geodetic data measured after earthquake to study the geophysical problems such as crustal viscosity structure, afterslip distribution, etc., only the displacement field generated by aftershocks considered, can uncertainty be reduced to minimum and realistic result be obtained. 展开更多
关键词 aftershockS displacement field focal mechanism Landers earthquakes
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Hysteretic energy prediction method for mainshock-aftershock sequences 被引量:3
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作者 Zhai Changhai Ji Duofa +3 位作者 Wen Weiping Li Cuihua Lei Weidong Xie Lili 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2018年第2期277-291,共15页
Structures located in seismically active regions may be subjected to mainshock-aftershock(MSAS)sequences.present study selected two kinds of MSAS sequences,with one aftershock and two aftershocks,respectively.The af... Structures located in seismically active regions may be subjected to mainshock-aftershock(MSAS)sequences.present study selected two kinds of MSAS sequences,with one aftershock and two aftershocks,respectively.The aftershocksThe MSAS sequence with one aftershock exhibited a 10%to 30%hysteretic energy increase,whereas the MSAS sequence with two aftershocks presented a 20%to 40%hysteretic energy increase.Finally,a hysteretic energy prediction equation is proposed as a function of the vibration period,ductility value,and damping ratio to estimate hysteretic energy for mainshockaftershock sequences. 展开更多
关键词 hysteretic energy mainshock-aftershock sequences SDOF system relative intensity prediction equation
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Uneven aftershock distribution of Wenchuan Ms8.0 earthquake and possible mechanism 被引量:1
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作者 Li Zhixiong Chen Zhangli +4 位作者 Zhao Cuiping Shao Zhigang Hua Wei Wang Qincai He Ping 《Geodesy and Geodynamics》 2011年第2期7-12,共6页
The aftershock activity of Wenchuan Ms8.0 earthquake showed different spatial and temporal distri- butions along two different segments of the Longmenshan fault. This difference was likely the result of segmentation o... The aftershock activity of Wenchuan Ms8.0 earthquake showed different spatial and temporal distri- butions along two different segments of the Longmenshan fault. This difference was likely the result of segmentation of the earthquake rupture process, which in turn may be the result of the fault' s segmentation in its long-term geotectonic condition. 展开更多
关键词 Wenchuan earthquake aftershock activities spatial and temporal unevenness mechanism study inheritance movement
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Depth and region dependence of b-value for micro-aftershocks of the May 12th,2008 Wenchuan earthquake and its tectonic implications 被引量:2
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作者 Mei Feng Meijian An Lin Zhao Jizhong Zhang 《Earthquake Science》 CSCD 2009年第6期589-594,共6页
Micro-aftershocks with magnitude range of 1.5--4 around the Wenchuan earthquake epicenter, the southern part of the Longmenshan fault zone, exhibit good frequency-magnitude linear relationships, thus enabling b-value ... Micro-aftershocks with magnitude range of 1.5--4 around the Wenchuan earthquake epicenter, the southern part of the Longmenshan fault zone, exhibit good frequency-magnitude linear relationships, thus enabling b-value analysis. The average b-value for micro-aflershocks of M1.5-4 from July to December of 2008 in our local study region is about 0.88, similar to the b-value for all aftershocks ofM3.0-5.5 from May, 2008 to May, 2009 along the whole Longmenshan fault zone. The similarity between the local and regional b-values possibly indicates that the southern part of the Longmenshan fault zone has similar seismogenic environment to the whole Longmenshan fault zone. Alternatively, it may also imply that b-values derived from all events without consideration of structural variation can not discriminate local-scale tectonic information. The present study shows that the b-value for the Wenchuan earthquake micro-aftershocks varies with different regions. The b-value in southwest of the Yingxiu town is higher than that in the northeast of the Yingxiu town. The high b-value in the southwest part where the Wenchuan earthquake main shock hypocenter located indicates that the current stress around the hypocenter region is much lower than its surrounding area. The b-values are also dependent on depth. At shallow depths of 〈5 km, the b-values are very small (-0.4), possibly being related to strong wave attenuation or strong heterogeneity in shallow layers with high content of porosity and fractures. At depths of-5-11 km, where most aftershocks concentrated, the b-values become as high as -0.9-1.0. At the depth below -11 km, the b-values decrease with the depth increasing, being consistent with increasing tectonic homogeneity and increasing stress with depth. 展开更多
关键词 micro-aftershocks frequency-magnitude relationship tectonic implication Wenchuan earthquake
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Models of wave duration and event fre-quency of explosion aftershocks 被引量:1
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作者 李学政 刘文学 沈旭峰 《地震学报》 CSCD 北大核心 2004年第5期539-546,共8页
The contained underground explosion (CUE) usually generates huge number of aftershocks. This kind of after-shocks induced by three CUEs was investigated in the paper. The conclusions show that the duration of aftersho... The contained underground explosion (CUE) usually generates huge number of aftershocks. This kind of after-shocks induced by three CUEs was investigated in the paper. The conclusions show that the duration of aftershock waveforms are rather short, 70 percent of them range from 2 to 7; the occurrences of the aftershocks conform to negative power function, which has the power of -1.6. The aftershock sequence attenuates a little bit faster, with power of -1.0, within two weeks of post-explosions. During the early stage of post-explosions the aftershocks show up in a cluster, however, they usually show up individually during the late stage of post-explosions. The number of aftershocks generated by the compatible explosions differs by several times because of different me-dium and geological structure; within one month after an explosion with Richater magnitude of 5.5, the number of aftershocks attenuates to the background. Hereafter there are still tiny numbers of aftershocks. 展开更多
关键词 封闭爆炸 余震序列 数学模型
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