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用钻孔应变数据探测2011年日本Tohoku大地震激发的低频地球环型自由振荡及其谱峰分裂
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作者 张赓 徐建桥 +3 位作者 陈晓东 张凌云 孙和平 龚立卓 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2024年第4期1383-1397,共15页
地震激发的地球自由振荡中,环型自由振荡(特别是低频环型自由振荡)的精确探测相比于球型自由振荡更加困难.环型自由振荡对SH波速度结构更加敏感,能更好地监测走滑断层运动,因此精确估算环型自由振荡的谱峰参数可为地球内部大尺度SH波速... 地震激发的地球自由振荡中,环型自由振荡(特别是低频环型自由振荡)的精确探测相比于球型自由振荡更加困难.环型自由振荡对SH波速度结构更加敏感,能更好地监测走滑断层运动,因此精确估算环型自由振荡的谱峰参数可为地球内部大尺度SH波速度结构和大地震的震源机制提供更强约束.本研究利用2011年日本Tohoku地震后四分量钻孔应变仪的观测资料,提取了该地震激发的1.3 mHz以下低频环型和球型自由振荡信号,与STS-1宽频带地震仪的结果相比较,发现四分量钻孔应变仪对1 mHz以下的环型自由振荡具有更强的探测能力.本研究还采用频率域自回归方法精确估计了0T2—0T6的简并频率,结果与PREM模型理论值相差非常小,平均相对误差仅为2.52×10^(-4).此外还用钻孔应变仪观测资料探测到了0T2谱峰分裂现象.研究结果表明,钻孔应变仪能有效探测到大地震激发的低频地球环型自由振荡信号,可为地幔大尺度各向异性结构研究提供高质量的基础数据. 展开更多
关键词 环型自由振荡 钻孔应变仪 tohoku地震 简正模谱峰分裂 STS-1地震仪
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利用重力观测约束2011日本Tohoku大地震的震源机制 被引量:14
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作者 薛秀秀 胡小刚 +1 位作者 郝晓光 柳林涛 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2012年第9期3006-3015,共10页
2011年3月11日,日本东北部(Tohoku)太平洋海域发生Mw9.0特大地震.一些国际学术机构用不同的震相和反演方法,计算了大地震的震源机制解.但这些结果存在一定的差异.地球长周期自由振荡的振幅主要依赖于地震矩的大小及地震断层的破裂方式,... 2011年3月11日,日本东北部(Tohoku)太平洋海域发生Mw9.0特大地震.一些国际学术机构用不同的震相和反演方法,计算了大地震的震源机制解.但这些结果存在一定的差异.地球长周期自由振荡的振幅主要依赖于地震矩的大小及地震断层的破裂方式,可以约束地震的震源机制、地震大小及持续时间.本文利用地球自由振荡0S0简正模对Tohoku大地震的震源机制解进行分析和约束.0S0振幅大小与地震断层的倾角(dip)、滑动方向角(slip)、震源深度及地震断层的破裂时间有关.我们利用震源机制解得到大地震后自由振荡模拟值,利用超导重力仪得到自由振荡的高精度重力观测值.二者比较后的结果显示:由GCMT震源机制解得到的0S0振幅与观测值符合较好,而由USGS CMT震源机制解模拟的结果明显大于观测值.2011Tohoku地震为逆冲型浅源大地震.进一步的分析表明:逆冲型浅源大地震的断层倾角对0S0振幅的影响很大,而滑动方向角以及震源深度对0S0振幅的影响较小.USGS CMT震源机制解中较大的断层倾角是导致其0S0振幅显著偏离观测值的主要原因. 展开更多
关键词 地球自由振荡 震源机制 tohoku大地震 重力观测
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利用GPS位移数据校正2011日本Tohoku地震的InSAR形变场 被引量:2
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作者 卢娟 伍吉仓 陈艳玲 《大地测量与地球动力学》 CSCD 北大核心 2017年第7期726-731,共6页
轨道误差是InSAR数据处理中的一个重要因素,对从最初的图像配准到最后的高程值或形变值图像的生成都有着重要影响。含有误差的轨道参数造成基线误差以残差条纹的形式存在于干涉图中。本文利用4个条带的61景PALSAR升轨数据,通过InSAR干... 轨道误差是InSAR数据处理中的一个重要因素,对从最初的图像配准到最后的高程值或形变值图像的生成都有着重要影响。含有误差的轨道参数造成基线误差以残差条纹的形式存在于干涉图中。本文利用4个条带的61景PALSAR升轨数据,通过InSAR干涉测量得到覆盖2011日本Tohoku地震的雷达视线向的地表同震位移场。通过联合GPS同震位移数据,采用二次多项式曲面拟合的方法去除InSAR同震形变数据中的卫星轨道误差,并分析雷达入射角变化对轨道误差去除的影响。对干涉图中拟合残差进行分析,改正后的InSAR同震形变场精度得到较大提高。 展开更多
关键词 tohoku地震 INSAR GPS 轨道误差 雷达入射角
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俯冲带地震循环的数值模拟——以日本Tohoku M_W9.0地震为例 被引量:2
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作者 翁辉辉 黄金水 《大地测量与地球动力学》 CSCD 北大核心 2016年第8期659-665,共7页
基于滑移弱化摩擦准则,以日本2011年Tohoku M_W9.0地震为例,建立一个以物理规律控制地震循环过程的二维有限元数值模型。结果显示,参考模型在1 000a间的6次大地震表现出特征地震的规律,地震重复周期约161a,单位破裂长度地震矩为1.13... 基于滑移弱化摩擦准则,以日本2011年Tohoku M_W9.0地震为例,建立一个以物理规律控制地震循环过程的二维有限元数值模型。结果显示,参考模型在1 000a间的6次大地震表现出特征地震的规律,地震重复周期约161a,单位破裂长度地震矩为1.13×1020 Nm/km,在两次大地震中间会发生一次5.62×1018Nm/km的小地震。参考模型的数值结果与地表同震GPS位移、震间GPS速度分布具有较好的一致性。模型弹性参数的不确定性对同震以及震间形变的影响有限,模型粘性参数主要影响震间形变场。数值计算也显示,假设震间形变仅由断层运动规律所决定,那么在一个地震周期内,模型空间重力异常基本上随时间均匀变化,在大陆一侧距海沟100km处可达-370μGal;速度场的变化主要发生在震后约5a的时间内,此后基本保持稳定增加。 展开更多
关键词 特征地震 有限元数值模拟 滑移弱化摩擦准则 tohoku地震
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Atmosphere-ionosphere response to the M9 Tohoku earthquake revealed by multiinstrument space-borne and ground observations:Preliminary results 被引量:10
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作者 Dimitar Ouzounov Sergey Pulinets +5 位作者 Alexey Romanov Alexander Romanov Konstantin Tsybulya Dmitri Davidenko Menas Kafatos Patrick Taylor 《Earthquake Science》 CSCD 2011年第6期557-564,共8页
We retrospectively analyzed the temporal and spatial variations of four different physical parameters characterizing the state of the atmosphere and ionosphere several days before the M9 Tohoku, Japan earthquake of Ma... We retrospectively analyzed the temporal and spatial variations of four different physical parameters characterizing the state of the atmosphere and ionosphere several days before the M9 Tohoku, Japan earthquake of March 11, 2011. The data include outgoing long wave radiation (OLR), GPS/TEC, lower Earth orbit ionospheric tomography and critical frequency foF2. Our first results show that on March 7th a rapid increase of emitted infrared radiation was observed from the satellite data and an anomaly developed near the epicenter. The GPS/TEC data indicate an increase and variation in electron density reaching a maximum value on March 8. Starting from this day in the lower ionosphere also there was confirmed an abnormal TEC variation over the epicenter. From March 3 to 11 a large increase in electron concentration was recorded at all four Japanese ground-based ionosondes, which returned to normal after the main earthquake. The joint preliminary analysis of atmospheric and ionospheric parameters during the M9 Tohoku, Japan earthquake has revealed the presence of related variations of these parameters implying their connection with the earthquake process. This study may lead to a better understanding of the response of the atmosphere/ionosphere to the great Tohoku earthquake. 展开更多
关键词 tohoku earthquake thermal anomaly GPS/TEC earthquake precursor early warning
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Rupture process of the 2011 Tohoku earthquake from the joint inversion of teleseismic and GPS data 被引量:6
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作者 Yong Zhang Lisheng Xu Yun-tai Chen 《Earthquake Science》 CSCD 2012年第2期129-135,共7页
Teleseismic and GPS data were jointly inverted for the rupture process of the 2011 Tohoku earthquake. The inversion results show that it is a bilateral rupture event with an average rupture velocity less than 2.0 km/s... Teleseismic and GPS data were jointly inverted for the rupture process of the 2011 Tohoku earthquake. The inversion results show that it is a bilateral rupture event with an average rupture velocity less than 2.0 km/s along the fault strike direction. The source rupture process consists of three sub-events, the first oc- curred near the hypocenter and the rest two ruptured along the up-dip direction and broke the sea bed, causing a maximum slip of about 30 m. The large-scale sea bed breakage may account for the tremendous tsunami disaster which resulted in most of the death and missing in this mega earthquake. 展开更多
关键词 2011 tohoku earthquake rupture process joint inversion teleseismic data GPS data
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Earthquake engineering research needs in light of lessons learned from the 2011 Tohoku earthquake 被引量:4
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作者 Masayoshi Nakashima Oren Lavan +1 位作者 Masahiro Kurata Yunbiao Luo 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第S1期141-149,共9页
Earthquake engineering research and development have received much attention since the first half of the twentieth century. This valuable research presented a huge step forward in understanding earthquake hazard mitig... Earthquake engineering research and development have received much attention since the first half of the twentieth century. This valuable research presented a huge step forward in understanding earthquake hazard mitigation,which resulted in appreciable reduction of the effects of past earthquakes. Nevertheless,the 2011 Tohoku earthquake and the subsequent tsunami resulted in major damage. This paper presents the timeline of earthquake mitigation and recovery,as seen by the authors. Possible research directions where the authors think that many open questions still remain are identified. These are primarily based on the important lessons learned from the 2011 Tohoku earthquake. 展开更多
关键词 research needs earthquake engineering quick recovery 2011 tohoku 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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GPS measured static and kinematic offsets at near and far field of the 2011 Mw 9.0 Tohoku-Oki earthquake 被引量:1
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作者 Param K.Gautam Rajesh Sathyaseelan +5 位作者 John P.Pappachen Naresh Kumar Arkoprovo Biswas George Philip ChANDra P.Dabral Sanjit K.Pal 《Geodesy and Geodynamics》 2019年第3期213-227,共15页
The Mw 9.0 Tohoku-Oki earthquake that hit the mainland Japan on 11 th March, 2011 had resulted a devastating Tsunami due to an active thrusting between the Pacific and the North American Plates. Static and kinematic o... The Mw 9.0 Tohoku-Oki earthquake that hit the mainland Japan on 11 th March, 2011 had resulted a devastating Tsunami due to an active thrusting between the Pacific and the North American Plates. Static and kinematic offsets at the offshore epicentre of the Mw 9.0 event remain unanswered and being investigated along with their near and far field limiting distances from the epicentre. Accordingly, offset measurements from 60 continuously operating IGS and GEONET GNSS stations were radially classified from the epicentre and interpreted with analytical models to find their linear offset decay rates. Co-and post-seismic static positional anomaly offsets of sixty days show almost all near field stations had strong or appreciable eastward or south eastward static shifts. Near stations(<250 km) showed both kinematic and static offsets. GEONET station ’0175’ showed maximum resultant static offset of-4.5 m, which diminishes approximately 1-2 cm at far sites like SMST and AIRA. Characteristic decay duration(’b’) of the mean kinematic co-seismic shift(’a’)of near field stations was 17.28 s during earthquake hours with an EW component shift >1.5 m. Spatial models of projected N-S static and kinematic offsets show their asymmetrical distributions around the epicentre with maximum model offset of-1.84 m displaced towards south at-45 km north of the epicentre. The Tohoku-Oki earthquake produced a resultant kinematic offset of-10.2 m towards East at its offshore epicentre;while the estimated near field static offset is ~9.82 m. However, both estimates are bigger than double the resultant offset measured value(~4.3 m) in the Japanese mainland using GPS. The difference in the kinematic and static near field offsets highlight that the near surface had elastic or in-elastic kinematic strain dissipation as against the lithospheric level viscoelastic static response, which resulted rapid kinematic strain release(1.12 cm/km)within the limiting radius of ~220 km from the Tohoku-Oki epicentre. 展开更多
关键词 2011 tohoku earthquake GPS time series NEAR and FAR field STATIC and KINEMATIC OFFSETS Spatio-temporal model
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Analysis of the co-seismic responses of the fluid well pattern system in Jiangsu Province to the Wenchuan and Tohoku earthquakes 被引量:1
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作者 Jiangrong Zheng1, Haolin Jiang1 and Zhengran He2 1 Earthquake Administration of Jiangsu Province, Nanjing 210014, China 2 School of Information Science and Engineering, Southeast University, Nanjing 210049, China 《Earthquake Science》 CSCD 2012年第3期263-274,共12页
This thesis discusses the earthquake reflecting ability of the observation well pattern system of Jiangsu Province, China, which has been digitally renovated, and probes into the cause of the major differences in the ... This thesis discusses the earthquake reflecting ability of the observation well pattern system of Jiangsu Province, China, which has been digitally renovated, and probes into the cause of the major differences in the earthquake reflecting abilities of well holes at different measurement points. This is achieved through the analysis of the co-seismic responses to the Wenchuan (2008; Ms8.0, China) and Tohoku (2011; Ms9.0, Japan) earthquakes. We found that the co-seismic response of water level from regional well holes in Jiangsu Province was stronger than that of water temperature. The water-level co-seismic response follows a consistent law and is closely related to the earthquake magnitude. The co-seismic response of water temperature strongly varied among well points, and was more often manifested as a slow restorative change. The co-seismic responses also varied based on tectonic elements. The response in central and northern Jiangsu was weaker than that of southern Jiangsu, possibly due to the thicker loess cover layer in central Jiangsu which makes it less effective at capturing the micro-changes of stress-strain states relative to the hilly land in the south. The more complicated geological structure in southern Jiangsu makes it contribute to greater changes in the state of underground water after a minor disturbance. 展开更多
关键词 fluid well pattern system 2008 Ms8.0 Wenchuan earthquake 2011 MS9.0 tohoku earthquake features of co-seismic responses
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Critical Factors for Run-up and Impact of the Tohoku Earthquake Tsunami 被引量:1
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作者 Efthymios Lekkas Emmanouil Andreadakis +1 位作者 Irene Kostaki Eleni Kapourani 《International Journal of Geosciences》 2011年第3期310-317,共8页
The earthquake of March 11 of magnitude 9 offshore Tohoku, Japan, was followed by a tsunami wave with particularly destructive impact, over a coastal area extending approx. 850km along the Pacific Coast of Honshu Isla... The earthquake of March 11 of magnitude 9 offshore Tohoku, Japan, was followed by a tsunami wave with particularly destructive impact, over a coastal area extending approx. 850km along the Pacific Coast of Honshu Island. First arrival times and measurements and maximum height were recorded by the Japanese monitoring system (wherever there was no failure of the equipment). The maximum run-up is well evident in satellite images available through USGS, Google and other institutes. Moreover, personal observations of Prof. Lekkas were made during a field survey in March 2011. The results of the study of the tsunami impact and run-up show the variety of factors affecting the run-up, creating zones with similar phenomena, but also specific locations where run-up exceeds by far the run-up zone maximum values. This differentiation, observed also in the past by other authors, is here attributed to the general orientation of the coast, the distance from the tsunami generation area, bathymetry offshore, the coastline morphology and land geomorphology. In certain cases that funnelling and reflection effects in narrow gulfs parallel to the tsunami propagation vector were combined with narrow valleys onshore, peak run-up exceeded 20m, or even 40 m (Miyagi coastline, Ogatsu, Onagawa, etc). 展开更多
关键词 tohoku EARTHQUAKE TSUNAMI RUN-UP
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Coseismic gravity and displacement changes of Japan Tohoku earthquake(Mw 9.0) 被引量:2
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作者 Xinlin Zhang Shuhei Okubo +1 位作者 Yoshiyuki Tanaka Hui Li 《Geodesy and Geodynamics》 2016年第2期95-100,共6页
The greatest earthquake in the modern history of Japan and probably the fourth greatest in the last 100 years in the world occurred on March 11, 2011 off the Pacific coast of Tohoku.Large tsunami and ground motions ca... The greatest earthquake in the modern history of Japan and probably the fourth greatest in the last 100 years in the world occurred on March 11, 2011 off the Pacific coast of Tohoku.Large tsunami and ground motions caused severe damage in wide areas, particularly many towns along the Pacific coast. So far, gravity change caused by such a great earthquake has been reported for the 1964 Alaska and the 2010 Maule events. However, the spatial-temporal resolution of the gravity data for these cases is insufficient to depict a co-seismic gravity field variation in a spatial scale of a plate subduction zone. Here, we report an unequivocal co-seismic gravity change over the Japanese Island, obtained from a hybrid gravity observation(combined absolute and relative gravity measurements). The time interval of the observation before and after the earthquake is within 1 year at almost all the observed sites, including 13 absolute and 16 relative measurement sites, which deduced tectonic and environmental contributions to the gravity change. The observed gravity agrees well with the result calculated by a dislocation theory based on a self-gravitating and layered spherical earth model. In this computation, a co-seismic slip distribution is determined by an inversion of Global Positioning System(GPS) data. Of particular interest is that the observed gravity change in some area is negative where a remarkable subsidence is observed by GPS, which can not be explained by simple vertical movement of the crust. This indicated that the mass redistribution in the underground affects the gravity change. This result supports the result that Gravity Recovery and Climate Experiment(GRACE) satellites detected a crustal dilatation due to the 2004 Sumatra earthquake by the terrestrial observation with a higher spatial and temporal resolution. 展开更多
关键词 tohoku earthquake(Mw 9.0) Co-seismic gravity change Co-seismic displacement change Coseismic geoid change Dislocation theory Global Positioning System Absolute gravity measurement Relative gravity measurement
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A Possible Causal Mechanism of Geomagnetic Variations as Observed Immediately before and after the 2011 Tohoku-Oki Earthquake 被引量:1
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作者 Yuji Enomoto Kosuke Heki +2 位作者 Tsuneaki Yamabe Shigeki Sugiura Hitoshi Kondo 《Open Journal of Earthquake Research》 2020年第2期33-49,共17页
During the Mw9 Tohoku-Oki earthquake, gradual increases in both ionosphere total electron content (TEC) and geomagnetic declination signals were observed, starting from ~40 minutes before the mainshock, followed by im... During the Mw9 Tohoku-Oki earthquake, gradual increases in both ionosphere total electron content (TEC) and geomagnetic declination signals were observed, starting from ~40 minutes before the mainshock, followed by impulsive enhancements ~10 minutes after the mainshock. There have been many studies on pre-seismic TEC enhancements, including their characteristics, debates regarding whether TEC anomalies are real signals or artefacts, and the explainable models, and many studies have reported that the impulsive TEC enhancement was caused by a tsunami-induced neutral atmospheric gravity wave. Since TEC and geomagnetic declination anomalies were synchronized so that their origin should be attributed to the same seismic activities, any models must explain both anomalous phenomena, but not the case considered herein. Compared with the corresponding TEC anomalies, we re-examined the characteristics of geomagnetic variation just before and after the mainshock, focusing on the generation process of the impulsive enhancement immediately after the mainshock. We showed that the observed anomaly could be explained if there are quasi-static electric currents of 20 - 30 kA generated near the epicentre area. The possible mechanism of the current generation is discussed in terms of the ionization process in the atmosphere near the sea surface. 展开更多
关键词 tohoku-Oki Earthquake GEOMAGNETIC DECLINATION TEC Blanchard Effect Tornado-Like Cloud
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Ionospheric anomaly before the 2011 Tohoku Mw 9.0 earthquake 被引量:1
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作者 Yang Jian Zhou Yiyan Su Fanfan 《Geodesy and Geodynamics》 2012年第3期17-22,共6页
Using Computerized Ionospheric Tomography (CIT) in combination with GPS observations from the Crustal Movement Observation Network of China (CMONOC), this study reconstructed the electron density distributions ove... Using Computerized Ionospheric Tomography (CIT) in combination with GPS observations from the Crustal Movement Observation Network of China (CMONOC), this study reconstructed the electron density distributions over China before the 2011 Tohoku Mw 9.0 earthquake and discovered a prominent ionospheric anomaly on March 8, 2011. Analysis of the solar-terrestrial space environment around the time of the Tohoku earthquake indicated that the March 8 ionospheric anomaly was likely related to the earthquake. Finally, the paper discusses the drift of the ionospheric anomaly, which was inferred from the anomaly being observed by GPS reference sites in China. 展开更多
关键词 IONOSPHERE TOMOGRAPHY ionospheric anomaly tohoku earthquake CMONOC
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Crustal attenuation characteristics of S-waves beneath the Eastern Tohoku region,Japan
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作者 Muhammad Adeel Arshad 《Earthquake Science》 CSCD 2016年第5期259-269,共11页
An inversion method was applied to crustal earthquakes dataset to find S-wave attenuation characteristics beneath the Eastern Tohoku region of Japan. Accelerograms from 85 shallow crustal earthquakes up to 25 km depth... An inversion method was applied to crustal earthquakes dataset to find S-wave attenuation characteristics beneath the Eastern Tohoku region of Japan. Accelerograms from 85 shallow crustal earthquakes up to 25 km depth and magnitude range between 3.5 and 5.5 were analyzed to estimate the seismic quality factor Qs. A homogeneous attenuation model Qs for the wave propagation path was evaluated from spectral amplitudes, at 24 different frequencies between 0.5 and 20 Hz by using generalized inversion technique. To do this, non-parametric attenuation functions were calculated to observe spectral amplitude decay with hypocentral distance. Then, these functions were parameterized to estimate Qs. It was found that in Eastern Tohoku region, the Qs frequency dependence can be approximated with the function 33 f 1.22 within a frequency range between 0.5 and 20 Hz. However, the frequency dependence of Qs in the frequency range between 0.5 and 6 Hz is best approximated by Qs (f) = 36 f 0.94 showing relatively weaker frequency dependence as compared to the relation Qs (f) = 6 f^ 2.09 for the frequency range between 6 and 15 Hz. These results could be used to estimate source and site parameters for seismic hazard assessment in the region. 展开更多
关键词 tohoku Generalized inversion technique Non-parametric attenuation function Seismic quality factor S-WAVE
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第19章 TOHOKU模式:日本东北大学波浪模式
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作者 Yoshiaki Toba Sanshiro Kawai Paimpillil S.Joseph 《海洋预报》 北大核心 1989年第S1期79-84,共6页
TOHOKU模式是一种混合型的,因为它把风浪的单一参数增长方程与涌分量相结合,而且包括涌浪与风浪之间的互换。 19.1 单一参数风浪部分的背景 风浪部分最基本的特征是在成长的风浪中应用一个自相似结构,即由TOba(1972)提出的一个关于... TOHOKU模式是一种混合型的,因为它把风浪的单一参数增长方程与涌分量相结合,而且包括涌浪与风浪之间的互换。 19.1 单一参数风浪部分的背景 风浪部分最基本的特征是在成长的风浪中应用一个自相似结构,即由TOba(1972)提出的一个关于成长的风浪的无量纲波高与周期之间的简单的指数定律来表示。 H<sub>s</sub><sup>*</sup>=BT<sub>s</sub><sup>*3/2</sup> B=0.062 (19.1)式中H<sub>s</sub><sup>*</sup>=gH<sub>s</sub>/u<sub>x</sub><sup> </sup>2 ,T<sub>s</sub><sup>*</sup>=gT<sub>s</sub>/u<sub>*</sub>是有效波高H<sub>s</sub>和有效周期T<sub>s</sub>通过重力加速度g和大气的摩擦速度u<sub>*</sub>标准化后的无量纲形式。这个指数定律是经过多组实验室和海上资料证明的(如Kawai等,1977;Mitsuyasu等,1980)。该定律不仅符合Wilson(1965)和Mut-suyasu等(1971)给出短风区的经验公式,如果除去无量纲风区的话,Wilson等1965年长风区的复杂公式,事实上也符合这个能量定律。图(19.1)给出了一组混合资料的比较情况,3/2次方的能量定律(19.1)可被转换为: 展开更多
关键词 有效波高 tohoku 摩擦速度 单一参数 风区 经验公式 自相似 日本东北大学 波能 谱形
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Focal depths and mechanisms of Tohoku-Oki aftershocks from teleseismic P wave modeling
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作者 Ling Bai Lorena Medina Luna +1 位作者 Eric A.Hetland Jeroen Ritsema 《Earthquake Science》 2014年第1期1-13,共13页
Aftershocks of the 2011 Tohoku-Oki great earthquake have a wide range of focal depths and fault plane mechanisms. We constrain the focal depths and focal mechanisms of 69 aftershocks with Mw 〉 5.4 by modeling the wav... Aftershocks of the 2011 Tohoku-Oki great earthquake have a wide range of focal depths and fault plane mechanisms. We constrain the focal depths and focal mechanisms of 69 aftershocks with Mw 〉 5.4 by modeling the waveforms of teleseismic P and its trailing near-surface reflections pP and sP. We find that the "thrust events" are within 10 krn from the plate interface. The dip angles of these thrust events increase with depth from ~ 5~ to ~ 25~. The "non-thrust events" vary from 60 km above to 40 km below the plate interface. Normal and strike-slip events within the overriding plate point to redistribution of stress following the primary great earthquake; however, due to the spatially variable stress change in the Tohoku-Oki earthquake, an understanding of how the mainshock affected the stresses that led to the aftershocks requires accurate knowledge of the aftershock location. 展开更多
关键词 tohoku-Oki aftershocks Focal depths Focal mechanisms Coseismic stress change
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Synthetic sensitivity analysis of high frequency radiation of 2011Tohoku-Oki(MW9.0) earthquake
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作者 Haoran Meng Yongshun John Chen 《Earthquake Science》 2014年第4期355-364,共10页
Frequency-dependent rupture behavior of sub- duction zone interplate megathrust faults has been observed by back-projection method in different frequency bands (from 0.05 to 5 Hz). It has been suggested that the dow... Frequency-dependent rupture behavior of sub- duction zone interplate megathrust faults has been observed by back-projection method in different frequency bands (from 0.05 to 5 Hz). It has been suggested that the down-dip region of the Tohoku megathrust radiated strongly at high frequencies (〉10 Hz) compared with that of the up-dip region. By assuming the same source tirne function of each fault patch, we perform a synthetic sensitivity analysis to compare the energy received from the shallower parts (and further way from the receiver sites) with that frona the deeper parts (and closer to the receiver sites) of the rupture. Our results indicate that regional onshore recordings are probably not adequate to constrain the presence of far-off shore high frequency radiations because of the strong attenuation of this region. 展开更多
关键词 tohoku-Oki earthquake - High frequencyradiation Frequency-dependent rupture behavior
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Dynamic Characteristics of a Damaged Nine-story Building during the 2011 off the Pacific Coast Tohoku Earthquake
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作者 Tsoggerel Tsamba Masato Motosaka +1 位作者 KazushiYoshida Kazuya Mitsuji 《Journal of Civil Engineering and Architecture》 2012年第8期1039-1046,共8页
This paper describes the dynamic characteristics of a damaged nine story building in Sendal during the 2011 Tohoku Earthquake. Dynamic hysteresis characteristic is investigated. The system identification using the ext... This paper describes the dynamic characteristics of a damaged nine story building in Sendal during the 2011 Tohoku Earthquake. Dynamic hysteresis characteristic is investigated. The system identification using the extended Kalman filter determined the amplitude dependency of natural frequency and damping factor, which are consistent with damage feature. Occurrence of partial uplifting in the transverse direction is suggested by the induced higher harmonics based on the wavelet analysis. Historical change of the amplitude dependent dynamic characteristics is also discussed based on the long-term monitoring data from microtremor level to strong motion level. 展开更多
关键词 2011 tohoku Earthquake dynamic characteristics damaged building long-term monitoring.
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Sendai Water Pipeline Response to the 2011 Tohoku Earthquake
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作者 Kazue Wakamatu Shigeru Nagata +1 位作者 Yoshihisa Maruyama Kyoko Ozawa 《Journal of Civil Engineering and Architecture》 2016年第4期461-470,共10页
Damage caused by the 2011 Tohoku Earthquake (Mw 9.0) to transmission and distribution pipelines in Sendai City is summarized. The locations of the pipeline repairs are discussed relative to earthquake intensity, geo... Damage caused by the 2011 Tohoku Earthquake (Mw 9.0) to transmission and distribution pipelines in Sendai City is summarized. The locations of the pipeline repairs are discussed relative to earthquake intensity, geomorphologic conditions and landform change in the developed areas of hilly land. Repair rate (repairs/km) is summarized according to pipe material and presence or absence of artificial landform change. The following findings were obtained: (1) More than 80% of the repairs took place in pipelines installed in higher lands such as hill and terrace areas consisting of hard soils; (2) Nearly all the pipe repairlocations in hill areas are where landform change was made through land development tor residential purposes over me past several decades; (3) The aforementioned repair rate was more than 3.6 times than that of other lowland areas where no landform change occurred. The heaviest concentrations of pipe repairs of vinyl chloride pipes and ductile iron pipes were observed within the boundary area between cutting and filling, having a thickness between -2.5 m and 2.5 m. Approximately 78% of the all pipe repairs occurred outside of areas where severe ground failures took place. A mechanism of pipe damage in the areas free of severe ground failure was discussed. 展开更多
关键词 Water pipeline damage the 2011 tohoku Japan Earthquake developed land landform change landslide.
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