2015年9月16日智利M_w 8.3级地震:海啸波从近场到远场的特征分析     

任智源  原野  王培涛  范婷婷  王君成  侯京明 《海洋学报(英文版)》2017,36(5):73-82

On September 16, 2015, an earthquake with magnitude of M_w 8.3 occurred 46 km offshore from Illapel, Chile,generating a 4.4-m local tsunami measured at Coquimbo. In this study, the characteristics of tsunami are presented by a combination of analysis of observations and numerical simulation based on sources of USGS and NOAA. The records of 16 DART buoys in deep water, ten tidal gauges along coasts of near-field, and ten coastal gauges in the far-field are studied by applying Fourier analyses. The numerical simulation based on nonlinear shallow water equations and nested grids is carried out to provide overall tsunami propagation scenarios, and the results match well with the observations in deep water and but not well in coasts closed to the epicenter. Due to the short distance to the epicenter and the shelf resonance of southern Peru and Chile, the maximum amplitude ranged from 0.1 m to 2 m, except for Coquimbo. In deep water, the maximum amplitude of buoys decayed from9.8 cm to 0.8 cm, suggesting a centimeter-scale Pacific-wide tsunami, while the governing period was 13–17 min and 32 min. Whereas in the far-field coastal region, the tsunami wave amplified to be around 0.2 m to 0.8 m,mostly as a result of run-up effect and resonance from coast reflection. Although the tsunami was relatively moderate in deep water, it still produced non-negligible tsunami hazards in local region and the coasts of farfield.  相似文献   

Distribution of boulders at Miyara Bay of Ishigaki Island,Japan: A flow characteristic indicator of tsunami and storm waves     

Kazuhisa Goto  Tetsuya Shinozaki  Koji Minoura  Kiyohiro Okada  Daisuke Sugawara  Fumihiko Imamura 《Island Arc》2010,19(3):412-426

This study investigates the distribution of boulders at Miyara Bay of Ishigaki Island, Japan. These boulders were deposited on a reef flat extending approximately 400–1300 m in width. Most boulders were rectangular to ellipsoidal, without sharp broken edges. They are reef and coral rock fragments estimated as <335 m³ (<633 t). Locally in the bay, the relationship between the boulder weight and position shows that boulders of a given weight have a clear limit on seaward distribution on the reef flat. For example, more than 1, 10, and 100 tons of boulders were deposited, respectively, more than 500, 300, and 100 m from the reef edge. The line is consistent with the possible landward transport limit by maximum storm waves at the Ryukyu Islands, suggesting that the line was formed by the reworking of some boulders by maximally strong storm waves, although we can not exclude the possibility that the line was formed by tsunamis. Furthermore, 68% of boulders at the bay are deposited beyond this line. Therefore, the presence of these boulders at their present positions is difficult to explain solely by storm waves, implying the possible tsunami origin of these boulders. The boulders are characteristically concentrated along the high‐tide line, suggesting the drastic reduction of the tsunami hydraulic force along the line. Previous studies using radiocarbon age dating, as well as our study, imply that at least 69 boulders at Miyara Bay were probably deposited at their present positions by the 1771 Meiwa tsunami, although some of these boulders might have been emplaced and displaced on the reef flat by prior tsunami or storm surges.  相似文献   

山东沿海地区地震海啸研究     

冯志泽  张建民  陈惠云 《华北地震科学》2010,28(1):26-30

地震海啸是一种极其严重的地震次生灾害。山东是世界上最早记录地震海啸的地区。收集整理了山东沿海地区记载的7次地震海啸史料,对每次地震海啸进行了信度评级,认为仅有一次可能是海啸。根据山东沿海地区历史地震海啸、地震类型、沿海地理环境、现代地震海啸记录资料等分析,表明山东沿海未来遭受破坏性地震海啸的可能性较小。  相似文献   

地震与海啸作用下重力式岸墙旋转位移拟静力分析          下载免费PDF全文

林永亮  李新星 《地震工程学报》2015,37(3):840-844

被动状态下位移预测是挡墙地震工程设计中的关键,而岸墙后回填土的孔隙水压力对墙体运动具有一定影响。采用拟静力法计算墙后部分浸水土体的被动动土压力,根据静力水压力理论近似计算土颗粒里的动水压力;同时考虑地震荷载和海啸力的作用,根据力矩极限平衡确定旋转门槛加速度系数,采用旋转块体方法计算岸墙被动旋转运动下的地震位移。探讨回填砂土内摩擦角、墙体与土间摩擦角、地震加速度系数、回填土地下水位、海啸波浪高度等参数对旋转位移的影响。  相似文献   

Comparison of two great Chile tsunamis in 1960 and 2010 using numerical simulation          下载免费PDF全文

Ruizhi Wen  Yefei Ren  Xiaojun Li  Rong Pan 《地震科学（英文版）》2011,24(5):475-483

Great differences in hazard and losses were shown from two tsunamis, both generated in Chile, one in 1960 and the other in 2010. Numerical simulation was applied to the tsunami analysis. The fault dislocation of the seafloor was assumed to equal to the initial tsunami wave field, which can be calculated by the formula of fault dislocation in the elastic isotropic half-space. The linear long wave theory was used as the tsunami hydrodynamic model, and the finite difference method and leap-frog scheme were selected for solving the equations. The accuracy of the simulated results was verified by the observed data in five tide gauges. By means of two scenario tsunamis, the analytical results show that the earthquake magnitude, bathymetry in rupture zone and rapid release of warning information in 2010 tsunami are the main explanations of the aforementioned great difference.  相似文献   

印度塔米尔那杜地区堪雅库玛里与奥瓦利之间海岸区域海啸灾后评估——事例分析(英文)          下载免费PDF全文

S.Saravanan  N.Chandrasekar  C.Hentry  M.Rajamanickam 《地学前缘》2009,16(6):129

海岸带是动态地区,由于众多因素,包括海平面的上升、波浪与洋流的类型、飓风乃至人类的影响,海岸地区经常受到变动。2004年12月26日巨大海啸席卷了堪雅库玛里至奥瓦利之间的海岸。当海浪冲上海滩时波高达30英尺。许多人因为巨浪的冲击和退浪的强力推拉而淹死在海里,许多村庄被毁。死亡总数超过300人,而且财产损失严重。海啸的规模与洋底移动的面积、移动距离是有关系的。该区显示为海成阶地、沙丘、滩脊、河口、洪积平原、海滩、红树林、准平原、高地、海蚀崖等等。我们试图通过现场在线勘查、政府记录以及采用遥感技术所做的海岸地貌研究等资料,通过海滩剖面测量和海岸环境的变化,进行海岸线动力学研究。文中也对主要的破坏予以认定。  相似文献   

东海海域潜在地震海啸的数值模拟初步研究   总被引：2，自引：0，他引：2       下载免费PDF全文

温燕林  朱元清  宋治平  薛艳  刘双庆  董非非 《地震学报》2008,30(5):456-463

针对东海冲绳海槽地区的地震地质背景,对东海海域潜在的地震海啸进行了预研究. 假设了冲绳海槽在发生8.5级大地震,断层错距高达15 m的极端地震情况引发的海啸对中国东部沿海地区的影响. 初步数值模拟结果表明,该地震引发的海啸的最大初始波高为4.3 m,4小时左右传至浙江沿岸,近岸各处波高为1——2 m,其中局部地区波高为2.4 m;约7——8小时靠近上海海岸线（若震源在中冲绳海槽地区,海啸传到上海最快大约7小时）,近岸波高约为1 m. 近岸区域地形变化复杂,海岛密布,局部地形条件可能会很大地影响实际各地点海啸波高,加上海啸在岸边爬高及港湾效应,估计波高还会升高. 给出了冲绳海槽南、中、北部发生潜在地震海啸的传播等时图. 笔者在东海设置了3个地震及海啸监测站,基于海啸模拟结果绘制了监测站处的海啸随时间演化曲线,分析了预研究成果对海啸预警可能发挥的作用.   相似文献   

越洋海啸的数值模拟   总被引：3，自引：0，他引：3  

温瑞智  任叶飞  周正华  史大成 《地震工程与工程振动》2008,28(4)

破坏性海啸基本上都是越洋海啸,如1960年智利海啸、2004年苏门答腊海啸。越洋海啸的传播机制与近场海啸不同,进行数值模拟所采用的数学模型也不同。本文分析比较Boussinesq方程和线性浅水方程,选用后者作为进行越洋海啸数值模拟的数学模型,基于有限差分法,运用蛙跃格式求解微分方程。以2004年苏门答腊海啸作为算例,把计算结果与NOAA和NGDC的计算结果进行对比,验证本文的数学模型和计算方法的可靠性,为以后进一步的海啸危险性分析和海啸预警等研究工作提供技术支持。  相似文献   

花东海盆综合地震探测及其重要的构造意义          下载免费PDF全文

赵明辉  王强  杨富东  张佳政  高红芳  孙龙涛  刘思青  张光学 《地球科学》2021,46(1):359-368

花东海盆位于欧亚板块与菲律宾海板块交汇处,是现今西太平洋俯冲体系中唯一遗留的早白垩纪洋盆,是研究西太平洋俯冲构造演化与动力学机制的一个关键区域.前期研究发现,关于花东海盆的基础科学问题迫切需要解决:花东海盆的性质、年龄及形成演化历史如何?南北走向的加瓜海脊是花东海盆的东部边界吗?其隆升机制和构造属性如何?花东海盆的西部...  相似文献   

珊瑚岛礁孤立波爬坡的平面二维数值模拟研究     

刘林平  刘维杰  孙志林 《海洋工程》2021,39(4):96-103

为了探究岛屿周围珊瑚礁在抵御海啸灾害中的作用,采用激波捕捉类Boussinesq模型FUNWAVE-TVD,对孤立波在理想化三维岛礁地形上的传播及爬坡开展了现场尺度的平面二维数值模拟,分析了入射波高、礁坪水深、礁坪宽度、礁前斜坡坡度、礁后斜坡坡度、珊瑚礁糙率对岛屿四周孤立波爬高分布的影响。结果表明,珊瑚礁的存在总体上可有效降低岛屿四周孤立波的最大爬坡高度;入射波高、礁坪水深、礁坪宽度、珊瑚礁糙率是影响珊瑚岛礁四周孤立波爬坡分布的主要因素,岛礁四周最大爬坡高度会随入射波高和礁坪水深的增大、礁坪宽度和珊瑚礁糙率的减小而不断增大;当礁坪水深增大到一定程度时,珊瑚礁主要会对岛屿背浪面的爬高失去影响,而当礁坪宽度和珊瑚礁糙率减小至一定程度时,会出现岛礁四周最大爬高高于无珊瑚礁时爬高的现象;礁后斜坡的变缓会使岛礁周围的最大爬高有所减小,而礁前斜坡坡度对珊瑚岛礁周围的最大爬高几乎没有影响。  相似文献