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Dieter Franke Michael Schnabel Stefan Ladage David R. Tappin S nke Neben Yusuf S. Djajadihardja Christian Mü ller Heidrun Kopp Christoph Gaedicke 《Earth and Planetary Science Letters》2008,269(1-2):118-130
Segmentation along convergent margins controls earthquake magnitude and location, but the physical causes of segment boundaries, and their impact on earthquake rupture dynamics, are still poorly understood. One aspect of the 2004 and 2005 great Sumatra–Andaman earthquakes is their abrupt termination along a common boundary. This has led to speculation on the nature of the boundary, its origin and why it was not breached.
For the first time the boundary has been imaged and, with newly acquired marine geophysical data, we demonstrate that a ridge on the subducting Indo-Australian oceanic crust may exert a control on margin segmentation. This suggests a lower plate influence on margin structure, particularly its segmentation. The ridge is masked by the sedimentary cover in the trench. Its most likely trend is NNE–SSW. It is interpreted as a fracture zone on the subducting oceanic plate. A ramp or tear along the eastern flank of the subducting fracture zone beneath Simeulue Island may be considered as an intensification factor in terms of rupture propagation barrier. 相似文献
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利用2012年1~6月川滇地区(21°～34°N, 97°～108°E)99个测震数字地震台的连续波形资料, 采用背景噪声层析成像方法反演了2012年4月11日苏门答腊8.6级地震前后川滇地区的波速变化, 同时研究了该地震前后川滇地区地震活动的变化特征。 结果表明, 川滇地区波速结构呈现龙门山断裂带南段至元谋—绿汁江断裂带和安宁河断裂带波速降低而两侧波速升高的特点。 同时, 波速变化与地震活动性变化具有明显的相关性: 在宁蒗—木里和乐山—雅安一带波速增高显著, 地震活动速率也增加; 在龙门山断裂带南段至安宁河断裂带上则表现为明显的波速降低, 而安宁河断裂带也是地震活动速率降低区域。 这表明本研究得到的波速变化的结果有一定的可信度, 也为背景噪声方法应用到地震预测提供了一种可能的途径。 相似文献
104.
2012��4�����Ŵ�����������������ܶ��쳣�о� 总被引：1，自引：0，他引：1
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105.
国际多元合作推动灾区重建的回顾和思考——以印度洋地震海啸印度尼西亚灾区为例 总被引：2，自引：1，他引：1
鉴于目前在灾区重建中的国际多元合作机制尚未成熟,以及以往研究过分强调国际援助中夹杂了援助方自身利益追求的因素,受此影响一部分受灾国对国际援助表现出消极态度等现状,本研究通过系统梳理国际组织发表的一系列有关2004年印度洋地震海啸后印度尼西亚灾区重建的文献资料,总结了此次有史以来最大规模的国际多元合作援助行动在及时性、可信性、针对性、实效性以及多元化诸方面的特点,进而明确了在应对重大自然灾害,特别是在灾后重建过程中加强国际多元合作的意义。 相似文献
106.
利用伸缩仪观测资料检测地球自由振荡 总被引：1，自引：1，他引：0
运用云南省云龙地震台和山东省泰安地震台伸缩仪的数字化观测资料,利用功率谱密度估计方法,在没有对资料进行去固体潮处理的情况下,准确地获得了2004年12月26日苏门答腊9.0级地震激发的0S3~0S26基频球形自由振荡,并与地球初步参考模型PREM的理论自由振荡周期进行了对比,发现实测振荡周期与PREM预测的振荡周期基本相一致。 相似文献
107.
利用怀来地震台水管仪的数字化观测资料,采用功率谱密度估计方法,在没有对资料去固体潮处理的情况下,准确获得2004年12月26日苏门答腊9.0级地震激发的_0S_2—_0S_(38)基频球型自由振荡,并与PREM模型的理论自由振荡周期进行对比,发现实测振荡周期与PREM预测的振荡周期吻合,除_0S_2、_0S_4、_0S_7振型的观测周期和PREM模型理论周期的相对误差大于0.3%外,其他振型的观测周期和PREM模型理论周期的相对误差大都集中在0.1%左右,同时检测到7个谐频球型振荡和10个环型振荡。可以从水管倾斜仪的观测资料中提取地球球型振荡信息,为地球自由振荡的研究提供一种新的仪器观测方法。 相似文献
108.
使用哈佛CMT资料， 研究了2004年12月26日印尼北苏门答腊以西近海MW9.0地震前的长期地震活动. 这次地震前， 在1/4世纪的时间尺度、 1 500 km的空间尺度上， 存在加速矩释放（AMR）现象. 在这一空间尺度范围内，MW9.0地震仍落在分段的幂律分布上. 因此, 从地震的类临界点模型的角度考虑， 对这次特大地震的发生和地震的大小既无预测、 亦无预报的情况， 并非由物理上的ldquo;不可预测性rdquo;所致. 相似文献
109.
印尼苏门答腊9.0级地震前地震活动图像异常特征研究 总被引：4，自引：1，他引：4
通过对2004年12月26日印尼苏门答腊9．0级大震前不同时空尺度地震活动性异常特征分析发现：①大震前10年，澳大利亚板块北部边界带深源地震活动显著增强，表现为频度增多、强度增大、震源深度增加等，特别是震源深度分布的非均匀性增大（即地震集中分布在500～689km深度间）；同期，苏门答腊岛及其附近肘≥7．0浅震活动也异常显著，形成长约1000km、宽300km的集中区。②震前1年全球肘≥7．0地震活动出现明显的平静一密集现象，且在密集阶段强震沿澳大利亚板块北部边界带呈带状展布；这时主震震源区附近出现5级地震空区。③震前半年澳大利亚板块北部边界带的东、西两端先后发生2次7级以上深震，其中1次发生在罕有深震活动的苏门答腊岛。④震前3天，澳大利亚板块北部边界带上4级以上地震呈带状展布。⑤震前4年澳大利亚板块北部边界带火山活动增强，特别是震前1年火山活动异常显著。 相似文献
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The December 26, 2004 Sumatra tsunami caused severe damage at the coasts of the Indian ocean. We report results of a sedimentological
study of tsunami run-up parameters and the sediments laid down by the tsunami at the coast of Tamil Nadu, India, and between
Malindi and Lamu, Kenya. In India, evidence of three tsunami waves is preserved on the beaches in the form of characteristic
debris accumulations. We measured the maximum run-up distance at 580 m and the maximum run-up height at 4.85 m. Flow depth
over land was at least 3.5 m. The tsunami deposited an up to 30 cm thick blanket of moderately well to well-sorted coarse
and medium sand that overlies older beach deposits or soil with an erosional unconformity. The sand sheet thins inland without
a decrease of grain-size. The deposits consist frequently of three layers. The lower one may be cross-bedded with foresets
dipping landward and indicating deposition during run-up. The overlying two sand layers are graded or parallel-laminated without
indicators of current directions. Thus, it remains undecided whether they formed during run-up or return flow. Thin dark laminae
rich in heavy minerals frequently mark the contacts between successive layers. Benthic foraminifera indicate an entrainment
of sediment by the tsunami from water depths less than ca. 30 m water depth. On the Indian shelf these depths are present
at distances of up to 5 km from the coast. In Kenya only one wave is recorded, which attained a run-up height of 3 m at a
run-up distance of ca. 35 m from the tidal water line at the time of the tsunami impact. Only one layer of fine sand was deposited
by the tsunami. It consists predominantly of heavy minerals supplied to the sea by a nearby river. The sand layer thins landward
with a minor decrease in grain-size. Benthic foraminifera indicate an entrainment of sediment by the tsunami from water depths
less than ca. 30 m water depth, reaching down potentially to ca. 80 m. The presence of only one tsunami-related sediment layer
in Kenya, but three in India, reflects the impact of only one wave at the coast of Kenya, as opposed to several in India.
Grain-size distributions in the Indian and Kenyan deposits are mostly normal to slightly positively skewed and indicate that
the detritus was entrained by the tsunami from well sorted pre-tsunami deposits in nearshore, swash zone and beach environments. 相似文献