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102.
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
103.
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
104.
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
105.
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
106.
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
107.
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
108.
Can electromagnetic disturbances related to the recent great earthquakes be detected by satellite magnetometers? 总被引：1，自引：0，他引：1
On December 26, 2004 the world's fourth largest earthquake since 1900 and the largest since the 1964 Prince William Sound, Alaska earthquake, occurred off the west coast of northern Sumatra with a magnitude of 9.3. On March 28, 2005 another event of magnitude 8.7 took place in the same region. The December 26, 2004 earthquake has prompted scientists to investigate possible electromagnetic signatures of this event, using ground magnetic observations. Iyemori et al. [Iyemori, T. et al., 2005. Geomagnetic pulsations caused by the Sumatra earthquake on December 26, 2004. Geophys. Res. Lett., 32, L20807, doi:10.1029/2005GL024083.] have suggested that a 3.6 min long geomagnetic pulsation, observed shortly after this event, was generated by the earthquake. They have speculated that a 30 s magnetic pulsation was also caused by the earthquake. Here for the first time, CHAMP satellite magnetic and electron density data are examined to find out if electromagnetic signatures which are possibly related to these recent megathrust earthquakes are observed in satellite magnetic data. We have shown that some specific features are observed after the two earthquakes, with periods of about 16 and 30 s. Our results favor an external source origin for the 30 s pulsation. Moreover, after more than 1 h, CHAMP magnetic data indicate the existence of a feature characterized by the same parameters (duration, amplitude, and frequency content), which could be associated with each earthquake, respectively. Further investigations are required in order to answer the question of whether these signals can be associated with earthquakes and to assign their possible usefulness with respect to earthquake development. 相似文献
109.
T. Rossetto N. Peiris A. Pomonis S. M. Wilkinson D. Del Re R. Koo S. Gallocher 《Natural Hazards》2007,42(1):105-124
On December 26, 2004 a great earthquake (M
W 9.3) occurred off the western coast of Sumatra triggering a series of tsunami waves that propagated across the Indian Ocean
causing damage and life loss in 12 countries. This paper summarizes the observations of lifeline performance, building damage
and its distribution, and the social and economic impact of the tsunami made by the Earthquake Engineering Field Investigation
Team (EEFIT) in Thailand and Sri Lanka. EEFIT operates under the umbrella of the UK’s Institution of Structural Engineers.
It is observed that good engineering practice can reduce economic losses, but additional measures are required to reduce risk
to life. 相似文献
110.
Thermally metamorphosed Tertiary age coals from Tanjung Enim in South Sumatra Basin have been investigated by means of petrographic, mineralogical and chemical analyses. These coals were influenced by heat from an andesitic igneous intrusion. The original coal outside the metamorphosed zone is characterized by high moisture content (4.13–11.25 wt.%) and volatile matter content (> 40 wt.%, daf), as well as less than 80 wt.% (daf) carbon and low vitrinite reflectance (VRmax = 0.52–0.76%). Those coals are of subbituminous and high volatile bituminous rank. In contrast the thermally metamorphosed coals are of medium-volatile bituminous to meta-anthracite rank and characterized by low moisture content (only < 3 wt.%) and volatile matter content (< 24 wt.%, daf), as well as high carbon content (> 80 wt.%, daf) and vitrinite reflectance (VRmax = 1.87–6.20%). All the studied coals have a low mineral matter content, except for those which are highly metamorphosed, due to the formation of new minerals.The coalification path of each maceral shows that vitrinite, liptinite and inertinite reflectance converge in a transition zone at VRmax of around 1.5%. Significant decrease of volatile matter occurs in the zone between 0.5% and 2.0% VRmax. A sharp bend occurs at VRmax between 2.0% and 2.5%. Above 2.5%, the volatile matter decreases only very slightly. Between VRr = 0.5% and 2.0%, the carbon content of the coals is ascending drastically. Above 2.5% VRr, the carbon content becomes relatively stable (around 95 wt.%, daf).Vitrinite is the most abundant maceral in low rank coal (69.6–86.2 vol.%). Liptinite and inertinite are minor constituents. In the high rank coal, the thermally altered vitrinite composes 82.4–93.8 vol.%. Mosaic structures can be recognized as groundmasss and crack fillings. The most common minerals found are carbonates, pyrite or marcasite and clay minerals. The latter consist of kaolinite in low rank coal and illite and rectorite in high rank coal. Change of functional groups with rank increase is reflected most of all by the increase of the ratio of aromatic C–H to aliphatic C–H absorbances based on FTIR analysis. The Oxygen Index values of all studied coals are low (OI < 5 mg CO2/g TOC) and the high rank coals have a lower Hydrogen Index (< 130 mg HC/g TOC) than the low rank coals (about 300 mg HC/g TOC). Tmax increases with maturity (420–440 °C for low rank coals and 475–551 °C for high rank coals).Based on the above data, it was calculated that the temperature of contact metamorphism reached 700–750 °C in the most metamorphosed coal. 相似文献