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1.
Izvestiya, Atmospheric and Oceanic Physics - The characteristics of the short-period S-wave attenuation field in the source zone of the strongest Tohoku earthquake of March 11, 2011 in the... 相似文献
2.
Ashok S. Patwardhan I. M. Idriss John M. Hobgood Ram B. Kulkarni K. Sadigh 《Marine Georesources & Geotechnology》2013,31(3):243-267
Abstract The characterization of earthquake sources in the Gulf of Alaska and the relative significance of earthquake sources for establishing seismic design inputs at a typical site for engineering purposes are discussed. Earthquake sources in the complex tectonic environment can be divided into two groups: (a) a subduction zone that underlies the entire region (maximum magnitude M = 8.5); and (b) individual thrust and strike‐slip faults associated with the plate motions (maximum magnitude M = 6 to 7.5). The sources of either group and individual earthquake events can be represented as planar surfaces for consistency with the physical process and a mathematically tractable computational scheme. Although the area is very active seismically, the degree of activity of individual sources varies significantly. Therefore, even for sources with the same maximum earthquakes, different magnitudes may apply for a selected design return period. The area is considered to be a “seismic gap.”; No great earthquakes have occurred in nearly 80 years. Estimates based on a temporally varying seismic function such as the semi‐Markov model indicate that the probability of occurrence of a great earthquake in the near future is significantly higher than the average probability inferred from a statistical analysis of historical seismicity data of the entire region. Separate attenuation relationships should be used for calculating ground motions due to earthquakes on the dipping subduction zone in the northern portion of the gulf. The dominant earthquake source for almost the entire Gulf of Alaska region is the subduction zone that contributes over 80 percent of the seismic exposure at a typical site. The dominant magnitude range is Ms = 6.5 to 7.5. “Gap filling”; earthquakes (Ms = 7.5 to 8.25) contribute a little over a third of the seismic exposure at a typical site. Deterministic assessments of ground motion values using the maximum earthquake on the subduction zone at the closest distance yield values significantly higher than those calculated for even 500‐year return periods. Estimated 100‐year return period accelerations in the area range from 180 to 340 cm/sec2. 相似文献
3.
At present, the problem of predicting tsunamis with source earthquakes near the shoreline remains practically unresolved. It is shown that, in the Pacific region, 87% of tsunamigenous earthquake epicenters are located closer than 100 km to the shoreline and 67% are closer than 50 km. For a more detailed analysis, the area of the Pacific Ocean was divided into ten subregions: Kamchatka, the Kuril Islands, Japan, Indonesia, Australia and Oceania, South and Central America, Alaska, and the Aleutian Islands. Each subregion was analyzed individually. All the earthquakes from 1950 to 2003 with Ms >= 6.0 causing tsunamis with intensities I > 0 were processed. The ITDB/PAC 2004 database was used as the data source. For each subregion, mean and minimal travel times were calculated. The minimal travel times for all the regions except for a single one are less than 10 min. It is shown that, in the near earthquake zone, no tsunami alert based sea-level gauge data is possible. One probable solution could be based on detecting hydroacoustic signals that precede strong earthquakes in the near-shore zone. 相似文献
4.
A. I. Lutikov 《Izvestiya Atmospheric and Oceanic Physics》2011,47(8):971-977
The results of a preliminary analysis of the source zone of the 2011 Tohoku earthquake (M
w
= 9.1) near the east coast of Honshu, Japan, are considered. We traced the seismic history of the release of the cumulative
scalar seismic moment for the last 110 years and temporal variations in the ordering index for the last 35 years. These parameters
are important characteristics of a seismotectonic deformation process. The foreshock activation stage and the initial phase
of the aftershock process are studied based on these characteristics. 相似文献
5.
Win-Bin Cheng 《Marine Geophysical Researches》2004,25(1-2):79-93
A joint analysis of gravity anomaly and seismic travel-time data has been used to construct a three-dimensional velocity structure for the northeastern extension of the northern South China Sea’s high-magnetic belt in the Taiwan region. The earthquake data used in this study was collected by the Central Weather Bureau Seismological Network from 1991 to 2002, while the gravity data around Taiwan was compiled by Hsu et al. (1998), Terr. Atmos. Oceanic. Sci., 9, 509–532, and Wang et al. (2002), >Terr. Atmos. Oceanic. Sc., 13, 339–354. A modified velocity model obtained by local earthquake tomography was used to construct an initial three-dimensional gravity model, using a linear velocity–density relationship. To derive a crustal velocity–density model that accounts for both types of observations, this study performed a sequential inversion of travel-time and gravity data. The main features of our three-dimensional velocity model are:(1) an uplifted zone with velocity greater than 6.5 km/s being observed in the lower crust, (2) the width and the shape of the uplifted zone being found to be strongly correlated with the high-magnetic belt, (3) a trend by which the lower crustal high-velocity zone turns from northeast to north in central Taiwan, where the high-magnetic zone was truncated. A combination of seismic, gravity, and structural interpretations suggests that the crustal deformation relating to the magnetic truncation observed in northwestern Taiwan could be correlated closely with the collision between the Philippine Sea plate and the Asian continental margin. 相似文献
6.
Numerical simulation of the earthquake and tsunami of November 15, 2006, and the spectral analysis of the distribution of
the wave fields in the basin made it possible to analyze in detail the tsunami generation by a seismic source and the pattern
of the wave propagation through the Bussol Strait, as well as to estimate the influence of this strait on the further propagation
of the waves in the basin of the Sea of Okhotsk and the near-field zones of the Kurile and Japanese Islands. 相似文献
7.
We perform the numerical analysis of the process of propagation of long waves in the northwest part of the Black Sea and consider
ten possible zones of the seismic generation of tsunamis. The numerical analysis is performed on a grid with steps of 500 m.
It is shown that the location of the tsunami source significantly affects the distribution of the heights of waves along the
coast. As a rule, the most intense waves are formed in the closest part of the coast. The earthquakes in the South-Coast seismic
zone do not lead to the formation of tsunamis in the west part of the sea. Only strong earthquakes in the northwest part of
the sea can be responsible for noticeable oscillations of the Black-Sea level. The period of tsunamis near Odessa is close
to 1 h and depends on the magnitude of the earthquake. In the region of Sevastopol, this period is 2--3 times smaller. In
the major part of the coastal points, the extreme elevations and lowerings of the sea level do not exceed (in modulus) the
initial displacements of the sea surface at the source of tsunamis. An intensification of waves emitted from the zones of
generation located in the deeper part of the investigated region was observed for some parts of the Romanian coast and the
west coast of Crimea. As the magnitude of the earthquake increases, the intensification of waves near the coast becomes more
pronounced. 相似文献
8.
印尼附近海域地震海啸发生的构造背景综述 总被引：3，自引：0，他引：3
2004年12月26日在印度尼西亚苏门答腊岛以西海域发生的里氏9级地震,引发了历史上第五大地震海啸,引起了地学界的高度关注。印度尼西亚西部位于环太平洋地震带和地中海-喜马拉雅地震带结合部位,处于洋壳和陆壳的汇聚边界以及弧状压缩构造格局中。苏门答腊陆缘NW—SE向延伸约1600km,苏门答腊俯冲带源于印度-澳大利亚和欧亚板块3°N的汇聚。苏门答腊弧前区沿着平行于俯冲海沟的两大走滑断裂——苏门答腊大断裂和明打威断裂向北运动。本文对印度尼西亚苏门答腊岛附近海域的地质背景、大地构造特征和地震活动评估等进行了综述,对该海域产生大地震的深部动力学机制进行了分析,并从地质、地球物理资料的获取与分析角度出发,对区域灾害模型进行了探讨。 相似文献
9.
The Tokachi-Oki earthquake was the strongest seismic event in 2003. The tsunami caused by the earthquake reached a height of four meters at the northeastern coast of Hokkaido. The JAMSTEC successfully recorded the variations of the near-bottom pressure in the region of the tsunami source. An analysis of the data reveals low-frequency (～ 0.15 Hz) elastic vibrations of the water layer. Estimates of the amplitude, velocity, and duration of the bottom deformation at the tsunami source were obtained. 相似文献
10.
Paul J. Grim 《Marine Geophysical Researches》1970,1(1):85-90
Magnetic data recently collected in the eastern tropical Pacific confirm that the Galapagos rift zone is connected to the Panama fracture zone by a short north-south fracture zone (the Ecuador fracture zone) and a short east-west center of sea floor spreading (the Costa Rica rift zone). These features were found approximately in the locations predicted by Molnar and Sykes from considerations of earthquake studies and plate tectonics. A spreading rate of 3.1 cm/year for the Costa Rica rift zone agrees with the rate found for the Galapagos rift zone but the anomalies associated with the two rifts differ markedly in amplitude. 相似文献
11.
S. F. Dotsenko 《Physical Oceanography》2000,11(2):109-115
Within the framework of the nonlinear theory of one-dimensional long waves, we performed the numerical analysis of the dependence
of the intensity of tsunami on the shelf of the South Coast of Crimea on the location of the epicentre of underwater earthquakes
near the continental slope of the basin. The calculations were carried out for the parameters of the model corresponding to
the Yalta tsunami of September 12, 1927. It is shown that, for the same magnitude of the earthquake, the smaller the distance
from its epicentre to the coastal line, the lower tsunami waves in the coastal zone and the smaller their vertical run-up.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
12.
S. F. Dotsenko 《Physical Oceanography》2001,11(5):411-424
We perform the analysis of tsunami waves in the shelf zone of the Crimean peninsula generated by underwater earthquakes whose
epicentres are located near the lower boundary of the continental slope. For this purpose, we use a one-dimensional nonlinear
dissipative numerical model of long waves. The investigated distributions of the depth of the basin correspond to four points
of the south coast of the Crimean peninsula. We use the empirical dependences of parameters of the sources of tsunami waves
on the magnitude of the earthquake obtained earlier for the Pacific Ocean. It is shown that the height, vertical climb, and
duration of tsunami waves increase with the magnitude of the earthquake. For equal magnitudes of the earthquake, the highest
tsunamis on the south coast of the Crimea are observed between Alushta and Yalta. We also deduced a generalized regression
dependence of the height of tsunami waves near the coast on the magnitude of the earthquake.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
13.
In this paper we analyze seismic regime and earthquake depth distribution and correlation of seismicity and mud volcanism in the Azerbaijan and the Caspian Sea region. For the present region we have calculated accurate source locations, seismic activity, earthquake repetition and released earthquake energy parameters. It is shown that the active tectonic processes in the region are concentrated within the thick sedimentary cover that we consider as a general source of contemporary stress and a main structural element responsible for the origin of regional earthquakes. The correlation of seismicity and mud volcanism is of paragenetic character. 相似文献
14.
本文以东海区海岸带为例，采用空间主成分分析法，对 2015 年东海区沿岸县级陆域的生态安全程度进行评价，并运用累积阻力模型，分析东海区海岸带的生态源地、廊道和核心节点，在此基础上提出优化布局思路。结果表明： （1） 林地、气候和地貌等自然要素及其质量对区域生态安全性有显著影响，植被覆盖度对生态安全的贡献率占 38.8%，是影响生态安全最重要的因子；此外，开发建设程度亦有影响生态安全的效果，此效果略小于自然要素； （2） 东海海岸带的生态安全指数在1.61~5.89 之间，表明东海区生态环境质量大体趋好，生态安全指数呈现出显著的南北分异和东西分异态势； （3） 构建以“四片区、三组团、两廊道、多中心”为核心的东海区海岸带生态景观的优化布局方案，以期为海岸带地区生态安全建设提供参考. 相似文献
15.
I. S. Kostenko A. I. Zaytsev D. D. Minaev A. A. Kurkin E. N. Pelinovsky O. E. Oshmarina 《Izvestiya Atmospheric and Oceanic Physics》2018,54(1):1-9
Observation data on the September 5, 1971, earthquake that occurred near the Moneron Island (Sakhalin) have been analyzed and a numerical simulation of the tsunami induced by this earthquake is conducted. The tsunami source identified in this study indicates that the observational data are in good agreement with the results of calculations performed on the basis of shallow-water equations. 相似文献
16.
A. I. Zaytsev E. N. Pelinovsky A. A. Kurkin I. S. Kostenko A. Yalciner 《Izvestiya Atmospheric and Oceanic Physics》2016,52(2):217-224
The earthquake that occurred on May 24, 2013, in the basin of the Sea of Okhotsk with a magnitude of 8.3 was the strongest in this region. We have modeled a possible tsunami caused by such an earthquake. The simulations confirm that the wave heights were sufficiently small because the earthquake epicenter depth was 640 km. We analyze the oscillations of the DART buoys in the vicinity of the earthquake source and show that they were not associated with the tsunami waves. Analysis of the available pressure gauge records at different points of the Sea of Okhotsk show that only in one case (Iturup Island) can the observed oscillations of the sea level with a height of approximately 4 cm be classified as tsunami waves. 相似文献
17.
M. B. Gokhberg G. M. Steblov S. L. Shalimov V. A. Veis E. A. Grekhova 《Izvestiya Atmospheric and Oceanic Physics》2011,47(8):929-940
Using available Russian and international Global Positioning System (GPS) network data, we studied the ionospheric response
to the M = 8.9 submarine earthquake of March 11, 2011, on the northeastern coast of Honshu Island, Japan, both near and far (about
2000 km away) from the epicenter. In the region over the epicenter, 8.7 min after the event, we detected a characteristic
signal of the total electron content (TEC) variations consisting of compression and rarefaction phases and a linear transition
zone in between, i.e., in the form of an N-type wave with a steep leading front indicating a rapid uplift of the water surface and, correspondingly, the bottom of the
ocean. The shape of the signal can be used for early tsunami warning; i.e., it may indicate the tsunamigenic character of
a submarine earthquake. We monitored the subsequent evolution of the ionospheric response as far as 2000 km from the epicenter.
It was shown that, besides the wellknown ionospheric N-type wave response to the earthquake, there is also a response in the form of an inverted N-wave, both nearby and far from the epicenter. We detected two more types of ionospheric responses far from the epicenter:
a solitary-like wave and an internal gravity wave (IGW). The detected signals have been interpreted. 相似文献
18.
Izvestiya, Atmospheric and Oceanic Physics - We present the results of studying anomalous variations in the lineament system during the preparation to the M = 5.6 earthquake that occurred on... 相似文献
19.
Statistical relations of the run-up height of Tsunami waves to the distance and energy of the source
A statistical analysis of the relation between the run-up height of historical tsunami events and the distance and magnitude of the source was performed on the basis of the known Historical Tsunami Data Base [5]. The sample from the database used for the analysis comprises 5638 run-ups caused by 628 seismic events. This analysis, together with the dimensionality theory, shows that the statistical average of the run-up height is inversely proportional to the distance from the source to a power close to 1/2 (that is characteristic of the cylindrically symmetrical case) and directly proportional to the 3/8 power of the earthquake energy. 相似文献
20.
韩江三角洲第四纪构造特征与区域稳定性分析 总被引：1，自引：0，他引：1
韩江三角洲第四纪构造特征主要表现在活动断裂，断块运动以及与其相关的第四系，岩浆，温泉，地震和构造应力场等，结合潜在震源区，灾害性地质等分析，按稳定程度自高而低把本区依次划分为棉湖－归湖次稳定区，潮阳－饶平次稳定区，普宁－潮州次不稳定区和广澳－南澳次不稳定区。认为自陆向海稳定程度降低的看法过于笼统。 相似文献