共查询到20条相似文献，搜索用时 15 毫秒
1.
Silver PG Beck SL Wallace TC Meade C Myers SC James DE Kuehnel R 《Science (New York, N.Y.)》1995,268(5207):69-73
The M(w) = 8.3 deep (636 kilometers) Bolivian earthquake of 9 June 1994 was the largest deep-focus earthquake ever recorded. Seismic data from permanent stations plus portable instruments in South America show that rupture occurred on a horizontal plane and extended at least 30 by 50 kilometers. Rupture proceeded at 1 to 3 kilometers per second along the down-dip azimuth of the slab and penetrated through more than a third of the slab thickness. This extent is more than three times that expected for a metastable wedge of olivine at the core of the slab, and thus appears to be incompatible with an origin by transformational faulting. These large events may instead represent slip on preserved zones of weakness established in oceanic lithosphere at the Earth's surface. 相似文献
2.
Seismological observations of the 2012 moment magnitude 8.6 Sumatra earthquake reveal unprecedented complexity of dynamic rupture. The surprisingly large magnitude results from the combination of deep extent, high stress drop, and rupture of multiple faults. Back-projection source imaging indicates that the rupture occurred on distinct planes in an orthogonal conjugate fault system, with relatively slow rupture speed. The east-southeast-west-northwest ruptures add a new dimension to the seismotectonics of the Wharton Basin, which was previously thought to be controlled by north-south strike-slip faulting. The rupture turned twice into the compressive quadrant, against the preferred branching direction predicted by dynamic Coulomb stress calculations. Orthogonal faulting and compressional branching indicate that rupture was controlled by a pressure-insensitive strength of the deep oceanic lithosphere. 相似文献
3.
We showed that the rupture produced by the great Peru earthquake (moment magnitude 8.4) on 23 June 2001 propagated for approximately 70 kilometers before encountering a 6000-square-kilometer area of fault that acted as a barrier. The rupture continued around this barrier, which remained unbroken for approximately 30 seconds and then began to break when the main rupture front was approximately 200 kilometers from the epicenter. The barrier had relatively low rupture speed, slip, and aftershock density as compared to its surroundings, and the time of the main energy release in the earthquake coincided with the barrier's rupture. We associate this barrier with a fracture zone feature on the subducting oceanic plate. 相似文献
4.
Variation of interplate fault zone properties with depth in the japan subduction zone 总被引：2，自引：0，他引：2
The depth dependence of physical properties along the Japan subduction zone interface was explored using teleseismic recordings of earthquake signals. Broadband body waves were inverted to determine the duration of rupture and source depth for 40 interplate thrust earthquakes located offshore of Honshu between 1989 and 1995. After scaling for differences in seismic moment, there is a systematic decrease in rupture duration with increasing depth along the subducting plate interface. This indicates increases in rupture velocity or stress drop with depth, likely related to variation in rigidity of sediments on the megathrust. 相似文献
5.
脱绒包衣棉花种子的力学特性 总被引：5，自引：0，他引：5
脱绒包衣棉花种子的力学特性是建立种子模型和精量排种器结构设计与优化的基础。以鄂抗棉10号棉种为试验对象,利用TMS-PRO质构仪与单片机测量系统对完整棉种进行挤压试验,且采用图像处理技术基于最小二乘法边缘轮廓曲线椭圆拟合获取棉种曲率半径,分析计算得出棉种泊松比与弹性模量力学参数,同时对棉种开展不同方位下的剪切试验。结果表明,棉种径向受压时,泊松比为0.142,弹性模量为9.154 MPa,平均挤压破坏力为48.510N;剪切方位对剪切破坏力和破坏能均无显著性影响,但对剪切位移有显著性影响,剪切破坏力为36.6~37.68 N。 相似文献
6.
南方冬种马铃薯压缩力学特性与理化指标相关性研究 总被引：1，自引：0，他引：1
研究以‘大西洋’和‘粤引85-38’(Solanum tuberosum L.)2种南方冬种马铃薯为研究对象,运用DW-100型电子万能试验机,沿3个不同方向在5种不同速率对马铃薯整茎进行压缩试验,分析品种、加载方向和加载速率对马铃薯压缩破裂时破裂力、变形量及破坏能的影响,并对马铃薯压缩特性参数与淀粉含量之间的相关性进行了研究。结果表明:品种和加载方向对破裂力和变形量影响极显著,其中与破裂力呈极显著正相关,与压缩变形量呈极显著负相关;加载速度对破裂力、变形量无显著影响;淀粉含量与压缩变形量呈极显著正相关,淀粉含量越高,压缩时破裂点变形量越大。 相似文献
7.
以山东省郯城县为案例,通过实地调研和问卷调查,将截面与时间序列相结合,深入细致地分析近年来农村家庭用能消费结构发生的变化。研究发现:村民家庭用能的消费结构已由20世纪90年代以前的"煤+薪柴"为主,变成"电+太阳能+煤"为主,液化气、薪柴为辅;既表现出电对煤、液化气对薪柴的替代,同时也显示出电和沼气对液化气的替代效应;村民家庭用能的增长主要来源于太阳能、电及沼气等农村非传统能源,且增长的能源主要用于生活享受;新能源和可再生能源成为农村家庭用能消费新的增长点。 相似文献
8.
Observations and modeling of 3- to 6-hertz seismic shear waves trapped within the fault zone of the 1992 Landers earthquake series allow the fine structure and continuity of the zone to be evaluated. The fault, to a depth of at least 12 kilometers, is marked by a zone 100 to 200 meters wide where shear velocity is reduced by 30 to 50 percent. This zone forms a seismic waveguide that extends along the southern 30 kilometers of the Landers rupture surface and ends at the fault bend about 18 kilometers north of the main shock epicenter. Another fault plane waveguide, disconnected from the first, exists along the northern rupture surface. These observations, in conjunction with surface slip, detailed seismicity patterns, and the progression of rupture along the fault, suggest that several simple rupture planes were involved in the Landers earthquake and that the inferred rupture front hesitated or slowed at the location where the rupture jumped from one to the next plane. Reduction in rupture velocity can tentatively be attributed to fault plane complexity, and variations in moment release can be attributed to variations in available energy. 相似文献
9.
Hirose H Asano Y Obara K Kimura T Matsuzawa T Tanaka S Maeda T 《Science (New York, N.Y.)》2010,330(6010):1502
We identified a strong temporal correlation between three distinct types of slow earthquakes distributed over 100 kilometers along the dip of the subducting oceanic plate at the western margin of the Nankai megathrust rupture zone, southwest Japan. In 2003 and 2010, shallow very-low-frequency earthquakes near the Nankai trough as well as nonvolcanic tremor at depths of 30 to 40 kilometers were triggered by the acceleration of a long-term slow slip event in between. This correlation suggests that the slow slip might extend along-dip between the source areas of deeper and shallower slow earthquakes and thus could modulate the stress buildup on the adjacent megathrust rupture zone. 相似文献
10.
The time history of energy release during earthquakes illuminates the process of failure, which remains enigmatic for events deeper than about 100 kilometers. Stacks of teleseismic records from regional arrays for 122 intermediate (depths of 100 to 350 kilometers) and deep (depths of 350 to 700 kilometers) earthquakes show that the temporal pattern of short-period seismic radiation has a systematic variation with depth. On average, for intermediate depth events more radiation is released toward the beginning of the rupture than near the end, whereas for deep events radiation is released symmetrically over the duration of the event, with an abrupt beginning and end of rupture. These findings suggest a variation in the style of rupture related to decreasing fault heterogeneity with depth. 相似文献
11.
Bakun WH Clark MM Cockerham RS Ellsworth WL Lindh AG Prescott WH Shakal AF Spudich P 《Science (New York, N.Y.)》1984,225(4659):288-291
The Morgan Hill, California, earthquake (magnitude 6.1) of 24 April 1984 ruptured a 30-kilometer-long segment of the Calaveras fault zone to the east of San Jose. Although it was recognized in 1980 that an earthquake of magnitude 6 occurred on this segment in 1911 and that a repeat of this event might reasonably be expected, no short-term precursors were noted and so the time of the 1984 earthquake was not predicted. Unilateral rupture propagation toward the south-southeast and an energetic late source of seismic radiation located near the southeast end of the rupture zone contributed to the highly focused pattern of strong motion, including an exceptionally large horizontal acceleration of 1.29g at a site on a dam abutment near the southeast end of the rupture zone. 相似文献
12.
Source parameters of stick-slip friction events measured in the laboratory show particle and rupture propagation velocities which are similar to those observed for earthquakes and inferred from seismic source theory. This dynamic similarity strongly supports the idea that stick-slip is the mechanism for shallow earthquakes. 相似文献
13.
Based on stable isotope measurements, Ghosh et al. (Reports, 27 January 2006, p. 511) concluded that the Bolivian Altiplano uplifted 3 to 4 kilometers between approximately 10.3 and approximately 6.7 million years ago as a result of gravitational loss of dense lithosphere. This result stands at odds with current geological knowledge of the Central Andes, and we propose a test for the reliability of the paleoaltimetry method. 相似文献
14.
Surface Displacement of the 17 May 1993 Eureka Valley, California, Earthquake Observed by SAR Interferometry 总被引：1，自引：0，他引：1
Satellite synthetic aperture radar (SAR) interferometry shows that the magnitude 6.1 Eureka Valley earthquake of 17 May 1993 produced an elongated subsidence basin oriented north-northwest, parallel to the trend defined by the aftershock distribution, whereas the source mechanism of the earthquake implies a north-northeast-striking normal fault. The +/-3-millimeter accuracy of the radar-observed displacement map over short spatial scales allowed identification of the main surface rupture associated with the event. These observations suggest that the rupture began at depth and propagated diagonally upward and southward on a west-dipping, north-northeast fault plane, reactivating the largest escarpment in the Saline Range. 相似文献
15.
[目的]利用微生物方法生产乙醇,从而替代化石能源。[方法}土曲霉M11利用纤维素为原料产酶并糖化纤维素成还原糖,利用酿酒酵母发酵生成乙醇。,[结果]通过对土曲霉M11生长条件的研究,确定了土曲霉M11的最佳培养时间是3d,最佳接种量为200μl,最适培养湿度为80％,最适培养温度为45℃,最适培养pH为3．0,此条件下可获得最大的产酶量。通过对糖化过程的研究,确定了纤维素酶的最适糖化温度为55℃,最适pH为5．0,此条件下可获得较高的还原糖量,且在酸性条件下酶活力较高,具有很好的热稳定性。通过发酵,还原糖量占原材料干重的62．42％,产生的乙醇占原材料干重的21．36％。[结论]此方法可以应用于工业发酵生产乙醇,有利于保护环、降低成本、提高社会效益,有很好的应用价值。 相似文献
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17.
The Nankai Trough is a vigorous subduction zone where large earthquakes have been recorded since the seventh century, with a recurrence time of 100 to 200 years. The 1946 Nankaido earthquake was unusual, with a rupture zone estimated from long-period geodetic data that was more than twice as large as that derived from shorter period seismic data. In the center of this earthquake rupture zone, we used densely deployed ocean bottom seismographs to detect a subducted seamount 13 kilometers thick by 50 kilometers wide at a depth of 10 kilometers. We propose that this seamount might work as a barrier inhibiting brittle seismogenic rupture. 相似文献
18.
Models predict that dynamic shear ruptures during earthquake faulting occur as either sliding cracks, where a large section of the interface slides behind a fast-moving rupture front, or self-healing slip pulses, where the fault relocks shortly behind the rupture front. We report experimental visualizations of crack-like, pulse-like, and mixed rupture modes propagating along frictionally held, "incoherent" interfaces separating identical solids, and we describe the conditions under which those modes develop. A combination of simultaneously performed measurements via dynamic photoelasticity and laser interferometry reveals the rupture mode type, the exact point of rupture initiation, the sliding velocity history, and the rupture propagation speed. 相似文献
19.
选择王家寨镇家猫村作为研究区域,通过入户访谈,发放调查问卷等方式,整理分析了家猫村人均使用农村能源的数量、结构、来源以及用途。调查数据显示,原煤和柴薪是家猫村农村经济发展的主要能源;沼气、电力、太阳能等清洁能源只占农村能源的10%左右;非法开采原煤和砍伐柴薪对岩溶地区环境的破坏十分严重;落后的牲畜喂养方式和粗放型能源消费是浪费农村能源的主要原因。 相似文献
20.
本文通过对玉溪市森林资源消长情况和农村再生能源结构的研究、分析,提出了以绿色再生能源为主的多能互补的农村能源方案。并对2000年的薪材需要量进行了预测,对新能源进行了探索。 相似文献