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1.
本文报道了山东省泰安地震台的高精度倾斜固体潮观测结果.所用仪器是 SQ-70B 型石英水平摆倾斜仪,使用格值可达0″.0004/毫米.观测资料稳定可靠.本文还报道了依据1980年5月以来的资料所算得的泰安地区的γ因子及相位滞后 k,其中,东西分量的主要潮波结果如下:γ(M_2)=0.648±0.004γ(K_2)=0.632±0.019γ(O_1)=0.699±0.028γ(K_1)=0.740±0.029γ(M_3)=0.731±0.126k(M_2)=-13.°6±0.°4K(K_2)=-14.°5±1.°9K(O_1)=-13.°9±2.°4k(K_1)=-14.°0±2.°0k(M_3)=11.°5±9.°9 相似文献
2.
本文报道了昆明地区1975年4月12到1979年2月28日的重力固体潮观测的结果。几个主要日波(O_1,K_1)和半日波(M_2,S_2,N_2)的振幅比例系数δ和位相差α是:δ(O_1)=1.144±O.006。α(O_1)=-O.4度。δ(K_1)=1.117±0.003。α(K_1)=-0.2度。δ(O_1)-δ(K_1)=O.027。δ(N_2)=1.135±0.002。α(M_2)=O.2度。δ(S_2)=1.136±0.005。α(S_2)=0.4度。δ(N_2)=1.150±0.014。α(N_2)=O.8度。并给出了振幅比例系数δ有可能随时间变化的例子。 相似文献
3.
根据国家地震局中比固体潮协作研究计划,比利时大地动力型 GEO783重力仪安放在广州地震基准台地下室进行重力固体潮观测。观测时间从1980年3月12日到1980年9月23日,共计206天。你们对观测资料,采用363个波的(Venedikov)调和分析方法,得到广州地区主要潮波的潮汐因子和位相差分别为:δ_0(O_1)=1.1833 φ_0(O_1)=-3.57δ_0(M_2)=1.1661 φ_0(M_2)=-1.68δ_0(M_3)=1.0664 φ_0(M_3)=0.04扣除海潮影响后的结果为:δ(O_1)=1.1451 φ(O_1)=-6.37δ(M_2)=1.1561 φ(M_2)=-2.33与比利时皇家天文台所得结果基本一致。δ_0(O_1)=1.1821 φ_0(O_1)=-2.39δ_0(M_2)=1.1649 φ_0(M_2)=-0.83δ_0(M_3)=1.0791 φ_0(M_3)=1.57δ(O_1)=1.1504 φ(O_1)=-4.81δ(M_2)=1.1549 φ(M_2)=-1.51经海潮校正后的潮汐因子比观测值下降1—3%,这些结果提供了该地区重力潮汐参数的基本数据。 相似文献
4.
震中距△<20°面波震级的测定 总被引：1，自引：1，他引：1
根据面波传播理论分別导出了对763长周期仪和SK地震仪的面波震级的量规函数σ_(763)(△)和σ_(SK)(△)。这两个量规函数在20°—160°的范围内,与国际上通用的IASPEI公式一致。而且它们比IASPEI公式具有更大的震中距适用范围(3°—177°)。选出了1985—1986年间发生在我国及邻区M_S≥5的全部地震,用σ_(SK)(A)测定了它们的震级M_(SC),结果表明,M_(SC)与美国NEIC用世界标准台网测定的震级M_(SZ)之间无系统差,两者的差值大部分在±0.2级之间。 相似文献
5.
6.
1.资料及方法1992年1月23日05时41分,在南黄海北部(35°17′N,121°12′E)发生了M_(?)5.3级地震。震后我们根据山东省地震台网及江苏省北部赣榆、连云港等台的观测资料,对33°50′—36°10′N,120°—124°E范围内1984年至1992年1月发生的59次3级(M_L)左右小震,利用和达法作图选出与和达线符合较好的台的纵波到时t_(?)与纵横波到时差t_(?)-t_(?),用最 相似文献
7.
一、前言 1986年7月10日和8月12日盐源发生Ms=5.1和Ms=5.4级两次地震,是继1976年11月7日和12月13日盐源—宁蒗一带发生6.7和6.4级地震之后,10余年中不断发生的强余震之一——属晚期强余震。其震级的最大差值ΔM_(max)=1.6,其震级的最小差值ΔM_(min)=1.0,与巴特(M·(?)ath)的余震定律:ΔM=1.2±0.5是吻合的。 相似文献
8.
1 地震基本参数发震时刻:1992年8月17日04时16分。震中位置:微观震中在墨竹工卡县尼玛江热乡北(北纬30°00′,东经91°54′);宏观震中在墨竹工卡县羊日岗乡脚岗村(北纬30°00′,东经91°58′)。震级:M_3=5.1。震中区烈度:Ⅶ度。震源深度:h=14公里 相似文献
9.
安徽及邻区平均波速比的测定及研究 总被引：6，自引：1，他引：5
将安徽及邻区(29°~36°N,114°~124°E),按1°×1°分成70个区,依据中国地震局分析预报中心编制的1998年1月1日至2003年12月31日全国地震月报目录,采用单事件多台观测资料,在所分区域里进行平均波速比值的计算,结果在其空间分布图像中显示了一定的特征。这些特征可能与地质构造环境即地质构造所形成的断裂带两侧的介质特性差异有关。计算所得的各区平均波速比对以后波速比值的变化分析有一定的参考作用。 相似文献
10.
本文论述了1983年土库曼西部Kum—Dag地震的构造特征,特别是地表变化的形态和运动学以及地球动力特征、第四纪末构造和现代构造模式的背景。 1983年3月14日12时12分54秒在涅比特达格东南40公里处发生了震级M_(LH)=5.7的地震。震后出现了一条地震破裂。我们认为这是地表出现的震源破裂现象并在1983年对此进行了详细调查。我们使用了土库曼地震台网的地震图和N.V Petrova和她在土库曼苏维埃社会主义共和国科学院,地震研究所的同事们所编绘的1983年Kum—Dag原始地震目录。根据这些资料得到主震的震中坐标如下:φ=39.20°N.λ=54.66°E(误差为±25公里)震源深度H=7—8公里。 相似文献
11.
The Rift Valley between 36° 42′N and 36° 55′N in the Atlantic Ocean is 31 km wide, with half-widths of 12 and 19 km for the western and eastern sides respectively. Both outer edges of the Rift Valley stand about 1500 m above an Inner Floor where very fresh pillow lavas occur. The Inner Floor probably includes the locus of new crust; and its bordering slopes, which are particularly well-defined on the western side, limit to less than about 2.5 km the width of the zone over which new crust may have evolved with little or no vertical displacement. The width of the locus of new crust may be less than 0.5 km between 36° 45′N and 36° 47′N, where the deepest slopes of the Rift Valley walls nearly merge. Near 36° 50′N, the Inner Floor accommodates an approximately 1 km wide, 4 km long Central High, with a height of up to 250 m. In this area, the locus of new crust may also occupy a very narrow zone; it may lie either along the Central High or along a trough flanking the Central High. The magnetic anomaly pattern indicates that, since the beginning of the Brunhes epoch (6.9 × 105 yr B.P.), the eastern limb has grown approximately twice as fast as the western limb. Using extrapolated spreading rates, the ages of the outer edges of the Rift Valley are 1.3 and 1.7 m.y. for the eastern and western sides respectively. Comparison with data for the Rift Valley in other parts of the ocean further suggests that the residence time of new crust in the Rift Valley is about 1.5 m.y. Uplift of crust from the Inner Floor, which may be dominated by lithospheric thickening, may thus be primarily a function of age. 相似文献
12.
Pierre Choukroune Jean Francheteau Roger Hekinian 《Earth and Planetary Science Letters》1984,68(1):115-127
Using the diving saucer “Cyana”, a portion of the East Pacific Rise between 12°38′ and 12°54′N has been studied and mapped. Four main zones are defined: (1) an active volcanic zone located in the central graben; the graben displays a variable relief along strike from less than 10 m up to 55 m and has an en-échelon pattern in plan view; (2) an active tectonic zone comprising the central graben and extending up to about 2 km from either side of the rise axis; (3) an inactive tectonic zone starting 2 km away from the axis and formed by discontinuous horst and graben type of structures; and (4) off-axis volcanoes (seamounts) located less than 20 km on either side of the rise axis. At 12°50′N, the active tectonic zone is extremely narrow and the mode of deformation is through fissuring in strong contrast with that observed in slow or intermediate rate ridges. The presence or absence of a magma reservoir at shallow depth explains the difference in the width of the active tectonic zone. The state of isostatic equilibrium or lack of equilibrium explains the different modes of deformation. 相似文献
13.
使用中国数字地震台网记录的区域宽频带波形,通过频率域和时间域多步反演,研究了2013年四川芦山“4·20”7.0级强烈地震的震源运动学特征.基于点源的震源机制解揭示：地震发震断层面参数分别为走向214°/倾角47°/滑动角96°,表现为一次高倾角的逆冲型事件.矩心在水平方向上位于震中（30.303°N/102.988°E）西南向约4.5 km,矩心深度约17 km.平均总标量地震矩M0为1.16×1019 N·m,矩震级Mw约6.6.进一步模拟高达0.5 Hz高频波形,获得了芦山地震破裂过程图像,结果显示：此地震为一次不对称双侧破裂事件.破裂半径约15 km,整个破裂面积为706.7 km2,平均滑动量约0.231 m.破裂在8 s内释放了大多数能量.震后0~3 s内,破裂以孕震点为中心向四周同时扩展,3 s后,破裂表现出明显的方向性,主要向北北东扩展,导致位于震中北东向多数台站视破裂持续时间总体偏小,最小值为4 s.破裂约8 s后基本停止. 相似文献
14.
P.F. Ballance 《Earth and Planetary Science Letters》1976,28(3):356-370
The Upper Cenozoic Magmatic Arc in northern New Zealand was initiated when the Indian-Pacific plate boundary first spread through the North Island approximately 20 m.y. ago. Six geographically separated magmatic arcs are recognized in succession. The first (20-15 m.y.) was sited over a basement depression; lavas were basic to intermediate and largely submarine; mineralization was minor. Subsequent arcs were sited over basement horst and characterized by sub-aerial intermediate to acid magmas. After prolonged andesitic/dacitic activity (18-6 m.y.) with minor mineralization, prolific rhyolite/ignimbrite eruption began at about 6 m.y., with abundant mineralization. Behind-arc activity produced localized basalt fields in the north, and geographically restricted high-potash andesites in the south.The first four arcs in the series are aligned at about 70° to the active Tonga-Kermadec-Taupo arc. The migration and rotation of the older New Zealand arcs are ascribed to four processes taking place at the plate boundary. These are: (1) anti-clockwise bending of the crust of western North Island, obliquely to the movement of the underlying lithosphere of the Indian plate, beginning at about 3 m.y., accompanying (2) dextral transcurrent displacement of 230 km with respect to eastern North Island; taking place mostly from 3 to 0 m.y.; (3) steepening of the Benioff zone from an initial 18° dip at 20 m.y. to the present 55° to 60°; and (4) fracturing of the west-dipping lithospheric slab to give two parallel, low-potash andesitic arcs between 18 and 15 m.y.Eastern North Island is deduced to have been “floating” while Pacific plate lithosphere passed beneath it throughout the Upper Cenozoic; accordingly it is designated the Hawkes Bay Crustal Microplate.There is good agreement between major tectonic events in the South Pacific deduced by Molnar et al. from magnetic anomaly studies and major tectonic events on land. A tentative history of the Southwest Pacific is proposed for the last 40 m.y. 相似文献
15.
Colin E. Thorn 《地球表面变化过程与地形》1979,4(3):211-228
Reduced major axis analysis is used to describe monthly temperature averages for daily maxima, minima, means and ranges at a sequence of bedrock microenvironments in the alpine zone of the Colorado Front Range. Seven thermistors buried at 1 cm in bedrock provide comparative data on easterly, southerly and westerly aspects, and also upon the impact of snow accumulation (?0.5m to ≥4.0m deep) against an east-facing rock wall. Intersite temperatures commonly differ by less than 5°C and, rarely, by more than 10°C. The freezing intensity of freeze-thaw cycles occurring within the confines of a seasonal snow patch rarely dropped to ?5°C, while at snowfree, vertical faces freezing dropped to ?5°C quite commonly. Comparison with laboratory established criteria for effective freeze-thaw weathering (abundant moisture and freezing to at least ?5°C) suggests that moisture rich microsites lack adequate freezing intensity, while adequately frozen sites lack moisture. Available data suggest that the overlap between freeze-thaw and hydration weathering requires careful re-evaluation. 相似文献
16.
QingYe Wang 《中国科学:地球科学(英文版)》2017,60(9):1719-1731
The three-dimensional structure of mesoscale eddies in the western tropical Pacific(6°S–20°N, 120°E–150°E)is investigated using a high-resolution ocean model simulation. Eddy detection and eddy tracking algorithms are applied to simulated horizontal velocity vectors, and the anticyclonic and cyclonic eddies identified are composited to obtain their three-dimensional structures. The mean lifetime of all long-lived eddies is about 52 days, and their mean diameter is 147 km. Two typical characteristics of mesoscale eddies are revealed and possible dynamic explanations are analyzed. One typical characteristic is that surface eddies are generally separated from subthermocline eddies along the bifurcation latitude(~13°N) of the North Equatorial Current in the western tropical Pacific, which may be associated with different eddy energy sources and vertical eddy energy fluxes in subtropical and tropical gyres. Surface eddies have maximum swirl velocities of 8–9 cm s~(-1) and can extend to about 1500 m depth. Subthermocline eddies occur below 200 m, with their cores at about 400–600 m depth, and their maximum swirl velocities can reach 10 cm s~(-1). The other typical characteristic is that the meridional velocity component of the eddy is much larger than the zonal component. This characteristic might be due to more zonal eddy pairs(two eddies at the same latitude),which is also supported by the zonal wavelength(about 200 km) in the high-frequency meridional velocity component of the horizontal velocity. 相似文献
17.
J.D.A. Piper 《Earth and Planetary Science Letters》1980,46(3):443-461
The major Proterozoic igneous intrusions in the Swedish sector of the Baltic Shield are the Ragunda complex (1293 m.y., palaeomagnetic pole 165°E, 54°N) and the Nordingrågabbro-granite-anorthosite complex (1385 ± 30 m.y.). The latter body has been partially remagnetised by later post-Jotnian dolerites (1254 m.y.), and sites influenced by the dolerites have a stable magnetisation with a mean direction D = 45°, I = ?39°, (α95 = 4.3°). Elsewhere, the gabbro-anorthosite facies have a magnetisation of dual polarity predating the dolerite and recoverable at various stages of thermal and/or a.f. cleaning with a mean of D = 48°, I = 37° (α95 = 5.3°); medium and high coercivity remanence resides in large magnetite grains and fine, predominantly hematite, rods in feldspar megacrysts. The Nordingrårapakivi granite yields a mean, also including dual polarities, of D = 221°, I = ?25° (α95 = 13°), and the Gävle granite yields a mean of D = 26°, I = 17° (α95 = 13°).New data define the a.p.w. path for the Baltic Shield after final uplift and cooling of the ca. 1800 m.y. Svecofennian mobile belt and prior to intrusion of the post-Jotnian dolerites at 1250 m.y.; this (ca. 1500–1200 m.y.) path defines a double loop similar in size and shape to the contemporaneous path for the Laurentian Shield and the paths can be superimposed to define relative positions of the shields. They were in juxtaposition prior to 1200 m.y. with the optimum reconstruction obtained by rotation of approximately 64° about a Euler pole at 1°E, 36°N. Pre-1500 m.y. palaeomagnetic data are also shown to fit this same unique reconstruction. The main geological correlations are an alignment of the Lower/Middle Proterozoic major strike-slip zones, the structural trends within the pre-1700 m.y. mobile belts, and the Grenville and Sveconorwegian (ca. 1100 m.y.) mobile belts. The anorogenic magmatism characteristic of Proterozoic times became gradually more restricted to one active margin of the continental reconstruction as temperature gradients decreased and the crust consolidated. All of these Proterozoic tectonic/magmatic trends are parallel to the long axis of the continental reconstruction. 相似文献
18.
为深入理解汶川地震破裂的构造运动机制,本文选取典型的观测点,利用多种地质地貌标志测绘分析得到了汶川MS8.0地震发震断裂的近地表三维同震滑移矢量.结果显示,北川—映秀断裂上的白水河—高川破裂段北西盘沿88°方位角水平滑移2.58 m、垂直滑移3.70 m;安县—灌县断裂上的白鹿—汉旺破裂北西盘沿134°方位角水平滑移1.63 m,垂直滑移2.00 m;小鱼洞破裂带南西盘沿76°~79°方位角水平滑移2.15~2.71 m,垂直滑移1.36~1.51 m.平行的白水河—高川破裂段和白鹿—汉旺破裂段合计形成1.72 m右旋走滑和3.49 m垂直断裂带的NW向水平缩短,总滑移方向（106°）与断裂带整体走向（42°）呈64°夹角,整个龙门山推覆构造带处于斜向挤压的构造环境.结合震源过程反演成果的分析显示,斜滑的白水河—高川破裂段和逆冲型白鹿—汉旺破裂段可能是在汶川地震中最大的一次子事件过程以滑移分解的形式而同时破裂形成的,滑移分解作用使两条断裂以斜滑与逆冲组合的力学性质产生破裂而非相同性质的斜滑破裂.小鱼洞破裂以低角度斜滑为主,可能是安县—灌县断裂与北川—映秀断裂以滑移分解形式同时破裂的纽带.小鱼洞断裂是龙门山断裂带长期处于斜向挤压的构造环境的产物,不只是逆冲断裂系中的捩断层. 相似文献
19.
J. Graham Cogley 《Earth and Planetary Science Letters》1984,67(3):284-296
A new and more detailed analysis of the hypsometry of the Antarctic continent, based upon 1° digital data on ice thickness and surface and subglacial elevations, shows that Antarctica, even when deglaciated according to a simple Airy-isostatic model, is an unusual continent. It is the only one with a markedly bimodal hypsometric curve, and separation of the two modes shows that they are the single modes of West Antarctica (at ?450 m a.s.1.) and East Antarctica (at 950 m a.s.1.) respectively; the two parts of the continent are probably distinct tectonic entities. The modal height of East Antarctica is 700 m higher than that of the global ensemble of continents, suggesting that hotspot epeirogeny or a less well-known mechanism has affected its recent history. The age of this modal-height anomaly has important tectonic and especially climatic implications: it is equivalent to a 4–6°C cooling of the continental surface. The area of dry land after deglaciation is 10.5 × 106 km2; the volume of ice in Antarctica is estimated at 26.9 × 106 km3, and of ice in the Northern Hemisphere at 2.5 × 106 km3; these figures lead to a eustatic sea-level equivalent for present-day glacier ice of 68 m or somewhat less. 相似文献
20.
《Journal of Atmospheric and Solar》2008,70(16):2014-2030
We study the solar dependence of the thermospheric dynamics based on more than 20 years Fabry–Perot interferometer O 6300 Å emission observation of polar cap thermospheric wind from three stations: Thule (76.53°N, 68.73°W, MLAT 86N), Eureka (80.06°N, 86.4°W, MLAT 89N), and Resolute (74.72°N, 94.98°W, MLAT 84N) in combination with the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM). All three stations showed a dominant diurnal oscillation in both the meridional and zonal components, which is a manifestation of anti-sunward thermospheric wind in the polar cap. The three-station observations and the TIEGCM simulation exhibit varying degree of correlations between the anti-sunward thermospheric wind and solar F10.7 index. The diurnal oscillation is stronger at Eureka (∼150 m/s) than that at Resolute (∼100 m/s) according to both observations and TIEGCM simulation. The semidiurnal oscillation is stronger at Resolute (∼20 m/s) than that at Eureka based (∼10 m/s) on data and model results. These results are consistent with a two-cell convection pattern in the polar cap thermospheric winds. The Thule results are less consistent between the model and observations. The simulated meridional wind diurnal and semidiurnal oscillations are stronger than those observed. 相似文献