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1985年12月30日,在甘肃成县进行了一次人工爆破,本文在分析研究该爆破的记录图中,发现了地壳中间界面上的反射波—P_D、S_D波。计算结果:地壳中间界面的平均埋深为25.7km;P_D、S_D波的真速度V_(PD)=5.98km/s,V_(SD)=3.37km/s;视速度V_(PD)′=6.37km/s,V_(SD)″=3.70km/s。 相似文献
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本文介绍利用地震转换波测深法研究1976年7.8级唐山大震区深部构造的某些结果,得出了沿两条测线的深部构造剖面图。发现在极震区的数十公里的范围内,地壳和上地幔具有异常结构,在地壳中部比震区外围多出一个中间层位,埋深约12-20km,地壳上部界面向上挠曲,而莫霍面和上地幔顶部界面却强烈地向下挠曲,引起了震区岩石圈厚度的加大,在震区存在深浅不等的深部断裂。深部构造与震源分布的对比表明,唐山主震和绝大多数余震均分布在壳内中间层之上,有的甚至就分布在壳内中间层的上、下界面附近。转换波测深结果表明,本区地壳上地幔中强烈的升降差异运动可能是唐山大震的重要促发因素。 相似文献
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本文利用在我国台湾海峡采用大容量气枪震源开展海陆联测获得的广角地震测线HX9， 采用二维射线追踪法反演得到了HX9剖面的地壳二维速度结构和地壳界面形态， 初步探明了福建—台湾海峡海陆过渡带的深部构造． 结果表明: HX9剖面的地壳内存在两个速度间断面， 即C界面和莫霍面， 其中: C界面为上、 下地壳的分界面， 是一个小的速度不连续面， 速度变化值达0.08—0.16 km/s； 而地壳底部的莫霍面则有较大的速度反差， 变化值达1.02—1.29 km/s， 莫霍面上、 下的速度分别为6.75—6.97 km/s和8.00—8.07 km/s． 沿剖面的地壳界面形态总体起伏不大， 陆域上、 下地壳的厚度和界面变化趋势均相似， 从陆域到海域呈微倾斜变化趋势， 表现为减薄陆壳的特征． 莫霍面陆域埋深约为31.6 km， 向福建东南沿海逐渐减薄至27.4 km左右． 相似文献
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利用压缩质面法反演重力资料,得到了喜马拉雅山脉中部地区的莫霍界面、康腊界面及花岗岩Ⅰ层底部界面的等深线图。从这些图可以看出,在喜马拉雅山区,上述各个地壳界面剧烈变化,喜马拉雅山正处于向北逐渐加深的斜坡上,地壳还缺乏“山根”,因而这个地区的地壳还未达到均衡。但藏南的楚中、查当至戛隆公巴一线以北地区,地壳已处于均衡状态。喜马拉雅山区目前还在逐步上升,说明有比均衡调整力更为强大的板块构造运动力存在。由地震机制的压力轴近于由南向北,以及一系列逆断层性质的大断裂,说明存在印度板块向北运动与亚洲板块互相挤压碰撞。由喜马拉雅山地区浅源地震震中呈带状分布及深部地壳构造特征得出,莫霍界面的急剧变化、地壳未达到均衡是容易发生大地震的深部构造环境。 相似文献
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利用穿过山西断陷带及五台山区的宽角反射/折射地震测深剖面所获得的资料对该区地壳结构进行研究，结果表明：五台山地区地壳呈明显的分层结构，上下地壳的分界是以壳内较为连续可靠的反射波P3所反映的界面为标志的，上地壳的厚度为23～28km，莫霍界面的深度为39～43km，五台山区是本区M界面最深的地区；地壳结构非均匀变化强烈的地区发生在五台山及其邻近地区，上地壳内较大范围低速异常体的存在和壳内强反射波组的出现可视为地壳深部岩浆活动的一种标志；壳内界面的中断、Pm波的局部不连续和地壳深断裂的存在等诸多现象均表明该地区地壳结构发生了强烈的挤压、变形和构造活动，从而形成了该地区复杂的地形地貌和地壳深浅部异常的结构特征. 相似文献
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应用矩谱和最大熵谱二种方法求解海城及周围地区地壳磁结构,对地壳进行磁性分层.研究结果表明,地壳从上至下可划分为3层,即无磁性层,磁性层和退磁层.还发现磁性层底界面(居里面)分布恰好与地壳速度结构上地壳下界面和中地壳顶界面相吻合.有趣的是,1975年2月4日海城7.3级地震就发生在居里等温面的深度梯级带上.因此,研究磁性层及居里等温面分布特征,对于判别潜在震源区是有益的. 相似文献
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青藏高原地壳结构的重力学研究主要集中于莫霍面深度反演及单个剖面的重力正演，但是，在亚东-格尔木与下察隅-共和之间没有地震测线的区域，地壳结构的研究受到限制.为了探讨从青藏高原中部到东部的地壳结构特征，本文采用三维重力正演的方法，对青藏高原三维地壳结构进行了重力正演模拟.研究结果显示，地壳各层界面起伏较大，表明高原地壳变形强烈.研究区域中，藏南喜马拉雅地体界面相对较浅，处于界面陡变带，往北进入拉萨地体，界面相对变深.正演剖面中，大的界面起伏与大的断裂构造有关，莫霍面的陡变也暗示着莫霍面存在错断现象.东构造结莫霍面有抬升现象，在玛多附近莫霍面有下凹现象.地壳分层正演显示，32 km以下地壳产生的重力异常占总异常的80%以上，低速层及高速体产生的重力异常最大可占到总异常的10%左右. 相似文献
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中国大陆下扬子及邻区地壳结构基本特征:深地震测深研究综述 总被引：1，自引：0，他引：1
系统回顾了20世纪70年代以来在中国大陆下扬子及其邻区开展的深地震测深工程,总结了相关宽角反射/折射地震资料的波组特征及地壳结构的基本特征。下扬子及邻区深地震测深资料普遍具有较清晰的初至震波Pg、上地壳底界面反射波P1、中地壳底界面反射波P3、莫霍界面反射波Pm及上地幔顶部首波Pn,震相连续,易追踪对比。受浅表沉积盖层或基岩等的影响,Pg波常出现局部延迟滞后或走时超前现象。尤其是大别造山带个别炮点的反射能量较弱或同相轴扭曲、波形紊乱等,均与地壳内界面和莫霍面的深度突变或破碎有关。该区域地壳结构大致分为上、中、下3层,但视资料情况中地壳和下地壳又可进一步划分为2个亚层。华北地台和扬子地台地壳厚度30~36km,莫霍界面形态变化较缓,存在局部隆起,下地壳平均速度6.7±0.3km/s。但大别造山带下方地壳厚度32~41km,莫霍界面下凹且出现4~7km垂向错断,下地壳平均速度6.8±0.2km/s。 相似文献
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P. A. Greet W. J. R. French G. B. Burns P. F. B. Williams R. P. Lowe K. Finlayson 《Annales Geophysicae》1997,16(1):77-89
The OH(6 – 2) band was monitored during 1990 at Davis, Antarctica (68.6°S, 78.0°E) using a Czerny-Turner scanning spectrometer. Spectra obtained with a 0.15-nm bandwidth and wavelength steps of 0.005 nm have been recorded in an attempt to isolate auroral features. This has enabled detailed study of weak features in the region 837.5–855.5nm. These weak features can contribute to the apparent intensity of P-branch lines and to the background. Their presence is allowed for in our calculation of rotational temperature, but the P1 (3) line is excluded because of significant contamination. An average temperature of 221 ± 2K is obtained from a selected data set of 104 spectra. The mid-winter average temperature, for the months of May, June and July, is 224 ± 2K, which is consistent with the 1986 CIRA model values for mid-winter at this height and latitude, but this result is dependent on the choice of transition probabilities. Preliminary assessments of seasonal and diurnal variations in rotational temperature and intensity are presented. 相似文献
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C. H. A. von Savigny I. C. McDade G. G. Shepherd Y. Rochon 《Annales Geophysicae》1999,17(11):1439-1446
Vertical profiles of nitric oxide in the altitude range 90 to 105 km are derived from 553 nm nightglow continuum measurements made with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The profiles are derived under the assumption that the continuum emission is due entirely to the NO+O air afterglow reaction. Vertical profiles of the atomic oxygen density, which are required to determine the nitric oxide concentrations, are derived from coordinated WINDII measurements of the atomic oxygen OI 557.7 nm nightglow emission. Data coverage for local solar times ranging from 20 h to 04 h, and latitudes ranging from 42°S to 42°N, is achieved by zonally averaging and binning data obtained on 18 nights during a two-month period extending from mid-November 1992 until mid-January 1993. The derived nitric oxide concentrations are significantly smaller than those obtained from rocket measurements of the airglow continuum but they do compare well with model expectations and nitric oxide densities measured using the resonance fluorescence technique on the Solar Mesosphere Explorer satellite. The near-global coverage of the WINDII observations and the similarities to the nitric oxide global morphology established from other satellite measurements strongly suggests that the NO+O reaction is the major source of the continuum near 553 nm and that there is no compelling reason to invoke additional sources of continuum emission in this immediate spectral region. 相似文献
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状门专业上Z术/,丹札,;。;、、-。-”。～_-。、。。。,,一、H,。,。h-十调凡刊仆人员w积极性。JX-’卜;拣过;厂;-卜。-_】_’-一、.----。j·D-人叮卜.丫-_,-_/口._丁-一 、、.;,八-人.--;、伙汁久不少问越。八中卜。。;观江木人。…--/〔。、:---回、——一、_、_-二-;-。;’。;H-卜蛀小足州与助任制工门、1壮,。、-儿,?y议枉:、;、\二一。,、”尖-‘’j:-(人从丁。:一十齐I一Z’和职称以个;/、-。,～V一1。-“。。;-汁-/、’。。‘、、人w门广让伯问题进行分忻,讣柳贝n一。。一、’。口。卜。、/、口_____-._一、/-。_.._.。;。。/_-… 相似文献
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A. Adriani F. Cairo L. Pulvirenti F. Cardillo M. Viterbini G. Di Donfrancesco J. P. Pommereau 《Annales Geophysicae》1999,17(10):1352-1360
The Stratospheric Regular Sounding project was planned to measure regularly the vertical profiles of several tracers like ozone, water vapor, NOx, ClOx and BrOx radicals, aerosol, pressure and temperature, at three latitudes, to discriminate between the transport and photochemical terms which control their distribution. As part of this project, the “Istituto di Fisica dell’Atmosfera” launched nine laser backscattersondes (LABS) on board stratospheric balloons to make observations of background aerosol and PSCs. LABS was launched with an optical particle counter operated by the University of Wyoming. Observations have been performed in the arctic, mid-latitudes and tropical regions in different seasons. Polar stratospheric clouds have been observed in areas inside and outside the polar vortex edge. A background aerosol was observed both in mid-latitudes and in arctic regions with a backscattering ratio of 1.2 at 692 nm. Very stratified aerosol layers, possibly transported into the lower stratosphere by deep convective systems, have been observed in the lower stratosphere between 20 and 29 km in the tropics in the Southern Hemisphere. 相似文献
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U. von Zahn G. von Cossart J. Fiedler K. H. Fricke G. Nelke G. Baumgarten D. Rees A. Hauchecorne K. Adolfsen 《Annales Geophysicae》2000,18(7):815-833
We report on the development and current capabilities of the ALOMAR Rayleigh/Mie/Raman lidar. This instrument is one of the core instruments of the international ALOMAR facility, located near Andenes in Norway at 69°N and 16°E. The major task of the instrument is to perform advanced studies of the Arctic middle atmosphere over altitudes between about 15 to 90 km on a climatological basis. These studies address questions about the thermal structure of the Arctic middle atmosphere, the dynamical processes acting therein, and of aerosols in the form of stratospheric background aerosol, polar stratospheric clouds, noctilucent clouds, and injected aerosols of volcanic or anthropogenic origin. Furthermore, the lidar is meant to work together with other remote sensing instruments, both ground- and satellite-based, and with balloon- and rocket-borne instruments performing in situ observations. The instrument is basically a twin lidar, using two independent power lasers and two tiltable receiving telescopes. The power lasers are Nd:YAG lasers emitting at wavelengths 1064, 532, and 355 nm and producing 30 pulses per second each. The power lasers are highly stabilized in both their wavelengths and the directions of their laser beams. The laser beams are emitted into the atmosphere fully coaxial with the line-of-sight of the receiving telescopes. The latter use primary mirrors of 1.8 m diameter and are tiltable within 30° off zenith. Their fields-of-view have 180 rad angular diameter. Spectral separation, filtering, and detection of the received photons are made on an optical bench which carries, among a multitude of other optical components, three double Fabry-Perot interferometers (two for 532 and one for 355 nm) and one single Fabry-Perot interferometer (for 1064 nm). A number of separate detector channels also allow registration of photons which are produced by rotational-vibrational and rotational Raman scatter on N2 and N2+O2 molecules, respectively. Currently, up to 36 detector channels simultaneously record the photons collected by the telescopes. The internal and external instrument operations are automated so that this very complex instrument can be operated by a single engineer. Currently the lidar is heavily used for measurements of temperature profiles, of cloud particle properties such as their altitude, particle densities and size distributions, and of stratospheric winds. Due to its very effective spectral and spatial filtering, the lidar has unique capabilities to work in full sunlight. Under these conditions it can measure temperatures up to 65 km altitude and determine particle size distributions of overhead noctilucent clouds. Due to its very high mechanical and optical stability, it can also employed efficiently under marginal weather conditions when data on the middle atmosphere can be collected only through small breaks in the tropospheric cloud layers. 相似文献
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新形势下地震监测预报发展的思考 总被引：1，自引：0，他引：1
本文从我国30多年地震监测预报历程、今后监测预报的发展方向以及改进监测预报管理工作等方面简明扼要地阐明了在新形式下如何推进地震监测预报发展的思考,文中所讨论的问题及新思维、新观点,相信对广大读者会带来更多的启迪,以此促进防震减灾事业的不断发展。 相似文献
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Chen Zhangli 《中国地震研究》2001,15(4):329-345
In the article the author looks back the hard development course and great progress in earth quake science and technology in China during the last near a half of century and expounds the following 3 aspects: (1) The strong desire of the whole society to mitigate seismic disasters and reduce the effect of earthquakes on social-economic live is a great driving force to push forward the development of earthquake science and technology in China; (2) To better ensure people‘ s life and property, sustainable economic development, and social stability is an essential purpose to drive the development of earthquake science and technology in China; and (3) To insist on the dialectical connection of setup of technical system for seismic monitoring with the scientific research of earthquakes and to better handle the relation between crucial task, current scientif ic level, and the feasibility are the important principles to advance the earthquake science and technology in China. Some success and many setbacks in earthquake disaster mitigation consistently enrich our knowledge regarding the complexity of the conditions for earthquake occurrence and the process of earthquake preparation, promote the reconstruction and modernization of technical system for earthquake monitoring, and deepen the scientific research of earthquakes. During the last 5 years, the improvement and modernization of technical system for earthquake monitoring have clearly provided the technical support to study and practice of earthquake prediction and pre caution, give prominence to key problems and broaden the field of scientific research of earth quakes. These have enabled us to get some new recognition of the conditions for earthquake oc currence and process of earthquake preparation, characteristics of seismic disaster, and mecha nism for earthquake generation in China‘s continent. The progress we have made not only en courages us to enhance the effectiveness of earthquake disaster mitigation, but also provides a basis for accelerating further development of earthquake science and technology in China in the new century, especially in the 10th five-year plan. Based on the history reviewed, the author sets forth a general requirement for develop ment of earthquake science and technology in China and brings out 10 aspects to be stressed and strengthened at present and in the future. These are: upgrade and setup of the network of digitized seismic observation; upgrade and setup of the network for observation of seismic pre cursors; setup of the network for observation of strong motion; setup of the laboratories for ex periment on seismic regime; establishment of technical system for seismic information, emer gency command and urgent rescue; research on short-term and imminent earthquake predic tion; research on intermediate- and long-term earthquake prediction; research on attenuation of seismic ground motion, mechanism for seismic disaster, and control on seismic disaster; ba sic research fields related to seismology and geoscience. We expect that these efforts will signifi cantly elevate the level of earthquake science and technology in China to the advanced interna tional level, improve theories, techniques, and methods for earthquake precaution and predic tion, and enhance the effectiveness of earthquake disaster mitigation. 相似文献
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W. J. R. French G. B. Burns K. Finlayson P. A. Greet R. P. Lowe P. F. B. Williams 《Annales Geophysicae》2000,18(10):1293-1303
OH(6/2) Q1/P1 and R1/P1 airglow emission intensity ratios, for rotational states up to j = 4.5, are measured to be lower than implied by transition probabilities published by various authors including Mies, Langhoff et al. and Turnbull and Lowe. Experimentally determined relative values of j transitions yield OH(6/2) rotational temperatures 2 K lower than Langhoff et al., 7 K lower than Mies and 13 K lower than Turnbull and Lowe. 相似文献