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新疆数字地震台网地方性震级量规函数的初步研究 总被引：2，自引：1，他引：1
基于2009～2014年新疆测震台网数字地震记录资料,运用震级残差统计方法,选择16269个2.0≤ML≤5.4地震事件,共计获得了179561个单台记录;利用最大地动位移衰减特性方法,选用3.6≤ML≤4.5的746个地震事件作为研究对象,对新疆数字台网地方性震级量规函数进行了研究。将得出的量规函数值进行对比后认为,现阶段使用的量规函数值在0～200km的震中距范围内偏小,导致此范围内台站测定的震级偏小;在200～800km的范围内,测算的震级值较稳定,偏差范围在±0.1的范围内;在400～800km震中距范围内,由最大地动位移衰减特性方法得出的量规函数偏小。由于目前各地震台站使用的地震计仪器响应不准确,造成量规函数偏小的原因有待用计量更加准确的台站仪器响应参数进行验证,以便得到更加精确的新疆台网地方性震级量规函数。 相似文献
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选取宁夏"十五"宽频带数字地震台网2009年1月—2016年12月的1 782个地震事件、7 345条地震记录资料,通过震级残差统计和多元回归分析计算各台站单台震级与台网平均震级的偏差、平均偏差和标准偏差,分析震级偏差的频次分布,修正M_L量规函数,得到宁夏地区的地方性均匀震级量规函数和台基改正量。且采用多元回归分析方法,得到最大地动位移的衰减关系及与之对应的量规函数。结果表明,修正后的震级均方差由原来的0.237 0降低为0.228 9,震级修正最大值为0.51。 相似文献
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通过对福建数字遥测台网1999年所监测到的“9.21”台湾南投大震群和“9.23”福州小震群中的一系列较大地震进行分析，利用地震的时间和空间相对集中这一特点，有效地避开震源、路径及随时间变化的地质背景等因素对测定震级的干扰，发现了对测定台网平均震级影响的主要因素，不仅仅来自于台站地质背景的影响、台网使用的起算函数的影响，而且还发现在一定距离内地震周期也会对台网平均震级测定产生明显的影响。通过计算地动位移随震中距衰减的系数和起算函数随震中距增幅的系数，求出起算函数引起震级偏差的大小，提出了改进和消除这些影响的方法。 相似文献
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由于震级量规函数具有显著的区域性,因此就难于在全国范围内使用统一的震级量规函数。本文参照陈培善等人介绍的方法,对短周期地震仪测定近震震级的量规函数进行了修正,以建立青海地区的震级量规函数。经初步修正使用的青海地区震级量规函数和台站校正值,能够提高震级的测定精度。其标准差由0.312降到0.235,离散系数由13.9％降到9.5％。基本上可以使测定震级的偶然误差不超过过0.7级,而台网的平均震级精度为±0.1级。研究结果还表明,利用新的量规函数R_3(Δ)测定的震级相对于原量规函数R_1(Δ)没有系统误差。即测定的精确度没有降低,R_3(Δ)基本上是适用于青海地区的。 相似文献
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在中国近震震级标度系统的基础上,依据我国大部分区域的实际观测资料,本文通过震级残差统计分析和近震最大震相平均衰减形态的研究,确立了我国东部地区和西部地区的中国近震震级量规函数R_(LE)(Δ)和R_(LW)(Δ),并约定了它们的使用区域。 中国东部地区:(Δ≤120km) (Δ≥120km) 中国西部地区:(Δ≤120km) (Δ≥120km) R_(LE)(Δ)和R_(LW)(Δ)的确立,突出反映了我国东部地区和西部地区的地震和地壳介质的地区性差异,是对中国近震震级标度系统的完善,它保持了近震震级测定的简单、方便、实用的优点,它的应用将减少震级测定值的离散度,提高区域台网测定近震震级的一致性。 相似文献
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选取广东数字遥测地震台网自2000年1月正式运行至2007年6月记录的广东省境内及邻区368次较大的地震事件,利用msdp-dm分析软件对其进行分析处理,计算了各单台震级与台网平均震级的偏差、平均偏差和标准离差,分析了仪器、量规函数、台基诸因素产生震级偏差的主要原因。结果显示,不同类型地震仪器对震级偏差影响很小,量规函数偏差明显,在震中距0～60km内,量规函数偏差为负值;在60～380km范围内偏差不大,认为在日常大震速报中,可直接用此震中距的台站量取震级;而大于380km以后台网量规函数偏差为正。给出了台基校正值。通过对样本数归类统计、计算、分析,给出了量规函数校正值和台基校正值。 相似文献
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《山西地震》2020,(3)
选用2008-2019年内蒙古自治区及邻省台网共43个台站记录到的4 410个地震事件,通过震级偏差统计方法计算单台震级偏差及其标准差,并统计台站震级平均偏差随震中距的变化。研究表明,各个台站震级偏差范围在-0.38～0.33之间,81.4%的台站偏差值(绝对值)小于0.2。与全国量规函数相比,新修定的量规函数震级偏差与震中距整体呈正相关,在0～150km范围内震级偏差为负值,在150～200km范围内震级偏差大于0且基本与100～150km内的震级偏差关于零轴对称,250～500km范围内为正值,新修定的量规函数更加符合内蒙古西部地区的地壳介质性质和构造条件。 相似文献
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本文通过对1980—1986年在宁夏及邻区发生400次M_L=1.8—5.1级地震的统计分析,修正了现行测定震级M_L的量规函数,并得到了新的量规函数R_s(Δ),同时计算了宁夏台网 相似文献
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乌鲁木齐遥测地震台网从1993年1月1日开始试运行。从这几个月的运行情况来看,对乌鲁木齐200km范围内的地震定出的震中位置和震级与新疆区域台网得到的结果基本一致;对北疆乌鲁木齐200km以外地震定出的震级和区域台网得到的震级差别较为明显;对遥测台网以外南疆发生的地震,定出的震中位置和震级误差较大。 究其原因:(1)遥测台网定震级选用的是经新疆修定后的量规函数(高国英等人结果),而区域台网使用的是3400km走时表所列的量规函数;(2)遥测台网所选用的地壳速度模型是 相似文献
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D. M. Pechersky A. A. Lyubushin Z. V. Sharonova 《Izvestiya Physics of the Solid Earth》2010,46(7):613-623
The data on geomagnetic reversals are compared with the changes in the organic world and with the lower-mantle plumes. The
times of the formation of plumes and the times of their appearance on the Earth’s surface relate to the intervals characterized
by the different frequencies of geomagnetic reversals, i.e., there is no interrelation between the formation of plumes and
the frequency of the changes in the geomagnetic field polarity. At the same time, a certain synchronism is observed between
the frequency of the geomagnetic reversals and the boundaries of the biostratigraphic ages, i.e., the changes in the organic
world in the long-period range. A hypothesis is proposed, which explains the change in the sign of the geomagnetic field by
the combined effect of the irregular rotation of the internal core relative to the mantle and the changes in the slope angle
of the axis of the Earth’s rotation, which, in turn, results in synchronous events on the Earth’s surface: the rates of changes
in the organic world. 相似文献
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Summary The maintenance of the axisymmetric component of the flow in the atmosphere is investigated by means of a steady-state, quasi-geostrophic formulation of the meteorological equations. It is shown that the meridional variations in the time-averaged axisymmetric variables can be expressed as the sum of three contributions, one being due to the eddy heat transport, another to the eddy momentum transport, and a third to the convective-radiative equilibrium temperature which enters the problem through the specification of a Newtonian form of diabatic heating. The contributions by the large scale eddies are evaluated through the use of observed values for the eddy heat and momentum transports.The contributions from each of the three forcing mechanisms to the temperature and zonal wind fields are invstigated individually and found to be of about equal importance. The sum of the three contributions are also presented for the temperature, the zonal wind, the stream function associated with the mean meridional circulation and the corresponding vertical motion. Although the results fail to reproduce the main observed features of the lower stratosphere, they are found to be in good agreement with observations in the middle latitude troposphere. At any pressure level, for example, the computed mean zonal wind has a jet-like profile and the axis of the jet is found to slope to the south with height, as observed in the atmosphere.Based in part on a thesis submitted by the first author as partial fulfillment of the requirements for the Ph.D. degree at the University of Michigan. — Publication No. 194 from the Department of Meteorology and Oceanography, The University of Michigan. 相似文献
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Prof. Dr. W. A. Heiskanen 《Pure and Applied Geophysics》1958,41(1):1-18
Summary The author mentions the aims of the World-wide gravity project he established in the Ohio State University in Columbus, in 1950. He outlines the practical procedure of the gravimetric computations of the undulationsN and the vertical deflection components and and emphasizes that only by the global international cooperation and additional gravity observations at sea carried out during the last decade it has been possible to gather to Columbus the needed gravity material. Since there exist still large gravimetrically unsurveyed areas it is of vital significance to study what gravity anomalies are best to be used for these regions. The given figures concerning the accuracy of theN, and , estimated theoretically and obtained in practice, indicate that in the gravimetrically well surveyed parts of the world like in Europe and the United States we can get gravimetrically on basis of existing gravity material theN-values with accuracy of about 5–10 meters, and and with the accuracy of about 1. The geoid undulationsN are already computed in Columbus for more than 6000 points of the northern hemisphere. The sample maps show the interesting geoid of Europe and vicinity between the latitudes 60° and 30° and longitude 5° W and 30° E, drafted on basis of more than 1000N-values computed at the corners of 1°×1° squares. It is interesting to realize that the geoid undulations in all this area are positive, the extreme values being between 40 and 50 meters. The geophysical significance of the geoid maps of this kind is pointed out. 相似文献
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综合APIA、HONOLULU、PAMATAI 3个地磁台三分量的11年周期变化的形态后,可定性地提出该变化源于内场。如内源为核幔边界的电涡流,则其中心点应位于3台之间。 相似文献
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The global database on the paleointensity, containing determinations of the virtual dipole moment (VDM) for a stable (normal) regime of the geomagnetic field in a time interval of up to 3.5 Ga, is supplemented by new VDM determinations and analyzed. The field generation process started no later than 3–3.5 Ga (earlier data are absent) at the stage of the Earth’s core formation. Since that time, the dipole value has differed from its present value by no more than an order of magnitude, and the deviations that have already been detected tend toward smaller values. The distribution of VDM values in the time interval 0–400 Ma is bimodal, which apparently reflects the presence of two different generation levels of the geomagnetic field distinguished by a relatively large value (close to the present field value) and a relatively small value (approximately half as large as the present value). The total duration of decreased VDM values appreciably exceeds that of increased VDM values (179.1 and 28.6 Myr, respectively). On the whole, data on the paleointensity do not contradict the hypothesis about the dipole nature of the field over the last 400 Myr; however, the number of determinations at high paleolatitudes is too small to draw decisive conclusions on the validity (or invalidity) of the dipole field approximation based solely on paleointensity data. 相似文献
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V. E. Pavlov T. Yu. Tolmacheva R. V. Veselovskiy A. V. Latyshev A. M. Fetisova I. V. Bigun 《Izvestiya Physics of the Solid Earth》2017,53(5):702-713
Until recently, the existing data prevented the geophysicists from accurately dating the Bysy-Yuryakh stratum, which outcrops in the middle reach of the Kotuy River, constraining the time of its formation to a wide interval from the end of the Late Cambrian to the beginning of the Silurian. The obtained paleomagnetic data unambiguously correlate the Bysy-Yuryakh stratum to the Nyaian regional stage and constrain its formation, at least a considerable part of it, by the Tremadocian. This result perfectly agrees with the data on the Bysy-Yuryakh conodonts studied in this work and yields a spectacular example of the successful application of paleomagnetic studies in solving important tasks of stratigraphy and, correspondingly, petroleum geology. Within the Bysy-Yuryakh stratum, we revealed a large normal-polarity interval corresponding to the long (>1 Ma) period when the geomagnetic reversals were absent. This result, in combination with the data for the Tremadocian and Middle–Upper Cambrian sequences of the other regions, indicates that (1) the rate of occurrence of the geomagnetic reversals on the eve of the Ordovician Moyero superchron of reversed polarity was at most one reversal per Ma; (2) the superchron does not switch on instantaneously but is preceded by a certain gradual change in the operation conditions of the dynamo mechanism which, inter alia, manifests itself by the reduction of the frequency of geomagnetic reversals with the approach of the superchron. This finding supports the views according to which a process preparing the establishment of the superchrons takes place at the core–mantle boundary. 相似文献
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The nutations of the planets Mars andEarth are investigated and compared. Alarge number of interior structureparameters are involved in the nutationcomputations. The comparison between the observations and the computationsprovides several constraints on these parmeters andtherefore allows a better understanding of the physics of the interior of theplanet. For the Earth, the high precision of the observations of the nutationshas led to a very good determination of interior properties of the planet. ForMars, observations of nutations are not yet available, and we review how theamplitude of the Martian nutations depends on the hypotheses consideredfor its interior. Although Mars is very similar to the Earth, its interior is not well known;for example, we don't knowif its core is liquid or solid. Only if the core is liquid,the Free Core Nutation (FCN) normal mode exists and can alter the nutationswhich are close to the resonance. From the observed geoids, it is known thatboth planets are not in hydrostatic equilibrium. The departure is larger forMars than for the Earth, and consequently, the implication of considering a convective mantle instead of a mantle in hydrostatic equilibrium described byClairaut's equation for the initial equilibrium state of the planet is largeron the Martian nutations than on the Earth nutations. The consequences of theuncertainty in the core dimensions are also examined and shown to be of a veryhigh influence for Mars if the core is liquid, due to the potential changes inthe FCN resonance. The influence of the presence of an inner core, which isknown to exist for the Earth, could be more important for Mars than for theEarth if the inner core is large. Due to the presence of Tharsis on Mars, thetriaxiality of this planet has, additionally, larger effects than on Earth. 相似文献
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Geomagnetism and Aeronomy - The evolution of the magnetic configuration in the solar corona is studied. The curvature of the K-corona helmets obtained from an analytical approximation of the... 相似文献