Distribution of empirical recurrence intervals for segment-rupturing earthquakes on active faults of the Chinese mainland

IntroductionInassessingtheprobabilitiesoftime-dependentandlong-termseismichazardsforsegmentsofactivefaults,itisnecessarytohavetheprobabilitydensity,f(O,fordescribingtherecurrenceintervaldistributionforsegment-rupturingearthquakes.Fromf(nandthefollowingequation,theconditionalprobability,pc,whichincreaseswiththetime,Te,elapsedsincethelatestearthquake,isabletobecalculated(Nishenko,Buland,1987,WorkingGrouponCaliforniaEarthquakeProbabilities,1995;Wen,1995,1998)fwhereATisthetimeintervalforthefor…     

Study on relationship between deep and shallow structures along north boundary fault of Yanqing-Fanshan basin

IntroductionTheYanqing-Huailaibasin,whichconsistsoftheYanqing-FanshanandHuailai-Zhuolusub-basins,ismainlycontrolledbythenorthboundaryfaultsofthesub-basins.AsabasictectonicunitattheintersectionofthenortheasternendoftheNNE-trendingShanxigrabensystemandtheNW-trendingZhangjiakou-Penglaifaultzone,ithaskepttheintensivetectonicactivityintheQuaternary(YANG,1982;XU,DENG,1988;XU,MA,1992;FANG,etal,1993;Pavlides,etal,1999).Overthepastdecade,manyresearchershaveconductedstudiesonthedetailedstr…     

Finite element modelling for formation of major regions of great earthquakes in the Chinese mainland and its vicinity

IntroductionInrecent2oyears,throughstudiesofthegreatearthquakesoftheChinesemainlandanditSvicinitysincel9OO,itiswidelyrecognizedthattheseeventSoccurredinsomeregionsinarelativelyconcentratingmannerfordifferentperiods(Ma,Zhang,l986;Zhang,etal,l994,Hong,l994;Hong,elal,l997;Huang,Dong,l997).Inthispapef,wecallthemmajorregionsofgreatearthquakesincertaintime,ormajorregionsinshort.Themajorregionsofdifferentperiodscanmigratethroughlongdistanceinspace.Thegeneralpatternofthegreatearthquakedistributio…     

Comparative study on degassing activities along the north fault zone of Western Qinling

IntroductionIncurrentstudiesofnewactivityofafault,orthecrustmovementandtheeallhdynamics,moreat'tentionshavebeenpaidonthedegassingactivities,andtheutilizationofGPStechniqueandtheseismicitydata(Kan,etal,1979,Li,etal,1993;1998).Beforetheoccurrenceofalargeearthquake,thegassesinnertheearthwillstronglyreleasealongthefaultduetotheactionofthetectonicstressfield.Suchphenomenahasbeendiscoveredandreportedintheearly1970s(Cat,etal,1980).Sincethe1980s,thetechniqueoffaultgashasbeendevelopedrapidlyandthegr…     

Interpretation of the short period variations in geomagnetic anomalies of Shaanxi region

1BriefintroductionoftheanomaliesofshortperiodgeomagneticvariationsinShaanxiAtemporarymeasurementprofilecomposedofmeasurementsitesofShiquan,Foping,Banfangzi,Zhouzhi,Wugong,Qianling,BinxianandNingxian,whichisbasicalalongnorth-southdirectionfromShiquaninthesouthernpartofShaanxitoNingxianinGansu,wassetupandsimultaneousobservationofthree-componentgeomagneticshortperiodvariationswereperformedateightsitesduringSeptemberof1996.Observationalresultsshowthatthereisareversalaxisofgeomagneticverticalv…     

The tempo-spatial evolution characteristics of the load/unload response ratio before strong earthquakes in California of America and its predicting implications

IntroductionThetheoryoftheload/unloadresponseratio(LURR)hasbeenproposedabouttenyears(YIN,YIN,1991).Thetheoreticalstudieshavebeendevelopedfromtheoreticalanalysistorockexperimentandnumericalsimulation(SHI,etal,1994;WANG,etal,1999).IncharacteristicsoftheLURRanomalies,atfirst,weonlyanalyzedthevariationoftheload/unloadresponseratio(LURR)versustimeinthefixedregions(YIN,etal,1994;YIN,etal,1995).Thenwestudiedthetempo-spatialevolutionfeaturesoftheLURRintheseismogenicprocessanddevelopedthe…     

MODELING OF INTERRILL EROSION IN THE LOESS PLATEAU OF CHINA

IINTRODUCTIONTheinterrillerosiononafieldplotisaffectedbythekineticenergyoftherainfall,wind,topographyfactors,propertiesofsoilandthecanopy.Theinterrillerosionoccursasthefirstdropimpactsthehillslopes.Theinterrillerosionoccursinallkindsofrainfallandtheamountofthesplasherosion,whichisthemainpartofinterrillerosion,canaccountforagreatpanofthetotalerosionamountinaheavystorm(Baner1990,Glymph1957,QianandWan1986,Zhou1981).Therefore,itisveryimportanttorevealthemechanismtoestimatetheamountofinterri…     

Spatio-temporal characteristics of acoustic emission during the deformation of rock samples with compressional and extensional en-echelon faults

Introduction By the experimental techniques of acoustic emission (AE) and surface strain observation, a lot of achievements on the study of deformation and fracture process of samples with en-echelon faults has been obtained (Bomblakis, 1973; LIU, et al, 1986; DU, et al, 1989; LI, et al, 1989; ZHANG, FANG, 1989; ZHANG, LI, 1989; MA, et al, 1995a, b; LI, et al, 2000). However, there still exist many problems. For example, most of discussion on the spatio-temporal evolution of microf…     

Summation and decomposition of principal stresses in the crust

InthecompilationofWorldStressMap,9%ofdatacomesfromovercoringandhydraulicfracturingmeas-urement,23%fromboreholebreakingoff,63%fromearthquakefocalmechanism,and5%fromyounggeo-logicalinvestigation(Zoback,etal,1989).Onlyovercoringandhydraulicfracturingcanprovideboththeorienta-tionandmagnitudeofthehorizontalstress,allothermethodscanonlyprovidetheorientation,butnothemagni-tudeofthestresses.Althoughsomeresearcherstriedtoestimatemagnitudesofstressesinearthquakemechanismresearchbasedonsomeadditionalass…     

1898年代县地震震级考

1898年代县发生过一次地震,《中国地震目录》将这次地震的震级定为5·5级,经考察,我们认为震级定得偏低,理由如次:①民国二十六年(1937年),县里设立了“续修代州志馆”,下属各区有访员采访,收集资料,其中有篇“戊戌代州地震”,为馆员贾湘(秀才,阳明堡东关人,已故)起草,馆员王巩(退休教师,现为县志办公室工作人员)誉真,经志馆负责人张有桐(举人,五里村人,已故)修改审阅,最后又经王巩誉真.原件现存县志办公室,经王巩先生鉴定,确为本人当年手笔.其中内容为:“光绪戊戌……六七月之间,阴雨连绵,不见天日者月余.八月初八夜三更后,有声自东北来,巨如霹雳,大地动摇,势若箕簸,行者仆,坐者晕,寝者亦倾侧不安.室内器具     

Philips T5-NT磁共振故障的维修

PhilipsT5-NT磁共振扫描仪出现显示屏半黑屏现象，并提示“start memory dump……”的软故障。清理硬盘垃圾文件后，才有足够的空间启动应用程序“gyroscan”，但故障依旧，经检测发现该故障与环境温度有关，在最佳上电机查找到通讯接口板TC－420性能下降，更换该板后，故障消失。     

数字化力平衡加速度传感器设计与应用

在传统模拟式力平衡加速度传感器技术的基础上,通过改进传感器机械结构、内嵌高精度采集器等方法,设计了1款数字化力平衡加速度传感器。针对传感器中三通道模数转换要求完全同步、高分辨率、高采样率等技术难点,本文选用高精度ADS1294模数转换器,以同1个驱动信号完成三通道同步模数转换,实现低干扰、高分辨率的模数转换;采用高速ARM微处理器对模数转换数据进行大容量数据存储、高速数据通讯、数据处理、波形显示和电源管理;采用高精度线性电源芯片作为可开关控制的高精度电源,实现仪器整机低功耗管理。该数字化力平衡加速度传感器实现了大动态测量范围、三通道同步数据转换、高达1000Hz的采样率,且具有网络通讯接口等功能。     

烟熏记录地震仪的技术改造：ARA放大器的应用之二

对六十年代生产的烟熏记录地震仪进行技术改造:保留烟熏记录,保留65摆(或DD—1摆)以ARA积分放大器代替线性放大器,以线性笔头代替积分记录笔,增配电子报警器及交直流自动切换电源,组成新的地震观测仪器系统。技术改造方案在广东地震台网实施、两年来仪器运行正常、效果很好。     

SplitRFLab: A MATLAB GUI toolbox for receiver function analysis based on SplitLab

We add new modules for receiver function (RF) analysis in SplitLab toolbox, which includes the manual RF analysis module, automatic RF analysis and related quality control modules, and H-k stacking module. The updated toolbox (named SplitRFLab toolbox), especially its automatic RF analysis module, could calculate the RFs quickly and efficiently, which is very useful in RF analysis with huge amount of seismic data. China is now conducting the ChinArray project that plans to deploy thousands of portable stations across Chinese mainland. Our SplitRFLab toolbox may obtain reliable RF results quickly at the first time, which provide essentially new constraint to the crustal and mantle structures.     

球载双球式电场仪及其应用

探测雷暴电场垂直分量幅度的球载双球电场仪,它由两个空心的、直径为１４．３ｃｍ,相距３．１ｃｍ的导电球构成,两球绕垂直于两球心连线的轴旋转,电场在球上的感应电荷按正弦变化,放大后由遥测发射机传输到地面．配有温度、湿度、气压传感器,既能进行高空大气温度、气压和湿度等常规气象要素的测量,又能完成雷雨云电场特殊参量的探测任务．电场探测电路及其电池组分别装在两个球内．仪器自１９９４年投入使用以来,先后参加了近２０颗卫星的升空安全保障任务,为“澳星”等卫星在雷雨期间安全升空,发挥了重要作用．仪器测量范围为１--１００ｋＶ／ｍ,性能良好．     

遥测地震仪发射机电路分析及检修

在无线遥测地震仪器中 ,发射机长期使用容易出现输出功率下降、无输出功率、发射频率不准等故障。分析了发射机典型电路——石英晶体主振电路、倍频电路、激励级电路、功率放大级电路的基本原理。排除发射机的故障时 ,先从不同单元电路逐一检查、测试 ,判断故障类型 ,最后进行发射机总调试     

JWP-2全集成电路可调稳频板设计——华北地区遥测地震台网联网论文续六

JWP-2稳频电路全部采用集成电路,应用锁相环频率合成技术,频率可调,性能稳定,组装调试方便,可做为原WP-1稳频电路板的更新换代产品.适当改进功放电路部分,可用在台网的768记录器及其它中小型交流同步电机稳频稳速电路中.     

短周期烟记录地震仪技术改进试验研究

针对烟记录地震仪存在的问题，采取仅改动其放大器、电源与记录部分，利用现有拾震器和大滚筒记录器，投入少量资金，即可改造成适合台站使用的新型ＤＹＪ－１型短周期墨水记录地震仪。     

大气模式估算的东亚区域人为硫酸盐和黑碳气溶胶辐射强迫及其时间变化特征

本文利用大气环流模式及大气化学模式所得气溶胶资料,估算了相对1850s时期硫酸盐和黑碳气溶胶引起的全球及东亚区域人为辐射强迫,重点分析其在东亚区域的季节和长期变化特征.结果表明,就当前全球年平均全天空而言,人为硫酸盐气溶胶对大气顶的直接和云反照率强迫分别为-0.37和-0.98 W·m-2,黑碳气溶胶对大气顶和整层大气的辐射强迫值为0.16和0.47 W·m-2;中国东部区域是目前上述气溶胶辐射强迫最强的区域,硫酸盐的直接和间接辐射强迫分别超过-2.0和-4.0 W·m-2,黑碳对大气顶和整层大气的直接辐射强迫分别可达2.0和5.0W·m-2;估算的东亚区域上述气溶胶辐射强迫仍在不断增强,峰值预计出现在2010s时段,而且中国东部较强的辐射强迫还可能维持至2030s左右;在未来中、高排放情景下,东亚区域以上两种气溶胶预计对全球气溶胶辐射强迫有更大的贡献.分析还表明,夏季东亚区域较强的水汽会增强吸湿性硫酸盐气溶胶的光学厚度和晴空直接辐射强迫;云的作用一方面会强化东亚区域全天空条件下大气顶黑碳的辐射强迫,另一方面会影响硫酸盐气溶胶间接云反照率强迫的季节变化;上述气候特征的差异使得东亚区域的气溶胶辐射强迫表现出与欧美区域有所不同的特征.本文所用的气溶胶资料与模式气象场的偏差会给气溶胶辐射强迫计算带来一些不确定性,进一步改进气候模式中气溶胶过程、水汽和云等气象场的模拟将有助于获得更为合理的区域气溶胶辐射强迫估算结果.