爆炸地震模拟磁带记录的采样与处理系统的应用研究

本文叙述了在IBM-PC-XT微机上实现爆炸地震模拟磁带记录的A/D转换及处理系统,该处理系统具备多种功能:采样、存盘、回放、CRT显示原始记录、CRT上直接读取波至、打印机上输出记录、解译二进制偏移码、数据予处理、绘制记录截面图、滤波处理和频谱分析等。该处理系统对MCP-1型和MCD-3型的解调器均适用,不仅在室内.而且也适合野外工作,这为野外爆炸地震模拟磁带记录的现场采样、处理、解释提供了简便、省时的有效途径,同时,由于该系统采样频率的可控性,故也适合于其他的用途。     

DP—260与IBM PC/XT联机回放系统

DP-260与 IBM PC/XT 联机回放系统主要有以下五个功能:1,在计算机显示器上显示指定事件的头数椐。2,在打印机上打印所回放的磁带上记录的全部事件序号和触发时间,作为磁带的目录,需要时可将该目录存入磁盘文件。3,将指定事件的数椐(包括头数椐)存入磁盘文件。也可一次指定若干事件,并将这些事件数椐依次存入磁盘文件。4,解译偏移二进制码,在显示器上显示所记录的事件的原始波形。5,根椐需要可将 DP-260的输出格式还原成磁带上的记录格式,以节约存贮空间(可节约存贮空间三分之二左右)。本系统主要有以下三个特点:1.回放事件数椐时,省略了误码判断,并以“(?)”号字符判断代替〈ACK〉、判断。实际运行证明,这样处理不仅能及时在屏幕上显示有关信息,而且节省了回放时间。2.除采用了回放仪所能接受的有效命令外,还采用了两个组合命令。当程序收到某组合命令后,能依次向回放仪发出多个有效命令,以实现打印磁带目录和用一个命令回放多个事件等十分重要的功能。3.在 BASIC 语言中,利用字符与 ASCII 码的转换功能,并通过对 ASCII 码的数字运算来实现字节内各位(bit)的分解和组合。     

爆炸地震深部探测的模拟磁带记录系统

为了进行西藏高原地区的爆炸地震研究,研制了一套模拟磁带记录系统。每台仪器包括三个两周的拾震器（LS-1型）、三个相应的低噪声线性放大器（DDF-5型）、三个调制器、一台低频磁带记录器（DCJ-1型）、石英钟、对时器和收音机。仪器频率范围是2周-20周（对速度）,时间误差小于0.1秒。采用抖动补偿和频率滤波的办法,使系统的信噪比提高到50分贝。系统的幅度误差小于10％。经过野外实地观测和资料整理分析,证明其性能和指标能够满足地壳与上地幔爆炸地震研究的需要。通过模/数转换器,把模拟磁带转录成数字磁带,可以在电子计算机上进行各种数字处理。     

SSQ-1型数字磁带记录水平摆式倾斜仪

SSQ-1型数字磁带记录水平摆式倾斜仪是测量地倾斜变化的高灵敏度仪器.它采用Zllner 双吊丝悬挂的石英水平摆接收地倾斜信号,通过电涡流传感器把摆端的位移变成电信号输出,由袖珍计算机采集数据并进行数字显示、数字打印及数字磁带记录,由笔绘记录连续监测仪器的工作情况.仪器的格值用胀盒————水银杯产生的已知倾角,通过计算机进行标定,格值为0.3——0.5m()/mV经台站试验,白家疃台东西向固体潮观测结果为r(O1):0.64900.0179,a(O1):-3.831.58r(K1):0.80490.0128,a(K1):1.400.90r(M2):0.66990.0040,a(M2):-0.270.34r(S2):0.73160.0075,a(S2):2.830.58r(M3):0.84970.0964,a(M3):1.616.51      

DVD盘库与地震数据的存储

引言随着数字地震观测系统在测震学中的应用 ,数字化地震数据的数量急剧增加 ,如何有效地存储地震数据一直是大家关心的事情。存储地震数据主要考虑存储地震数据介质的寿命、价格、容量、读写速度、普适性、使用的方便性等方面的问题。软盘、硬盘、磁带和CDROM都是比较常用的地     

A-700型固态加速度强震记录器简介

继数字磁带记录器之后,美国泰奈达因-吉奥泰克公司又研制出 A-700型固态加速度强震记录器(A-700 ACCELOCORDER,StrongMotion Recorder),这是信息记录方式的又一进步。特点这种加速度强震记录器的主要特点为:①采用固态记录方式,不运动的部件;②采用力平衡型加速度计;③事件存储判别、触发记录;④内附编码数字钟;⑤内附标定和自校装置;⑥记录数据可快速转录到数字磁带机上。A-700型加速度计是全部固态和数字化的强震记录器,它把36分钟记录的地震数据输入     

一种地震流动观测数据采集器

流动地震数据采集器 ,除必须具备固定地震观测台站地震记录仪器相同的技术性能 ,如大动态范围、高分辨率外 ,还须具有野外流动观测的特殊性 :1高可靠性 .仪器必须能够在无人值守运行中长期稳定可靠工作 ;2强野外环境适应能力 .野外流动观测可能经常遭遇恶劣的工作环境 ,如潮湿、灰尘、环境温度等 ,仪器必须能够在各种野外恶劣环境下正常工作 ;3良好抗振性能 .仪器必须能够抵抗流动观测中的长途颠簸运输 ;4巨大数据存储能力 .地震观测数据量巨大 ,但野外流动观测数据收集困难 ,如何可靠存储和收集巨大的地震观测数据一直是困扰流动观测技术领…     

基于频谱分析识别电磁波信号干扰与地震异常

处理北京地区2009-2012年5个高采样率数字CNEM08-Ⅰ型电扰动台站数据,通过频谱分析,研究数字电磁波正常本底信号,地铁、地电供电、电磁感应等于扰信号,以及地震异常信号的频谱特征.结果表明：在时间域,数字电磁波的持续型干扰信号与震前电磁波信号表现相似,为连续高值脉冲信号;而在频域,数字电磁波干扰信号往往影响频带较窄,优势频率能量突出,优势频率频带窄到近乎以谱线的形式出现,谱线具有离散性、谐波性、衰减性特征;而震前信号具有连续的较宽频带,衰减较慢.     

辽宁台网记录爆破、矿震与地震的识别

从1999年6月辽宁数字遥测地震台网正式采用数字记录与模拟台站资料结合，编报辽宁省地震月报目录和地震观测报告，数字地震观测技术具有宽频带、动态范围大、分辨率高而且便于用电脑处理等优越性，改变了传统的模拟台网在地震图上识别和辨认震相，取而代之利用人机交互实时处理地震系统在计算机上识别和分析震相。每天有许多触发事件显示在屏幕上或存储在计算机里，这其中有相当多的事件不是地震事件，需要人为加以排出。有些事件是典型的、具有显著的震相特征，是便于识别的。而这些事件缺乏典型特征，不易识别，需要用多台记录进行综合分析，才能做出最后的判断。     

南海海底地震仪异常数据的分析和处理

海底地震仪(Ocean Bottom Seismometer,OBS)数据处理至关重要,是获取深部地壳结构的基础与前提.2006年实施OBS2006-2测线时,有2台OBS(OBS03,OBS06)数据出现异常,无法使用.由于海上航次花费巨大,采集到的数据弥足珍贵.本文采用数据格式检查、邻近台站对比分析、重采样等方法,成功地对这2台OBS数据进行了解编处理,得到了这两个台站的综合地震记录剖面;利用上述方法对2011年实施的OBS973-3测线中的异常台站OBS03进行了分析处理,同样得到了OBS03台站的综合地震剖面;通过查看两次海上实验班报发现,OBS2006-2测线之OBS06与OBS973-3测线之OBS03内部Sedis编号相同,为同一台记录仪器,再一次验证上述处理方法正确可行;然后对OBS2006-2测线2个台站进行震相识别与走时拾取后,利用前人纵波速度模型开展了射线追踪与走时模拟.此次对异常OBS数据的重新处理工作,不仅为OBS探测提供了宝贵的数据处理经验,而且将提高OBS2006-2测线地壳结构的可靠性和约束性,具有重要的研究意义.     

地震测深的观测与回放系统

地震测深数据处理系统的建立是为了利用现代技术,实现从野外观测到剖面解释的自动化处理。本研究中,模拟磁带记录通过相应的解调系统,使时间讯号与地震讯号分别送入计算机进行模数转换,其数字化的PS格式磁带又经过解编与拼装形成标准化的CGG格式磁带,各记录道的参数和观测数据分别被记入带头与数据块中。这种标准化的磁带格式便于进行国内外资料交流和调用产业部门的应用软件。该系统采用相关迭加技术使正点时刻的确定精度提高到5—10ms。利用Robbins公式高精度地测定了方位角和炮检距。绘制时间剖面图的程序具有简便通用和功能较全的特点。本研究结果已经用于实际工作中,取得了良好的效果。      

Determination of a shallow velocity–depth model from seismic refraction data by coherence inversion1

Seismic refractions have different applications in seismic prospecting. The travel- times of refracted waves can be observed as first breaks on shot records and used for field static calculation. A new method for constructing a near-surface model from refraction events is described. It does not require event picking on prestack records and is not based on any approximation of arrival times. It consists of the maximization of the semblance coherence measure computed using shot gathers in a time window along refraction traveltimes. Time curves are generated by ray tracing through the model. The initial model for the inversion was constructed by the intercept-time method. Apparent velocities and intercept times were taken from a refraction stacked section. Such a section can be obtained by appling linea moveout corrections to common-shot records. The technique is tested successfully on synthetic and real data. An important application of the proposed method for solving the statics problem is demonstrated.     

Application of the virtual refraction to near‐surface characterization at the Boise Hydrogeophysical Research Site‡

Seismic interferometry is a relatively new technique to estimate the Green's function between receivers. Spurious energy, not part of the true Green's function, is produced because assumptions are commonly violated when applying seismic interferometry to field data. Instead of attempting to suppress all spurious energy, we show how spurious energy associated with refractions contains information about the subsurface in field data collected at the Boise Hydrogeophysical Research Site. By forming a virtual shot record we suppress uncorrelated noise and produce a virtual refraction that intercepts zero offset at zero time. These two features make the virtual refraction easy to pick, providing an estimate of refractor velocity. To obtain the physical parameters of the layer above the refractor we analyse the cross‐correlation of wavefields recorded at two receivers for all sources. A stationary‐phase point associated with the correlation between the reflected wave and refracted wave from the interface identifies the critical offset. By combining information from the virtual shot record, the correlation gather and the real shot record we determine the seismic velocities of the unsaturated and saturated sands, as well as the variable relative depth to the water‐table. Finally, we discuss how this method can be extended to more complex geologic models.     

小当量激发的远距离信号检测研究

为了研究利用小当量震源进行远距离探测的可能性,通过现场试验进行了研究.野外实验采用1次大当量激发和16次小当量激发,研究结果表明：①有可能利用数十公斤当量的炸药实现200km距离的探测;②在激发条件相同（或相近）时,不同当量的激发波形滤波后存在一定的相似性;③依据人工震源可重复性采用以下的激发组合方式和处理方法能够有效提高信噪比：针对大当量激发与小当量激发波形的相似性,利用大当量激发的波形作模板与小当量激发的波形作相关,可判断台站是否接受到小当量激发的信号并检测其震相到时信息.针对小当量激发波形的相似性,采用小当量多次激发的方式,通过N次根加权叠加方法,能有效提高记录的信噪比和震相识别精度.     

M-1型数字地磁脉动观测系统<

DCM-1型数字地磁脉动观测系统,是为开展地磁测深及地磁脉动观测工作而研制的.该系统由高灵敏度磁通门磁力仪、多路数据采集器、盒式磁带记录与回放器,以及时间服务装置等部分组成.系统具有大动态、低噪声、高精度、低功耗,以及操作简单、使用方便等特点.系统可直接与计算机接口,也可直接回放进行模拟恢复.利用该系统进行了多次野外观测,取得了较好的野外观测资料,并显示出比进口的模拟系统能记录到较为丰富的信息[1].      

A TUNNEL RESOLUTION INVESTIGATION USING AN AUTOMATED RESISTIVITY TANK ANALOG*

The examination of apparent resistivity space sections over two-dimensional targets requires the accumulation of large amounts of data, if the resistivity field is to be adequately described. Whilst such data may be obtained from an intensive sounding traverse in the field, it is desirable for interpretation purposes to be able to generate such space sections for a range of model variations. Within their limitations, tank analogs can be used to provide such interpretation material, but the collection of data can itself be time-consuming. In this paper, an account is given of the development of an automated tank analog, where an entire space section can be scanned and the output obtained in paper tape format for later processing on a digital computer. The resistance measurement accuracy attained is comparable with normal field measurement accuracy. A practical example of the use of this analog in investigating the problem of resolving and discriminating between two horizontal cylindrical tunnels is given. This problem is basic to an understanding of the minimum size and disposition of targets which can be observed on a space section. The square array has been used in this example because of its good resolution properties in general prospecting rather than its particular suitability for the targets investigated. The directional response of the array is also illustrated and discussed.     

国际部署加速度仪台网的磁带记录格式及解析软件

国际部署加速度仪台网(IDA)是全球性的数字化高增益长周期地震加速度观测系统,在北京和昆明设有观测台站。通过国际交换,我国可得到全球的 IDA 资料,这些资料急待我国学者开发与利用。在 IDA 的磁带数据文件中包含有两种不同的记录。一种是用 EBCDIC 码写成的说明,有台站名和起始时间等信息;另一种是二进制补码的整型数据记录。前者占1个记录,后者占18个记录.正确的使用 IDA 数据必须充分利用这两种记录所提供的信息。在 VAX11机上所研制的 IDA 解析软件为开发与利用 IDA 数据资源提供了方便.     

An intelligent digital magnetic recording system (DIMARS)

The system consists of three magnetic variometers with electrical output signals for theH, D, andZ components, a proton magnetometer for the total field, a data acquisition system, two cassette recorders, an analogue chart recorder, a calendar clock, and a telex. The analogue and digital input data are sampled at 10 sec intervals, averaged over a minute, and recorded on a magnetic tape cassette. The computed hourly and daily mean values and the daily minimum and maximum values are recorded together with the occurrence times on a second cassette, at the operator's request. Rapid run recording of the 10 sec values of each measured component is initiated automatically during magnetic storms.DIMARS incorporates several test functions as ROM test, A/D converter test, recorder test, telexline test and checking the memory content. The test functions can be activated by the equipment keyboard, or via the telex. The telex can also be operated as an output printer.     

Dipping-interface Mapping Using Mode-separated Rayleigh Waves

Multichannel analysis of surface waves (MASW) method is a non-invasive geophysical technique that uses the dispersive characteristic of Rayleigh waves to estimate a vertical shear (S)-wave velocity profile. A pseudo-2D S-wave velocity section is constructed by aligning 1D S-wave velocity profiles at the midpoint of each receiver spread that are contoured using a spatial interpolation scheme. The horizontal resolution of the section is therefore most influenced by the receiver spread length and the source interval. Based on the assumption that a dipping-layer model can be regarded as stepped flat layers, high-resolution linear Radon transform (LRT) has been proposed to image Rayleigh-wave dispersive energy and separate modes of Rayleigh waves from a multichannel record. With the mode-separation technique, therefore, a dispersion curve that possesses satisfactory accuracy can be calculated using a pair of consecutive traces within a mode-separated shot gather. In this study, using synthetic models containing a dipping layer with a slope of 5, 10, 15, 20, or 30 degrees and a real-world example, we assess the ability of using high-resolution LRT to image and separate fundamental-mode Rayleigh waves from raw surface-wave data and accuracy of dispersion curves generated by a pair of consecutive traces within a mode-separated shot gather. Results of synthetic and real-world examples demonstrate that a dipping interface with a slope smaller than 15 degrees can be successfully mapped by separated fundamental waves using high-resolution LRT.