共查询到19条相似文献,搜索用时 140 毫秒
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研究了一种在大地震前出现的异常次声波,揭示其与地震发生的空间、时间、强度的对应关系.利用CASI-ICM-2011型次声测量传感器在一系列Ms6.0级以上大地震发生前2周以内检测到的一种频率范围0.001 Hz至0.01 Hz的次声波,其特征有:幅值范围50 Pa至200 Pa,持续时间0.5 h至4 h,传播速度10 m/s至30 m/s,震级越高信号越强.通过建立广域次声传感器网络,成功定位了芦山地震前4天出现的异常次声波,以及巴基斯担地震前12天出现的异常次声波.通过对8年时间连续监测数据的分析,研究了这类次声波的出现规律.同时,对其产生机理提出了大地起伏激发次声波的假设,进行了理论论证,并用智利地震测量信号和玉树地震测量信号证明S波可以激发出本地同振的次声波.文中所列举的数个震前异常次声信号的观测结果对于地震预测的信息获取具有参考价值. 相似文献
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对次声波在大气中传播进行了建模。通过结合保色散关系空间差分格式和Runge-Kutta时间格式的数值方法,建立了次声波传播模型。应用该次声波模型,研究了在耗散的重力分层大气中次声波的平流层导行传播。数值模拟结果表明,当次声波波包在平流层高度上被反射时,反射区域存在焦散现象,在声波的声压下降的同时,声波的能量得到聚焦。通过数值模拟结果与射线计算结果的对比表明,大气中声波传播的轨迹的精确描述需要应用全波解。 相似文献
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1993年7月12日日本北海道地震次声波 总被引:12,自引:0,他引:12
1993年7月12日北京时间21点21分19秒在北京中关村次声接收阵上及时地发现并完整地记录了日本北海道地震所产生的当地次声波(包括地震纵波、横波、表面波所辐射的声波)和震中次声波。其中当地次声波分别有:周期为12s,振幅为0.8Pa,持续3.4min;及周期为12s,振幅为0.4Pa,持续1min和周期为30s,振幅为1.3Pa,持续12min;震中次声波周期为137s,振幅为6.9Pa,持续28min。它们叠加在周期为12min、幅度为10Pa的大气异常现象的波列上。 相似文献
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研究了一种用于检测高压输气管道泄漏次声波的次声传感器。针对管道泄漏频带宽,频率低的特点,该次声传感器换能元件选用电容式传声器,设计了一个前端耐压壳,将前端敏感单元与前置放大器隔离,可耐12 MPa静态压力;通过对比信号放大电路,实现了对调制电路优化设计,使得在1 Hz以下频段仍有较高灵敏度,传感器自噪声降低;该传感器只对声波敏感,对振动的灵敏度平均值1 mV/g,具有很好的抗振动干扰性能。测试结果表明:该传感器能有效地检测到声波信号,频率响应范围0.5 Hz至300 Hz,覆盖了管道泄漏次声频带和低频可听声频段,不放大的Ⅰ档灵敏度200 mV/Pa,Ⅱ档和Ⅲ档分别将信号放大5倍和20倍,输出信号的自噪声小于15 mV,该传感器可适用于天然气输气管道的泄漏监测。 相似文献
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在中国科学院声学所大气次声波观察网实地采集的,爆炸、地震、闪电、再入四类次声事件105组阵列数据集的基础上,提出应用非负矩阵分解的特征提取方法,对次声信号的计算机自动分类方法进行了研究。针对特征设计过程复杂的问题,本方法使用非负矩阵分解自动挖掘目标信号的隐含结构作为特征。将此特征作为支持向量机和卷积神经网络输入进行分类,以提高特征设计的效率与分类的识别准确率。研究结果指出,在测试集上的平均识别准确率达到了83.13%, 相对于传统方法,简化了特征设计过程,并取得更好的分类结果。 相似文献
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海上风暴激起的驻波式大浪可以辐射出次声波[1].如果能在远距离接收到台风产生的次声波,并测定出它的方位,那么就可以用次声方法探测台风. 我们自1975年开始在广东、福建和浙江等地设置了许多次声观察站,在福建省气象局和海军部门的协作下,记录到大量台风产生的次声波.说明了次声方法可以用于探测台风.在试验中发现今年8号台风次声信号发生异常,与台风突然转向并登陆有一定联系.声压异常变化与台风转向在时间上有相应提前量,如果今后试验证明它具有普遍性,那么次声方法将可用于预报台风路径. 本文叙述次声测试方法及其结果、台风产生次声波… 相似文献
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Gibbons SJ Ringdal F Kvaerna T 《The Journal of the Acoustical Society of America》2007,122(5):EL158-EL164
A database has been established of seismic and infrasonic recordings from more than 100 well-constrained surface explosions, conducted by the Finnish military to destroy old ammunition. The recorded seismic signals are essentially identical and indicate that the variation in source location and magnitude is negligible. In contrast, the infrasonic arrivals on both seismic and infrasound sensors exhibit significant variation both with regard to the number of detected phases, phase travel times, and phase amplitudes, which would be attributable to atmospheric factors. This data set provides an excellent database for studies in sound propagation, infrasound array detection, and direction estimation. 相似文献
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The Hunga-Tonga-Hunga-Ha'apai volcano in Tonga erupted violently on January 15, 2022. After 8 hours and 39 minutes, an infrasound array in Kunming at a distance of 10151 km away from the volcano recorded a sequence of strong infrasonic waves. The average period of the first four infrasonic waves is 443 s with propagation speed of 321 m/s. The azimuth angle of this event has been estimated by applying the progressive multi-channel correlation(PMCC) method to process the received signals. During continuous monitoring, the infrasonic waves propagating along and opposite to the direction towards the Kunming array around the earth are recorded respectively. 相似文献
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Park J Garcés M Fee D Pawlak G 《The Journal of the Acoustical Society of America》2008,123(5):2506-2512
Plunging surf is a known generator of infrasound, though the mechanisms have not been clearly identified. A model based on collective bubble oscillations created by demise of the initially entrained air pocket is examined. Computed spectra are compared to infrasound data from the island of Kauai during periods of medium, large, and extreme surf. Model results suggest that bubble oscillations generated by plunging waves are plausible generators of infrasound, and that dynamic bubble plume evolution on a temporal scale comparable to the breaking wave period may contribute to the broad spectral lobe of dominant infrasonic energy observed in measured data. Application of an inverse model has potential to characterize breaking wave size distributions, energy, and temporal changes in seafloor morphology based on remotely sensed infrasound. 相似文献
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次声事件的分类识别方法应用广泛,传统分类方法在很多方面进行了尝试,但由于次声信号具备非线性的特点,致使分类难度较大,分类精度不高,这对次声事件的分类工作提出了挑战。针对次声事件中的化学爆炸与天然地震信号分类问题,文章构建了一种改进的深度卷积神经网络分类模型用于实现两类次声信号的分类。论文采用"全面禁止核试验条约组织"官网上收集到的化学爆炸和天然地震次声信号进行数据集的构建,使用改进的深度卷积神经网络分别与BP网络和一维LeNet-5网络进行对比分析。实验结果表明,论文的测试识别率能够达到82.72%,较上述算法有优势。 相似文献
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XIE Jinlai 《声学学报:英文版》1996,(2)
I.IntroductionTheinfrasonicwavesradiatedbytheseismicwaves1knownasseismicinfrasound,canspreadoutandcanbereceivedbytheinfrasoundmonitoringsystemwhichhavebeendevelopedandarebeingperfecteddaybydayI1-1o].Theseismicwavspropagateinal1directionswithintheearthbodyandradiateseveraltypesofinfrasonicwaves.Oneofthemcalledthelocalinfrasonicwaveisradiatedbyearthsurfaceattheveryinfrasoundstationwhereseismicwavesarepassingthrough;thesecondtypecalledepicentralinfrasonicwavesareradiatedbythestrongmotionoftheear… 相似文献
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O. P. Borchevkina I. V. Karpov A. I. Karpov 《Russian Journal of Physical Chemistry B, Focus on Physics》2017,11(6):1024-1027
Results of observations of atmospheric and ionospheric parameters during the solar eclipse of March 20, 2015 have been described. The observations have been conducted by lidar sensing in the lower atmosphere and analysis of the total electron content (TEC) in the ionosphere in Kaliningrad. Observations at the troposphere altitudes have been conducted using an atmospheric lidar. Ionospheric parameter TEC has been determined according to observations of navigation satellite signals. The spectral analysis of the monitored parameters during the solar eclipse has shown that, in the lower atmosphere and the ionosphere in a period range of 2–20 min, internal gravity waves (IGWs) and infrasonic waves are excited. During the main phase of the eclipse, the major contribution to variations in the parameters of the medium comes from infrasonic vibrations. Changes in the variations in the atmospheric and ionospheric parameters with IGW periods are observed only in the initial and final phases of the eclipse. 相似文献
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In order to study the response characteristics of infrasound in coal samples under the uniaxial loading process, coal samples were collected from GengCun mine. Coal rock stress loading device, acoustic emission tested system and infrasound tested system were used to test the infrasonic signal and acoustic emission signal under uniaxial loading process. The tested results were analyzed by the methods of wavelet filter, threshold denoise, time–frequency analysis and so on. The results showed that in the loading process, the change of the infrasonic wave displayed the characteristics of stage, and it could be divided into three stages: initial stage with a certain amount infrasound events, middle stage with few infrasound events, and late stage gradual decrease. It had a good consistency with changing characteristics of acoustic emission. At the same time, the frequency of infrasound was very low. It can propagate over a very long distance with little attenuation, and the characteristics of the infrasound before the destruction of the coal samples were obvious. A method of using the infrasound characteristics to predict the destruction of coal samples was proposed. This is of great significance to guide the prediction of geological hazards in coal mines. 相似文献