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1.
1998年11月17日狮子座流星雨的次声观测   总被引:4,自引:1,他引:3       下载免费PDF全文
苏昉  苏骁 《应用声学》2000,19(3):1-6
采用三台CSH-1型次声接收器,在北京昌平区布置了一个次声测量三点阵,并观测到1998年11月17日狮子座流星雨产生的次声波P-t曲线和波速波向图,借助快速富立叶变换,分析P-t曲线的波形得到次声的三维动态谱,频谱分析结果表明,(1)各流星产生的次声波大都很短暂,持续时间在1-5分钟内;(2)流星次声波的周期都在40-408秒内,少数在1-480秒内;(3)在11月17日19:21-20:41期间  相似文献   

2.
强地震的前兆次声波研究   总被引:1,自引:0,他引:1       下载免费PDF全文
邵长金  唐炼  李相方 《应用声学》2005,24(3):152-156
利用在北京昌平安装的次声三点阵,对强地震前兆次声波进行了5年的连续观测。统计分析结果表明:强震前约10天内常能测到振幅很强的前兆次声。其三维动态频谱的特点是,振幅由弱逐渐加强,达到极值后变弱;先为长周期波(10-20分),紧跟着短周期波(5-10分),然后又出现更长的周期波,最后长短周期波一起出现。提前时间与三点阵到震中距离之间没有明显的关系,与震级之间也没有明显的关系。  相似文献   

3.
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   

4.
杨亦春  郭泉  吕君  滕鹏晓 《物理学报》2014,(13):224-237
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   

5.
汤加火山喷发所产生的次声波   总被引:1,自引:0,他引:1       下载免费PDF全文
程巍  滕鹏晓  吕君  张天予 《声学学报》2022,47(2):289-291
2022年1月15日汤加火山发生了剧烈的喷发。在火山喷发后的8 h 39 min,距离火山喷发位置10151 km的昆明次声台阵记录到很强的次声波信号。次声波波列前几个周期平均为443 s,传播速度约为321 m/s,其波形幅度与频率随时间变化与核爆炸产生的次声波形相似。采用相关检测方法估计次声信号的方位角为119°。在持续监测中,还观测到了火山喷发产生的次声信号沿反方向绕地球到达的信号和沿正方向绕地球一周后再次到达的信号。   相似文献   

6.
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   

7.
火箭发射的次声信号分析*   总被引:1,自引:0,他引:1       下载免费PDF全文
在距离发射点20km和230km的两个阵列上,记录了我国一次火箭发射产生的次声波。从信号中识别出点火与声爆事件,观察到火箭在飞行中产生持续的次声波,以及声爆前后明显能量特征上的变化,观测到完整的火箭发射和飞行过程中系列次声波。为了验证采集信号中包含声爆事件,使用Fisher检测估计方位角和视速度,计算结果与火箭飞行轨迹一致,并且声爆信号的预计到达时间和估计方位与实际的时间和方位角相符合。结合火箭速度变化的特征,给出了声爆前低频能量较弱现象的解释和火箭超声速后次声能量特征的变化,揭示了火箭产生次声波的机理,为火箭发射等目标的监测提供有益的借鉴和参考。  相似文献   

8.
宋杨 《声学学报》2017,42(6):747-754
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   

9.
本文在文献(1)的基础上,试验用两种声源和多次声暴露研究次声对人血压的影响,此外还观察了异常血压和和人年龄的关系,这些试验结果对制定安全次声级有参考意义。  相似文献   

10.
次声波及其应用   总被引:1,自引:0,他引:1  
 次声波又称亚声波,是频率低于可听声频率范围的声波,其频率范围大致是10-4Hz~20Hz。这种声波人耳虽然听不到,但是可以感觉到它的存在。这种声波在声学范围内还是一个比较新的领域。由于它具有较强的穿透能力,因此具有很大的实践意义。次声波与超声波不同,通常具有破坏作用,是有害的。次声波的研究开始于第一次世界大战期间,在以后的50多年时间虽然少有研究,但人们发现天然次声和人工次声都对人的状况和行为具有强烈的作用。次声波还可以作为一种新式武器,不仅能用来消灭敌人,而且还可以用来摧毁工业和民用目标。  相似文献   

11.
Generation of infrasonic radiation into a water medium by sea surface waves is analyzed. The analysis is carried out for the situation in which the infrasound is generated by surface waves with frequencies close to those of dominant waves. The presence of two wave systems on the sea surface is assumed: swell and wind waves. It is shown that if the frequencies of spectral peaks of wind waves and swell diverge by 20%, the maximum value of the radiation spectrum decreases by approximately 40% (if the general directions of the two wave systems are oriented strictly towards each other). A deviation of the general directions of the two wave systems from the opposite direction by 45° leads to a decrease in the maximum value of the radiation spectrum by more than two times.  相似文献   

12.
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   

13.
大气中一种低频次声波观测研究   总被引:2,自引:0,他引:2  
分析大气中存在的一种低频次声波。利用宽频带次声测量传感器阵列组成的广域分布网络,对此种次声波进行了近5年不间断的检测。对所测次声信号的观察统计发现,它与自然事件密切相关。对这种信号波形、频谱、时频图及相关性进行分析进一步发现,该波通常以一组或间歇性多组形式出现,频率主要在0.001~0.02 Hz之间、幅度一般可达50~200 Pa。在2008年3月20日新疆于田地震、2008年5月12日四川汶川地震以及2009年10月29日陕甘川三省交界处的地震前,均检测到了大幅值的低频次声波。本文的分析结论对研究大气次声波的多样性及其与自然现象的关系提供了新的参考,对地震信息探测具有一定的实际意义。  相似文献   

14.
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   

15.
The results of observations of acoustic-gravity waves in the troposphere and the ionosphere at middle latitudes during periods of passage of the solar terminator are presented. Tropospheric observations were performed using a lidar. The frequency characteristics of variations of the tropospheric parameters are determined based on observations of the intensity of the scattered lidar signal. The characteristics of variations of the total electron content (TEC) in the atmosphere are determined from data collected by GPS navigation satellites. An analysis of the observational data showed that the spectrum of variations of the atmospheric and ionospheric parameters is indicative of acoustic-gravity waves (AGW) propagating from the lower atmosphere. Modeling studies of the vertical propagation of AGW from the Earth’s surface showed that such waves quickly (within ~15 min) reach altitudes of the upper atmosphere (~300 km). The refraction and dissipation of waves in the upper atmosphere produces perturbations of the background state of the atmosphere and gives rise to the waveguide propagation of infrasonic wave components. The observed manifestations of TEC disturbances caused by AGW propagating from the lower atmosphere can be explained by the diurnal variation of the altitude of the ionosphere and the waveguide propagation of infrasonic waves.  相似文献   

16.
We consider the principles of development of a parametric antenna in the atmosphere. It is shown that to excite an infrasound at a frequency lower than 1 Hz in the atmosphere, one can use an acoustic system emitting simultaneously two waves whose frequencies differ by the infrasound frequency. In the pump-wave frequency range 20–500 Hz, the main contribution to infrasound emission is given by the region located at altitudes from 30 to 75 km, in which the oscillatory velocity in the pump wave is maximum. We propose an algorithm for calculation of the infrasound amplitude in the E and F layers of the ionosphere. Realization of a parametric antenna in the atmosphere makes it possible to broaden the capabilities of experiments based on the modification of the ionosphere by an infrasound. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 7, pp. 570–576, July 2006.  相似文献   

17.
I.IntroductionTheinfrasonicwavesradiatedbytheseismicwaves1knownasseismicinfrasound,canspreadoutandcanbereceivedbytheinfrasoundmonitoringsystemwhichhavebeendevelopedandarebeingperfecteddaybydayI1-1o].Theseismicwavspropagateinal1directionswithintheearthbodyandradiateseveraltypesofinfrasonicwaves.Oneofthemcalledthelocalinfrasonicwaveisradiatedbyearthsurfaceattheveryinfrasoundstationwhereseismicwavesarepassingthrough;thesecondtypecalledepicentralinfrasonicwavesareradiatedbythestrongmotionoftheear…  相似文献   

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