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| 强地震前兆低频波的实验研究 | |
| 引用本文： | 唐林波,李世愚,苏昉,孙为,和雪松,刘建新.强地震前兆低频波的实验研究[J].中国地震,2003,19(1):48-57. |
| 作者姓名： | 唐林波 李世愚 苏昉 孙为 和雪松 刘建新 |
| 作者单位： | 1. 中国地震局地球物理研究所和中国地震局构造物理开放实验室,北京,100081;石油大学(北京)数理系,北京,102249 2. 中国地震局地球物理研究所和中国地震局构造物理开放实验室,北京,100081 3. 石油大学(北京)数理系,北京,102249 |
| 基金项目： | 科技部社会公益研究专项资金项目 2 0 0 1DIB2 0 10 7，地震科学联合基金项目，中国地震局地球物理所论著号 :0 3AC10 11 |
| 摘 要： | 声波透射实验表明，对于板状材料，声音的一部分能量可以透射到空气中。另一部分能量在板中产生简正波，使板产生较大的振幅，在空气中产生能被话筒接收到的声音信号，而信号的简正频率与板的尺寸有关。另外，破裂过程中的声发射实验证实：随着微破裂的集结和裂纹的扩展，所辐射波的频谱会逐渐向低频移动，而且当频率很低时，可以透射出岩石，被话筒接收到。根据尺度相似性原理，推广到野外，强地展前破裂集结可能会辐射出超低频波，这种超低频波不能被常规的地震仪记录到，但可以被超低频传感器或次声接收器记录到。在地震前，产生前兆的源非常复杂，大多数情况下可能并非脆性破裂，而是塑性蠕滑或者有流体的参与。而后两种情况产生的波的周期会更长，而且缺乏脆性破裂所固有的高频成分，这可能就是多数地震前缺乏前震的原因。 |
| 关 键 词： | 地震前兆 声发射实验 微破裂 裂纹 板状材料 地震仪 超低频传感器 次声波 震源物理 |
| 文章编号： | 1001-4683(2003)01-0048-10 |
Experimental Study on Precursory Low-Frequency Waves of Earthquakes |
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| Tang Linbo,Li Shiyu,Su Fang,Sun Wei,He Xuesong,Liu Jianxin.Experimental Study on Precursory Low-Frequency Waves of Earthquakes[J].Earthquake Research in China,2003,19(1):48-57. | |
| Authors: | Tang Linbo Li Shiyu Su Fang Sun Wei He Xuesong Liu Jianxin |
| Institution: | Tang Linbo 1)2) Li Shiyu 1) Su Fang 2) Sun Wei 2) He Xuesong 1) Liu Jianxin 1) 1) |
| Abstract: | It is demonstrated that some of the energy of the sonic wave in a plate material can transmit into the air. At the same time, the normal vibration in the plate can give rise to large amplitude vibration on the surface of the plate, generating measurable sound in the air. The characteristic frequency is related to the size of the plate. From the experiment of AES in the process of fracture, it is demonstrated that with the nucleation and propagation of the fracture, the spectrum of the radiated wave will transfer to lower band. When the frequency becomes very low, the wave can transmit through the rock and be received by the microphone. According to the theory of size comparability, there will be ultra-low-frequency waves occur before strong earthquakes because of nucleation, which cannot be received by ordinary earthquake detection instruments but can be received by special ultra-low-frequency transducer or infrasonic receiver. Before earthquakes, the sources of precursors could be very complicated. They might be produced by plastic creep or can attribute to liquids but not crisp fracture in most cases. So the periods of the produced waves will be longer. This perhaps account for the lack of foreshocks. |
| Keywords: | Precursor of earthquake Infrasonic wave Physics of earthquake source Nucleation of micro-fracture Low-frequency radiation |
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