论文部分内容阅读
介绍了几种强震前超低频事件的观测证据,并通过实验,研究了产生和传播机理。初步结果表明,微破裂的集结和断层的破裂起始会出现超低频脉冲,并透射到空气中形成次声波。塑性体的冲击或超临界流体的膨胀比脆性破裂更容易激发（超）低频波,且不伴随明显高频辐射成分。这样可以较为合理地解释震前“平静”背景下的（超）低频事件。对实验中破坏前的低频脉冲给出了断裂力学解释。断裂力学的实验和膨胀——扩容理论证明了震前会产生断层的张裂隙,从而为超临界流体提供了运移空间。流体在运移过程中突然涨缩会激发（超）低频辐射波。讨论了改进（超）低频事件的观测条件问题。
Several kinds of observational evidence of ultra-low frequency events before strong earthquakes are introduced, and the mechanism of generation and propagation is studied through experiments. The preliminary results show that ultra-low frequency pulses appear at the beginning of micro-bursting bursting and fault rupture and are transmitted into the air to form infrasound. Plastic body impact or supercritical fluid expansion more easily than the brittle fracture (ultra) low frequency waves, and without obvious high-frequency radiation components. This can be a more reasonable explanation of the pre-earthquake “calm” background (ultra) low frequency event. Fracture mechanics explanation is given for the low frequency pulse before failure in experiment. Fracture mechanics experiments and expansions-dilatancy theories show that there are fractures that generate fractures before the earthquake, providing space for the supercritical fluids to migrate. Sudden fluctuations in fluid migration will stimulate (ultra) low frequency radiation waves. The problem of observing the condition of improving (super) low frequency event is discussed.