The new techniques include oversampling technique in digitalization of seismicwaveform, spectrum contraction technique in data - transmitting and error-controlling and so on.
这些新技术包括地震波形数字化的过采样技术，数据传输中使用的紧缩频谱调制技术和差错控制技术等。
2
Roof is composed of heterogeneous rock. When roof failure happens, a large amount of energy would release in the form of seismicwave.