Abstract In daily monitoring of seismic crustal deformation, we often found out that there are some abnormal microseisms in the tidal signals. These microseisms called abnormal tremor wave are observed by the broadband digital seismograph. This article reports a lot of the abnormal tremor waves recorded by DZW gravimeter and VS1 tiltmeter in HUST seismic and tidal station. According to the principle of seismic measuring techniques and observations, we present a unified characteristic curve for seismic crustal deformation observation techniques, analyze and explain them to the roots of different precursory response. The differences of the response to the abnormal tremor waves are mainly decided by the transfer function and the features of the instruments. The seismic crustal deformation instruments are sampling per minute, so the abnormal tremor waves are the aliasing or mapping of the real signals, it can not reflect the true ground motion. Are the abnormal tremor waves before an earthquake related to the earthquake? Is it precursor? We need to analyze and research deeply. This article aims to discuss and expound how to more effectively and accurately obtain earthquake precursor, promote earthquake precursory observation techniques scientific and standardization, breakthrough earthquake monitoring by the bottleneck, and improve the ability of earthquake monitoring and prediction.
