Abstract: Interference problems are becoming more and more serious to seismic observation with subsurface fluids, which influence the effectiveness of seismic monitoring and prediction. How to assess the interference and protect the observation conditions of those stations is a big topic for seismic monitoring and research of subsurface fluids in China. After one-year study on this issue, the authors propose a technical index for assessing the observation conditions of subsurface fluidsinterference degree. The four main observation items such as water level, water temperature, water radon and water mercury are all given a permit interference degree to guarantee an effective observation. The interference degree refers to the percentage of anomaly range caused by all interference factors to maximum anomaly range under normal conditions. Permit interference degree prescribes the degree of seismic anomaly range observed, generally referring to the minimum percentage of anomaly range.

Key words: Subsurface fluids, Observation conditions, Interference degree, Permit interference degree