Abstract: Inorder tomake sure whether the observed data th rough high precisionearth resistivity measurement have the short-term and imminent seismic precursor information, we analyzed the observed data, earth resistivity integral point value from May 1987 to March 2001, which observed by using earth-electricity instrument ZD8 at Baodiseismic station. We conducted overall analysis and re search on the short-term and imminent precursor variation corresponding situation and anomaly pattern characteristic of the data obtained before moderately strong earthquakes occurred a round Bao diseismic station and M≥ 5 earthquakes occurred in North China. The results of re search indicate that the short-term and imminent index of anomaly data is 0. 5% and 1. 0%. The forecast efficacy value Ris 0. 411 and 0. 373, respectively.

Key words: Earth-electricity instrument ZD8, Short-term forecast, Precursor anomaly, earth resistivity