Abstract: The increment of sampling rate in the digital deformation observations provides us a possibility to detect and study the imminent and short-term anomaly characteristics prior to some earthquakes. In this paper, we calculated and analyzed anomaly temporal-spatial characteristics of tilt and gravity observation by the digital techno logy before the Yong sheng MS 6. 0 earthquake, 27 Oct. 2001 and Kunlunshan MS 8. 1, 14 Nov. 2001, and have obtained the thresholds for anomaly identification and anomaly imagesprior to these earthquakes. The result s demo nstrated that the tidal-and non-tidal parameters and daily anomaly frequency might be possible to estimate the occur rence time and location for the future earthquakes.

Key words: Digital deformation observation, Imminent and short-term precursor, Kunlun mountain earthquake, Yongsheng earthquake