Abstract: An earthquake (MS 4. 0) occurred in Shengzhou city of Zhejiang Province on Aug. 17, 1998. The seismogeological background, focal mechanism, and the precursory characteristics of this earthquake are described in this paper. Based on the fault plane solution of the earthquake foci and the direction of long axis of is oseimic line, the rupture direction of this earthquake is concluded as N 63°W, which is coincident with strike of the Xiaofeng-Sanmen active fault. The epicentral intensity of Sheng zhou earthquake is higher than V. When the earthquake occurred, many people felt strong erground shake. A few of buildings were damaged. Some narrow fissures with a length of 20～30 m appeared on the riverbank and the roads. This is an earthquake for which a short-term prediction has been made.

Key words: Focal mechanism, Seismic precursor, Short-term prediction, Shengzhou earthquake