Abstract: We draw a conclusion that the subsurface fluid in Fujian region has the following earthquake-reflecting characteristics based on the analysis of 4 earthquakes with magnitude 4.0 happened in 2007. That is, the seismic precursors have a regular and hiberarchy development in different observed items and they always perform well in short-impending, imminent and short term anomalies. The analogue observation wells' earthquake-reflecting ability is better than the digital wells', water radon and the hydrochemistry are the especially sensitive observation items in Fujian region. The hotsprings' earthquake-reflecting ability is better than the common ones'. The number of observation anomalies are decided by the number of observe stations around the epicenter. Also we point out that in order to serve the earthquake forecast better, we must construct a group of high quality water observational stations, which are able to meet the requirement of earthquake forecast so as to make all precursor observational stations to form a field or a net, strengthening the most sensitive wells and sensitive observational components.

Key words: Fujian region, Subsurface fluid network, The M4 earthquake, Seismic precursor, Earthquake-reflecting ability