| Increasing evidences show that quite a few strong to intermediate-strength earthquakes are preceded by a period of accelerating seismic activity. It is claimed that this phenomena could be used for seismic hazard estimation or intermediate-term medium-range earthquake prediction, leading to the necessity for the discussion on the generality and objectivity of such a phenomenon. We consider the Benioff strain for the earthquakes over Ms 6.0 in China from 1978 to 2003. Regular spatial range and unified temporal span (8 years) are taken for all the earthquakes under consideration. Characteristics of the moment release (accelerating or decelerating) are judged by both visual inspection and nonlinear curve-fitting. Among the 67 earthquakes considered, there are 29 events exhibiting the characteristics of AMR, 12 events showing deceleration of moment release, 8 events whose moment release characteristics of accelerating or decelerating are hard to be specified due to lack of earthquake data, and 18 events having no stable characteristics of moment release. Using this result, we discuss the relation of moment release and focal mechanism. The result shown that moment release of accelerating and decelerating haven't a significantly difference in strike-slip earthquakes; and AMR occurs before most non-strike-slip earthquakes, especially in dip-thrusting earthquakes. In order to get more information about the seismic activity before the strong to intermediate-strength earthquakes, we consider all the earthquakes occurred in China with 6.0 from 1990 up to 2003, and use different spatial and temporal ranges for the same earthquake. It is found that the real seismic activity seems much more complex than the simple pattern as described by the accelerating strain release model. Therefore, the potentials of application of accelerating strain release model to the estimation of seismic hazard are in need of future research.
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