近二十年四川中短期地震预报工作的进展和问题

Some Improvements and Problems in Earthquake Prediction of Medium-short Period in Sichuan in Recent twenty years

近二十年来四川地区地震和前兆观测台网得到了较大的发展，获得了丰富的各类连续观测资料，积累了一批宝贵的震例；在中短期地震预报方法和指标的研究，包括观测前兆，地震活动图象、地震波分析、综合预报和现场工作方面取得多项成果；在９次中强地震前作出了一定程度的中短期预报；同时也存在不足和诸项困难有待解决。

A great improvements have been made in the research of earthquake prediction and inobservation network in Sichuan areas in recent twenty years. Rich data of many kinds of continuous observation and the data relate to some important earthquakes are got in the researchs of medium-short period methods and indications which include precursor observation, seismicity pattern, seismic wave analySis, comprehensive prediction and field work. Alot of progresses have also been made. For instance, we had made predictions of mediumshort period limit to a certain extent before nine earthquakes of medium-strong occurred. However, some problems and difficulties still are in front of us.