Abstract: Progress in observation techniques, data processing techniques and software for crustal deformation observations and studies on earthquake precursors in the last decades is reviewed. Earthquake predictions in China have obtained rare successes but suffered more tragic failures since the Xintai earthquake in 1966, and have developed with twists and turns under the influence of the assertion that earthquakes are unpredictable and etc.. Though the 2008 M8.0 Wenchuan earthquake and the 2011 M9.0 East Japan earthquake were failed to predict, GPS observations before and after these two events and other events have shown that there were precursors to these events and large earthquakes are predictable. Features of different observation techniques, data processing methods are compared and some recent studies on precursory crustal deformations are summarized, so various advantages of GPS technique are emphasized. The facts show that anomalies or precursors detected from GPS observations before the great Wenchuan earthquake have been the most remarkable results of explorations in crustal movements and earthquake precursors in China.

Key words: Crustal deformation, Earthquake prediction, Earthquake precursor, M8.0 Wenchuan earthquake M9.0 East Japan earthquake, GPS