The real-time liquefaction monitoring and warning techniques are novel ways to mitigate liquefaction hazard. The key point for the techniques is to establish a reverse liquefaction detection method based on seismic records. However

the reliability of the existing liquefaction detection methods is lack of verification by earthquake records. There were serious liquefaction damages in Christchurch in New Zealand Earthquake in 2011 and creates a wonderful chance to exam the existing liquefaction detection methods. The acceleration records in the earthquake are employed to perform the blind detection of liquefaction situation by frequency decrease rate(FDR) method presented by the authors before. The results indicate that in all 27 sites of which the distances from epicenter are less than 50 km; there are 9 liquefaction sites and others are identified as non-liquefaction sites. Two liquefaction sites among the 9 liquefaction sites; have been confirmed by the news reports; and it means the detection results by FDR method are correct. The identified liquefaction sites by method are mainly located near the Avon River in the eastern of Christchurch

which are agreeable to the corresponding news reports. From the analysis of the paper

two earthquake records are in doubt because of the un-normal phenomena with significant high frequency components in the middle or beginning part of the waves

separately; and the revised results for the two seismic waves are given after filtering the records.