Analysis on the anomaly of water level in Kaiyuan well, Yunnan

By analyzing observations of water level in Kaiyuan well, Yunnan, China, it is found that there exist some correlations between the water level in Kaiyuan well and the precipitation in its adjacent areas. After the disappearances of these correlations, there always are earthquakes greater than 5 (6 or 6.5) happened within a radius of 300 km (400 or 500 km) near the Kaiyuan well. The low-water level anomalies in Kaiyuan well, having been appearing since 2009, are not entirely relevant with precipitation in the same period. Comprehensive analysis results indicate that the persistent low-water level anomalies in Kaiyuan well in this period are correlated with recent regional extensional tectonic activity to a certain degree, deduced from GPS observations in 2009—2010, besides the precipitation reduction.