Schumann resonance anomaly before the M_W9.0 Japan earthquake

Schumann resonance (SR) anomalies related to the 11 March 2011 giant earthquake near the east cost of Honshu, Japan, were analyzed based on the data from 3 observatories in Yunnan province, China. The result reveals that the resonance amplitude was enhanced 3-4 days before the earthquake, and the most obvious anomalies occurred on March 8, when the anomalies mainly appeared during 7:00-10:00 (Beijing time) and 12:00-15:00 in NS component, and 12:00-15:00 in EW component. Based on a joint analysis of 41 days' (March 1-11 plus 15 days before and 15 days after each day) data, the amplitude increase on March 8 is 1 or 2 times higher than the standard deviation, while the variation on a normal day is far below the standard deviation. In the end, it is proved that anomalies caused by earthquakes in Japan could be observed in Yunnan according to the anomaly mechanism proposed by some Japanese scholars, and the anomalies are mainly first- to third-mode SR anomalies, which are consistent with the observed phenomenon that anomalies mainly occurred in low modes.