An integrated study of anomalies observed before four major earthquakes: 2004 Sumatra M9.3, 2006 Pingtung M7.0, 2007 Chuetsu Oki M6.8, and 2008 Wenchuan M8.0

In this paper, we cross-examine anomalies before four major earthquakes, Sumatra (Indonesia) 2004.12.26 M9.3; Pingtung (Taiwan) 2006.12.26 M7.0 × 2; Chuetsu Oki (Japan) 2007.7.16 M6.8; and Wenchuan (China) 2008.5.12 M8.0. Measurements of the crustal stress, infrasonic wave, and budgerigar jumping rate recorded at Institute of Earthquake Prediction are used to monitor in the lithosphere and atmosphere, while the total electron content over the four epicenters are employed to detect anomalies in the ionosphere. These cross-examinations allow us to have better understanding on the leading time of the four observed anomalies, the earthquake preparation process, and the lithosphere–atmosphere–ionosphere coupling before the earthquakes.