Comparison of Natural and Predicted Earthquake Occurrence in Seismologically Active Areas for Determination of Statistical Significance

by Neupane, Ganesh Prasad

Qiang et al. (2001) successfully predicted 100 earthquakes in the Western Pacific Rim including China, Japan, Taiwan, and Philippine, using a temperature anomaly method. Their model is based on a predicted increase of ground temperatures in the lower atmosphere from 2 to 8 days before an earthquake of with a Richter Scale magnitude of 5 or greater. Mixed gases, such as CO2 and CH4, in different ratios under the action of a transient electric field, cause the temperature of the lower atmosphere to increase up to 6 °C, while solar radiation only increases temperature by 3 °C. The authors detected the thermal anomalies using ground-based evidence and thermal infrared anomalies in METEOSAT thermal infrared image data. Despite their apparent success at predicting the earthquakes, they did not compare their prediction with the natural rate of occurrence in the area, which experiences an earthquake of Richter magnitude greater than 4 every week. In order to evaluate the apparent success of Qiang et al's. (2001) method, a study was undertaken to compare their predictions to the natural occurrence of earthquakes within the region. Qiang et al's. (2001) predictions were compared to earthquakes in the Chinese and United States Geological Survey earthquake database using a specific area, magnitude and time (SMT) analysis. The Chinese database shows 81% of the predicted earthquake epicenters occurred out of SMT window whereas, the USGS earthquake database shows 88% of the predicted earthquake epicenters occurred out of the SMT window. The expected value and Poisson probability of the 12% (occurred in the SMT window) of the earthquake predictions show 75% of those are significant (0-10% expected and 0-0.1 Poisson probability value)significant, and 25% (25-50% expected and 0.1 to 0.25 Poisson probability value) are moderately significant. It is clearly seen that more than 80% earthquakes occurred outside the predicted window. Thus, the ability of Qiang et al's. (2007) method to predict earthquake epicenters can be called into question.