Correlation between Earthquake Occurrence, Day times and Rainfalls in Iran

In this research has been tried to do a statistically study in Iran and geomorphic zones to open a statistically discussion about time of earthquakes and their probably correlation to amount of rainfalls at some days before earthquakes.Earthquakes including 4 Richter and above records was obtained from site of IIEES (International Institute of Earthquake Engineering and seismology ) and the rainfall records occurring 10, 15, 20, 30 and 40 days before the earthquakes occurrence (DFEO). All of data and then data relation to each geomorphic states sort on excel spreadsheet and analyzed at 19 version of SPSS software using to different tests. X2 test and phi test show that there isnt any significant difference between occurrence of earthquakes frequency at day times and nights during 30 years. Spearman correlation coefficient didn’t show a significant relationship between amount of rainfalls during 4 periods (10, 15, 20, 30, and 40 DFEO) and earthquakes. X2 test and Cramer's V test also showed a poor association between rainfalls and earthquakes numbers. However, more study on data elucidate that it can find a significant correlation at some years. Results showed there is a relation between frequencies of occurrence rainfalls for 10 DFEO and frequencies of earthquakes at the Zagros state. Nonetheless, it wasnt observed any relation when the rainfalls under 10 mm unaccounted in analysis. So, this clears that more earthquakes at the Zagros state occurred at lack or less rainfall situation. But, a more study on data during the time periods showed a significant relation for 10 and 15 DFEO in 1996 on which occurrence of earthquakes has increased along with increasing of precipitation to 38 mm limit namely, among of 52 earthquakes, 14 cases of earthquakes have included more than 10 mm and less than 38 mm rainfall, whiles, it has occurred 28 cases of earthquake when rainfalls have passed from 38 mm limit.