Research on the changes of the tidal force and the air temperature in the atmosphere of Lushan (China) MS7.0 earthquake

Abstract

The cycle process of the tidal force of celestial body for Lushan M7.0 earthquake, occurred in Lushan county of Sichuan, China on April 20, 2013, was calculated. The earthquake occurred at the lowest point phase. It indicated that the type of seismogenic fault that the tide force acted on belonged to the thrust fault. According to the tidal cycle, the abnormal air temperature change was analyzed based on National Center for Environmental Prediction satellite data around the whole China before and after the earthquake. The result showed that the air temperature changed evidently with the tide force changing. In temporal, the change went through: initial air temperature rise → strength → reaching abnormal peak → gradually decline; in spatial, the abnormal area winded its way along the margin of the southern Qinghai-Tibet Plateau and went through: scattered→conversion→ scattered procession. The procession was similar to the change procession of a rock breaking under the stress loading. This shows that the stress change of rock may cause the air temperature change in the atmosphere before and after earthquake. It indicated that the tidal force of celestial body could trigger the earthquake, when the tectonic stress reaches its critical broken point and the air temperature anomaly was proportional to the seismic tectonic stress change. It was useful to combine air temperature and tidal force in earthquake precursory.