College of Resources Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.
Earthquake association ,Earthquake prediction ,Plate waves ,Probability ,Ultra-low-frequency infrasonic waves ,

There is still no reliable method to forecast short-term and imminent earthquakes. We presume that major earthquakes of magnitude ≥ 7 (C site) are mostly associated with a little-smaller earthquake of magnitude ≥ 5.6 (A site; 2700- 15000 km from C; 1-10 days before the earthquake C) and then a more-smaller earthquake of magnitude 3.8-5.6 (B site; distribute between A and C; 10-55 hours after the earthquake A). Here we propose a hypothesis of pressure waves (plate Pwave, mainly from A to B) and shear waves (plate S-wave, mainly from A to C) propagating deep in tectonic plates to explain such associations. Besides, the plate waves also induce ultra-low-frequency infrasonic waves, which could be detected at the earth's surface (D sites) from a few hours to two days before the earthquake C occurrence. Accurate position of the future epicenter (C site) could be calculated with the time lags among the four (or more) D sites. Therefore, large earthquakes may be predicted roughly by the ABCD model. Historical earthquakes in Chile, China, Japan and Southeast Asia and their associations to earthquakes in surrounding areas are summarized to assess the feasibility of the ABCD prediction method.

7 , 9 , 2017