Strong Earthquakes and Semi-Annual Behaviour

Abstract

Abstract To date, very little has been written about earthquake distribution and cyclicality although, when looking at the available data, certain apparent cyclic trends can be seen as generating new conditions that activate complex, tectonic dynamo behavior. This paper discusses our research on global, primary earthquake distribution, where we attempted to identify and understand how and when earthquakes occur. After tracing earthquakes (M ≥ 6.8) over a period of 37 years and filtering out subsequent aftershocks, evidence appears to support cyclical activity, rather than the activity of a system that is traditionally thought of as random, unpredictable and chaotic. Our results show how primary earthquakes relate to, variations that change with seasonal fluctuations between the equinoxes and solstices and might follow the classic semi-annual variation of the geomagnetic field. We argue that magnetism may effect primary, earthquakes a distribution and could play a key role in complex, tectonic dynamo behavior.