Geomagnetic Kp Index and Earthquakes

In the ionosphere, the solar winds generate electrical currents. On the Earth surface, these currents cause magnetic field fluctuations. These fluctuations, penetrating the Earth interior, induce the electrical currents J, and, in the presence of the Earth magnetic field B, generate electromagnetic force, known as Lorentz force F = J × B. To study the relation of earthquakes and the Lorentz force, acting at the near onset times of strong earthquakes, we examine the Kp index, a logarithmic measure of the magnetic field deviation. The time varying Kp index gives us J, which in turn determines F. The variations of the Kp index were stacked by aligning their central times to the times of main earthquake shocks. This stacking method has been a popular and powerful tool in image processing, because it lifts up only the geomagnetic effect like carving a relief. The Lorentz force tilts the subtle force balance in the earth crust towards triggering the release of stress strain energy, initiating an earthquake in a similar way as a mountain climber’s step can trigger the avalanches. The internal dynamics, however, are highly statistical. Conventional statistical methods are used in combination with a newly devised method, which compares the time sequences of hypothetical random earthquakes to real ones. We find that the distinctive patterns of the Kp surges often strongly correlate to the onset of earthquake. This correlation depends on the seismic regions and the magnitudes of earthquakes. The stronger the earthquake is, more closely the Kp surge is associated. The statistical significance of nearly 100% is obtained for the Kp variations, synchronizing with more earthquakes in the Pacific Rim region. In parallel with the data analysis the historical studies are reviewed. The solar activities have been considered to influence the earthquake occurrences and the relation of the two has been studied extensively in the recent years as well as in the past century. A comprehensive list of publications is created with the brief introductions for each in the last chapter.