External forcing of Moon and Earth seismicity at Rieger periods

Abstract

As I recently showed from InSight mission 2018-2020 data, seismicity on magnetically defenseless Mars arises in a planetary rupturing response to Rieger instability of the interplanetary magnetic field (IMF) in the 1-6month (385.8-64.3-nHz) band of highest solar-system energies. I next examine lunar and terrestrial seismicity in the same bend. Moonquakes and earthquakes during traversals of the Earth magnetotail were analyzed separately from IMF events to decouple magnetosphere and IMF effects. The analysis showed with 99-67% confidence and very high (Φ>>12) fidelity that (an unspecified majority of) moonquakes and Mw5.6+ earthquakes also reoccur at Rieger periods. About half of the spectral peaks split but into clusters that average to the usual Rieger periodicities also, where magnetotail reconnecting clears the signal. This confirmation of the Mars result means that Rieger disturbance of the IMF co-drives dynamics of solid-surface bodies, including the Moon and, to an extent, magnetically shielded Earth.