Abstract
I recently showed that Mw5.6+ earthquakes occur due to (as the
lithosphere rides on) vast waves of the Moon-driven and gravitationally
aided 1–72h long-periodic Earth body resonance (EBR). Here I report a
methodologically independent proof: observation of actual EBR waves in
solid matter using continuous GPS (cGPS). Superharmonic resonance
periods from the EBR’s 55’–15 days (0.303 mHz–0.771605 μHz) band are
thus recoverable in spectra of ITRF2014 positional components solved
kinematically from 30-s cGPS samplings. The signal is so pure, strong,
and stable that even daylong components are always and only periodic
with Earth resonance periods constantly 99%-significant and of very
high fidelity (ϕ>>12); very low fidelity
(ϕ<<12) characterizes overtones and undertones. The
examined cGPS stations have diurnal EBR fingerprints: unique sets of
~13-18 EBR periods, most clearly formed during
~M6+ quiescence, enabling depiction of EBR orientation
for real-time EBR mapping. Furthermore, weeklong component time series
reveal complete EBR and unavoidable undertone series (with very high
fidelity, too) as the signature of an EBR’s companion sympathetic
resonance. Also, I demonstrate the concept of EBR mapping using the
Mexico City–Los Angeles–San Francisco cGPS profile alongside a
tectonic plate boundary, successfully depicting the preparation phase of
the 2020 Puerto Rico Mw6.4–Mw6.6 sequence. I finish by showing that the
EBR has triggered the 2019 Ridgecrest Mw6.4–Mw7.1, sequence too. EBR
maps can now be produced — for seismic prediction and to unobscure
(decouple EBR from) geophysical observables such as stress/strain.
Applications of EBR include geophysical prospecting and detection at all
scales and at any time.