The 26-Second Microseism of the Gulf of Guinea: Towards a Hypothesis of Exogenous Excitation of a Geological Resonator-Antenna

Since the early 1960s, seismometers worldwide have recorded a repeating microseism with a period of approximately 26 seconds (0.038 Hz), emanating from a fixed location at approximate coordinates (0°N, 0°E) in the Gulf of Guinea. The signal is characterized by exceptional spectral narrowness (nearly monochromatic), absolute temporal stability over six decades, and global detectability as Rayleigh waves traveling at approximately 3.5 km/s. Existing interpretations — ocean wave interaction with the continental shelf and volcanic/hydrothermal activity — cannot simultaneously account for the uniqueness of the source location and the perfection of its temporal stability. This paper proposes a novel alternative hypothesis: the geological structure at (0,0) functions as a geophysical resonator-antenna, excited by an exogenous, possibly gravitational, periodic energy source at 0.038 Hz. This hypothesis collectively explains all observed characteristics of the phenomenon, including the longstanding impasse of identifying a continuous, sufficient local energy source. Testable predictions are presented, including implications for next-generation space-based gravitational wave detectors such as LISA.