Validating SCUBAS Predictions of Geomagnetically Induced Voltage in Submarine Cables Using Legacy Superstorm Observations

Modern submarine communication cables, though fiber-optic in nature, remain vulnerable to space weather hazards due to their internal conductive cables used for powering repeaters. During geomagnetic storms, variations in the geomagnetic field induce geoelectric fields that drive geomagnetically induced voltages along these cables. This study validates the Submarine Cable Upset By Auroral Streams (SCUBAS) model framework by analyzing the induced voltages on two transatlantic submarine cables—TAT-1 and TAT-8—during the 11 February 1958 and 13 March 1989 superstorms, respectively. SCUBAS models the cable as a segmented conductor placed atop oceanic and subsea conductivity structures and calculates voltages from both cable-parallel electric fields and coastal Earth potential at cable terminals. Model outputs are compared against digitized observations from historical literature. SCUBAS successfully captures both large-scale voltage patterns and event-specific dynamics, reproducing peak voltages within a median percentage error of <30%. High skill scores (>0.85) further confirm the reliability of the model across events and spatial locations. The results highlight that both subsea induction and coastal Earth potential shifts contribute significantly to geomagnetically induced voltages, emphasizing the need for comprehensive modeling in space weather risk assessments. This validation positions SCUBAS as a robust tool for evaluating the vulnerability of submarine cables to geomagnetic disturbances, with relevance for space weather forecasting, improving infrastructure resilience, and future mitigation strategies.