Overview
Geophysicist Stefan Burns presents a solo explainer connecting the June 2026 new supermoon — described as the closest new moon to Earth that year — to elevated tidal forces and their potential influence on earthquake and volcanic activity. The episode covers the mechanics of king tides, the science linking tidal rhythms to fault and volcano behaviour, and a survey of current seismic and volcanic activity across the Pacific and North America.
Bottom Line
Listeners will come away with a reasonable grounding in how tidal forces interact with geological systems, including the distinction between ocean, atmospheric, and solid-earth tides. The episode is accessible rather than technical, and draws on real research papers alongside live earthquake data. It will be most useful to people already curious about earthquake science or space weather; those looking for rigorous analysis may find the speculative elements outweigh the established science.
Key Themes
- Mechanics and timing of king tides and supermoons
- Tidal loading as a trigger for earthquakes and eruptions
- Current stress levels on California fault systems
- Recent seismic and volcanic activity in the Pacific
- The Cascadia subduction zone and North American earthquake risk
- The relationship between fluid pressure in faults and tidal cycles
What Was Discussed
King tides and the supermoon: Burns explains that king tides — unusually high tides — typically occur in winter when Earth is closest to the Sun. The June 2026 event is unusual because the new moon falls at the Moon's closest orbital point to Earth (perigee), producing tidal forces comparable in strength to winter maxima. He notes that San Francisco Bay Area tides may set records for this time of year, with water levels projected to reach two feet above normal.
Tidal influence on faults and volcanoes: Burns argues, citing peer-reviewed research, that faults and volcanoes near critical stress thresholds become more sensitive to tidal forces. The mechanism involves not just ocean tides but also solid-earth tides — a measurable vertical deformation of the crust — and changes in fluid pressure within porous fault zones. He references a study showing Kīlauea eruptions correlate with fortnightly tidal maxima at 89% confidence, and notes Stromboli eruptions are roughly 1.9 times more likely around new and full moons.
Current volcanic and seismic activity: Burns points to a Stromboli eruption and nearby deep earthquakes in Italy as a timely example, and notes that Kīlauea's 49th eruptive episode was anticipated around the time of the supermoon. He surveys recent earthquake swarms in Nevada's Walker Lane, activity on the Garlock fault, and tremor near the Cascadia subduction zone.
California's stress accumulation: Burns summarises a 2026 study from the University of Hawaii finding that stress on the Southern San Andreas and San Jacinto fault systems has reached or exceeded the highest levels recorded in 1,000 years, with more than 160 years elapsed since the last major rupture. He extends this concern to Northern California and Cascadia, which last produced a major subduction earthquake in 1700.
Broader North American seismic risk: Burns briefly covers the New Madrid seismic zone, historical earthquakes in the Caribbean and Gulf of Mexico, and notes a magnitude 6.1 earthquake near Cuba as an example of rupture occurring on faults not previously considered active.
Notable Points
Tidal forces as a trigger, not a cause: Burns is careful to frame tidal forces as a triggering mechanism rather than the primary driver of earthquakes. He notes that tidal stress variations of 1–35 kilopascals are small relative to total fault stress (which can reach ~1,000 kilopascals), but are significantly larger than the annual tectonic stress accumulation rate of roughly 0.1 kilopascals per year — meaning they can tip a fault that is already near its threshold.
Kīlauea eruption timing: Burns cites research showing that 34 of 52 historic Kīlauea eruptions began within three days of a fortnightly tidal maximum — a finding the cited paper places at 89% confidence. He predicts the then-imminent 49th eruptive episode would coincide with the June 15 supermoon.
Conductive fault fluids and electromagnetism: Burns raises the point that brine-filled fault zones — common in seismically active regions — carry dissolved ions, making them electrically conductive. He suggests that tidal modulation of fluid movement therefore produces oscillating electrical currents within faults, adding an electromagnetic dimension to the tidal influence beyond simple gravitational loading.
Saturn–Neptune conjunction as historical parallel: Burns notes that the 1989 Loma Prieta earthquake (magnitude 6.9) occurred during a Saturn–Neptune conjunction, and that a full synodic cycle of that conjunction has now elapsed. He presents this as a point of resonance with current conditions, though he does not claim it as a predictive tool.
Worth Listening If…
- You want a non-technical introduction to how tidal forces interact with earthquake and volcanic systems, backed by references to real research.
- You follow earthquake or space weather topics and want context for the June 2026 supermoon and current North American seismic activity.
- You are interested in the current stress state of California's fault systems, including the San Andreas, Cascadia, and Walker Lane.
Skip If…
- You are looking for a rigorous, peer-reviewed breakdown of the science — the episode mixes well-supported findings with speculative claims (the Saturn–Neptune conjunction, the Moon's role in mantle convection) without always distinguishing between them.
- You have no prior interest in geology or space weather; the episode assumes a degree of curiosity about these topics and does not build a case for why they matter from first principles.