Massive, mysterious ‘hot blob’ beneath Eastern US

[putnam6]

Interesting you should post this today as there was an earthquake yesterdady in the NY area...wonder if it is related

https://www.scientificamerican.com/artic...after-the/

I don't have a clue. I'd think they would be more sure about East Coast earthquakes than the West Coast, but hell, who knows, they may know less because it's less active and fewer earthquake events to study
 

Here's Grok's short and long answers

There’s no substantial evidence to suggest a direct correlation between recent New York seismic activity (e.g., the July 28, 2025, magnitude 1.7 event) and the Northern Appalachian Anomaly.


Potential Correlation with the Northern Appalachian Anomaly
The NAA, a thermal upwelling of hot rock moving southwest at 12 miles per million years, is a deep mantle feature (125 miles down) identified through seismic tomography. Here’s an analysis of any possible link to recent seismic activity:

• Geological Mechanism:
  • The NAA is thought to have formed 80 million years ago during rifting events and may contribute to uplift in the Appalachians by weakening the continental lithosphere. This process, described as a "mantle wave," involves slow convective movements that could reactivate ancient faults, such as the Ramapo Fault System, the most active fault zone in the region.
    
  • Intraplate earthquakes in the Northeast are often attributed to stress release along pre-existing faults, as noted in the Wikipedia entry on New York seismicity. The NAA’s heat could theoretically increase stress in the crust over millions of years, potentially influencing seismic activity.
    
• Time Scale Discrepancy:
  • The NAA’s movement is extremely slow (12 miles per million years), and its estimated arrival near New York is 10-15 million years away. This timescale is vastly longer than the recurrence interval of minor earthquakes (e.g., magnitude 2-3 events occur sporadically), making a direct causal link to recent activity unlikely.
    
  • The 2008 Columbia study suggested a higher risk of larger earthquakes due to accumulated stress, but this is more related to regional fault dynamics than the NAA’s current position, which is still northeast of the Appalachians.
    
• Scientific Evidence:
  • The Newsweek article (July 29, 2025) and the University of Southampton study focus on the NAA’s role in past volcanism and uplift, not recent seismicity. There’s no mention of current seismic triggers from the anomaly. Seismic data from the region (e.g., limited records in Newfoundland) shows no clear correlation with the NAA’s movement.
    
  • Rare volcanic intrusions, like the Palisades sill (200 million years old), indicate past activity, but modern seismicity is more likely tied to local fault reactivation than the NAA’s deep thermal influence.
    
• Expert Consensus:
  • Geologists, including lead author Tom Gernon, emphasize the NAA’s long-term geological impact (e.g., mountain uplift) rather than immediate seismic hazards. The lack of recent significant earthquakes (beyond minor tremors) aligns with New York’s low seismicity, as noted by FEMA’s 2008 assessment ranking it fourth for building-related earthquake risk due to pre-1995 construction.
    

Conclusion
There’s no substantial evidence to suggest a direct correlation between recent New York seismic activity (e.g., the July 28, 2025, magnitude 1.7 event) and the Northern Appalachian Anomaly. The NAA’s deep, slow-moving nature operates on a geological timescale incompatible with short-term seismic events. Any minor earthquakes are more likely due to natural stress adjustments along faults like the Ramapo system, a phenomenon independent of the NAA’s current influence. That said, ongoing research into mantle waves (as pioneered by Gernon’s team) might refine our understanding of long-term seismic risks, but for now, the "huge blob of magma" remains a distant, non-imminent concern—more sci-fi than science fact for today’s New Yorkers!