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Precariously balanced rocks in New York, Vermont provide limits on earthquake shaking
https://phys.org/news/2024-09-precariously-york-vermont-limits-earthquake.html
ive boulders, delivered by glacier and balancing delicately on rocky pedestals in northern New York and Vermont, can help define long-term maximum shaking intensity of earthquakes in the region.
Seismologists examine the fragility of precariously balanced rocks, or PBRs, to determine the intensity of shaking that would be needed to dislodge them from their perch. The age of the rock formations provides information on how long it's been since a particular region experienced that level of shaking.
According to a report in the Bulletin of the Seismological Society of America, data from the set of five New York and Vermont PBRs are generally consistent with the average level of earthquake ground shaking for the region predicted by the U.S. Geological Survey's 2023 National Seismic Hazard Model.
Only one PBR, measured at Blue Ridge Road in New York, suggested a possible reduction in median hazard for the nearby region. The continued "survival" of this PBR may exclude magnitude 7.0 earthquake sources from large parts of the Adirondack Mountains and the southern Lake Champlain valley, according to Devin McPhillips and Thomas Pratt of the U.S. Geological Survey.
Seismologists examine the fragility of precariously balanced rocks, or PBRs, to determine the intensity of shaking that would be needed to dislodge them from their perch. The age of the rock formations provides information on how long it's been since a particular region experienced that level of shaking.
According to a report in the Bulletin of the Seismological Society of America, data from the set of five New York and Vermont PBRs are generally consistent with the average level of earthquake ground shaking for the region predicted by the U.S. Geological Survey's 2023 National Seismic Hazard Model.
Only one PBR, measured at Blue Ridge Road in New York, suggested a possible reduction in median hazard for the nearby region. The continued "survival" of this PBR may exclude magnitude 7.0 earthquake sources from large parts of the Adirondack Mountains and the southern Lake Champlain valley, according to Devin McPhillips and Thomas Pratt of the U.S. Geological Survey.