What to know about ‘doublet’ earthquakes like the destructive pair that hit Venezuela The U.S. Geological Survey has described the pair of earthquakes — a 7.1-magnitude and a 7.5-magnitude — as a doublet sequence, a phenomenon in which two temblors of similar magnitude strike roughly the same area at around the same time. The first earthquake “will probably have weakened some buildings or structures,” Tobin said. “Then collapses would happen during the second earthquake, even if they made it through the first one.” A 7.5-magnitude temblor is about three times bigger than a 7.1, since the Richter scale is logarithmic. https://www.nbcnews.com/science/earthquakes/venezuela-doublet-earthquakes-rcna351799
When massive 9.0 magnitude earthquake shook Japan on March 11, 2011, the ground also made a more lasting move. About 15 minutes after the event began at 2:46 p.m. local time, nearly the entire country shifted eastward, according to GPS station measurements. The lurch was small — 5 to 6 millimeters, or 0.20 to 0.24 inches — but permanent and at the time went largely unnoticed or was passed off as a data glitch. However, University of Chicago geophysicist Sunyoung Park felt the recorded signals that indicated a shift pointed to something tangible. In fact, the ground movement reflected an “extraordinary” and previously undocumented seismic phenomenon, according to a new study. “What was unusual about this movement is basically the whole of Japan was moving nearly uniformly at the same time,” said Park, who led the research. She added that the movement, which affected mainland Japan — Hokkaido to Kyushu — an area approximately 1,800 miles (3,000 kilometers) in length, did not match the timing of the initial earthquake, and it happened before any significant aftershocks. After years of analyzing GPS and seismic data, Park and her colleagues found that waves from the earthquake had traveled down to Earth’s core and then rebounded to the crust, displacing four major tectonic plates. https://www.cnn.com/2026/06/24/science/japan-earthquake-core-seismic-waves
What say you, @rimrocker, and why did it take so long? For the first time, federal wildland firefighters are authorized to use N95 respirators on the fireline after receiving formal training on their safe use in the wildland fire environment. Expanded N95 use provides a meaningful, immediate tool to reduce the inhalation of particulates that can result in future health impacts. At the same time, both departments are pursuing a full respiratory protection program that is complaint with Occupational Safety and Health Administration requirements. https://www.fs.usda.gov/about-agenc...ds-long-sought-protections-limit-health-risks
