Yellowstone Eruption Update | October 2025 Scientists reanalyzed seismic records and found 86,000 micro-earthquakes beneath Yellowstone that earlier methods missed. Microquakes help map where fluids and hot rock move and why the caldera remains active. Ground motion and swarms can shift over time, which is why monitoring combines seismic data, GPS uplift, gas, and temperature. This does not mean an eruption is imminent, but it is a reminder that Yellowstone is alive and under constant watch. In