Geologic and Hydrologic Hazards

The Pacific Ring of Fire, a roughly 40,000-kilometer horseshoe-shaped zone tracing the boundaries of the Pacific Plate with numerous surrounding tectonic plates, hosts about three-quarters of the world's active and dormant volcanoes and is the source of the large majority of the planet's most powerful earthquakes. Its seismicity results from ongoing subduction, in which denser oceanic plates are forced beneath adjacent continental or oceanic plates, generating friction that periodically ruptures in major earthquakes, such as the magnitude 9.0 To̍hoku earthquake that struck Japan in 2011. These geologic hazards are driven by plate tectonics operating on timescales of millions of years and are unrelated to current climate change, a distinction that is important given how often environmental hazards are discussed together in the news.