Tsunamis Explained: What They Are and How to Prepare

A massive 8.8-magnitude earthquake struck off Russia’s Kamchatka Peninsula this week, one of the four strongest quakes this century, according to the U.S. Geological Survey. The quake triggered tsunami alerts across the Pacific, from Japan and Hawaii to the U.S. West Coast.

But what exactly causes a tsunami, and how can people prepare?

Tsunamis are typically triggered by underwater earthquakes, volcanic eruptions, or landslides that displace huge columns of seawater. These waves can travel thousands of miles across oceans at jetliner speeds and arrive as powerful surges, not just a single wave.

In the U.S., the National Weather Service issues three alert levels: a Watch (be aware), an Advisory (stay away from shore), and a Warning (evacuate immediately). The recent tsunami generated wave activity as far as San Francisco and Hawaii, reinforcing the importance of early-warning systems and public preparedness.

Even small tsunamis can cause deadly flooding, making awareness and rapid response critical.