Air traffic over active volcanoes in the Aleutians

North Pacific and Russian Far East air routes (gray lines) pass over or near more than a hundred potentially active volcanoes (red triangles). Aircraft flying along these routes, some of the busiest in the world, carry more than 50,000 passengers and millions of dollars of cargo each day to and from Asia, North America, and Europe. In the North Pacific region, several explosive eruptions occur every year. Ash from these eruptions, which has caused jet engines to fail, is usually blown to the east and northeast, directly across the air routes.