Though it appears static during our brief human life spans, Earth's surface is continually molded by natural forces and many of these ongoing events place the lives of humans at risk. Those who live in geologically active regions are at most risk; such areas include subduction zones, continental collision zones, rift valleys, transverse faults and active volcanic hotspots.
Most of the Continents harbor a number of these high risk areas. Subduction zones (where oceanic plates dip beneath the Continents), which produce earthquakes, tsunamis and volcanism, line the Pacific rim, including the west coasts of North and South America and the eastern edge of Asia; they are also found along the southeast coast of Asia and in isolated areas of southern Europe and southwest Asia. Collision zones are prominent across southern Asia (at the northern edge of the Indian Subcontinent), across the Middle East, through the Alps of southern Europe and in eastern Siberia. Rift Valleys, sites of earthquakes and volcanism, are found in East Africa, in the Rio Grande Valley of the American Southwest and across Iceland. Transverse faults, where one tectonic plate is scraping past another, include the San Andreas Fault of southern California and faults along the east and west sides of the Arabian Plate. Potentially catastrophic volcanic hotspots are found in North America (Yellowstone) and Indonesia.
Though it is subject to floods, droughts, tropical storms and wildfires, Australia, which sits near the center of its tectonic plate (far from active margins), is relatively immune from earthquakes and volcanism; in that respect, it might be considered the most stable Continent on which to live (excluding Antarctica which, at least for now, does not invite human habitation). On the other hand, old suture lines, potential sources for earthquakes, criss-cross the bedrock of all continents, new volcanic hotspots (resulting from mantle plumes) may develop almost anywhere and no place on Earth is immune from cosmic collisions with asteroids.
