Earthquakes, volcanoes, landslides and tsunamis are all seismic hazards that happen worldwide. Hot spots are those places where tectonics, volcanic activity, sea floor spreading and quakes are affected by deep, hot magma rising, plates moving and pressures beneath the Earth's crust. These all contribute to land and marine geology creation, including deep sea trenches.
However, it is the ring around the Pacific Ocean that circle called a “Ring of Fire,” which contains the most seismically active areas on the globe. The Pacific Ring of Fire includes all those nations which align with the boundaries of the Pacific Ocean. Tectonic plates, specifically the Pacific Plate, have been actively moving northwest for millions of years. As it moves, hot spots, such as the chain of islands known as Hawaii, pop up from beneath the sea floor from slow-building volcanoes, coastal mountain ranges are lifted, earthquakes and tsunamis ravage coastlines, and humans over history witness nature’s acts of creation through such forces.
Other areas, such as the Cascade Volcanoes and those running down the west coast through Mexico and all the down to Chile, erupt. These seismic hot spots are also where fault lines occur. The Pacific Plate is moving north, and, as it moves, it grinds against the North American Plate along many fault lines running through the west coast. Subduction zones mark rises and falls that correspond to the many earthquakes known from Alaska on down. In California are the Hayward Fault in the San Francisco Bay area, and in southern California, the Newport, Inglewood, San Jacinto and San Andreas faults. Each of these has produced major quakes in the last few thousand years.
Alaska is known as the most seismically active of the United States, but as the population is low there, more people are affected by earthquakes in California and Mexico. Here, there are far more people and hence buildings, roads, gas lines and more to be affected by quakes, landslides and tsunamis. Tsunamis, such as the Indian Ocean Tsunami in 2004 and the Tohoku quake which devastated Japan in 2011, are examples of relative hot spots of intense geologic activity in recent times. These were so destructive that new emergency response systems have been created, new standards for nuclear power and industry are being enacted and new technologies for tracking are being implemented worldwide.
Other very seismically active hot spots include China, Turkey and Indonesia. The lethal force of any seismic event is often more severe in very populous areas with more make-shift housing, city markets and impoverished infrastructure. Because of this, although more quakes may occur in California or Japan, usually more damage is done in places like Haiti and Mexico. There are many factors to be measured, from city site planning to emergency responsiveness.
Hot spots that are not within the Ring of Fire are places where there are lots of sub-surface welling up and release of hot gases. Yellowstone National Park is one such place. Another is Iceland. Just as the Pacific Ocean hot spot that formed the Hawaiian Volcanic Islands, Iceland's hot fissures and volcanoes are slow moving. They produce much geothermal energy but are not generally explosive such as the volcanoes of the western Cascades and Andes.
The structure of Earth, and the creative forces that built it, are also destructive on a timely scale. Although most days are without major incident, in the long-history timeline of land and sea, seismic activity is required and can be quite destructive. As to the next most devastating seismic event, it is never a question of if, but always when.