Active continental margins, including most of those bordering continents facing the Pacific Ocean, have many earthquakes. These continental margins mark major plate boundaries and are usually flanked by high mountains and deep trenches, departing from the main elevations of continents and ocean basins, and they also contain active volcanoes and, sometimes, active fault zones. Thus, most earthquakes occur predominantly at deep‐sea trenches, mid‐ocean spreading ridges, and active mountain belts on continents. These earthquakes generate seismic waves; strong vibrations that propagate away from the earthquake focus at different speeds, due to the release of stored stress. Along their travel path from earthquake hypocenters to the recording stations, the seismic waves can image the internal Earth structure through the application of seismic tomography techniques. In the last few decades, there have been many advances in the theory and application of the seismic tomography methods to image the 3D structure of the Earth's internal layers, especially along major plate boundaries. Applications of these new techniques to arrival time data enabled the detailed imaging of active fault zones, location of magma chambers beneath active volcanoes, and the forecasting of future major earthquakes in seismotectonically active regions all over the world.
Part of the book: Earthquakes