Damping the Dangers from Tectonics-Driven (Natural) Hazards: Earthquakes and Volcanoes

Abstract

Our habitat Earth has a radius of 6370 km (3960 mi). If we were able to see a section cut through the center of the Earth we would see that it is comprised of nearly concentric layers of materials with different measurable properties that allow us to divide it into several parts. The outer rocky layer is the crust that is from 10 to 40+ km (6–24+ mi) thick depending on whether you measure it from the ocean floor or under mountainous region. It is made up of several large bordered masses called plates. The crust is underlain by a mainly rock layer called the mantle that reaches a depth to 2900 km (1800 mi). The upper 100–250 km (60–150 mi) of the mantle is comprised of non-rigid material (perhaps molten-like in nature) at 1300 °C that underlies the crust and is called the asthenosphere. Beneath the mantle lies the iron-rich molten outer core that reaches to 5000 km (3100 mi) and the solid inner core that extends to 6370 km (3960 mi).