Unit 2 – P

Apuntes

Unit 2 – Plate Tectonics and Internal Geological Processes 1. The Internal Structure of the Earth Scientists study Earth's interior indirectly using seismic waves, density and gravity data, and meteorites. P-waves travel through solids and liquids, while S-waves only through solids, proving a liquid outer core. Discontinuities (Moho, Gutenberg, Lehmann) mark boundaries where seismic waves change speed. Geochemical model: crust, mantle, core. Geodynamic model: lithosphere, asthenosphere, mesosphere, outer and inner core. 2. Plate Tectonics The lithosphere is divided into tectonic plates moving over the asthenosphere. Vertical movements are caused by density changes; horizontal by continental drift and seafloor spreading. Wegener proposed continental drift; Hess explained seafloor spreading with mid-ocean ridges. The theory of plate tectonics combines both, driven by mantle convection and gravity. Types of boundaries: divergent (ridges), convergent (subduction or mountains), transform (faults). Mantle plumes create intraplate volcanoes and hot spots like Hawaii or Canary Islands. 3. Internal Geological Processes Earthquakes release energy when rocks break along faults. Focus is insid...