Earth’s Structure and Landforms: A Comprehensive Overview
Earth’s Structure and Composition
The Earth is a sphere, slightly oblate at the poles, and divided into three main zones.
The Mantle
The mantle is composed of various materials, some of which are partially melted and known as magma.
The Nucleus
The nucleus is divided into two layers: an inner core, which is solid, and an outer core, containing molten material.
The Crust
The crust varies significantly in thickness. In some areas, it is very thick, forming the continents. In other areas, it is much thinner, such as beneath the oceans.
Earthquakes
Earthquakes are shocks that originate within the Earth and spread in all directions as seismic waves, similar to ripples formed by dropping a pebble into a lake.
- Hypocenter (or Focus): The area inside the Earth where the earthquake originates.
- Epicenter: The location on the Earth’s surface directly above the hypocenter.
Volcanoes
- Crater: The opening at the top of the volcanic vent where materials are ejected.
- Lateral Vent: A smaller vent located on the side of the volcano.
- Magma: Molten rock found inside the Earth, consisting of liquid materials due to high temperatures and pressure.
- Volcanic Cone: The part of the volcano formed by ejected material.
- Main Vent: The conduit through which magma rises.
- Lava Flow: The path of molten rock flowing down the volcano’s slopes.
Landforms
- Mid-Ocean Ridge: A very long underwater mountain range.
- Cape: A part of the coast that extends into the sea.
- Ria: A marine inlet, usually elongated, formed when the sea floods the lower stretch of a river valley.
- Valley: A depression in the landscape, typically elongated. It can be a river valley (V-shaped, formed by a river) or a glacial valley (U-shaped, formed by a glacier).
- Peninsula: A piece of land surrounded by water on three sides, connected to the mainland by a narrow strip called an isthmus.
- Abyssal Plain: A flat area on the deep ocean floor, between 3000 and 7000 meters deep.
- Marine Trench: A deep depression in the ocean floor, often reaching depths of 6000 meters or more, sometimes even 11000 meters.
- Island: A piece of land completely surrounded by water. A group of islands forms an archipelago.
- Mountain: A natural elevation of the Earth’s surface.
- Mountain Range: A continuous chain of mountains.
- Plain: A flat or gently undulating surface of considerable continental extent.
- Continental Slope: The steep slope connecting the continental shelf to the abyssal plain.
- Continental Shelf: The submerged edge of a continent, sloping down to about 400 meters. Its width varies from a few meters to several kilometers.
- Depression or Basin: An area characterized by a lower altitude than the surrounding terrain, often formed by river erosion or tectonic collapse.
- Highland or Plateau: An elevated area with a relatively flat surface.
- Gulf: A large sea inlet, usually rounded. A bay is similar but smaller.
The Iberian Peninsula
The Iberian Peninsula is located in southwestern Europe, bordered by the Cantabrian Sea, the Atlantic Ocean, and the Mediterranean Sea.