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1. The geological activity of the Earth Relief , external geological processes and internal geological processes .

2. The Earth’s relief It is the set of geographical features (mountains, valleys, plains, etc.) that we can observe on the earth's surface.
The landscape is the set formed by the relief and the vegetation that covers it, as well as the action that human beings exert on them.
The relief is something dynamic, in continuous change thanks to the internal processes that build it and the external processes that shape it.
These changes usually occur at a very slow speed, imperceptible on a human timescale .

3. Factors that condition the relief The main factors are: The climate , especially temperature and precipitation.
The type of rock , its greater or lesser resistance to erosion .

4. The sculptors of relief External geological agents are the factors causing changes in surface rocks. They model the relief.
The most common are: water, wind and ice. The role of living beings, especially plants and human activity, also produce changes in relief.

5. External geological processes

6. Weathering It consists of the set of changes or alterations that surface rocks undergo due to the effect of water, the atmosphere and living beings. It can be of two types:

7. Erosion, Transport and sedimentation.

8. River Relief Esta foto de Autor desconocido está bajo licencia CC BY-NC-ND

9. In the rivers we can distinguish several sections : The high section, where the slope is steep and where erosion and transport predominate. It originates a V-shaped valley. Rapids and waterfalls are formed. Middle course: the slope is softening, the river is losing energy and the channel is widening. Presence of meanders. Lower course: sedimentation of river materials occurs. Two types of mouth: Delta and estuary. Esta foto de Autor desconocido está bajo licencia CC BY-NC

10. Groundwater Aquifers are masses of rocks or sediments that allow the storage and circulation of groundwater within them. Therefore, an aquifer must have two properties: Porosity: the presence of pores or voids capable of filling with water. Permeability: ability to allow water to circulate inside and exit through wells, boreholes or springs. Rainwater infiltrates the ground by gravity until it reaches an impermeable layer. Esta foto de Autor desconocido está bajo licencia CC BY

11. Karst Karst is a landscape formed by the action of surface water and, especially, groundwater . Limestone rocks undergo a type of chemical weathering called carbonation. Rainwater, loaded with carbon dioxide, behaves like a weak acid that attacks limestone until it dissolves . Esta foto de Autor desconocido está bajo licencia CC BY-SA-NC

12. Esta foto de Autor desconocido está bajo licencia CC BY-SA-NC

13. Coastal relief On the coast, a large part of the energy of the sea is discharged against the coast.
Rivers also influence their modeling, through the sediments they deposit at their mouths, the action of the wind and human presence. One of the main factors that contribute to coastal modeling is the movements of the sea: Waves: undulatory movements of the sea caused by the wind. Tides: the advance and retreat of the sea caused by the gravitational pull of the Moon. Drift currents: currents parallel to the coast when the swell hits oblucuously.

14. The power of the wind Esta foto de Autor desconocido está bajo licencia CC BY-NC-ND The influence of the wind is only important in desert areas due to the abundance of loose materials and the absence of vegetation . Wind erosion can be caused by deflation (the wind removes fine sediments and gives rise to a desert of stones or reg) and by abrasion (the wind hits the surface of the rocks with the washed sand, forming the rocks into a mushroom)

15. The power of ice Glaciers are large masses of ice that slide by gravity to areas where it melts.
They form in areas of perpetual snow, where accumulation in winter exceeds summer melting. Depending on their size, there are two main types of glaciers: Continental glaciers : cover large areas . Greenland Alpine: in mountainous areas . Glaciers, due to their high thickness and viscosity, have a great capacity for erosion and transport.
The sediments carried by the glacier are called till.

16. INTERNAL GEOLOGICAL PROCESSES Esta foto de Autor desconocido está bajo licencia CC BY-SA-NC

17. Internal geological processes are those that act from the Earth's interior and are driven by the Earth's internal heat.
The main ones are:

18. Tectonic plates and internal processes. The lithosphere or rigid surface layer of the Earth is divided into fragments of different sizes called lithospheric or tectonic plates. These plates are in continuous movement, dragging the continents with them and interacting with each other. Most of Earth's seismic and volcanic activity takes place at or near plate boundaries. Earthquakes are the most obvious sign of friction between plates. Esta foto de Autor desconocido está bajo licencia CC BY-SA

19. Plate boundaries

20. The plates move by convection currents due to the Earth's internal heat and gravity. The materials of the lower mantle, when they come into contact with those of the core, heat and expand, become lighter and tend to rise by flotation. When the materials reach the base of the lithosphere, the colder they cool and contract, become denser and tend to descend, closing the cycle. Esta foto de Autor desconocido está bajo licencia CC BY-NC

21. VOLCANOES They are cracks or holes through which magma emerges to the outside, cooling. Magma is a mixture of molten rocks, solid fragments, and dissolved gases formed in the Earth's interior, in the lower crust or upper mantle. The magma rises, due to its lower density, and accumulates in the magma chamber. Magma accumulates gases that increase the internal pressure of the magma chamber. If the magma finds a path, conduit or fracture to the outside, a volcanic eruption occurs. When magma comes to the surface, it loses its gases and is called lava. Volcanoes throw materials classified according to their size and physical condition: Cenizas <2mm Lapilli 2 y 64mm Bombas >64mm Lava

22. The viscosity of the magma that feeds the volcano is a key factor that determines the explosiveness of the eruption. It depends on the amount of silica the magma contains. Esta foto de Autor desconocido está bajo licencia CC BY-SA-NC

23. Volcanic hazards Destruction of populations and their environment.
Release of toxic gases.
Reduced temperatures.
Earthquakes and tsunamis.

24. EARTHQUAKES They are sudden shaking of the lithosphere caused by the displacement of large blocks along a fracture called a fault line. Seismic waves are vibrations of the ground that travel both inwardly (P and S waves) and above the surface (surface waves) Esta foto de Autor desconocido está bajo licencia CC BY-SA

25. Effectos of eartquakes Building collapse.
Slope landslides and avalanches.
Tsunamis. Esta foto de Autor desconocido está bajo licencia CC BY