Dynamic Earth: Natural Hazards and Resource Sustainability

Equilibria in a Dynamic Planet

The water cycle, powered by solar energy, involves a series of ocean currents called the ocean conveyor belt. This cycle depends on the Earth's climate. The movement of mantle material causes the elevation of depths, which feeds volcanoes. These gases are composed of carbon, nitrogen, and sulfur, which are essential for the climate and the biosphere. Usually described as cycles, these are rather complex exchanges among many deposits. These flows and cycles form a very dynamic system.

Geological Risks and Hazards

Risk is the interaction of a geological process with human resources or assets. Risk depends on hazard (the probability of a phenomenon occurring) and damage (exposure and vulnerability).

Flooding and Flash Floods

Flooding is the natural phenomenon causing the most victims. Floods or flash floods are overflowing rivers or streams that are intermittent water resources.

Landslides and Slope Instability

Landslides involve the fall of materials due to slope instability and gravitational forces, contributed to by earthquakes, heavy rains, and rock types. These processes constitute a formidable risk in mountain areas.

Earthquakes and Tectonic Plates

An earthquake results from the sudden release of energy accumulated by the displacement and friction of various crustal plates (phenomena grouped under the name of plate tectonics).

How Earthquakes Occur

They occur when the ground vibrates; when this happens, buildings can collapse. The movement of plates causes high-energy lithospheric earthquakes, especially at so-called destructive plate boundaries.

Measuring Magnitude and Intensity

Earthquakes are measured according to:

• Richter Scale: Measures energy released from 1 to 10 using a seismograph.
• Mercalli Scale: A 12-point scale developed to assess the intensity of earthquakes based on damage.

Tsunamis and Submarine Activity

A tsunami is a series of giant waves that can occur after an earthquake, volcanic activity, submarine landslides, meteorite impacts in the sea, or even large chunks of an island sliding into the ocean.

Causes of Tsunamis

This is due to a sudden deformation of the sea; this deformation may be caused by an earthquake affecting the seabed (tidal wave) or the explosion of a volcanic island.

Volcanoes and Magma

Volcanoes are mountains located at plate boundaries, where magma reaches the surface.

Types of Volcanic Eruptions

• Effusive: Emits flows of lava and gases.
• Explosive: Emits ash, gases, clouds, and pyroclastic material.

Prediction and Prevention Strategies

Prediction means anticipating that something will happen. Prevention involves measures taken to minimize damage.

Consumption of Scarce Natural Resources

Humanity uses Earth's resources to build, move, feed, or express culture. Large amounts of energy are used for the processing and use of consumer goods. Population growth has been accompanied by increased consumption of natural resources per inhabitant.

Carrying Capacity and Environmental Impact

• Carrying Capacity of the Planet: The maximum number of people that the Earth can sustain.
• Environmental Impact: Any interaction produced by humans in the environment; these can be beneficial if positive or unbalanced if they cause negative effects.