Understanding Earthquakes: Origins, Measurement, and Risk

Understanding Earthquakes

Earthquake Origins

As an earthquake originates:

  • Stress builds up.
  • Tension increases, and materials deform.
  • Materials fracture, releasing energy that vibrates the ground.

Measuring Earthquakes

Seismometers detect even very weak earthquakes that go unnoticed by people, drawing graphic seismograms. The magnitude of an earthquake is the amount of energy released, measured on the Richter scale, which is open-ended and has no limit.

Intensity vs. Magnitude

Intensity and magnitude are

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Geological Processes and Landforms: Definitions & Examples

Geological Processes and Landforms

Seismogram: A chart created by a seismograph (a device that detects earthquakes and deformations). These graphs allow us to locate the epicenter of the earthquake, its magnitude, and the depth of focus.

Subsidence: The slow and gradual sinking of the ground, often due to soil settlement after the extraction of fluids (water and oil), or by seismic liquefaction phenomena.

Collapses: Sharp vertical drops, such as the collapse of a cave resulting from the dissolution

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Understanding Earth’s Hydrosphere: Oceans, Rivers, and Glaciers

The Hydrosphere: Earth’s Waters

The hydrosphere encompasses all of Earth’s water.

Approximately 70% of the Earth’s surface is covered by seawater, primarily in oceans and seas.

The remaining water is found in inland rivers, lakes, groundwater, and glaciers.

Marine Waters

Marine waters differ from inland waters due to their salinity. The average salinity of the oceans is 35%. Oceans are large bodies of saltwater.

Major Oceans

  • Pacific Ocean: The oldest and largest ocean, characterized by its great depth
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Soil Composition, Types, and Land Pollution Issues

Understanding Soil Composition and Structure

Soil is the loose material on the Earth’s surface situated above solid rock.

Soil Layers (Horizons)

Soil is typically composed of three main layers or horizons:

  • Topsoil (A horizon): The uppermost layer, which gains organic material from the decomposition of plants and animals.
  • Subsoil (B horizon): Located beneath the topsoil, this layer accumulates materials leached from the horizons above.
  • Weathered Bedrock (C horizon): This layer contains loose pieces of
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Understanding Orogeny: Formation of Mountain Ranges

Orogeny: The Birth of Mountains

Orogeny: The set of geological processes that give rise to large mountain ranges or orogens. They form on the borders of converging tectonic plates and, depending on the type of convergence, may be of the Andean and island arc collision type.

The Tectonic Orogeny Before Plate Theory: Fixism

Early orogenic theories did not consider the mobility of the masses. According to the fixist hypothesis, the distribution of continents and oceans has always been the same. The main

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Understanding Earth’s Relief, Rock Formation, and Textures

Earth’s Relief and Landforms

The Earth’s surface exhibits diverse relief features.

Types of Relief

Relief areas can be emergent (above sea level) or submerged. Major relief features include:

  • Mountain Ranges: Formed by the convergence of tectonic plates.
  • Plains: Flat or gently undulating areas. Plateaus are elevated plains.
  • Depressions: Areas lower than the surrounding terrain.

Rock Formation and the Rock Cycle

The Earth’s surface is composed of various rock types, including sedimentary rocks.

Sedimentary

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