Notes, summaries, assignments, exams, and problems for Geology

Understanding Cavitation in Fluid Dynamics

Cavitation, sometimes referred to as suction vacuum, is a hydrodynamic effect that occurs when water or another liquid fluid passes at high speed over a sharp edge, producing a fluid decompression due to the conservation of the Bernoulli constant (Bernoulli's Principle). It can reach the vapor pressure of the liquid so that its constituent molecules immediately change to a vapor state, forming bubbles or, more correctly, cavities. The formed bubbles travel to areas of higher pressure and implode (the vapor suddenly returns to a liquid state, abruptly collapsing the bubbles), producing a trail of gas and potentially damaging the metal surface where this phenomenon occurs.

Discharge Cavitation Explained

Discharge... Continue reading "Cavitation and Water Hammer Phenomena in Fluid Systems" »

Earthquake Causes, Effects, and Prevention

Causes of Earthquakes

• Regional-Global Scale: Lithospheric subduction zones (cause of large earthquakes).
• Local Causes:
  • Volcanic eruptions
  • Escape of materials related to large surface currents
  • Fractures
  • Fluid extraction: groundwater, petroleum
  • Excavation collapse: mining, filling of reservoirs

Effects of Earthquakes

• Shaking of soil and buildings (the majority of deaths are caused by the collapse of buildings).
• Ground displacements taking place across fault lines.
• Landslides (a violent earthquake can trigger thousands of them).
• Tsunamis or tidal waves (traveling at high speed).
• Explosions: nuclear tests, exploration for mineral and oil deposits, mining operations.

Increased Seismic Risk Factors

• Human overpopulation

Characteristics of Earth as a Planet

Source: Earth was formed approximately 4.6 billion years ago by the agglomeration of matter subject to gravitational attraction.

Mass: Approximately 5,976 trillion tons (estimated from the formula of universal gravitation and gravitational acceleration).

Gravity: This force influences the arrangement of materials according to their density (less dense at the top, more dense at the bottom). On Earth, air, water, and rocks are arranged in this way.

Greenhouse Effect

Visible solar radiation penetrates the atmosphere and warms the Earth's surface. The Earth radiates heat as infrared radiation into the atmosphere; some of it escapes into space, and some is sent back to the surface. Increasing greenhouse gases in the... Continue reading "Earth's Characteristics and Atmospheric Layers" »

Tidal Power

Tidal energy is produced by the movement of water masses caused by rising and falling tides and the waves that originate on the sea surface due to wind action.

Benefits:

• It is a clean energy source.
• No waste.
• Almost inexhaustible.

Disadvantages:

• They can only be in sea areas.
• May be affected by weather disasters.
• Depends on the tidal ranges.
• Facilities are large and expensive.

Hydraulic Power

Hydropower is produced by the water retained in dams and reservoirs at high altitudes (which has gravitational potential energy). If at one point dropped to a lower level, this energy is converted into kinetic energy and then into electricity in a hydroelectric power station.

Advantages:

• It is a source of clean energy.
• No waste.
• Easy to store.
• The water stored

Eutrophication: A Threat to Lakes

Rivers, due to their erosive power, carry salts, organic matter, and suspended solids. To this, human action adds waste from domestic and industrial activities (solids and metals mining), agriculture, and livestock (nitrates, phosphates, pesticides, etc.). The self-purification capacity of rivers cannot always handle this load, which triggers pollution processes. The effects of this pollution include:

• Restriction on the use of water
• Alteration in wildlife and/or aquatic flora
• Unpleasant appearance and odor

Rivers are better equipped to handle pollution dynamics, allowing them to dilute pollutants. In contrast, lakes tend to accumulate waste. One of the main problems affecting lakes is the process of eutrophication.... Continue reading "Eutrophication in Lakes: Causes and Solutions" »

Geological risk is any condition, process, phenomenon, or event that, due to its location, severity, and frequency, can cause health damage or death to humans, economic losses, and environmental damage.

Wilson Cycle

1. First Volcanic Eruptions

Initial magmatism occurs, leaving a long area. It is forming a long fault line that divides the two lithospheric plates.

2. Formation of an Incipient Rift

The fracture of the previous phase is enlarged to be more clearly defined. In the central part of the opening, magma cools, forming oceanic lithosphere. The presence of magma at depth causes lithospheric swelling, forming a thermal dome. A rift valley, surrounded by topographic elevations, lies in the central part.

3. Expansion of the New Ocean Floor

New... Continue reading "Geological Risks: Understanding Plate Tectonics and Continental Drift" »

Parallels and Meridians

Parallels: Circles perpendicular to the Earth's axis. Latitude 0° is the Equator, which divides the Earth into two hemispheres.

Meridians: Semicircles that run from pole to pole. The 0° meridian, also known as the Prime Meridian, passes through Greenwich, a town near London.

Geographic Coordinates

Latitude: The angular distance from any point on Earth to the Equator. It can be north or south.

Longitude: The angular distance from any point on Earth to the Prime Meridian (0°). It can be east or west.

Maps and Scale

Map: A representation of the Earth's spherical surface on a flat, reduced, and simplified form.

Scale: The relationship between a measured length on a map and the corresponding length in reality.

Landforms

Plateau:

Deserts: Arid Ecosystems

A desert is an ecosystem that receives little precipitation. While often reputed to have little life, this depends on the type of desert. Many deserts support abundant life, with vegetation adapted to low humidity. Fauna typically hide during the day to preserve moisture. A desert ecosystem is arid, and this characteristic even enables the establishment of sustainable social groups.

Deserts are the most extensive land area on the planet, covering a total area of 50 million square kilometers, approximately one-third of the land surface. This constitutes 30% of the land surface (16% hot deserts and 14% cold deserts).

Dunes of the Namib Desert

Common Desert Characteristics

Deserts share several characteristics. The desert... Continue reading "Deserts: Ecosystems, Characteristics, and Adaptations" »

External Geological Cycle

The external geological cycle describes how land areas, primarily the land surface of the continents, are subject to the continuous action of the atmosphere, hydrosphere, and biosphere. This leads to the destruction or denudation of topographic relief in the so-called cycle of denudation of the continents. This cycle comprises phases of erosion, transport, and sedimentation of the products resulting from the fragmentation and breakdown of surface rocks.

Weathering

Weathering is a set of processes due to the action of the atmosphere, hydrosphere, and living things, which cause the decomposition of rocks and the minerals that constitute them. Depending on the type of mechanisms that act on the rock, there are two types... Continue reading "External Geological Cycle: Weathering, Erosion, Transport, Sedimentation" »

Workshop Building Summary

Buildings are structures created throughout history to provide shelter.

Tunnels

Tunnels are complex and costly constructions, including walkways, highways, waterways, and rail tunnels.

Tunnel Guidance

Excavation occurs simultaneously from both ends, requiring precise alignment using modern laser systems or traditional methods like theodolites.

Digging, Blasting, and Securing

Tunnels are dug using compressed air drills on vehicles. Explosives break rock, conveyor belts remove debris, and concrete linings support the tunnel. Boring machines with rotating heads are also used.

Tunnel Challenges

Risks include flooding, landslides, computer malfunctions, and dust from explosions.

Bridges

Bridges span depressions or obstacles like water,... Continue reading "Civil Engineering Structures: Tunnels, Bridges, Ports, and More" »