Geological structures and discontinuities are the very essence of geology; geology, in turn, plays a very significant role in understanding the Earth's crust. Geological structures and discontinuities form part of the Earth's pan-crust, created by several tectonic, sedimentary, and metamorphic processes. Details of folds, faults, joints, and unconformities shape a landscape and influence the distribution and behavior of natural resources. Bedding planes, foliations, and shear zones are among the most significant discontinuities that can widely affect the mechanical properties of rocks, with engineering, seismology, hydrogeology, and environmental management implications. The features that create these discontinuities are currently driving geologists, engineers, and environmental scientists to explore earth resources, and utilize, and protect them. Here's a detailed explanation:
Geohazards
Geological hazards, also known as geohazards, are natural events that pose threats to life, property, and the environment due to the Earth's geological processes. These hazards are typically associated with the movement of the Earth's tectonic plates, volcanic activity, and various surface processes. Understanding geological hazards is crucial for mitigating their impacts and preparing for potential disasters. This article will explore the different types of geological hazards, their causes, effects, and mitigation strategies.
Types of Geotechnical investigation methods
Geotechnical investigations employ a variety of methods to assess subsurface conditions. Here are the main types of geotechnical investigation methods:
1. Surface Exploration
Site Reconnaissance:
- Involves a visual inspection of the site.
- Identifies surface features like slopes, drainage patterns, and existing structures.
Geological Mapping:
- Maps surface geology to understand soil and rock formations.
- Uses geological maps and satellite imagery.
How to choose the best geotechnical investigation method ?
Choosing the appropriate geotechnical investigation method for a site requires several considerations to be made to ensure that sufficient data have been gathered for safe and efficient design and construction. The step-by-step procedure to help in making a decision is presented below:
1. Project Requirements
Scope of the work: Size, type, and purpose of structure, residential, commercial, or industrial.
Load Requirements: The applied loads and stresses that the structure is going to impart on the soil are determined.
Local Building Codes: Any statutory or regulatory requirement or guidelines that may exist for a geotechnical investigation.
Branches of Geology
Minerals and Mineralogical Analysis
Minerals are the building blocks for soils and rocks present in the Earth, and they have distinctive physical properties namely; color, streak, hardness, cleavage, fracture, luster, habit (or form), tenacity, specific gravity, magnetism, odor, taste and feel.
The streak of a mineral is the
color of its powder.
The hardness of a mineral is its abrasion resistance.
The cleavage of a mineral is its
tendency to break down along a particular direction; it is described as one set
of cleavage, two sets of cleavage, and so on.
Fracture is the character of the
broken surface of the mineral in a direction other than the cleavage direction.
Luster is the appearance of the
mineral in reflected light.
Habit (or form) of a mineral
refers to the size and shape of its crystals.
Tenacity describes the response of a mineral to hammer blows, to cutting with a knife, and to bending.
What is Rock?
Introduction
Rocks are the naturally occurring aggregate of minerals and matter forming the Earth's crust, the final products of various geologic processes that ultimately lead to igneous, sedimentary, and metamorphic rocks. Each of these kinds of rocks has its features and processes, all of which are critical for understanding the Earth's history and the role of active processes in shaping our planet. Knowing the rocks and details of their formation is very crucial in many applications related to construction, resource extraction, or environmental management.