This document discusses studying the Earth's interior and determining its structure through indirect means like seismic data. Seismic waves generated by earthquakes travel through the Earth's layers at different velocities depending on the material's density, and are reflected and refracted in ways indicating the Earth is not homogeneous. The crushing strength of rocks depends on factors like their mode of formation, composition, texture, moisture content, and extent of weathering. Principal factors controlling rock strength are mineral composition, structure, texture, presence of joints or fractures, water content, and stress state.
This document discusses studying the Earth's interior and determining its structure through indirect means like seismic data. Seismic waves generated by earthquakes travel through the Earth's layers at different velocities depending on the material's density, and are reflected and refracted in ways indicating the Earth is not homogeneous. The crushing strength of rocks depends on factors like their mode of formation, composition, texture, moisture content, and extent of weathering. Principal factors controlling rock strength are mineral composition, structure, texture, presence of joints or fractures, water content, and stress state.
This document discusses studying the Earth's interior and determining its structure through indirect means like seismic data. Seismic waves generated by earthquakes travel through the Earth's layers at different velocities depending on the material's density, and are reflected and refracted in ways indicating the Earth is not homogeneous. The crushing strength of rocks depends on factors like their mode of formation, composition, texture, moisture content, and extent of weathering. Principal factors controlling rock strength are mineral composition, structure, texture, presence of joints or fractures, water content, and stress state.
This document discusses studying the Earth's interior and determining its structure through indirect means like seismic data. Seismic waves generated by earthquakes travel through the Earth's layers at different velocities depending on the material's density, and are reflected and refracted in ways indicating the Earth is not homogeneous. The crushing strength of rocks depends on factors like their mode of formation, composition, texture, moisture content, and extent of weathering. Principal factors controlling rock strength are mineral composition, structure, texture, presence of joints or fractures, water content, and stress state.
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MATRIC NO: 21D/7HCE/00708
NAME: GANIYU OLATUNJI ISMAIL
COURSE: HGEM 319
QUESTION ONE Studying the Earth’s interior poses a significant challenge due to the lack of correct access. Many processes observed at the Earth’s surface are driven by the heat generated within the earth, however, making an understanding of the interior essential.
Volcanism, earthquakes and many earth’s surface features are a result of process happening within the earth.
Much of what we know regarding the earth’s interior is through indirect means such as using seismic data to determine earth’s interior structure.
Scientists discovered in the earth 1900s that seismic waves generated by
earthquake could be used to help distinguish the properties of the earth’s interior layers
The velocity of these waves ( called primary and secondary waves) changes based on the density of the materials they travel through.
As a result seismic waves do not travel through the earth in straight lines, but rather get reflected and refracted, which indicates that the earth is not homogeneous throughout.
The crushing strength of a rock depends on a number of factors, such as its
.Mode of formation
.Composition
.Texture and structure
.Moisture content and
.Extent of weathering it has already suffered.
The principal factors controlling the strength of solid rocks are:
1. Mineral composition, structure and texture;
Rocks containing tectosilicates like Quartz and Feldspars are strong like Granite and Quartzite, whereas rocks that have phyllosilicates like Muscovite and clay minerals are weak.
Fissile rocks like Shale and Slate and Foliated rocks like Schists are weak, whereas massive and compact rocks like most igneous rocks have high strength.
2. Bedding, jointing and anisotropy;
The presence of joints, fractures, bedding planes, all of which are planes of weakness makes the rock overall weak.
3. Water content;
The petrophysical properties of rocks decrease with increasing moisture and this can result in an increase in the mechanical compliance in some cases.
4. State of stress in the rock mass.
A rock under a high state of stress for a long period of time is weaker in comparison to the same type of rock under no stress.
