Category: Geography Notes PPT

Seepage is the movement of water in soils or the ground. The flow of water through the soil or ground is called seepage. But seepage meaning does not only limit itself to water only but other fluids as well. Thus, seepage meaning is the flow of water or any fluid through the soil or the ground. Seepage is often a critical problem in geology. A common example of such a problem is the flow of water or fluids through the building foundations. This flow of water or other fluids occurs through the pores or interstices. It is a common phenomenon around hydraulic structures in buildings or water bodies. 

Seepage – A Menace

Seepage, as already introduced above, is the flow of water through the pores or interstices especially in building foundations, it becomes a critical factor to be understood. Water seepage meaning depends on several factors. These factors include pressure gradient and the permeability of the soil which is essentially the combination of the forces of gravity through other factors. The permeability can vary widely over a range depending on the soil structure and the composition making it possible for the safe design of such structures as earth dams and reservoirs with very little or negligible loss via leakage and other structures such as roadbeds and filtration beds in which the rapid drainings are desirable. 

Some of the following factors can be checked when seepage is to be observed, especially water seepage meaning is satisfied in any of the leaks. They are Water, Dampness, Moisture, Corrosion, Discoloration, Staining, Exudations, Efflorescence, and Incrustations. When any such leakage and seepage meaning fulfilling symptoms are visible then they are to be reported since the seepage can cause serious problems to the building foundations. This water seepage meaning becomes a common menace when the iron or steel used commonly in modern building constructions gets corroded thus weakening the foundations and the structure of the building and the constructions. 

Seepage of Groundwater

Commonly speaking seepage synonyms is leakage. But there is a difference between the two. Leakage is the flow of water not through the interstitial or very minute spaces in-between material molecules but through the cracks of damaged materials carrying water or any other fluids. Also, the flow of water through leakage is generally faster than the seepage. Another concept that is related to the flow of fluids is permeability. But permeability is the allowance of the fluid through the material and it’s an intrinsic property of the material. Whereas seepage is generally seen in damaged construction materials or sometimes occurs in materials with the passage of time. There is also groundwater seepage. In this, the water seeps through the soil. Sometimes when there is excess groundwater available it can seep through the porous soil material against the gravity and get collected in the basements of construction sites or already constructed buildings. Thus, seepage occurs from a reservoir to drainage i.e. from sites having a higher quantity of water to sites with a lesser quantity of water. In many ways, seepage is an undesirable phenomenon, unlike permeability which can be desirable under special conditions.

Thus, it is clear that seepage is the slow flow of water or any other fluid through spaces present in between porous materials and can be considered as leakage as well but is significantly different from the permeability of fluids. 

Have you ever seen the sky? You must have seen the sun in the day and the moon at the night long with the presence of some stars or have heard of the news bout something in space coming towards the earth and can damage it, etc. Well, there are a lot of things that we cannot see with our naked eyes. Here, we will talk about the stars and solar system, various celestial bodies in the solar system, solar system definition geography, the 8 planets name, sun, moon and stars, etc. This page will give you basic information about the space and the solar system we live in and its related features and will help you in Geography and Science subjects and will also increase your knowledge.

Celestial Body Definition and Meaning

All those heavy objects which are present in space such as the sun, the moon and other bodies are called celestial bodies.  There are a number of celestial bodies present which have different features which are mentioned below.

Galaxy and Universe

If you have ever seen a white glowing path in the sky at night full of stars, that band is actually called the Milky way which is also known as Akash Ganga. It is a cluster of stars where our solar system lies and this cluster of stars is called a galaxy and there are a huge number of galaxies that comes together to form the universe. We still do not know the exact size of the whole universe and the number of different galaxies present in the universe.

Solar System

From the above information, you have already come to know that the solar system is a subpart of a galaxy and a system that comprises the sun, the planets and their satellites and other celestial bodies, is called a solar system. There are a number of celestial bodies in the solar system which we will discuss below:

Stars

The celestial bodies which are larger in size and hot and made of various gases, have their own heat and light are called stars. For example, the sun in our solar system is a star that is huge in size and emits light in larger amounts. It also a great source of energy and heat for our planet Earth. There are millions and billions of stars in our solar system.

At night, you must have noticed the twinkling stars which are similar to the sun but we cannot feel their heat as they are far from us and looks like a tiny dot at the night in the sky. Sometimes you have seen some patterns of stars in the night sky, those patterns are called constellations. For example, Ursa Major or Big Bear. The most famous and easily recognizable is the Saptarishi or group of 7 stars. There is also a star namely the Pole star which has a fixed position and was used by the ancient people to locate directions. Now you can answer the question – Is constellation a part of the solar system? 

The Sun

It is called the centre of the solar system which binds it with its pulling force. It is made up of huge amounts of gases such as hydrogen and helium. Its mass is 99.8% of the total mass of the entire solar system. It is almost 150 mn km away from our planet and is a huge source of heat and energy. From the above information, you will able to answer one question- Is the sun a star or a planet?

Planets

These are those celestial bodies that do not have a light of their own and move around the sun in fixed paths called orbits. 8 planets namely are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Earlier, Pluto was also considered as a planet but now has been excluded from the list and is known as a dwarf planet.

The Earth

This is the third planet from the Sun and it is the only planet where life exists. It is the fifth-largest and has a Geoid shape because it is flattened at the poles. It is also called the blue planet and venus’s twin.

The Moon

It is the only satellite of the planet Earth having a diameter of one-quarter of the Earth and 3,84,400 kms away from the planet. It moves around the planet earth and takes 27 days for one revolution. It does not support life like earth.

Asteroids

There are some other tiny bodies as well in addition to the above-mentioned ones which move around the sun and are found between Mars’; and Jupiter’s orbits. As per the scientists, they were once parts of the planet which have been broken off.

Meteoroids 

These are other pieces of rocks that revolve around the sun and sometimes also reach the earth and in that process, they start burning sometimes and emit light because of which they look like a shooting star. 

The study of the formation of rocks is classified as geology. It is basically a science that deals with the study of solid matter such as rock or rock strata. And the rock strata conveys the history of the earth and its life, especially what is recorded in it. This can be categorized into stratum geology. The rock strata meaning can be better understood by studying the stratum that is formed from deposits or piles of layers for many years. Stratum is used when there is a single rock consisting of many (several parallel layers) layers. And the term strata is used as a plural noun for stratum to describe a giant pile of the deposited sediments. 

Rock Strata and Stratification

Rock Strata Meaning- The term ‘rock strata’ is often used by geologists when referring to many rock layers in a generic sense that appears over large areas. The singular form stratum, which is derived from a Latin word that means spread out, can be used for a single layer, but individual rock layers or even rock beds are more commonly referred to using this specific name as a stratum. Now that you have understood the rock strata meaning, let us understand the formation and features. Rock strata are formed via stratification. 

Stratification – A bed or layer of sedimentary rock which is formed by the accumulation or deposition of mineral or organic particles at the Earth’s surface, and is then followed by cementation of the deposits naturally over time that is visually distinguishable from adjacent beds or layers and this layering of such rocks or sediment is called stratification. Stratigraphy can be considered a sub-discipline of geology that involves the study of rock strata. A sequence of sedimentary layers stacked one atop the other is known as a stratigraphic section and though this is the basic layer of foundation its arrangement and sequence can completely vary according to Steno’s law of stratigraphy. Something that is formed in layers is referred to as a stratiform deposit by geologists. And the term stratification planes are referred to the planes of parting, or separation between individual rock layers. 

Features of Stratum from Stratification

• Formed from the igneous rocks on the earth’s surface, sedimentary rocks, from the volcanic lava flows and its fragments deposits.

• The layers vary greatly in shape and thickness ranging from several millimetres to metres.

• The strata can be a lenslike thick body that only extends a few metres.

• The layers can also be very thin sheets that spread up to several kilometres horizontally.

• The layers are horizontally aligned and a few inclinations are seen on the deposition sites.

• The texture of the stratum changes and with time, some coarser particles become finer, colour changes are seen due to change in mineral composition as time passes. 

• The thickness of the rock strata is independent of the time of deposition; an inch or 2.5 centimetres of stratum layer may take longer to form than strata with a 3-metre thickness.

• The prominence and the details of the strata can vary vastly even within the same strata.

• Rock strata are only a feature of strata formed by sedimentary rocks while the volcanic rocks formation can differ in a few ways as it is influenced by gravity, sea, liquid lava flow and wind. 

Variants in Formation of Rock Strata

There are many factors that can influence, interrupt and change the course of rock strata formation and all these variants help are of primary importance when studying to interpret the geological events and transformation that occurred on the Earth. They are:

• Transporting ability of the depositing agent

• Water

• Wind flow direction

• Size and weight of the mineral agents

• The shape of the deposits

• Homogeneity of the sediments that are deposited

Stratigraphy Laws

1. Steno’s laws describe the patterns of rock layers formation of strata. The first law is the superposition law which states that the younger layers or the new deposits sit atop the older layers and this pauses the change of their growth and texture.

2. The second law is the law of original horizontality that states the original deposition of sedimentary rock layers are flat but orientation may change and even can be found to be tilted when they are heavily influenced by variants.

3. The Law of cross-cutting is the third law of stratigraphy which states that there is a disruption in the rock layers formed wherein there is no particular pattern and younger ones overlap with the older layers of deposition.

4. The law of lateral continuity is the fourth law which states that the deposition to form rock layers continues laterally without any opposition till they encounter other solid-body matter and no deposition is possible. 

Uses of Rock Strata 

• To study the stratification of volcanic rocks, especially the layered ones.

• Used to study the preserved movements of the earth’s surface through the deformed surface.

• Through the interpretation of geologic events, one can gain such practical results that can be helpful in tracing the petroleum fields, the location of mineral deposits, and groundwater reservoirs. 

• The branch of geology that deals with stratification are also called biostratigraphy which uses fossils to study the earth ages.

• Fossils are a great way to determine the relative ages of the rocks.

• Fossils interpretation is helpful in correlating the successions of sedimentary rocks within and between depositional basins.

Conclusion

Stratum geology is a great way of understanding the eras gone by and the endurance of the planet earth through various seasonal changes. It is also a great way to predict what is possible ahead if there are repeating patterns of depositing nature. The Grand Canyon is a pandora’s box for studying the rock strata. It is remarkable that the stratification process that preserves so much information about the past earth’s movement still endures and sustains as new movements are also being recorded. And these recordings are extremely helpful to study earth patterns throughout their history since their formation and that can provide interesting details and help find missing pieces in historical studies. 

The ultimate source of heat and energy is the Sun. The divergent heat received from the sun on the different regions on Earth is the utmost reason behind the different climate features. So understanding the pattern of temperature distribution on Earth in different seasons is important for understanding different climatic features such as precipitation, wind system, pressure system, etc.  

In this article, we will discuss the horizontal and vertical distribution of temperatures along with the factors affecting and factors controlling the temperature distribution on Earth. 

Horizontal Distribution of Temperature

The distribution of temperature across latitude over the Earth’s surface is known as the horizontal distribution of temperatures. The horizontal distribution of temperature on Earth is shown by Isotherms. Isotherms are the line joining points that have an equal temperature. When the isotherm map is analyzed, it can be observed that the horizontal distribution of temperature is uneven. 

Following are the Factors Accountable for the Uneven Horizontal Distribution of Temperature is:

• Latitude

• Altitude

• Land And Sea Contrast

• Ocean Currents

• Passage of Air Masses

• Vegetation Cover

Vertical Distribution of Temperature

As we are aware, the temperature in the troposphere decreases with an increase in altitudes but the rate of decrease in the temperature changes according to seasons. The decrease of temperatures is known as the vertical temperature gradient or normal lapse rate which is 1000 times more than the horizontal lapse rate. The decrease of temperature upward in the atmosphere proves the fact that the atmosphere gets heat from the Earth’s surface through the process of conduction, radiation, and convection. Hence, as the distance from the Earth’s surface ( the source of direct heat energy to the atmosphere) increases ( i.e as the altitude increases ), the air temperature decreases.

Factors Affecting Temperature Distribution

Some of the factors affecting the temperature distribution are:

1. Latitude: The temperature of the surface water decreases from the equator towards the poles because the sun rays become more and more inclined and hence the amount of insolation minimizes poleward.

2. Unequal Distribution of Land And Water: The oceans in the northern hemisphere receive more heat because of their contact with the larger extent of land than the equivalent parts in the southern hemisphere.

3. Prevailing Winds: The winds blowing from the land towards the ocean drive surface water away from the coasts resulting in an upwelling, in which deep cold water rises into the surface.

4. Ocean Current: Warm ocean current increases the temperature in cold areas whereas the cold current decreases the temperature in the warm ocean. For example: in a gulf stream, a warmer current increases the temperature of the Eastern coast of North America and the west coast of Europe.

5. Other factors affecting the temperature distribution are local weather conditions like storms and cyclones.

Factors Controlling Temperature Distribution

The factors controlling the temperature distribution on the Earth’s surface are discussed below:

• The latitude of the Place

• The altitude of the Place

• Distance From The Sea

• The presence of warm and cold ocean Currents

• Local Aspects

Global Distribution of Temperature

The global distribution of temperature can be effectively understood by considering the temperature distribution for January and July. The distribution of temperature is usually shown on the map using the isotherms. The isotherms are line joining places of equal temperature. Generally, the effects of latitude are well shown on the map as isotherms are generally parallel to the latitudes. The deviation from this trend is more generally observed in January rather than in July, especially in the northern hemisphere. The land surface is much larger in the northern hemisphere than in the southern hemisphere. Hence, the effects of land masses and ocean currents are well observed.

Temperature Distribution – January

• In January, there is winter in the Northern hemisphere and summers in the southern hemisphere.

• The western margins of continents in January are much higher than the Eastern counterparts as the westerlies can carry high temperatures into the landmasses.

• The temperature gradient is much closer to the Eastern margins of continents. The isotherms observe more steady behavior in the southern hemisphere.

Temperature Distribution – July

• During July, it is winter in the Southern hemisphere and summers in the Northern hemisphere. The isotherm behavior is the opposite of what it was in January.

• The isotherms are generally parallel to the latitudes in July. The equatorial oceans record warmer temperatures more than 27 degrees celsius. More than 30 degrees celsius is noticed over the land in the subtropical continent region of Asia, along the 30 ° N latitude.

Conclusion

notes enable students to be sufficiently prepared for the Geography exam and guarantee that students will score good marks.

Triangulation is the method of calculating a dot’s direction from either end of a fixed baseline, by only measuring angles to the dot, rather than measuring distances explicitly as in the trilateration process. And the point may be set as the third point of a triangle with two known angles and one known side. That being said, Triangulation methods are mostly used for measuring the scale of the earth and the distances between different sites.

History Associated with Triangulation Trigonometry

Current triangulation is used for many applications, including surveys, navigation, metrology, astrometry, binocular vision, missile modelling, and arms guidance.

In the region, triangulation techniques were not appreciably employed in medieval Spain by Arabic astrolabe treaties like that of Ibne Al-Saffar by Roman land surveyors, agrimensores (d. 1035). Triangulation methods for measuring the scale of the earth and the distances between different sites were also used by Abu Rayhan Biruni (d.1048).

Simplified Roman methods then seem to have coexisted with more advanced techniques used by skilled inspectors. But it was seldom to translate these practices into Latin (the geometry textbook, the uncertain Geomatria Auctoris of the eleventh century is a notable exception), and these approaches seem only slowly to have been percolated into the rest of Europe.

The medieval Jacob’s staff, primarily used for measurement angles, dating from about 1300, and the presence of precisely monitored shorelines in the Portolan maps, the earliest of which is dated 1296, can demonstrate increased knowledge and usage of such techniques in Spain.

Theory of Triangulation Trigonometry by Gemma Frisius

In a new version of the best-selling 1524 Cosmographica by Peter Apian, on-site, the cartographer Gemma Frisius suggested the precise use of triangulation to position far-away plazas for maps in his booklet Libellus de Locorumratione in 1533 (booklet for a describing place). The technology distributed through Germany, Austria, and the Netherlands has been very influential. The Scandinavian astronomer Tycho Brahe used the technique to complement the extensive triangulation, in 1579, of the island of Hven, where he was located on his observatory, which produced a property plan for the island in 1584 concerning the main sites on both sides of Øresund.

Theory of Triangulation Trigonometry by Willebrord Snell

The Dutch mathematician’s work, Willebrord Snell, examined the distance from Alkmaar to Breda in 1615 by a total of approximately 116 kilometers (72 miles) using a chain of 33 triangles is based on the current method of the use of triangulation networks. The gap was quickly underestimated by 3.5%. The two villages had been divided by a degree on the meridian so that he could derive a value from his calculation of the earth’s diameter – an achievement praised by his book Eratosthenes batavus, published in 1617. Snell measured how to correct the planar formula to account for the earth’s curvature.

He also demonstrated how the location of the point within a triangle can be resected or calculated using the angels cast between the unknown spots. These may be much more precisely determined than vertical bearings depending on a compass. This led to the fundamental idea to first survey and subsequently locate secondary subsidiary points within a vast primary network of control points.

Principle of Triangulation Trigonometry

Calculation

We have l being the distance from A to B:

l = d/tanα + d/tanβ

Using the trigonometric identities tan α = sin α / cos α and sin(α + β) = sin α cos β + cos α sin β, this is equivalent to:

l = d(cosα/sinα + cosβ/sinβ)

l = d (sin(α+β)/sinαsinβ)

therefore:

d = l (sinαsinβ/sin(α+β))

The distance of the unknown point from any point of observation, the north/south, east/west offsets of the point of observation, and the full coordinates of the point are also simple to calculate.

 

Theodolite

Theodolite, the essential instrument used to calculate horizontal and vertical angles, dates back to Leonard Digges, an English mathematician from the 16th century. It consists, in its present form, of a horizontal and vertical fixed telescope. The levelling is achieved using a spiritual degree, crosshairs in the telescope allow for precise synchronization with the sighted object. The corresponding two measurements, vertical and horizontal, are read while the telescope is precisely calibrated.

The Volcanic eruptions might be a spectacular event to watch but it is really dangerous to encounter one. The volcanic eruptions explode when the lava and the gas are discharged from the volcanic vent. One of the most common consequences of this eruption is the population movements. A large crowd is often forced to flee as the molten lava from the volcano flows. Volcanic eruptions are often caused temporary food shortages and also leads to volcanic ash landslides known as Lahar.

We will know about six basic types of volcanic eruptions which are sure to amaze us. It has different variants and nature which will be worthy to learn. 

Six Types of Volcanic Eruptions 

In the Volcanic landforms, we have learned the classification of volcanoes by their size and shape. While in this section we will also classify the volcanoes by their eruptive habits. To note, the type of volcanic eruption which occurs plays a prior role in the evolving a volcanic landform, which forms a significant link between the eruptive habit and between the volcanic structure. 

Generally speaking, the eruptions can be categorized as being effusive or being explosive. 

The Effusive eruptions involve outpouring of the basaltic magma which has a lower viscosity and gaseous content. Explosive eruptions are generally involved with magma and have more viscosity with higher gaseous content. This magma is often broken down into pyroclastic fragments which are caused by explosive gas expansion at the time of expansion.

Based on the eruption behaviour of the volcano, volcanic activity is generally divided into six major types. The types are:

1. Icelandic

2. Hawaiian

3. Strombolian

4. Vulcanian

5. Pelean

6. Plinian

The Icelandic type is characterized by effusions of molten basaltic lava that flow from long and parallel fissures.  After it is cooled down these outpourings get to build into lava plateaus.

The Hawaiian type of volcano eruption is a lot similar to the Icelandic type. In Hawaiian eruption type, however, the fluid lava which flows from the volcano’s summit and the radial fissures to create the shield volcanoes, are very large and have gentle slopes on them.

Strombolian eruptions, yet another type of eruption which involves moderate bursts of the expanding gases, ejects clots of incandescent lava in the cyclical or moreover by continuous small eruptions. These are known as the “lighthouse of the Mediterranean” as they have small frequent outbursts on the Stromboli Island, located on the northeast coast of Italy.

The Vulcanian eruption type is named after the Vulcano Island, located near Stromboli, this eruption generally involves moderate explosions of the gas laden accompanied with volcanic ash. The mixture forms dark, turbulent eruption clouds which rapidly ascend and thus expand in folded shapes.

Next type, Pelean eruption. This type of eruption is associated with explosive outbursts which also release the pyroclastic flows, a dense mixture of the hot volcanic fragments, and the gas that is described as lava, gas, or other hazardous substances. These eruptions are named after the destructive eruption of Mount Pelée which is located on the Caribbean island in the year 1902. The fluids produced by these volcanic eruptions are heavier than air but are of low viscosity and thus pour down from the valleys and sloped with higher velocity. Thus, causing extreme damage. 

Last on the list is the Plinian type of eruption which is an intensely violent kind of volcanic eruption that is illustrated by the outburst of Mount Vesuvius in Italy. In this type of volcanic eruption, the gases boiling out of the gas-rich magma produces an enormous and nearly continuous jetting blast. 

Fun Fact

1. Some volcanic eruptions are quite explosive while others are spectacular and relatively harmless.

• The reason for this out, there are at least four factors .

• The number of gaseous constituents dissolved in the magma.

• The thickness or the viscosity of the magma coming out.

• Rate of decompression of the magma as it proceeds onto the surface. 

• The number of nucleation sites on which the gases form bubbles. 

2. A volcanic eruption occurs when?

When the hot materials from the Earth’s interior surface are thrown out from a volcano, eruptions take place. Eruptions can explode from the side branches or the top vent of the volcano. Even there are some eruptions that are very terrible and thus throw out huge amounts of rock and volcanic ash which can kill many people.