Faults are the fractured surface in the Earth’s crust. During the formation of a fault, the vertical displacement of a rock block may occur up to several 100 meters and horizontally the rock blocks may be displaced up to several kilometers. A fault represents weaker zones of the earth where crustal movements become operative for a longer …
Plant and animal communities change through time. Walk through the country and you’ll see patches of vegetation in many stages of development—from open, cultivated fields through grassy shrublands to forests. Clear lakes gradually fill with sediment and become bogs. We call these changes—in which biotic communities succeed one another on the way to a stable …
A thunderstorm is any storm that produces thunder and lightning. At the same time, thunderstorms can also produce high winds, hail, and tornadoes. They are typically associated with cumulus clouds that indicate the presence of rising, unstable air. It is this rising motion that produces the characteristic rainfall and lightning that accompany thunderstorms. Thunderstorms can …
In humid climates, water-saturated soil, regolith, or weak shale can move down a steep slope in just a few hours. This is an earthflow. It’s common to see shallow earthflows, affecting only the soil and regolith, on sod-covered and forested slopes that have been saturated by heavy rains. An earthflow can affect a few square …
The Earth is surrounded by air—a mixture of various gases that reaches up to a height of many kilometers. This envelope of air makes up our atmosphere. It is held in place by the Earth’s gravity. Almost all the atmosphere (97 percent) lies within 30 km of the Earth’s surface. The upper limit of the …
Streams erode in various ways, depending on the nature of the channel materials and the tools with which the current is armed. The flowing water drags on the bed and banks and also forces particles to hit the bed and banks. These actions easily erode alluvial materials, such as gravel, sand, silt, and clay. This …
A lake is a body of standing water with an upper surface that is exposed to the atmosphere and does not have an appreciable gradient. Ponds, marshes, and swamps with standing water can all be included under the definition of a lake. Lakes receive water from streams, overland flow, and ground water, and so they …
The interior of the Earth is divided into different layers and in many ways such as based on chemical composition or mechanical properties. Chemically, Earth’s interior is divided into the crust, mantle, and core. Mechanically, it can be divided into lithosphere, asthenosphere, mesosphere, and barysphere. Source of Information: Most of our knowledge about the interior of the earth is largely based on …
The idea of lateral movement of continents or continental drift was put forward in 1912 by Alfred Wegener in a book ‘The Origin of Continents and Oceans’. The continental drift theory of Wegener ‘grew out of the need for explaining the major variations of climate in the past’. According to A. Wegener, The climatic changes which have occurred on the …
Drainage system refers to the origin and development of streams through time. The examples of drainage systems are consequent, subsequent, and antecedent and superimposed streams, etc. The origin and subsequent evolution of any drainage system in a region are determined and controlled by two main factors: The nature of the initial surface and slope and …