Choosing UPSC 2020 optional subjects can prove to be a hassle but if you are inclined towards geography, this article will prove to be helpful.
Important Geophysical Phenomena: Earthquake is a natural phenomenon in which the earth's surface shakes and trembles due to the release of energy in Earth's lithosphere creating seismic waves. When underground rocks break down or crush against each other along the fault line, the tectonic plates that are present in the form of rocks, move very slowly. This causes the creation of seismic waves or earthquake waves. Earthquake is measured on the Richter scale.
A tsunami is a result of an earthquake or volcanic eruption adjacent to oceans and results in unexpected movement of the water column. It causes serious loss of life and economy in the area where it hits. It involves the movement of water from the surface to the seafloor and is directly linked to the depth of the water body. Deeper the water body, higher would be the movement of water.
A volcano is a kind of vent on the surface of the Earth which transmits molten rocks called magma from the inside to the outside of the earth's surface. Volcanic activity is when an increase in the pressure within the basin drives the magma through structurally weak zones to explode as lava at the surface. There are three types of volcanos-
1. Shield Volcano
2. Composite Volcano
3. Caldera Volcano
A cyclone is a natural phenomenon on the surface of the earth in which low barometric pressure is accompanied by strong winds that revolve counter-clockwise in the northern hemisphere and clockwise direction in the southern hemisphere.
Geographical features and their location: These are created naturally and consist of ecosystems and landforms. There are two types of habitat- Ecosystem (A community of organisms) and biome (Occupy large areas of the globe and encompass many geographical features, including mountain ranges).
Landforms are categorized as elevation, slope, orientation, stratification, rock exposure, and soil type. They include cliffs, mounds, hills, berms, rivers, valleys and numerous other elements. Continents and oceans are the highest-order landforms.
The changes in the geographical features can cause a very critical effect on the environment and the planet. Climate change can alter river flow regimes, which will result in changes in surface water availability. Groundwater is an important source of water and has been a reliable source of water supply for human society for centuries. An increase in sea-level is dangerous for both humans (increased flood-risks, degraded groundwater quality, etc.) and ecosystems (impact on mangrove forests and coral reefs, etc.), especially in coastal regions. Coastal cities in developing regions are highly vulnerable to the rise in sea-level because of high population densities and urban migration leads to extra burden on the already inadequately planned urban cities. Glaciers and ice caps react strongly to climate change and are close to the melting point which poses a serious risk to the planet.
UPSC 2020 notification will be released in February so it is imperative that you choose your optional subject and start preparing. All the best!