Drainage Systems (Drainage Patterns) Drainage systems, also known as river systems, are the patterns formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by tectonic irregularity, nature of underlying rock strata, and the gradient of the land. Based on the correlation between the topology and the direction of flow, drainage … [Read more...]

The landforms created as a result of degradational action (erosion and transportation) or aggradational work (deposition) of running water are called fluvial landforms. Fluvial Erosional Landforms Fluvial Erosional Landforms are landforms created by the erosional activity of rivers. Various aspects of fluvial erosive action include: Hydration: the force of running … [Read more...]

Soil Erosion Soil erosion is the loosening and displacement of topsoil from the land due to the action of agents like wind and water. Soil erosion in nature may be a slow process (geological erosion) or a fast process promoted by human activities like overgrazing, deforestation. Weathering and erosion lead to the simultaneous process of ‘degradation' and … [Read more...]

Tsunami is a Japanese word for “Harbour wave”. A tsunami is a series of very long-wavelength waves in large water bodies like seas or large lakes caused by a major disturbance above or below the water surface or due to the displacement of a large volume of water. They are sometimes referred to as tidal waves because of long wavelengths, although the attractions of the Moon … [Read more...]

Richter Magnitude Scale Charles F. Richter developed the Richter magnitude scale (ML) for measuring the strength (amount of energy released) of earthquakes in 1930s. Because of the various shortcomings of the ML scale, seismologists now use moment magnitude scale (Mw). Both the scales are logarithmic and are scaled to have roughly comparable numeric values. Moment … [Read more...]

Earthquakes An earthquake is shaking or trembling of the earth’s surface, caused by the seismic waves or earthquake waves that are generated due to a sudden movement (sudden release of energy) in the earth’s crust (shallow-focus earthquakes) or upper mantle (some shallow-focus and all intermediate and deep-focus earthquakes). A seismograph, or seismometer, is an … [Read more...]

Rocks are an aggregate of one or more minerals held together by chemical bonds. Feldspar and quartz are the most common minerals found in rocks. The scientific study of rocks is called petrology. Based on the mode of formation three major groups of rocks are defined: igneous, sedimentary, and metamorphic. Igneous Rocks — solidified from magma and lava. … [Read more...]

Hotspot Volcanism Hotspot volcanism is a type of volcanism that typically occurs at the interior parts of the lithospheric plates rather than at the zones of convergence and divergence (plate margins). The Iceland Hotspot and Afar Hotspot which are situated at the divergent boundary are exceptions. Hotspot volcanism explains the so-called anomalous volcanism — the … [Read more...]

Volcanism Types Four types of volcanism can be identified. Exhalative Volcanism (vapour or fumes) Effusive Volcanism (lava outpouring) Explosive Volcanism (violent ejection solid material) Subaqueous Volcanism Exhalative Volcanism (vapour or fumes) This includes the discharge of material in gaseous forms, such as steam, fumes and Hydrochloric … [Read more...]

Volcanic landforms are divided into extrusive and intrusive landforms based on whether magma cools within the crust or above the crust. Rocks formed by the cooling of magma within the crust are called Plutonic rocks. Rocks formed by the cooling of lava above the surface are called Igneous rocks. In general, the term ‘Igneous rocks’ is used to refer to all rocks of … [Read more...]