Magnitude of Earthquakes

The intensity of an earthquake is assessed on the Rickter Scale, which was developed by geophysicist Charles Richter in 1935. This scale assigns a number to an earthquake based on the severity of the ground motion It ranges from 0 to 8+. It is logarithmic so that an earthquake with a magnitude 4 causes 10 …

What is an Earthquake?

An Earthquake may be defined as the shaking and trembling of the Earth’s surface caused by sudden releases of stress with the crust of Earth. Thus an earthquake releases the energy that has been gradually stored through the stress of increasing deformation of rocks. The released energy takes the form of seismic waves that radiate …

Volcanic Production/ Lava Composition

Volcanic eruptions produce many products out of which the following are very important; (1). Tuff: Rocks comprising of fine ash. (2). Agglomerates: Rocks consisting of pieces larger than 20 mm. (3). Volcanic Bombs: Rock pieces with a diameter of more than 32 mm. (4). Cinders: Fragments with diameter between 4 mm -32 mm. These are …

What is denudation

The process of breakage and separation of sediments and particles of the rocks from the rock surface is known as weathering, while the process of wearing away/ transportation of these sediments from the rock surface to the low lying areas is known as erosion. The process of weathering and erosion collectively are known as Denudation. …

Volcanism and Landform formation (Landscape)

Volcanism and Landform Formation Denudation upon the forms produced by vulcanicity results in the evolution of a volcanic landscape. In the views of F.J. Monkhouse, “The product of vulcanicity vary from hardest of lavas to the softest of ashes often in close juxtaposition.” It has been witnessed that volcanic activity creates unique and distinct landscapes. …

Volcanic Form

Volcanic Form The erupted volcano comes in different forms. These forms are given as under: (1). Ash Cone: These are also called Tuff Cones. When heated rapidly by lava, water flashes to steam and expands violently, fragmenting huge amounts of lava into plumes of very fine grains of ash. This ash falls around the volcanic vent, creating an ash …

Active, dormant and Extinct Volcanoes

Active Volcanoes: An active volcano may be defined as the one which is definitely known to have erupted periodically in historic times. Kilauea volcano on Hawaii is the world’s most active volcano, followed by Etna in Italy and Piton de la Fournaise on La Réunion island. Further ordering the value of the activity of volcanoes …

Global distribution of Volcanoes

According to improved knowledge of ocean floor, topography, and geology the entire Pacific Ocean floor constitutes a very large tectonic plate with smaller Cocos and Juan de Fuca Plates. Most of the global volcanic activity is concentrated at convergent plate boundaries. The majority of the world’s active volcanoes lie along the Pacific Ring of Fire. …

What is crater (Volcanic crater)

A crater is the mouth/ opening of the volcano. The molten magma is ejected through the vent of the volcano. The uppermost part of the vent or in other words the top opening of the vent is known as the crater. The crater is generally wider than the vent. When the lava/ejected material is sprayed …

What are Calderas (Volcano)?

The empty chamber of a volcano formed after the completion of the eruption is known as the Caldera. As the eruption of the volcano comes to an end, the vent and crater remain as a hollow shaped cavity. According to H.J de Blij, “A volcano‘s lava and pyroclastics come from a subterranean magma chamber, a …