The landforms created by internal volcanic activity are mainly basaltic lava flows, which occur when lava erupts from within the earth. Basaltic lava is a type of lava that has low viscosity and flows easily downslope, creating large sheets of rock that can extend for miles. The sheets of basaltic lava can be up to several miles wide. The most common types of internal volcanic activity include pyroclastic flows, lahars, and avalanches.
The following are some major landforms formed by volcanic activity:
Volcanic Cone
The material that comes out of the volcano accumulates around the mouth, which takes the form of a cone-like base, called a volcano cone. There are many types of cones based on their size, extent, and composition, some of which are notable.
- Lava Cones: These cones are formed by the eruption of an active volcano. They are created by lava flow and do not have boulders. Their shape varies depending on their composition. Some famous types include acid lava cones, which are formed from more sand-mixed lava and have a dome shape with a sharp slope, and super silicic lava cones, which are formed from mixed lava with low mass and have a slow cone slope.
- Cinder Cones: These cones are formed by the eruption of an active volcano and have more rocks and high ash content. Their shape is that of a perfect cone with convex and sloping edges. They have an angle of friction based on the ash and ember, with ash resting on 300 and embers on 450.
- Mixed Cone: These cones are formed by explosive and peaceful eruptions. Layers of rock, boulders, and lava form one after another. Hence, they are also called Straya Cones. The best examples of this are the Mayans of the Philippine Islands and the Fujiyama of Japan.
- Slope Cone: These cones are formed by the deposition of fast-moving lava. Due to the rapid flow of lava, the areas of the cone widen, and parallel folds are formed around the mouth. They are low in height and appear like plateaus with simple slopes.
- Stopper Dome Cone: These cones are formed by the accumulation of glutinous episodic magma near the volcano. The magma rises over the previously collected magma, and the dome continues to grow. The hard part gets divided into pieces, and cell debris is formed around the dome.
- Dependent Cones: Compound cone walls are often broken in the explosion, and many holes are formed on their sides. In these cracks, small ash cones form in a line all around the edge. This gives the cone a strange shape, and they are called dependent cones.
- Lavalava Cones: Narrow gas streams of lava flow through dependent cones. If there is a gradual eruption, the lava emanating from it is ephemeral. The gas bubbles of lava break up to form a sharp-sloping horn shape. This conical shape is called a lavalava cone.
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