What is the volcanism?

VOLCANISM

 Temperature and pressure within the mantle are high enough to melt rock producing what is called magma. Because magma is less dense than the overlying solid rocks, it will rise towards the surface. So magnetic gases expand to generate the localized pressure and within a magma chamber that cause an eruption molten magma coming out from mantle towards the surface of crust is called volcanism. Some magma erupted at the surface and some are cooled inside crust. The magma eruption may be continuous, continual once erupted and stopped. The volcanic activity is mostly associated with tectonism so that volcanic vulnerable area lies at end around the tectonically sensitive belts and plate construction.

ORIGIN AND LOCATION OF VOLCANO

How it origin?

Volcanism results from need to transport heat from hot earth interior to cooer surface. This heat arises from two important sources, Volcanism is found where: Two plates pull apart and leave thinner Volcanic igneous rocks are by magma that cools at surface. Plutonic igneous rocks are produced by magma that cools beneath surface. Added localized is supplied from the lower mantle or possibly outer core melting caused by this phenomenon occurs at earth’s hot spots. Mantle material can also melt if its composition is changed.

GENERAL SETTING FOR VOLCANIC ACTIVITY   

What are the general setting for volcanic activity?                                                     

·        HOT SPOT

The places known as hotspots or hot spots in geology, that is anomalously hot compared with mantle elsewhere.

·        SEA FLOOR SPREADING

Seafloor spreading helps explain continental drift in the theory . Stress causes fractures to occur in the lithosphere. Older rocks will be found further away from spreading zones.

TYPES OF VOLCANOES

·        FISSURE VOLCANO

Most common volcano, located mostly beneath ocean surface.

·        SHIELD VOLCANO

Distinguished by low profile, typically formed from basalite magmas

·        DOME VOLCANO

Formed from more viscous silica-rich magmas

·        CNIDER CONE VOLCANO

Volcanic pipe and solidifying into cinder in mid-air. Most common volcano in continental setting.

·        COMPOSITE OR STRATO VOLCANO

Formed of alternating layer of ash and solidified larva flows.