L2.1 VOLCANIC ACTIVITY.pptx presentation volcanic act

volcanic activity

1. CHAPTER 2 PLATE TECTONICS: VOLCANISM

2. LESSON 2.1 VOLCANIC ACTIVITY VOLCANISM is a mechanism by which magma rises onto Earth’s crust through a volcanic vent and flows along Earth’s surface. VOLCANISM is the process through which eruption happens. Volcanoes that have undergone and still undergo volcanism are considered as ACTIVE VOLCANOES. DORMANT VOLCANOES which have not erupted in a long time but may still do in the future. EXTINCT VOLCANOES that no longer expected to erupt.

3. TYPES OF VOLCANISM SPREADING CENTER VOLCANISM SUBDUCTION ZONE VOLCANISM INTRAPLATE VOLCANISM

4. 1. SPREADING CENTER VOLCANISM Occurs commonly at divergent plate boundaries in the ocean floor. Two separating oceanic plate create an oceanic rift or mid-ocean ridge from which magma rising from Earth’s mantle escapes. When the risen lava interacts with water, it solidifies eventually and turns into a new section of ocean floor. Examples of volcanoes that shape along ridges are the Mid-Atlantic Ridge in the Atlantic Ocean and the East Pacific Rise in Pacific Ocean.

5. Happens when two plates diverge, move away from each other plates next to them. The collision plates forms a convergent plate boundary, in which subduction of the lithosphere occurs, specially during an oceanic convergence or an oceanic-continental convergence. Subduction consumes the older sections of the lithosphere and drags them back into the mantle where extreme heat and pressure tear them into pieces and melt the pieces onto magma. Subduction creates magma in Earth’s interior and thus, contribute to the formation of volcanoes. the sections overlying the subducting lithosphere melt faster and produce magma in the process. Magma then rises up and erupts from the volcanoes , forming a volcanic arc on the surface. 2 . SUBDUCTION ZONE VOLCANISM

6. Is a volcanic activity that takes place deep within Earth’s interior region. The earth’s core generate heat, which is absorb by the mantle. The heat absorbed within the plates and the mantle can induce volcanic activity as it melts rocks and pushes the resulting magma up a volcanic vent. These regions in the mantle are called the HOTSPOTS. HOTSPOTS are result from the convection of materials inside the mantle. When these materials are heated, they become lighter and accumulate into a mushroom-shaped object called MANTLE PLUME, which rises to the based of the lithosphere. The rising mantle plumes generate huge amounts of magma which erupt onto the surface of earth. The formation of flood basalt – the spreading of basaltic lava over a wide expanse of earth’s crust – is presumed to have resulted from mantle plumes. The H awaiian volcanic islands are best examples of volcanoes that undergo intraplate volcanism. 3 . Intraplate or hotspot volcanism

7. ACTIVITY Get your no. 4 book, open your book on page PAGE 29-30 Answer the ‘LET US APPLY” and “LET US ENRICH”