III. Plate Boundaries

        Tectonic plates are also known as lithospheric plates that fit together on the Earth’s surface like a jigsaw puzzle. It is believed by the scientists that the plates float on the asthenosphere which is a hot, semi-solid region of the mantle. The movement is called plate tectonics. The movements are easily observed at the plate boundaries, where the plate converges, diverges, or slips sideways. It is also near or along lithospheric plate boundaries where earthquakes or volcanoes occur.

Convergent Plate Boundaries - it is where two plates converge or collide into each other. It is sometimes called subduction zones, because the heavier, denser plate pushes beneath the lighter plate in a process called subduction. Subduction zones are associated with strong earthquakes and spectacular volcanic landscapes. A direct result of plate convergence and subduction is the Ring of Fire which is around the margins of the Pacific Ocean. Moreover, continental plates with similar density collide and neither is enough to create a subduction zone. This created the Himalayan Mountains where the brittle crust of the continental plate folds up and splinters as the plates collide. 

Divergent Plate Boundaries - it is where the lithospheric plates are moving away, or diverging from each other under the sea. Divergent boundaries create a new crust through a form of volcanism, in contrast to convergent boundaries that destroy old crust by subduction. When the plates move apart, magma wells up from beneath the surface to fill the spaces left by the diverging plates. This magma rises and cools in a continuous process forming mid-ocean ridges. Mid-ocean ridges are chains of volcanic mountains and rift valleys. The process of oceanic spreading occurs when the magma cools and forms a new crust, and it pushes the plates apart. 

Transform Plate Boundaries - it is sometimes called conservative boundary. It is because the crust is neither created nor destroyed at the boundary. This occurs in a region where plates are sliding horizontally past each other. It is typically found on the ocean floor but occasionally occurs on land. The San Andreas fault in California is the most visible manifestation of transform boundary movement. Earthquakes in this boundary are generally shallow. They are caused by the accumulation and sudden release of stress and tension as the plates slip past each other.