GEOLOGY

Detailed explanation-1: -Craters are present at many volcanic vents. The size and shape of volcanic craters vary a great deal from volcano to volcano, and they even change during the lifespan of an active volcano. Craters can become filled by lava domes or lava flows, and new craters may form during subsequent eruptions.

Detailed explanation-2: -A volcanic crater is a bowl-or funnel-shaped depression that usually lies directly above the vent from which volcanic material is ejected. Craters are commonly found at the summit of volcanic edifices, but they may form above satellite (flank) vents of composite and shield volcanoes.

Detailed explanation-3: -Every time a volcano erupts, it changes in shape and size because the lava it releases cools and hardens around it.

Detailed explanation-4: -The explosion pulverizes or vaporizes material underground, and the earth above sinks. Craters formed by underground explosions are called subsidence craters. (Craters formed by explosions at or near the surface of the Earth are simply called explosion craters.)

Detailed explanation-5: -The crater is the bowl shaped opening located at the top of the volcano. The crater is also the steep sided walls made of hardened lava that surround the main vent. Lava can flow from the main vent, but not all volcanoes eject large amounts of lava.