Craters that form on the sides of volcanoes are called flank craters.Eruptions from flank craters can be much more dangerous than eruptions from summit craters.
Volcanic material in some summit craters is near the surface, but not visible.
During volcanic eruption, the temperature is very hot and can get up to 600C.
Expanded landform areas like this are common in Hawaii.
Volcanoes may have one summit crater, such as Mount Fuji in Japan. Mount Erebus, a volcano in Antarctica, has a lava lake in its summit crater.
Lava lakes are where magma has bubbled up to the surface.