Craters are bowl-shaped depressions at a volcano’s top, caused by eruptions or impacts. Calderas, however, are larger and basin-shaped. Craters form from impact events or volcanic eruptions. Calderas, however, come from massive volcanic eruptions and then collapse. This collapse changes the landscape, sometimes creating new lakes or geothermal systems.
Craters and calderas differ greatly in size. Craters are usually a few meters to a couple of kilometers wide, while calderas can be tens of kilometers wide. For example, the Ngorongoro crater in Tanzania is 260 square kilometers and 600 meters deep.
Craters have a bowl shape with steep walls and a central depression. Calderas are more complex, sometimes with smaller craters or new volcanic domes. The Empakaai crater, near Ngorongoro, is a great example. It has walls up to 300 meters high and is about 8 kilometers wide.
Types of Calderas and Their Formation
Calderas are diverse, each with its caldera characteristics and formation ways. I’ll examine three main types: crater lakes, shield volcanoes, and resurgent calderas. These geological wonders show the power of volcanic activity and tectonic processes.
Crater-Lake Calderas
Crater-lake calderas form after big eruptions called Plinian eruptions. These eruptions leave huge depressions that can fill with water. Crater Lake in Oregon is a great example, formed 7,700 years ago.
Shield Volcano Calderas
Shield volcano calderas grow slowly through lava releases. They are different from explosive ones, forming nested or terraced depressions. Olympus Mons on Mars is a massive shield volcano that shows similar growth.
Resurgent Calderas
Resurgent calderas are the biggest volcanic structures. They form when huge magma chambers collapse, creating big depressions. The Yellowstone Caldera is a big example, about 55 kilometers wide.
These calderas can also host geothermal systems, providing renewable energy.
