The tallest volcano on Earth is Mauna Kea, one of the 5 volcanos that make up the Big Island of Hawaii. The summit of Mauna Kea is 4,205 meters above sea level, but its true height is much larger. When measured from the sea floor, Mauna kea is more than 9,000 meters tall, making it the tallest mountain on Earth.
Mauna Kea is part of the network of volcanos above the Hawaiian hotspot. The tectonic plate that has the Hawaiian islands is slowly moving above the hotspot, and it recently carried Mauna Kea away from the hotspot. Scientists believe that Mauna Kea is now dormant; it last erupted about 4,500 years ago. Although, researchers do think it’s going to erupt again, the time between eruptions is measured in hundreds of years. The most active volcano on the island, Kilauea, erupts every few years.
Even though the Hawaiian islands are warm and tropical, Mauna Kea is so tall that it has regular snowfalls in the winter months. Geologists have even found deposits created by glaciers during recent ice ages. There were probably three glacial episodes in the last 200,000 years. People regularly ski on the slopes of Mauna Kea.
Although Mauna Kea is the tallest volcano, it’s only about 40 meters taller than the nearby Mauna Loa, which is the biggest volcano on Earth. Mauna Loa has more than 75,000 cubic kilometers of material.
And the biggest volcano in the Solar System isn’t on Earth, but on Mars. The enormous Olympus Mons is 27 km tall, and contains 100 times more material than Mauna Loa.
We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.