Why Is Mars’ Olympus Mons So Big?


  • Olympus Mons is the largest known volcano in the Solar System, located on Mars.
  • It is a shield volcano, created by lava slowly flowing down its sides.
  • The volcano is made up of basalt lava flows and towers about 16 miles above Mars’ surface with a diameter of 374 miles.
  • The volcano must have had a lot of activity and eruptions to grow to its current size, with lava being quite runny to result in the smooth slopes seen.
  • Scientists believe the volcano last erupted about four billion years ago, making it a dormant volcano.
  • The rocks on the surface are cold, indicating that the volcano has not been active for a long time.
  • The temperature of Mars today is -63°C, which is too low for a volcano to erupt, and the lava must have been extremely hot to be runny, probably around 1,200°C.
  • The difference in the lower surface gravity of Mars, combined with faster eruption rates, allowed the lava to pile up higher and form a shield volcano instead of a stratovolcano.
  • Plate movement on Earth hinders the continuous build-up of lava, resulting in the formation of a series of volcanic islands instead of a single large volcano-like Olympus Mons.
  • We can learn a lot about the rocks and how they formed by using satellites and rovers, as well as comparing them to similar volcanoes here on Earth.

Want to know more? Watch the video for details!


Copyright @smorescience. All rights reserved. Do not copy, cite, publish, or distribute this content without permission.

Join 20,000+ parents and educators
To get the FREE science newsletter in your inbox!