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This translation was generated by AI and may contain wording that differs from the facts. Please check the Japanese original or official sources for anything important. Japanese original
🎛 Set it up
Click the map to drop it there.
💥 Results
🌠 Compare with real events
- Chelyabinsk, Russia (15 February 2013): an asteroid about 20 m across exploded about 30 km up. The shock wave shattered windows over a wide area and about 1,500 people were injured, mostly by broken glass.
- Tunguska, Russia (30 June 1908): an object thought to be a few tens of metres across exploded in the air and flattened trees across about 2,000 square kilometres of forest. No crater has been found.
- Meteor Crater (Arizona, USA): a crater about 1.2 km across made about 50,000 years ago by an iron meteorite a few tens of metres wide.
- Chicxulub (Yucatán, Mexico): about 66 million years ago an object about 10 km across struck, leaving a crater roughly 180 km wide and triggering the mass extinction that ended the dinosaurs. (This simulator's simplified formula gives a smaller crater.)
- Apophis: an asteroid about 340 m across that will pass very close to Earth on 13 April 2029. NASA's observations rule out an impact for at least the next 100 years; here you can try 'what if'.
⚙️ How it works
The calculations use the formulas of the Earth Impact Effects Program published by Collins, Melosh and Marcus (2005), researchers at Imperial College London and elsewhere.
First it works out whether the air pressure breaks the asteroid apart as it enters the atmosphere. If it shatters and releases its energy high up, that is an airburst; if it reaches the ground, it is an impact and leaves a crater.
The energy comes from the mass and speed and is shown in tons of TNT (1 megaton = one million tons of TNT; the Hiroshima bomb was about 15 kilotons).
Blast ranges use scaling laws based on nuclear test data, and heat ranges assume a fixed share of the energy turns into light and heat. Terrain, buildings, weather and ocean impacts (tsunamis) are not modelled.
📚 Sources and further reading
- Collins, G. S., Melosh, H. J., Marcus, R. A. (2005) Earth Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of a meteoroid impact on Earth. Meteoritics & Planetary Science 40(6).
- NASA JPL Center for Near Earth Object Studies (CNEOS)
- NASA Planetary Defense
- Map data © OpenStreetMap contributors
This simulator gives rough estimates using published research formulas. Real damage depends heavily on terrain, buildings and weather. For disaster planning or evacuation decisions, use official estimates and information from your government and local authorities.
Try the other simulator: Earthquake simulator → Japan disaster guide
Frequently asked questions
How big does an asteroid have to be to cause damage on the ground?
A rocky asteroid around 20 m across can break windows with the shock wave of its airburst (Chelyabinsk, 2013). Around 50 m it can flatten buildings and forests over a wide area, and above about 100 m it reaches the ground with enough energy to destroy a city.
Is any asteroid going to hit Earth?
NASA and others constantly track asteroids that come near Earth, and none currently known is expected to cause major damage within the next 100 years. The latest data are published on NASA JPL's CNEOS website.
What happens if it lands in the ocean?
A large impact in the ocean can cause a tsunami. This simulator assumes a land impact and does not model tsunamis.
