iPhone / iPad App
Veiscend
If Mt. Fuji is "1," how big was that eruption?
Press play and the map flies from one volcano to the next around the world, presenting eruptions in order from smallest to largest. Circles on the map show how far pyroclastic flows and ashfall reached, while the multiple of Mt. Fuji's Hōei eruption counts up. From Mt. Ontake's 2014 eruption through Sakurajima, Pinatubo, and Tambora to some of the largest eruptions in Earth's history, 60 eruptions are included.
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What's Inside
60 eruptions
23 eruptions in Japan and 37 elsewhere in the world, from recent eruptions to giant caldera eruptions tens of thousands of years ago and super-eruptions tens of millions of years ago.
What happened and the damage
Explains what happened in each eruption and what damage it caused, including death tolls, climate effects, and stories surrounding the eruption.
VEI and erupted volume
Shows the VEI (Volcanic Explosivity Index), a measure of explosive strength, along with the approximate volume of erupted material, revealing differences the VEI alone can't capture, such as lava-dominated eruptions.
Features
Plays automatically, like a ranking video
Starting from the smallest eruption, the map flies to each volcano in turn. Playback speed ranges from 0.5× to 2×, and you can skip back and forth or pause.
Hazard zones on the map
Circles on the map show the reach of pyroclastic flows, lava flows, and similar hazards, as well as ashfall. You can also overlay Mt. Fuji's 1707 ashfall area for comparison.
Compare sizes as cubes
Compares erupted volume with Mt. Fuji's as cubes, making differences in scale that are hard to grasp from numbers alone clear at a glance.
Music that changes with scale
Includes two original background music tracks composed for this app. When an eruption exceeds 10 times Mt. Fuji's, the music switches to a more intense track.
Full ranking list
See all 60 eruptions in a list and tap one to jump to that volcano.
Available in 9 languages
Japanese, English, Chinese (Simplified and Traditional), Korean, Spanish, French, German, and Portuguese. Everything is translated, right down to the eruption descriptions.
Pricing
- The app is free, and all features are available to everyone.
- No ads are shown.
- For those who would like to support development, three optional tips are available: Buy Me a Small Eruption, Buy Me a Medium Eruption, and Buy Me a Big Eruption. Tips do not unlock any features.
Requirements
Supports iPhone and iPad running iOS 26.0 or later. An internet connection is required, as the app uses Apple Maps to display the map.
About the Figures
Figures for erupted volume, dates, damage, and so on are approximate, based on sources including the Japan Meteorological Agency, the Geological Survey of Japan (AIST), the Smithsonian Institution Global Volcanism Program, and various research papers. Some values differ greatly between sources.