Earthquake simulator
Move the magnitude and depth sliders and watch seismic waves radiate across a city in real time. Every read-out updates from standard seismology relations.
Peak intensity
VII
Very strong
Shaking
11s
strong-motion
Energy
84.8
kilotons of TNT
vs Hiroshima
6×
atomic bombs
Rupture length
25 km
fault slip
Felt radius
433 km
≈ MMI II+
Closest real analogue
Christchurch, NZ (2011)
Shallow and highly destructive.
How to read the simulation
Magnitude vs intensity
Magnitude is one number for the energy at the source. Intensity is how hard the ground actually shakes at a place — it fades with distance, which is why the city tiles change colour the further they sit from the epicentre.
P-waves then S-waves
The fast cyan front is the P-wave — it arrives first and does little harm. The slower orange front is the S-wave, which carries the damaging side-to-side shaking. The gap between them grows with distance.
Depth changes everything
Push the depth slider down and the same magnitude feels weaker at the surface: the energy has farther to travel. Shallow quakes are the destructive ones.
Want the real physics behind the shaking? Explore what drives earthquakes, plate tectonics, or browse live earthquakes.
FAQ
Earthquakes: frequently asked questions
What is the difference between magnitude and intensity?+
Magnitude is a single number for the energy released at the source (the moment magnitude, Mw). Intensity (the Modified Mercalli scale, I–XII) measures how strongly the ground shakes at a particular place, so it decreases with distance and changes with depth and soil. One earthquake has one magnitude but many intensities.
What are P-waves and S-waves?+
P-waves (primary) are fast compressional waves that arrive first and do little damage. S-waves (secondary) are slower shear waves that shake the ground side to side and cause most of the damage. Surface waves are slowest and largest. The delay between the P and S arrivals tells you how far away the earthquake was.
How much more energy is a magnitude 7 than a magnitude 6?+
About 32 times more energy per whole step on the magnitude scale (10^1.5). So a magnitude 7 releases ~32× the energy of a 6, and a magnitude 8 releases ~1,000× the energy of a 6.
Why does earthquake depth matter?+
For the same magnitude, a shallow earthquake shakes the surface much harder because its energy has less distance to travel. Deep earthquakes (hundreds of km down) spread their energy over a wider area and usually feel weaker at the surface.
Can earthquakes be predicted?+
No — there is no reliable way to predict the exact time, place and size of an earthquake. Scientists instead forecast long-term probabilities and map seismic hazard, and issue rapid alerts in the seconds after a rupture begins.