Terra Guard Simulator

Click the map to place the epicenter. Trigger a quake and watch P and S waves expand as perfect circles at true speeds (scaled by time exaggeration).

Press Trigger Earthquake to start.
Tip: click map = move epicenter • Ctrl+Click = add seismic station

Map style

Dark / Light tiles may show watermarks (provider now wants an API key). Streets, Satellite, Terrain are keyless.

1 · Source parameters

Magnitude (Mw)7.0 Depth (km)15 km · shallow

Lat

Lon

Origin date

Origin time

Epicenter = point on surface above hypocenter. Deeper quakes are felt wider but weaker directly above.

2 · True wave speeds (km/s)

P-wave

S-wave

Time exaggeration×1 Real P-waves cross 100 km in ~17 s — too slow to watch. Exaggeration multiplies simulated seconds per real second. Ring radius = speed × sim-time, so relative speeds stay exact.

P 6.0 S 3.5 km/s

3 · Run

Energy: —

How to read it

• Blue front = P-wave (fast, compressional, first to arrive, small shake).
• Red front = S-wave (slower, shear, stronger shaking). S−P time grows with distance.
• Fronts are perfect circles: radius = speed × sim-time — but each only appears once a station detects it.
• Intensity (MMI, Allen et al. 2012) lives on the station badges and the top-left banner — no map shading.
• Top-left banner = simulated EEW feed: early revisions are rough estimates, converging to final as more (simulated) data arrives.

NO SHAKING DETECTED