Tsunami Travel-Time & Wavefront Map (2D)

Rupture

Bottom shift 7.0 m

Epicenter distance from coast 400 km

Bathymetry

Deep-ocean depth 4200 m

Shelf width 60 km

Live Readout

Elapsed time

0.0 min

Front distance

0 km

Front speed

0 m/s

Coast amplitude

—

ETA at coast

0.0 min

Countdown

0.0 min

How it works

Tsunami warning centers don't integrate the full shallow-water PDE to publish an ETA — they solve the eikonal equation |∇T|·c(x,y) = 1 for the travel-time field T(x,y), using local wave speed c = √(g·h) from the depth map h(x,y). This lab solves that same equation on a 2D grid with the Fast Sweeping Method (Godunov upwind stencil, four alternating sweep directions):

a = min(T[i-1,j], T[i+1,j])
b = min(T[i,j-1], T[i,j+1])
f = 1/c(i,j)          (slowness)
if |a-b| ≥ f·dx:  T = min(a,b) + f·dx
else:             T = (a+b+√(2f²dx²-(a-b)²)) / 2

The depth map has a deep-ocean basin, a continental shelf that shoals toward the coast, and a fixed seamount that locally slows the wave — the wavefront visibly bends (refracts) around it, exactly as real bathymetry bends real tsunami fronts. Amplitude is set by Green's Law (energy-flux conservation as depth decreases, H ∝ h^-1/4) combined with cylindrical geometric spreading from the point source, which is why the leading pulse grows as it climbs the shelf even though it's losing energy to spreading everywhere else.

Color field — the traveling pulse's height, sampled from the precomputed travel-time grid, not a re-simulated PDE each frame.
Front distance / speed — measured along the straight epicenter→coast line, speed from the local c=√(g·h) at the front.
ETA — the eikonal solver's own T value at the nearest coastal point; recomputed whenever bathymetry or the epicenter moves.

Wave height (eikonal + Green's Law) Epicenter / coast marker Seamount (refracts the front)