Magma is lighter than the rock around it and collects in a chamber. New magma raises the pressure: dP/dt = K · Qin / V (K = effective stiffness of magma + rock, V = chamber volume, Q_in = magma supply). With K = 1 GPa, V = 5 km³, Q_in = 0.01 km³/yr the pressure rises 2.0 MPa per year and reaches a rock strength of 10 MPa in 5 years Model Typical K 1-10 GPa. Not modelled: dissolving gas, plastic rock, several chambers.

• Tremors. Cracking rock makes small earthquakes. The Gutenberg-Richter law log₁₀ N = a − b·M (b = 1) says there are 10× fewer quakes for each +1 magnitude Typical.
• Speeding up. Before many eruptions the tremor rate grows like Ω(t) = A / (tf − t) (Voight 1988), so 1/Ω falls on a straight line that hits zero at the eruption day tf Model.
• Tilt and uplift. A swelling chamber lifts the ground: uz(r) = (1 − ν) ΔV / π · d / (d² + r²)3/2 (Mogi 1958). With ν = 0.25, ΔV = 10⁶ m³, d = 3 km the ground above rises 2.65 cm. Tilt is the slope of that bulge Model.
• Gas. Rising magma releases SO₂; the curve is drawn from a simple rule Visual.

The Forecast fits a straight line to 1/Ω (blocks of 5 tremors, minus the normal background) and finds where it reaches zero. The grey band is ± one standard error from the scatter. In our test (120 simulated runs, A = 50/day, t_f = 100 d, data to day 90) the median estimate was within a few percent, yet 1 run in 5 was off by more than 10%. Real volcanoes are messier. Early forecasts are wide; they tighten as the eruption nears.

Lava is a thick liquid. On a slope its mean speed is u = ρ g h² sin α / (3 η) (Jeffreys). With ρ = 2600 kg/m³, h = 1 m, α = 5°, η = 1000 Pa·s this is 0.74 m/s Model. The flow is simulated on the island grid with heat loss by radiation; a 1 m slab cools from 1400 K to 1000 K in 3.45 h (1/T³ = 1/T₀³ + 3εσt/ρch; the crust cools much faster, the inside slower). Cooled lava is new land: area = volume / thickness, and the ledger keeps Σ(area × thickness) equal to the erupted volume.

The column height grows with the eruption rate V (dense-rock m³/s): H = 2.00 · V0.241 km (Mastin et al. 2009). V = 1000 m³/s gives 10.6 km Typical. The drawn plume leans with the wind Visual.

Radius 6371 km: crust (~7 km under oceans), mantle to 2891 km depth, liquid outer core, solid inner core of radius 1221.5 km. 3480 − 1221.5 = 2258.5 km of outer core; the four layers sum to 6371 km. The crust is drawn thicker than real Visual.

One island, one chamber, no gas chemistry, no rain, no sea waves from eruptions. Alert levels are a simple generic scale, not any country's official one. The people are safe in every scenario: the game measures how much time the ferry had.