Eruption plume and ballistic bombs (2D)Switch to 3D
Checks (measured vs predicted)
The science

The height of an eruption column scales with the heat and mass delivered at the vent. Mastin et al. (2009) fitted observed plumes with H = 2.00 V0.241, H in km above the vent and V the dense-rock-equivalent volume flux in m3/s. A tenfold increase in flux therefore raises the plume only by about 74%. Mass flux is V times a magma density near 2500 kg/m3.

Volcanic bombs (blocks thrown from the vent) follow projectile motion with quadratic drag in an exponential atmosphere: m dv/dt = m g − ½ ρ(z) Cd A |v| v, ρ(z) = 1.225 e−z/8500, Cd = 0.47 for a sphere, dense rock 2500 kg/m3. Small bombs lose range quickly; very large ones approach the vacuum parabola R = v² sin 2θ / g, which is checked numerically.

Simplifications: the column lean in the cross-section is schematic; no gas-thrust phase, no supersonic Cd rise, no spinning or fragmentation; bombs launched from the vent altitude over level ground. Educational physics, not a hazard map.