Table 2 Gas modelling inputs for an expected most likely future eruption (a 200 tons/day or 800 tons/day scenario) at Santorini

Vent elevation

113 m

From Pyle and Elliot, 2006

Exit temperature

1000 K

Typical temperature of magmatic gases from dacitic magma

Proportion of SO₂

5 %

As a proportion of erupted gas, the other gas being water

Gas exit velocity

10 m/s

Estimate made from typical values

Gas exit density

0.12 kg/m³

Density of water at 1000 K

Vent diameter

7 or 14 m

Given gas density and concentration, a 7 m diameter vent is required to emit 200 tons/day. To conserve mass, keeping temperature and velocity constant, an 800 tons/day emission requires a 14 m diameter

Albedo

0.25

Fraction of total incident solar radiation reflected by the surface (typical value for grassland used)

Bowen ratio

5

Net radiation at a surface (typical value for grassland used)

Surface roughness

0.15 m

Typical value for grassland used