Time variations in the chemical and isotopic composition of fumarolic gases at Hakone volcano, Honshu Island, Japan, over the earthquake swarm and eruption in 2015, interpreted by magma sealing model

Earth, Planets and Space

Table 4 Parameters used in the model calculation of vapor phase in terms of isotopic ratio of H₂O and CO₂/H₂O ratio

Parameter	Value	Unit
Temperature of magmatic gas	900	°C
Temperature of local meteoric water	15	°C
Temperature of vapor and thermal water	265	°C
Temperature of vapor condensation	100	°C
δD of H2O in magmatic gas	− 10	‰ to SMOW
δ¹⁸O of H2O in magmatic gas	8.0	‰ to SMOW
δD of H2O in local meteoric water	− 51	‰ to SMOW
δ¹⁸O of H2O in local meteoric water	− 8.5	‰ to SMOW
CO2/H₂O ratio of magmatic gas (high)	0.013	Molar ratio
CO2/H₂O ratio of magmatic gas (low)	0.0045	Molar ratio