Physical parameters (12): viscosity of magma
Magma: very large range of viscosities
Basalts are less viscous
Basalts leads to gentle eruptions
Consequences:
Effusive activity: basalts 10-2 to 1 m/s -- lava domes: 10-5 to 10-4 m/s
viscosity is important
Explosive activity: velocity is
independant of lava chemistry
Plinian
column: 200 - 300 m/s