jupitersterrain four

that certain territories may seem peaceful and dormant until another event triggers a large outburst of violence



21.26

 a spark or other source of heat could cause the contents to deflagrate

primitive melt 

As magma buoyantly rises it will cross the solidus-liquidus and its temperature will reduce by adiabatic cooling. At this point it will liquefy and if erupted onto the surface will form lava. Melting can also occur due to a reduction in pressure by a process known as decompression melting

The presence of volatile phases in a rock under pressure can stabilize a melt fraction