What factors affect lava formation?

Lava formation is primarily influenced by temperature, pressure, composition of the magma, and the presence of volatiles such as water and gases. The temperature determines the viscosity of the magma, while pressure affects the magma's ability to rise to the surface. Composition determines the type of lava flow produced, whether it be mafic, intermediate, or felsic. The presence of volatiles can lead to explosive eruptions by contributing to increased pressure within the magma chamber.