 The internal extensional forces and isostatic loading generated by intruding magma volumes (either associated with the magma chamber or subsequent dyke and sill formation extending outward from that chamber), in conjunction with accumulation of erupted materials, contribute to the mass and slope of the forming edifice.It is the weight of the edifice exceeding its material strength, with the additional stresses of the magma inflating the internal regions of the edifice, that can generate the initial cracking around a developing volcanic summit.Additionally, tectonic activity such as normal faulting is also commonly associated with formation of rifts along volcanic flanks.