Dikes and sills may form when magma rises and bulges Earth's crust.
The opening in the earth crust which magma rise to the surface are Volcanoes
Magma rises through the crust above it because of pressure and depending on the magma (Pahoehoe or Aa). Pahoehoe is thin and runny and pours outside of the crust but, Aa is think and chunky and it can not pour out of a crack in the crust. It is more likely to blow out.
eruption
A divergent boundary is formed when magma rises to the surface and new crust is formed. This process occurs at mid-ocean ridges where tectonic plates move away from each other, allowing magma to fill the gap and solidify into new oceanic crust.
Magma rises through the crust due to differences in density between the magma and surrounding rock. Magma is less dense than the solid surrounding rock, so it moves upwards through cracks and fractures in the crust. As it rises, magma can also be driven by pressure differences and heat from the Earth's mantle.
magma comes from the outer core and when an earthquake or something happends, a crack froms and the pressure of lava shoots up like a geyser.
The process that makes new crust when the sea floor moves apart and magma rises up is called seafloor spreading. Magma from the mantle rises to the surface at mid-ocean ridges, cools, and solidifies to form new crust as the tectonic plates move apart. This process contributes to the continuous growth of the seafloor and the expansion of the ocean basins.
Magma if it's beneath the crust, lava if it's above the crust
Seafloor Spreading
It is called a volcano.
sea floor spreading
Volcanoes