Location of magma in the surface of the earth is affected by the arrangement of geomaterial in the interior of the earth and places near the ridges see a large volcanic eruption and have high rising mountains and all this is due the presence of magma inside the earth and bulge in the volcanoes can clearly show its presence.
Generally, magma is composed of silica, iron and magnesium and calcium contents and has a high gas content the explosive nature of the volcanoes is a significant factor in the thickness of the lava.
The viscosity of lava and magma is dependent on the long-lasting temperature and pressure as high-density lava can be found basalt then Andesite and then Rhyolite with the presence of water and carbon contents.
Felsic lava is more viscous and erupts more violently than the mafic lavas which erupt effusively thus have a difference in the characteristic formation of volcanoes.
