Assertion: volcano's magma | /r/Causes | volcanic eruptions
Facets:
Source sentences:
text: Volcanism is caused by magma, which either rises directly to the earth's surface from the upper regions of the earth's mantle or, in the majority of cases, gathers in a magma chamber, several tens of kilometres deep, at the base of the earth's crust, from which magma rises at irregular intervals and causes volcanic eruptions.
text: The magma then escapes through vents in the Earth’s crust, causing volcanic eruptions.