How Volcanoes Work
What causes the formation of volcanoes? Before humans understood that the center of the Earth was made of
molten iron, scientific hypotheses pointed to chemical (1) reactions in superficial layers of magma, thinking
they had solved the mystery. Through modern geology, humans have a clearer--though hardly
complete--understanding of the mechanism magma flow, and they can analyze the vibrations of the earth to warn
of upcoming eruptions. The increasing (2) vibration from the plates, causes monitors to alert surrounding
Most volcanoes are the result of magma flowing out of the surface of the earth and hardening, usually
near a subduction zone. Two tectonic plates (3) collide it causes one to stack on top of the other. Then the
seabed rock melts to form new, low-density magma.
This (4) process named, magma flow, is red-hot and eventually penetrates unstable pockets of the Earth’s surface.
Revealed at Earth’s (5) surface, and some magma will form a new volcano or add more mass to an existing one.
Not all volcanoes are formed at continental boundaries, however.
Hotspot volcanoes form by a different mechanism. In the 1960s, scientists (6) wondered, if they could explain volcanoes
that are not at a plate boundary? The probable
explanation is a hotspot, which is a fixed point beneath the Earth’s crust where a narrow plume of magma rises into the crust
where a narrow plume of magma rises into the crust and appears at the surface as a continental volcano or a
(7) Geologic processes themselves, are slow, so research must include the study of ancient
human accounts of eruptions and layers of rock millions of years old. In general, eruptions seem to occur
every several hundred or even thousand years, and many volcanoes seem to be completely dormant, or unlikely to
No scientists or (8) experts fully proving whether these volcanoes will erupt again.
Predicting volcanic eruptions is not an exact science, and only within the briefest geological moment can
people be warned to evacuate. Since volcanoes remained a mystery, a number of geologists--in addition to
other scientists-- studied them, (9) building a greater understanding of their causes and effects.
Understanding the mechanisms of the earth’s interior and continuing to study volcanoes will advance the
development of reliable early warning systems for dangerous eruptions. Volcanoes--both feared and revered for
their beauty and awesome destructive power--show that humans have much more to learn about the planet (10)
Earth, for they contain endless mysteries.
Created for Albert.io, 2016.
(1) reactions in superficial layers of magma,