Eruption Types & Volcano Shape

Question 1

Volcano X erupted very runny lava with little trapped gas for many years, then had one short blast that sent out a cloud of ash. Volcano Y has erupted thick, bubbly magma many times. Which volcano is more likely to have a steep, cone‑shaped mountain?

Accepted Answer

Volcano Y

Answer

Both would look the same

Answer

Neither; volcano shape doesn’t depend on eruption style

Answer

Volcano X

Question 2

A volcano that has broad, gently sloping sides most likely results from which type of eruption?

Accepted Answer

An effusive eruption that releases thin, runny lava

Answer

An effusive eruption that releases thick, sticky magma

Answer

An explosive eruption that blasts thick, gas‑rich magma

Answer

An explosive eruption that releases thin lava

Question 3

During a school trip, Maya watches two volcanoes erupt. Volcano Aqua sends out lava that spreads thinly across the ground and only a little steam rises. Volcano Spike erupts with a loud blast that throws up thick clouds of ash and rock fragments. Which explanation correctly describes why the two volcanoes erupt so differently?

Accepted Answer

Aqua’s magma is thin and contains very little trapped gas, so it flows gently; Spike’s magma is thick and holds lots of gas, so it erupts explosively.

Answer

Aqua’s magma is thin but has a lot of gas, while Spike’s magma is thick but has no gas at all.

Answer

Aqua’s magma is thick and gas‑rich, causing a gentle flow; Spike’s magma is thin and gas‑poor, causing a violent blast.

Answer

Both volcanoes have the same type of magma, but Aqua erupts at night while Spike erupts during the day, making the eruptions look different.

Try three questions

Volcano X erupted very runny lava with little trapped gas for many years, then had one short blast that sent out a cloud of ash. Volcano Y has erupted thick, bubbly magma many times. Which volcano is more likely to have a steep, cone‑shaped mountain?

A volcano that has broad, gently sloping sides most likely results from which type of eruption?

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