Why are Hawaiian eruptions less dangerous than Plinian eruptions?

Hawaiian eruptions use low-viscosity basaltic magma — gas escapes easily, producing gentle lava flows rather than explosive blasts.

What makes pyroclastic flows so deadly?

They're superheated clouds of gas, ash, and rock fragments traveling at 100+ km/h at temperatures up to 700°C — impossible to outrun.

Pro 🔒~20 min

Volcano Eruption Types

Effusive vs explosive eruptions, magma viscosity, and volcano shapes

How it works

Volcanic eruption style is primarily determined by magma viscosity and gas content. Basaltic magma (low SiO₂, ~50%) has low viscosity, allowing gas to escape easily — producing gentle effusive eruptions with lava flows (Hawaii-type shield volcanoes). Andesitic magma (intermediate SiO₂, ~60%) produces moderate explosive eruptions (Strombolian/Vulcanian). Rhyolitic magma (high SiO₂, ~70%) is extremely viscous, trapping gas until pressure builds to catastrophic levels — producing violent explosive eruptions with pyroclastic flows and ash columns (Plinian, like Mt. St. Helens). Temperature also matters: hotter magma is less viscous. Water content reduces viscosity but increases explosive potential as it flashes to steam during eruption.

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Step-by-step

Select a magma type and adjust gas content and temperature.
Press Erupt to simulate the volcanic eruption.
Compare the eruption style, height, and products for different combinations.

Key formulas

$\eta \propto e^{E_a / RT} \cdot f(\text{SiO}_2, \text{H}_2\text{O})$ Magma viscosity depends exponentially on temperature and silica/water content

Frequently asked questions

Why are Hawaiian eruptions less dangerous than Plinian eruptions?: Hawaiian eruptions use low-viscosity basaltic magma — gas escapes easily, producing gentle lava flows rather than explosive blasts.
What makes pyroclastic flows so deadly?: They're superheated clouds of gas, ash, and rock fragments traveling at 100+ km/h at temperatures up to 700°C — impossible to outrun.