🌋 Caldera Formation

Drain the magma chamber beneath the cone. Once the roof loses enough support it fails along a ring fault and the summit subsides into a caldera basin — much wider than an ordinary crater.

Real Calderas

Magma Chamber Geometry

Roof depth 3.2 km

Chamber radius 3.0 km

Eruption / Withdrawal

Magma volume 100%

Post-Collapse

Fill caldera lake

Resurgent doming

Recharge 0%

Live Readouts

Magma left

100%

Subsidence

0 m

Basin diameter

0.9 km

Roof aspect (D/T)

0.97

Crater vs. caldera: a normal summit crater is an explosion/vent pit, tens to hundreds of metres across. A caldera forms when the chamber roof itself fails along a ring fault and drops — kilometres across. Crater Lake (Mt. Mazama, ~7,700 yr ago), Yellowstone, Santorini (Thera) and Krakatoa (1883) all formed this way.

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