MAGMA PATHWAYS, CALDERAS, AND PIT CRATERS -- At a Glance

Lesson at a glance:
Students will trace the path that magma takes from the mantle to the surface and learn how calderas and pit craters form.

Key Concepts:

Melting in the Hawaiian hot spot generates magma that ascends through conduits to the surface. The magma accumulates in a shallow reservoir beneath the summit of the volcano. Magmatic pressure around the shallow reservoir produces fractures. Magma travels through the fractures to make tabular bodies of magma or rock called dikes. Eruptions result when dikes reach the surface. Dikes also extend down rift zones to make flank eruptions.

Calderas and pit craters are common landforms on Hawaiian shield volcanoes. Calderas and pit craters are topographic depressions that develop when magma near the surface is erupted or removed. Calderas are located at the summit of the volcano and are larger than pit craters. Calderas can include one or more vents. Craters can form within or near the summit caldera or along rift zones of the volcano.

Lesson Outcomes:

The students will:
    1. Trace the path of magma from origin to eruption
    2. Compare and contrast calderas and pit craters
    3. explain how calderas and pit craters form.



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