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:
- Trace the path of magma from origin to eruption
- Compare and contrast calderas and pit craters
- explain how calderas and pit craters form.