Which type of underground magma formation is usually dome shaped?

The correct answer should be calderas

They are formed when magma erupts rapidly and with high intensity which breaks the structural support of the volcano which goes down towards the magma chamber. This makes it look like a dome because the volcano is falling in towards the magma.

Lave-dome in underground magma formation is usually in dome shape.

Explanation:

A lava dome is a type of crater that is circular and forms when eruption of magma is slow later forming a pile around the vent. The volcanic eruption of this type of lava doesn't flow a great distance due to its thickness and stickiness but it forms a pile.  

The thickness and slow movement are caused by the high silica content or by degassing of the fluid magma. Lava domes volcanoes are typically found on the convergent boundaries. Rocks formed from the eruptions include basalt, dacite, rhyolite, etc.

The answer is the magnetosphere.

Themes; subfields is the answer