A volcanic eruption typically proceeds through three identifiable phases. In the precursor phase, magma rises through fractures, producing small earthquakes and ground deformation that scientists can measure. The main phase follows: gas-rich magma reaches the surface and erupts explosively or as flowing lava. Finally, in the post-eruptive phase, activity diminishes while subsurface pressure equilibrates.
Which choice best describes the structure of the text?
- A
It defines a problem and provides its solution.
- Bcheck_circle
It outlines a chronological sequence of stages and characterizes each.
- C
It refutes a misconception about earthquakes.
- D
It compares two different volcanic systems.
Explanation
The text walks through three sequential phases. B is correct.