Why a Crack Moves After an Earthquake 1. The Earth is still adjusting. After a big quake, the rocks underground may not have completely settled. Smaller aftershocks or continuous movement of tectonic plates can cause the crack to widen, rise, or shift slightly for days or even weeks. 2. It’s part of an active fault line. If that crack marks where two blocks of the Earth’s crust met and slipped, it’s a fault line — a zone of weakness that can move again during future quakes. 3. Ground deformation

These are the 5 deadliest volcanic eruptions in human history. | Insider Science

512K views · 9.9K reactions | In January 2022, one of the most powerful volcanic eruptions in recorded history rocked the Pacific islands of Tonga. Within minutes, tsunami waves crashed into the shores. These are stories of the survivors: | NOVA l PBS | Facebook