Where is tephra located?

Tephra are fragments of rock and lava expelled from a volcano during an eruption. They can range in size from tiny ash particles to large blocks and bombs. In general, tephra are the smallest of the five categories of volcanic projectiles, which also include lava bombs, blocks, lapilli, and volcanic ash. Tephra are not unique to a specific tectonic setting but is produced during different eruption types across volcanoes around the world.