Deep quakes occur in a narrow band between two colliding tectonic plates.
The band moves southeast as it approaches the surface.
At the surface, quakes blossom like a flower across the entire state.
These patterns reveal plate boundaries known as the Aleutian Megathrust and the Yakutat Block.
With only one month of data from the USGS,
you're seeing effects of the Pacific plate as it migrates north, plunging underneath the North American plate.
You can interact with the map by dragging the brush on the lower scatterplot with your mouse or finger.