Corals grow at water depths from a few tens of meters to as shallow as low tide level. When a tectonic event raises a coral in shallow water above or below its normal zone, the coral acts as a living tide gauge by growing in a pattern that records the event. Annual layers within the coral record when the event occurred.

The coral head the boy is standing on was raised 2.5 meters during one earthquake event in April 2007, in the Solomon Islands, near Australia. It has since died and has now become a permanent record of the earthquake.

Key contact persons:
Paul Mann (e-mail: paulm@ig.utexas.edu)
Fred Taylor (e-mail: fred@ig.utexas.edu)

Image Credits: Paul Mann, Fred Taylor.

We can use radiometric dating, such as Carbon-14, on the corals to get a time line of tectonic activity.