Corals can be of great help to scientists working out earthquake-frequencies dating back millions of years! And the Australian scientists are using these natural tools for charting the history of thousands-of-years old underwater earthquakes.
Extremely receptive to light, coral can record earth-shifts caused by earthquakes over time.
Doctor Mike Gagan, from the Australian National University (ANU) says,
This allows scientists to work out the frequency of earthquakes dating back millions of years.
What we’ve found is that when a coral goes up or down on the sea floor during an earthquake the carbon isotope record that we see in the skeleton also changes… If a coral comes up into shallower water depths the coral responds to the change in light intensity and then we can sample very finely along the growth axis of the coral and define the timing of that earthquake.
I guess it’s the underwater equivalent of tree-ring research where the corals have annual growth bands so we can count back the number of years.
But I guess different to tree-ring research we can analyze the chemistry of the coral skeleton very accurately – we can look at things like sea surface temperature and salinity and also changes in light intensity.
