'Fault-finding' coral reefs can predict site of future earthquakes
Washington: In the wake of Japan disaster, the urgent question is where the next big earthquake will hit.
Geologist Prof. Zvi Ben-Avraham and his doctoral student Gal Hartman of Tel Aviv University have discovered that ‘fault-finding’ coral reefs could be a reliable indicator to predict the site of future earthquakes.
They are examining coral reefs and submarine canyons to detect earthquake fault zones.
Ben-Avraham and his team are developing a new method to determine what areas in a fault zone region are most at risk.
Using a marine vessel, they are surveying a unique geological phenomenon of the Red Sea, near the coastal cities of Eilat and Aqaba — but their research could be applied anywhere, including Japan and the west coast of the U.S.
The research details a ‘mass wasting’ of large detached blocks and collapsed walls of submarine canyons along the gulf region of the Red Sea. They believe the geological changes were triggered by earthquake activity.
“Studying fossil coral reefs and how they''ve split apart over time, we''ve developed a new way to survey active faults offshore by looking at the movement of sediment and fossil structures across them,” said Hartman.
“What we can''t say is exactly when the next major earthquake will hit. But we can tell city engineers where the most likely epicenter will be,” he added.
While geologists have been tracking underwater faults for decades, the new research uniquely tracks lateral movements across a fault line (a ‘transform fault’) and how they impact the sediment around them.
This is a significant predictive tool for studying the San Andreas Fault in California as well, said Hartman.
The researchers analysed the structure of the seabed and discovered active submarine canyons, mass wasting, landslides, and sediment slumps related to tectonic processes and earthquake activity.
“There are several indicators of seismic activity. The most significant is the location of the fault. Looking at and beneath the seafloor, we saw that the faults deform the upper sediments. The faults of the Red Sea are active. We managed to find some other faults too and now know just how many active faults are in the region. This should help make authorities aware of where the next big earthquake will strike,” said Hartman.
What made their study particularly unique is that they used the offset along linear structures, of fossil coral fringing reefs to measure what they call ‘lateral slip across active faults’.
The study is recently published in the journal Geo-Marine Letters.