AUSTIN (KXAN) — With more than 500,000 earthquakes each year, scientists are hard at work trying to predict them and their intensity. A new study published this week in the journal Science may help us do just that.
Demian Saffer and Srisharan Shreedharan with the University of Texas were taking a closer look at a basic physics problem: Why does it take more effort to move a heavy box when it is still than it does to keep it moving?
According to the researchers, they discovered fault lines that are slow to “heal” after a previous earthquake are more likely to move harmlessly, causing “slow earthquakes”. This is like the heavy box that is still in motion.
While faults with soil that “heals” quickly is more likely to cause a damaging quake. This is much like the heavy box at a standstill.
Frictional “healing”, according to the paper, is the ability of a material to re-strengthen over time.
To test their theory, the pair and their research team looked at a fault line off the coast of New Zealand, which lies in the Ring of Fire, one of the most active tectonic places on Earth. The fault has clay-rich rocks, which they believed were slow to heal.
“Slow-motion” earthquakes are well documented along the fault, according to the paper.
Testing an earthquake model
Using their theory and soil samples, the team developed a computer model. The model predicted that slow earthquakes would happen in the area every few years.
“With the right samples and field observations we can now start to make testable predictions about how big and how often large seismic slip events might occur on other major faults, like Cascadia in the Pacific Northwest,” Saffer, who is also director of UT’s Institute for Geophysics at the Jackson School of Geosciences, said in a press release.
Saffer said that by gathering soil samples along faults, they may be able to determine how destructive future earthquakes may be in the area.
What are slow earthquakes?
As opposed to typical earthquakes, which last minutes, slow earthquakes can take several hours. Compared to regular earthquakes, they are relatively quiet.
According to Smithsonian Magazine, slow earthquakes were discovered in the past 20 years. People believed they were a prelude to massive earthquakes, but that may not be the case.
The research was funded by the University of Texas Institute for Geophysics, the International Ocean Discovery Program, and New Zealand’s GNS Science.