An international group of researchers uncovered new details on one of nature's "earthquake gates" while studying New Zealand's Alpine Fault, a new study published in Nature Geoscience reveals.
"An earthquake gate is like someone directing traffic at a one-lane construction zone. Sometimes you pull up and get a green 'go' sign, other times you have a red 'stop' sign until conditions change," UC Riverside geologist Nicolas Barth explained in a press statement.
The Southern California Earthquake Center (SCEC) recently made earthquake gates a high research priority as they can help to shed light on future earthquake behaviors.
The researchers on the new study determined that the gate has an approximately 75 percent chance of producing a damaging earthquake within 50 years. Their models also suggest the next earthquake has an approximately 82 percent chance of being magnitude 8 or larger.
Combining findings from the evidence of past earthquakes with computer simulations run by geophysicists, the researchers uncovered new findings on the expected behavior of future earthquakes on the Alpine Fault.
"Big earthquakes cause serious shaking and landslides that carry debris down rivers and into lakes," said lead author Jamie Howarth, Victoria University of Wellington geologist. "We can drill several meters through the lake sediments and recognize distinct patterns that indicate an earthquake shook the region nearby. By dating the sediments, we can precisely determine when the earthquake occurred."
100,000 years of computer simulated earthquakes
The researchers compared data of the 20 most significant earthquakes to occur over the past 4,000 years with a 100,000-year record of computer-generated earthquakes.
"The simulations show that a smaller magnitude 6 to 7 earthquake at the earthquake gate can change the stress and break the streak of larger earthquakes," Barth said. "We know the last three ruptures passed through the earthquake gate. In our best-fit model the next earthquake will also pass 82% of the time."
Artificial intelligence (AI) has been a great boon for the field of geophysics in recent times, allowing advanced models to help predict future Earth behaviors. As an example, the world's fastest computer, Fugaku, is currently being used to predict tsunami patterns in Japan following earthquakes. Stanford researchers, meanwhile, are developing AI for fine-tuned real-time seismic readings.
Research focused into earthquake gates has the potential to allow increasingly detailed predictions and forecasts of earthquakes. These would not only allow us greater insight into the period in which an earthquake might occur, but also the strength of the oncoming earthquake.