© Angelo_Giordano/PixabayScientists have found global earthquake sequences tend to occur in clusters -- outbursts of seismic events separated by long but irregular intervals of silence.
Previously, scientists and their models have theorized that earthquake sequences happen periodically or quasi-periodically, following cycles of growing tension and release. Researchers call it the elastic rebound model. In reality, periodic earthquake sequences are surprisingly rare.
Instead, scientists found global earthquake sequences tend to occur in clusters -- outbursts of seismic events separated by long but irregular intervals of silence.
The findings, published this week in the journal Bulletin of the Seismological Society of America, suggest large earthquakes increase the probability of subsequent seismic events.
Previous models failed to account for the interconnected nature of global fault systems. Seismic event don't occur in isolation. Each major quake alters the dynamics of other fault systems.
While the research suggests large quake sequences are "burstier" than previously thought, they remain as unpredictable as ever. The gaps between bursts are irregular, making it exceedingly difficult to anticipate the next cluster.
"Mathematically described as the devil's staircase, such temporal patterns are a fractal property of nonlinear complex systems, in which a change of any part -- e.g., rupture of a fault or fault segment -- could affect the behavior of the whole system," scientists wrote in their paper.
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