News Earth Small earthquakes can have a big impact on the movements of major faults The little quakes can disrupt the growth of slow-slip events along megathrust faults Megathrust faults can generate some of Earth’s largest quakes. One example is the 2011 Tohoku earthquake, which rocked Japan and fomented a tsunami that devastated coastal areas, as shown. These same faults can also release immense amounts of seismic energy over days or weeks in harmless slow-slip events. enase/Getty Images By Nikk Ogasa 15 hours ago Seismic symphonies of minor earthquakes may affect grand movements on major faults. Small and distant earthquakes can disrupt the growth of slow-slip events — gradual fault movements that can release tremendous amounts of energy at gentle tempos, a new analysis of seismic data suggests. Reported in the May 16 Science Advances, the research shows that the more frequently small earthquakes occur near a fault’s slow-slip zone, the less synchronized the slipping becomes. Megathrust faults — massive fractures where one tectonic plate pushes under another — are notorious for hatching Earth’s most devastating temblors. These same faults can also slide steadily for days or weeks in slow-slip events while emitting faint vibrations called tectonic tremor. First identified around two decades ago, these softly humming events can shift stress on faults and may influence the timing of large, destructive earthquakes. But it’s not clear why these enigmatic events can grow for hundreds of kilometers along some faults while remaining restricted to small parts of others. Sign up for our newsletter We summarize the week's scientific breakthroughs every Thursday.