Another notable oceanic strike-slip event near a subduction zone is the 2012 magnitude 8.6 Indian Ocean strike-slip earthquake. The 2018 Gulf of Alaska earthquake was a strike-slip event, which is an unusual occurrence in ocean crust near subduction zones. “The viscoelastic stress transfer will speed or delay the trigger events, but other parameters such as the elapsed time since the last event and the interseismic stress rate are also crucial in an earthquake cycle,” said Huang. Huang and colleagues note, however, that this type of stress transfer isn’t the only factor that would influence the timing between megathrust events and triggered earthquakes. The closest distance between the two rupture zones is about 100 kilometers. Huang and colleagues developed a viscoelastic spherical model to include the topographical relief and variations in viscosity in the Alaskan region, to calculate how stress might be transferred from the site of the 1964 earthquake to the 2018 rupture over time.īased on this model, the researchers concluded that viscoelastic stress relaxation by the 1964 earthquake transferred through the crust could have created stresses that exceeded the amount needed to trigger the 2018 rupture fault. (Toothpaste and play dough are common examples of materials that demonstrate viscoelastic properties.) The lower crust and upper mantle are viscoelastic materials, deformed by the application and relaxation of stress during earthquakes.

The model developed by Luyuan Huang at China’s National Institute of Natural Hazards and colleagues could help seismologists better understand the stress interactions between megathrust earthquakes that take place at tectonic plate boundaries, like the magnitude 9.2 event in 1964, and interplate earthquakes like the magnitude 7.9 quake in 2018. 28 January 2022–Stress transferred through the crust and upper mantle after the 1964 Great Alaska Earthquake may have been enough to trigger the 2018 Gulf of Alaska earthquake, according to a new study published in the Bulletin of the Seismological Society of America.

Alaska quake