Stress Interaction and Earthquake Triggering Mechanisms

Earthquake triggering arises when stress perturbations caused by one rupture alter the likelihood of failure on neighbouring faults or within volcanic and fluid‐bearing systems. Static stress transfer refers to the permanent change in shear and normal stresses imparted by fault slip, whereas dynamic stress triggering relates to transient stress oscillations from passing seismic waves. Both mechanisms can advance or delay failure, producing clusters of earthquakes, aftershocks and occasionally volcanic unrest. Coulomb failure stress changes serve as a unifying metric, combining shear stress increases and unclamping effects to predict fault stability. Regions of decreased stress, known as stress shadows, may experience reduced seismicity for extended periods. Models that integrate rate-and-state friction laws capture the time-dependent evolution of fault strength following stress change, yielding forecasts of aftershock decay and seismicity rate variations. Globally, these processes inform seismic hazard assessments by identifying faults brought closer to critical stress thresholds and by mapping zones of heightened post-earthquake risk for both tectonic and volcanic systems.

Research from Nature Portfolio

Recent studies have refined our understanding of how large earthquakes influence deep fluid systems and volcanic conduits. A novel classification framework for earthquake-triggered volcanic unrest outlines the roles of magma viscosity, degassing regime and hydrothermal activity in determining susceptibility to seismic perturbations. This approach reveals that even distant, moderate-magnitude events can instigate degassing or eruption only when pre-existing volcanic systems are primed by high fluid pressure or open pathways. Complementary work on subduction environments has shown that coseismic normal stress increases of tens of bars along feeder faults can dilate fault-controlled conduits, mobilising greenhouse gases and potentially provoking episodic fluid expulsion. Elastic strain relaxation following a megathrust rupture further modifies permeability, with implications for seafloor seepage and subseafloor fluid budgets.

Stress Interaction and Earthquake Triggering Mechanisms publication trend

The graph below shows the total number of articles in stress interaction and earthquake triggering mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Coulomb failure stress (ΔCFS): Combined measure of shear stress increase and effective normal stress decrease on a fault plane that indicates how close the fault is to failure.

Static stress transfer: Permanent alteration of the stress field surrounding a rupture, adjusting the loading conditions on adjacent faults.

Dynamic stress triggering: Transient stress oscillations produced by passing seismic waves that can advance or delay failure on faults or volcanic conduits.

Stress shadow: Region in which stress is reduced following an earthquake, leading to a temporary suppression of seismic activity.

Rate-and-state friction law: Constitutive model describing how fault strength evolves with slip rate and the history of contact conditions, crucial for forecasting post-earthquake seismicity rates.

References

1. “Aftershock Faults” and What They Could Mean for Seismic Hazard Assessment. The Seismic Record (2023).
2. A review framework of how earthquakes trigger volcanic eruptions. Nature Communications (2021).
3. Using the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake to test the Coulomb stress triggering hypothesis and to calculate faults brought closer to failure. Earth, Planets and Space (2011).
4. Rate/state Coulomb stress transfer model for the CSEP Japan seismicity forecast. Earth, Planets and Space (2011).
5. Seismic loading of fault-controlled fluid seepage systems by great subduction earthquakes. Scientific Reports (2019).
6. Remotely triggered seismicity in north China following the 2008 Mw 7.9 Wenchuan earthquake. Earth, Planets and Space (2010).