Seismic Slip Dynamics in Subduction Zones

Seismic slip in subduction zones encompasses a spectrum of fault movements at convergent plate boundaries, ranging from abrupt rupture during megathrust earthquakes to gradual, transient displacement known as slow slip. The interplay of frictional properties, pore-fluid pressure and structural heterogeneity along the plate interface governs whether stress is released seismically or aseismically. Fluid migration through damaged zones in the overriding plate can weaken fault zones and facilitate slow slip, while variations in rigidity and fault geometry influence up-dip rupture propagation and tsunami potential. Advances in seafloor geodesy and seismic imaging are now resolving slip processes across a wide depth range, illuminating the mechanisms of earthquake nucleation, the distribution of slow earthquakes and the conditions that lead to large near-trench slip. Understanding these dynamics is critical for assessing seismic hazard, constraining the physics of faulting and improving early warning systems for tsunamigenic events.

Research from Nature Portfolio

High-resolution seismic velocity models off Kyushu have revealed kilometre-scale low-velocity conduits in the upper plate that channel fluids from the plate boundary, correlating with the spatial distribution of slow earthquakes and indicating that fluid drainage patterns exert a primary control on seismic slip behaviour. Investigations in the Nankai trough using seafloor observatories have demonstrated that shallow very-low-frequency earthquakes and slow-slip events originate from the same fault patches and share nearly identical moment-release histories, suggesting that low-frequency signals represent fluctuations within a broader slow-slip process. Analysis of the 2014 Iquique Mw 8.2 rupture has identified months-long accelerations in both seismic and aseismic slip preceding the mainshock, highlighting a transition zone where fast and slow slip modes interact to nucleate large megathrust earthquakes.

Seismic Slip Dynamics in Subduction Zones publication trend

The graph below shows the total number of articles in seismic slip dynamics in subduction zones across all publications each year (not limited to Nature Index journals).

Technical terms

Subduction zone: A region where one tectonic plate descends beneath another, forming a convergent plate boundary prone to seismic and aseismic slip.

Seismic slip: Sudden rapid displacement along a fault plane that radiates seismic waves and generates an earthquake.

Slow-slip event (SSE): Transient fault slip occurring over days to months that releases strain without generating high-frequency seismic waves.

Very-low-frequency earthquake (VLFE): A seismic event dominated by energy at periods of tens of seconds, often associated with slow slip on the plate interface.

GNSS-Acoustic geodesy (GNSS-A): A technique combining satellite navigation and underwater acoustics to precisely measure seafloor movements and infer fault slip.

References

1. Upper-plate conduits linked to plate boundary that hosts slow earthquakes. Nature Communications (2023).
2. Shallow very-low-frequency earthquakes accompany slow slip events in the Nankai subduction zone. Nature Communications (2018).
3. Accelerated nucleation of the 2014 Iquique, Chile Mw 8.2 Earthquake. Scientific Reports (2016).
4. Centimeter-level-precision seafloor geodetic positioning model with self-structured empirical sound speed profile. Satellite Navigation (2023).
5. Possible large near-trench slip during the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake. Earth, Planets and Space (2011).
6. Short-term slow slip events along the Ryukyu Trench, southwestern Japan, observed by continuous GNSS. Progress in Earth and Planetary Science (2014).