Coulomb stress transfer

Coulomb stress transfer is a seismic-related geological process of stress changes to surrounding material caused by local discrete deformation events. Using mapped displacements of the Earth's surface during earthquakes, the computed Coulomb stress changes suggest that the stress relieved during an earthquake not only dissipates but can also move up and down fault segments, concentrating and promoting subsequent tremors. Importantly, Coulomb stress changes have been applied to earthquake-forecasting models that have been used to assess potential hazards related to earthquake activity.

Coulomb stress change

The Coulomb failure criterion requires that the Coulomb stress exceeds a value σ<sub>f</sub> defined by the shear stress τ<sub>B</sub>, normal stress σ<sub>B</sub>, pore pressure p, and coefficient of friction μ of a failure plane, such that

<div class="center" style="width: auto; margin-left: auto; margin-right: auto;"> These effects are incorporated into an effective coefficient of friction μ’, such that

Earthquake stress triggering

Stress triggering describes the responsive rupturing of faults from increases in Coulomb stress caused by exogenous deformation events.

Earthquake prediction

Although no official Coulomb stress transfer prediction model is being used by government agencies, geologic surveys often analyze earthquake threats using Coulomb stress theory. As an example, the last of the previous thirteen earthquakes along Turkey's North Anatolian Fault, near the town of Duzce, was successfully predicted by local geologists before the rupture occurred. This allowed for engineers to evacuate unstable structures and limit significant damage.

2005 Nias–Simeulue earthquake – triggered by the 2004 Indian Ocean earthquake 3 months prior
2007 Kuril Islands earthquake – normal faulting from an outer rise area next to where the 2006 Kuril Islands earthquake nucleated
2012 Indian Ocean earthquakes
2018 Sulawesi earthquake – inferred to have been related to the 1996 Sulawesi earthquake
2023 Turkey–Syria earthquakes

References

External links

Earthquake Hazard Program – Coulomb 3 software – USGS