Figure 4 from paper by Preuss et al. [2019]
The fault tip propagates from point S1, when growth is aseismic, to S2, when growth is co-seismic. The contours around the fault (and grey shading in [b] & [c]) show the plastic strain. [b] and [c] show snapshots of the stress state near the fault tip at stage S1 and S2, respectively. Red lines with circle indicate local direction of principal compression and red contours indicate magnitude. At stage S2 of co-seismic fault propagation the local principal stress directions are altered from the interseismic pattern of at S1, which impacts propagation direction. Boxes and points demonstrate sampling distribution for model results plotted in the paper. Credit: Preuss et al. [2019], Figure 4
Source: Journal of Geophysical Research: Solid Earth

Using an innovative approach, Preuss et al. [2019] provide insights into the propagation of faults both between and during earthquakes. By using a model set-up that joins long-term elasto-viscous-plastic deformation with earthquake rupture simulation, the authors are able to study faulting from fault initiation through stages of both aseismic growth between earthquakes and co-seismic growth during earthquakes. The innovative physics of the model permits the emergence of seismic slip after years of aseismic quasi-static fault growth.

These results shed insight into the potential development of fault bends, which are often observed along strike-slip faults. Because the angle of fault propagation changes as the fault slip speed evolves, cycles of earthquakes may produce a change in fault orientation along propagating faults. The findings of this study have interesting implications for the evolving behavior of active faults that are often decorated with bends, branches and secondary faults.

Citation: Preuss, S., Herrendörfer, R., Gerya, T. V., Ampuero, J.‐P., & vanDinther, Y. [2019]. Seismic and aseismic fault growth lead to different fault orientations. Journal of Geophysical Research: Solid Earth, 124.

—Michele Cooke, Associate Editor, JGR: Solid Earth

Text © 2019. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.