Journal cover Journal topic
Solid Earth An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 2.921 IF 2.921
  • IF 5-year value: 3.087 IF 5-year
    3.087
  • CiteScore value: 4.8 CiteScore
    4.8
  • SNIP value: 1.314 SNIP 1.314
  • IPP value: 2.87 IPP 2.87
  • SJR value: 0.993 SJR 0.993
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 38 Scimago H
    index 38
  • h5-index value: 36 h5-index 36
Preprints
https://doi.org/10.5194/se-2020-16
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/se-2020-16
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 25 Feb 2020

Submitted as: research article | 25 Feb 2020

Review status
A revised version of this preprint was accepted for the journal SE and is expected to appear here in due course.

Characteristics of earthquake ruptures and dynamic off-fault deformation on propagating faults

Simon Preuss1, Jean Paul Ampuero2, Taras Gerya1, and Ylona van Dinther3 Simon Preuss et al.
  • 1Geophysical Fluid Dynamics, Institute of Geophysics, Department of Earth sciences, ETH Zürich, 8092 Zürich, Switzerland
  • 2Géoazur Laboratory, Institut de Recherche pour le Développement – Université Côte d'Azur, Campus Azur du CNRS, 06560 Valbonne, France
  • 3Tectonics, Department of Earth Sciences, Utrecht University, Princetonlaan 4, 3584 CB, Utrecht, the Netherlands

Abstract. Natural fault networks are geometrically complex systems that evolve through time. The evolution of faults and their off-fault damage pattern are influenced by both dynamic earthquake ruptures and aseismic deformation in the interseismic period. To better understand each of their contributions to faulting we simulate both earthquake rupture dynamics and long-term deformation in a visco-elasto-plastic crust subjected to rate-and-state-dependent friction. The continuum mechanics-based numerical model presented here includes three new features. First, a 2.5-D approximation to incorporate effects of a viscoelastic lower crustal substrate below a finite depth. Second, we introduce a dynamically adaptive (slip-velocity-dependent) measure of fault width to ensure grid size convergence of fault angles for evolving faults. Third, fault localization is facilitated by plastic strain weakening of bulk rate-and-state friction parameters as inspired by laboratory experiments. This allows us to for the first time simulate sequences of episodic fault growth due to earthquakes and aseismic creep. Localized fault growth is simulated for four bulk rheologies ranging from persistent velocity-weakening to velocity-strengthening. Interestingly, in each of these bulk rheologies, faults predominantly localize and grow due to aseismic deformation. Yet, cyclic fault growth at more realistic growth rates is obtained for a bulk rheology that transitions from velocity-strengthening friction to velocity-weakening friction. Fault growth occurs under Riedel and conjugate angles and transitions towards wing cracks. Off-fault deformation, both distributed and localized, is typically formed during dynamic earthquake ruptures. Simulated off-fault deformation structures range from fan-shaped distributed deformation to localized Riedel splay faults. We observe that the fault-normal width of the outer damage zone saturates with increasing fault length due to the finite depth of the seismogenic zone. We also observe that dynamically and statically evolving stress fields from neighboring fault strands affect primary and secondary fault growth and thus that normal stress variations affect earthquake sequences. Finally, we find that the amount of off-fault deformation distinctly depends on the degree of optimality of a fault with respect to the prevailing but dynamically changing stress field. Typically, we simulate off-fault deformation on faults parallel to the loading direction. This produces a 6.5-fold higher off-fault energy dissipation than on an optimally oriented fault, which in turn has a 1.5-fold larger stress drop. The misalignment of the fault with respect to the static stress field thus facilitates off-fault deformation. These results imply that fault geometries bend, individual fault strands interact and that optimal orientations and off-fault deformation vary through space and time. With our work we establish the basis for simulations and analyses of complex evolving fault networks subject to both long-term and short-term dynamics.

Simon Preuss et al.

Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Simon Preuss et al.

Data sets

Model data sets and videos to "Characteristics of earthquake ruptures and dynamic off-fault deformation on propagating faults" S. Preuss, J.-P. Ampuero, T. Gerya, and Y. van Dinther https://polybox.ethz.ch/index.php/s/2rLw6kreSMHNBov

Model code and software

Model data repository for the STM-RSF reference models of the paper "Characteristics of earthquake ruptures and dynamic off-fault deformation on propagating faults" S. Preuss, J.-P. Ampuero, T. Gerya, and Y. van Dinther https://polybox.ethz.ch/index.php/s/vmSRTxueMawsfZ9

Video supplement

Model data sets and videos to "Characteristics of earthquake ruptures and dynamic off-fault deformation on propagating faults" S. Preuss, J.-P. Ampuero, T. Gerya, and Y. van Dinther https://polybox.ethz.ch/index.php/s/2rLw6kreSMHNBov

Simon Preuss et al.

Viewed

Total article views: 459 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
329 121 9 459 10 8
  • HTML: 329
  • PDF: 121
  • XML: 9
  • Total: 459
  • BibTeX: 10
  • EndNote: 8
Views and downloads (calculated since 25 Feb 2020)
Cumulative views and downloads (calculated since 25 Feb 2020)

Viewed (geographical distribution)

Total article views: 302 (including HTML, PDF, and XML) Thereof 301 with geography defined and 1 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 11 Jul 2020
Publications Copernicus
Download
Short summary
In this paper, we present newly developed numerical models to simulate episodic growth of geological faults. This growth of faults occurs during the seismic cycle with spontaneously generated primary and secondary fault structures. With these models we are able to show the evolution of complex fault geometries. Additionally, we can quantify the impact of earthquakes on fault growth.
In this paper, we present newly developed numerical models to simulate episodic growth of...
Citation