Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Long-lived shallow slow-slip events on the Sunda megathrust

Nature Geoscience volume 14, pages 327–333 (2021)Cite this article

Subjects

Abstract

During most of the time between large earthquakes at tectonic plate boundaries, surface displacement time series are generally observed to be linear. This linear trend is interpreted as a result of steady stress accumulation at frictionally locked asperities on the fault interface. However, due to the short geodetic record, it is still unknown whether all interseismic periods show similar rates, and whether frictionally locked asperities remain stationary. Here we show that two consecutive interseismic periods at Simeulue Island, Indonesia experienced significantly different displacement rates, which cannot be explained by a sudden reorganization of locked and unlocked regions. Rather, these observations necessitate the occurrence of a 32-year slow-slip event on a shallow, frictionally stable area of the megathrust. We develop a self-consistent numerical model of such events driven by pore-fluid migration during the earthquake cycle. The resulting slow-slip events appear as abrupt velocity changes in geodetic time series. Due to their long-lived nature, we may be missing or mis-modelling these transient phenomena in a number of settings globally; we highlight one such ongoing example at Enggano Island, Indonesia. We provide a method for detecting these slow-slip events that will enable a substantial revision to the earthquake and tsunami hazard and risk for populations living close to these faults.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Tectonic setting of the study (inset map).
Fig. 2: Observations and modelling results for the eighteenth- and nineteenth-century coral record at Simeulue projected along the cross-section shown in Fig. 1a.
Fig. 3: Numerical model of an SSE on a velocity-strengthening fault.
Fig. 4: Illustration of the pore-fluid-driven SSE model presented in this paper.
Fig. 5: A possible ongoing long-lived SSE near Enggano Island.

Similar content being viewed by others

Data availability

The coral data used in this paper are from ref. 20 (https://doi.org/10.1016/j.quascirev.2015.06.003), also available at https://doi.org/10.21979/N9/5QCLZX. The daily RINEX files for the GNSS station MLKN are available for public download at ftp://ftp.earthobservatory.sg/SugarData. The processed time series is provided at https://doi.org/10.21979/N9/LMK36Z. Topography and bathymetry plotted in Figs. 1 and 5 are from the ETOPO1 dataset available at https://doi.org/10.7289/V5C8276M. The figures in this paper were made using MATLAB and Generic Mapping Tools70.

Code availability

All computations in this study were carried out using MATLAB; code is available at https://researchdata.ntu.edu.sg/dataverse/longlivedsse/.

References

  1. Michel, S., Gualandi, A. & Avouac, J. P. Similar scaling laws for earthquakes and Cascadia slow-slip events. Nature 574, 522–526 (2019).

    Article  Google Scholar 

  2. Gomberg, J., Wech, A., Creager, K., Obara, K. & Agnew, D. Reconsidering earthquake scaling. Geophys. Res. Lett. 43, 6243–6251 (2016).

    Article  Google Scholar 

  3. Bürgmann, R. The geophysics, geology and mechanics of slow fault slip. Earth Planet. Sci. Lett. 495, 112–134 (2018).

    Article  Google Scholar 

  4. Chen, T. & Lapusta, N. Scaling of small repeating earthquakes explained by interaction of seismic and aseismic slip in a rate and state fault model. J. Geophys. Res. Solid Earth 114, B01311 (2009).

    Google Scholar 

  5. Liu, Y. & Rice, J. R. Aseismic slip transients emerge spontaneously in three-dimensional rate and state modeling of subduction earthquake sequences. J. Geophys. Res. Solid Earth 110, B08307 (2005).

    Article  Google Scholar 

  6. Liu, Y. & Rice, J. R. Spontaneous and triggered aseismic deformation transients in a subduction fault model. J. Geophys. Res. Solid Earth 112, B09404 (2007).

    Article  Google Scholar 

  7. Liu, Y. & Rice, J. R. Slow slip predictions based on granite and gabbro friction data compared to GPS measurements in northern Cascadia. J. Geophys. Res. Solid Earth 114, B09407 (2009).

    Article  Google Scholar 

  8. Segall, P., Rubin, A. M., Bradley, A. M. & Rice, J. R. Dilatant strengthening as a mechanism for slow slip events. J. Geophys. Res. Solid Earth 115, B12305 (2010).

    Article  Google Scholar 

  9. Audet, P. & Kim, Y. H. Teleseismic constraints on the geological environment of deep episodic slow earthquakes in subduction zone forearcs: a review. Tectonophysics 670, 1–15 (2016).

    Article  Google Scholar 

  10. Saffer, D. M. & Wallace, L. M. The frictional, hydrologic, metamorphic and thermal habitat of shallow slow earthquakes. Nat. Geosci. 8, 594–600 (2015).

    Article  Google Scholar 

  11. Audet, P. & Schaeffer, A. J. Fluid pressure and shear zone development over the locked to slow slip region in Cascadia. Sci. Adv. 4, eaar2982 (2018).

    Article  Google Scholar 

  12. Hawthorne, J. C. & Rubin, A. M. Laterally propagating slow slip events in a rate and state friction model with a velocity-weakening to velocity-strengthening transition. J. Geophys. Res. Solid Earth 118, 3785–3808 (2013).

    Article  Google Scholar 

  13. Im, K., Saffer, D., Marone, C. & Avouac, J.-P. Slip-rate-dependent friction as a universal mechanism for slow slip events. Nat. Geosci. 13, 705–710 (2020).

    Article  Google Scholar 

  14. Suzuki, T. & Yamashita, T. Dynamic modeling of slow earthquakes based on thermoporoelastic effects and inelastic generation of pores. J. Geophys. Res. Solid Earth 114, B00A04 (2009).

    Article  Google Scholar 

  15. Bernaudin, M. & Gueydan, F. Episodic tremor and slip explained by fluid-enhanced microfracturing and sealing. Geophys. Res. Lett. 45, 3471–3480 (2018).

    Article  Google Scholar 

  16. Lavier, L. L., Bennett, R. A. & Duddu, R. Creep events at the brittle ductile transition. Geochem. Geophys. Geosyst. 14, 3334–3351 (2013).

    Article  Google Scholar 

  17. Yin, A., Xie, Z. & Meng, L. A viscoplastic shear-zone model for deep (15–50 km) slow-slip events at plate convergent margins. Earth Planet. Sci. Lett. 491, 81–94 (2018).

    Article  Google Scholar 

  18. Marone, C. J., Scholtz, C. H. & Bilham, R. On the mechanics of earthquake afterslip. J. Geophys. Res. 96, 8441–8452 (1991).

    Article  Google Scholar 

  19. Scholz, C. H. Earthquakes and friction laws. Nature 391, 37–42 (1998).

    Article  Google Scholar 

  20. Meltzner, A. J. et al. Time-varying interseismic strain rates and similar seismic ruptures on the Nias–Simeulue patch of the Sunda megathrust. Q. Sci. Rev. 122, 258–281 (2015).

    Article  Google Scholar 

  21. Tsang, L. L. H. H., Meltzner, A. J., Hill, E. M., Freymueller, J. T. & Sieh, K. A paleogeodetic record of variable interseismic rates and megathrust coupling at Simeulue Island, Sumatra. Geophys. Res. Lett. 42, 10585–10594 (2015).

    Article  Google Scholar 

  22. Meltzner, A. J. et al. Persistent termini of 2004- and 2005-like ruptures of the Sunda megathrust. J. Geophys. Res. Solid Earth 117, B04405 (2012).

    Article  Google Scholar 

  23. Qiu, Q., Feng, L., Hermawan, I. & Hill, E. M. Coseismic and postseismic slip of the 2005 Mw 8.6 Nias–Simeulue earthquake: spatial overlap and localized viscoelastic flow. J. Geophys. Res. Solid Earth 124, 2018JB017263 (2019).

    Article  Google Scholar 

  24. Hsu, Y.-J. et al. Frictional afterslip following the 2005 Nias–Simeulue earthquake, Sumatra. Science (80-.) 312, 1921–1926 (2006).

    Article  Google Scholar 

  25. Melnick, D. et al. The super-interseismic phase of the megathrust earthquake cycle in Chile. Geophys. Res. Lett. 44, 784–791 (2017).

    Article  Google Scholar 

  26. Loveless, J. P. Super-interseismic periods: redefining earthquake recurrence. Geophys. Res. Lett. 44, 1329–1332 (2017).

    Article  Google Scholar 

  27. Simoes, M., Avouac, J. P., Cattin, R. & Henry, P. The Sumatra subduction zone: a case for a locked fault zone extending into the mantle. J. Geophys. Res. Solid Earth 109, B10402 (2004).

    Article  Google Scholar 

  28. Klingelhoefer, F. et al. Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra–Andaman earthquake: results from seismic refraction and wide-angle reflection surveys and thermal modeling. J. Geophys. Res. Solid Earth 115, B01304 (2010).

    Article  Google Scholar 

  29. Hippchen, S. & Hyndman, R. D. Thermal and structural models of the Sumatra subduction zone: implications for the megathrust seismogenic zone. J. Geophys. Res. Solid Earth 113, B12103 (2008).

    Article  Google Scholar 

  30. Almeida, R. et al. Can the updip limit of frictional locking on megathrusts be detected geodetically? Quantifying the effect of stress shadows on near-trench coupling. Geophys. Res. Lett. 45, 4754–4763 (2018).

    Article  Google Scholar 

  31. Lindsey, E. O. et al. Slip rate deficit and earthquake potential on shallow megathrusts. Nat. Geosci. https://doi.org/10.1038/s41561-021-00736-x (2021).

  32. Mavrommatis, A. P., Segall, P. & Johnson, K. M. A physical model for interseismic erosion of locked fault asperities. J. Geophys. Res. Solid Earth 122, 8326–8346 (2017).

    Article  Google Scholar 

  33. Mavrommatis, A. P., Segall, P. & Johnson, K. M. A decadal-scale deformation transient prior to the 2011 Mw 9.0 Tohoku-oki earthquake. Geophys. Res. Lett. 41, 4486–4494 (2014).

    Article  Google Scholar 

  34. Mavrommatis, A. P., Segall, P., Uchida, N. & Johnson, K. M. Long-term acceleration of aseismic slip preceding the Mw 9 Tohoku-oki earthquake: constraints from repeating earthquakes. Geophys. Res. Lett. 42, 9717–9725 (2015).

    Article  Google Scholar 

  35. Tsang, L. L. H. et al. A 15 year slow-slip event on the Sunda megathrust offshore Sumatra. Geophys. Res. Lett. 42, 6630–6638 (2015).

    Article  Google Scholar 

  36. Radiguet, M. et al. Slow slip events and strain accumulation in the Guerrero gap, Mexico. J. Geophys. Res. Solid Earth 117, B04305 (2012).

    Article  Google Scholar 

  37. Li, S., Freymueller, J. & McCaffrey, R. Slow slip events and time-dependent variations in locking beneath Lower Cook Inlet of the Alaska–Aleutian subduction zone. J. Geophys. Res. Solid Earth 121, 1060–1079 (2016).

    Article  Google Scholar 

  38. Bruhat, L. & Segall, P. Coupling on the northern Cascadia subduction zone from geodetic measurements and physics-based models. J. Geophys. Res. Solid Earth 121, 8297–8314 (2016).

    Article  Google Scholar 

  39. Sibson, R. H. Implications of fault-valve behaviour for rupture nucleation and recurrence. Tectonophysics 211, 283–293 (1992).

    Article  Google Scholar 

  40. Perfettini, H. & Ampuero, J.-P. P. Dynamics of a velocity strengthening fault region: implications for slow earthquakes and postseismic slip. J. Geophys. Res. 113, B09411 (2008).

    Google Scholar 

  41. Sibson, R. H. Stress switching in subduction forearcs: implications for overpressure containment and strength cycling on megathrusts. Tectonophysics 600, 142–152 (2013).

    Article  Google Scholar 

  42. Husen, S. & Kissling, E. Postseismic fluid flow after the large subduction earthquake of Antofagasta, Chile. Geology 29, 847–850 (2002).

    Article  Google Scholar 

  43. Hughes, K. L. H., Masterlark, T. & Mooney, W. D. Poroelastic stress-triggering of the 2005 M8.7 Nias earthquake by the 2004 M9.2 Sumatra–Andaman earthquake. Earth Planet. Sci. Lett. 293, 289–299 (2010).

    Article  Google Scholar 

  44. Materna, K., Bartlow, N., Wech, A., Williams, C. & Bürgmann, R. Dynamically triggered changes of plate interface coupling in southern Cascadia. Geophys. Res. Lett. 46, 12890–12899 (2019).

    Article  Google Scholar 

  45. Sibson, R. H. Conditions for fault-valve behaviour. Geol. Soc. London Spec. Publ. 54, 15–28 (1990).

    Article  Google Scholar 

  46. Sleep, N. H. & Blanpied, M. L. Creep, compaction and the weak rheology of major faults. Nature 359, 687–692 (1992).

    Article  Google Scholar 

  47. Moore, D. E. et al. in The Seismogenic Zone of Subduction Thrust Faults 317–345 (Columbia Univ. Press, 2007); https://doi.org/10.7312/dixo13866-011

  48. Bradley, K. et al. Stratigraphic control of frontal décollement level and structural vergence and implications for tsunamigenic earthquake hazard in Sumatra, Indonesia. Geochem. Geophys. Geosyst. 20, 1646–1664 (2019).

    Article  Google Scholar 

  49. Saffer, D. M. & Marone, C. Comparison of smectite- and illite-rich gouge frictional properties: application to the updip limit of the seismogenic zone along subduction megathrusts. Earth Planet. Sci. Lett. 215, 219–235 (2003).

    Article  Google Scholar 

  50. Heimisson, E. R., Dunham, E. M. & Almquist, M. Poroelastic effects destabilize mildly rate-strengthening friction to generate stable slow slip pulses. J. Mech. Phys. Solids 130, 262–279 (2019).

    Article  Google Scholar 

  51. Hyndman, R. D. & Peacock, S. M. Serpentinization of the forearc mantle. Earth Planet. Sci. Lett. 212, 417–432 (2003).

    Article  Google Scholar 

  52. Audet, P., Bostock, M. G., Christensen, N. I. & Peacock, S. M. Seismic evidence for overpressured subducted oceanic crust and megathrust fault sealing. Nature 457, 76–78 (2009).

    Article  Google Scholar 

  53. Johnson, K. M. & Tebo, D. Capturing 50 years of postseismic mantle flow at Nankai Subduction Zone. J. Geophys. Res. Solid Earth 123, 10091–10106 (2018).

    Article  Google Scholar 

  54. Yarai, H. & Ozawa, S. Quasi-periodic slow slip events in the afterslip area of the 1996 Hyuga-nada earthquakes, Japan. J. Geophys. Res. Solid Earth 118, 2512–2527 (2013).

    Article  Google Scholar 

  55. Rolandone, F. et al. Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip. Sci. Adv. 4, 2–10 (2018).

    Article  Google Scholar 

  56. Tsang, L. L. H. et al. Imaging rapid early afterslip of the 2016 Pedernales earthquake, Ecuador. Earth Planet. Sci. Lett. 524, 115724 (2019).

    Article  Google Scholar 

  57. Paul, J. & Rajendran, C. P. Short-term pre-2004 seismic subsidence near South Andaman: is this a precursor slow slip prior to a megathrust earthquake? Phys. Earth Planet. Inter. 248, 30–34 (2015).

    Article  Google Scholar 

  58. Harris, R. A. Large earthquakes and creeping faults. Rev. Geophys. 55, 169–198 (2017); https://doi.org/10.1002/2016RG000539

  59. Prawirodirdjo, L., McCaffrey, R., Chadwell, C. D., Bock, Y. & Subarya, C. Geodetic observations of an earthquake cycle at the Sumatra subduction zone: role of interseismic strain segmentation. J. Geophys. Res. 115, B03414 (2010).

    Google Scholar 

  60. Dieterich, J. H. Modeling of rock friction experimental 1. Results and constitutive equations. J. Geophys. Res. 84, 2161–2168 (1979).

    Article  Google Scholar 

  61. Ruina, A. Slip instability and state variable friction laws. J. Geophys. Res. Solid Earth 88, 10359–10370 (1983).

    Article  Google Scholar 

  62. Kanda, R. V. S. & Simons, M. An elastic plate model for interseismic deformation in subduction zones. J. Geophys. Res. Solid Earth 115, B03405 (2010).

    Article  Google Scholar 

  63. Bradley, K. E., Feng, L., Hill, E. M., Natawidjaja, D. H. & Sieh, K. Implications of the diffuse deformation of the Indian Ocean lithosphere for slip partitioning of oblique plate convergence in Sumatra. J. Geophys. Res. Solid Earth 122, 572–591 (2017).

    Article  Google Scholar 

  64. Rice, J. R. Spatio-temporal complexity of slip on a fault. J. Geophys. Res. 98, 9885 (1993).

    Article  Google Scholar 

  65. Segall, P. Earthquake and Volcano Deformation. Van Nostrand’s Scientific Encyclopedia (Princeton Univ. Press, 2010); https://doi.org/10.1515/9781400833856

  66. Okada, Y. Internal deformation due to shear and tensile faults in a half space. Bull. Seismol. Soc. Am. 82, 1018–1040 (1992).

    Article  Google Scholar 

  67. Hayes, G. P. et al. Slab2, a comprehensive subduction zone geometry model. Science (80-.) 362, 58–61 (2018).

    Article  Google Scholar 

  68. Neal, R. M. Slice sampling. Ann. Stat. 31, 705–767 (2003).

    Article  Google Scholar 

  69. Lindsey, E. O. & Fialko, Y. Geodetic slip rates in the southern San Andreas Fault system: effects of elastic heterogeneity and fault geometry. J. Geophys. Res. Solid Earth 118, 689–697 (2013).

    Article  Google Scholar 

  70. Wessel, P. & Smith, W. H. F. New, improved version of generic mapping tools released. Eos 79, 579–579 (1998).

    Article  Google Scholar 

Download references

Acknowledgements

This research was supported by the National Research Foundation Singapore under a Singapore NRF Investigatorship to E.M.H. (proposal ID NRF-NRFI05–2019–0009), Singapore NRF Fellowship to A.J.M. (NRF-NRFF11–2019–0008), the Earth Observatory of Singapore (EOS), the National Research Foundation of Singapore, and the Singapore Ministry of Education under the Research Centers of Excellence initiative. Data for the Enggano GPS station MLKN were taken from the SuGAr network maintained by EOS and the Indonesian Institute of Sciences (LIPI). This is EOS contribution number 335.

Author information

Author notes

  1. Louisa L. H. Tsang

    Present address: International Study Centre, University of Surrey, Guildford, UK

  2. Eric O. Lindsey

    Present address: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, USA

Authors and Affiliations

  1. Asian School of the Environment, Nanyang Technological University, Singapore, Singapore

    Rishav Mallick, Aron J. Meltzner & Emma M. Hill

  2. Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore

    Rishav Mallick, Aron J. Meltzner, Eric O. Lindsey, Lujia Feng & Emma M. Hill

  3. Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, IRD, Géoazur, Campus CNRS, Sophia Antipolis, Valbonne, France

    Louisa L. H. Tsang

Authors
  1. Rishav Mallick
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Aron J. Meltzner
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Louisa L. H. Tsang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Eric O. Lindsey
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Lujia Feng
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Emma M. Hill
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

R.M., A.J.M., L.L.H.T. and E.M.H. designed the study. R.M. and E.O.L. developed the inverse method. R.M. conducted the data analysis and developed the numerical models for the study. L.F. processed the GPS data and provided the time series for MLKN. All authors jointly wrote the paper.

Corresponding author

Correspondence to Rishav Mallick.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Geoscience thanks Daniel Melnick and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Stefan Lachowycz.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Testing multiple hypotheses to explain the trends in the coral time series.

Testing multiple hypotheses to explain the trends in the coral time series. a, Assuming a piecewise linear fit for the time series with a common timing for the velocity change, Tchange, we evaluate the misfit (with Gaussian error statistics - thick blue line). b, We evaluate the reduced χ2 and the significance of error reduction using the F-test for the following hypotheses: piecewise linear fits with an abrupt velocity change at Tchange (blue line - this is the preferred model), continuous acceleration (red line) and piecewise linear fits with an abrupt velocity change whose timing varies for each station (red diamonds).

Extended Data Fig. 2 PDFs for spatial extent of locked and creeping regions on the megathrust.

PDFs for spatial extent of locked and creeping regions on the megathrust. a, Geometric setup and terminology used to describe the 4 segments of the megathrust: shallow creeping, frictionally locked, unlocked/transition zone and freely sliding plate boundary. b, PDFs of the spatial extent of ζup for two time periods (1738–1829 and 1829–1861) assuming steady frictional locking and creep governs the evolution of slip on the megathrust. Maximum aposteriori probability (MAP) of ζup for 1738–1829 is shown as green thick line (95 % confidence interval - thin green lines); MAP of ζup for 1829–1861 is shown as red thick line (95 % confidence interval - thin red lines). To explain the 1829–1861 coral observations with only steady interseismic processes, the upper limit of the locked zone ζup would have to migrate down-dip by 50–100 km while the (c) deeper transition zone ζdown would have to migrate to a depth of 50–60 km. d, The transition from ζdown to ζfree (W) would have to narrow to infinitesimal widths (pdf is maximum at W=0) making this model unphysical.

Extended Data Fig. 3 Observations and modelling results for the 18th-19th century coral record in Simeulue.

Observations and modelling results for the 18th-19th century coral record in Simeulue. a, Subsidence rates for the two time periods, 1738–1829 (grey) and 1829-1861 (red). We assume the velocities from each epoch collectively show the average response of southern Simeulue Island to tectonic changes (filled error bar). The individual site vertical velocities are plotted with error bars, while the model predictions are shown as polygons (67% confidence level, with darker colours showing regions closer to the median). b, Estimated slip rate for 1738-1829 is shown as a grey polygon (67% confidence level). The slip rate for the period 1829-1861 is estimated using two different models: (1) steady interseismic processes with a change in locked/unlocked regions (blue polygon), (2) SSE (orange polygon) superimposed on the existing locking from 1738-1829.

Extended Data Fig. 4 1-d and 2-d marginal PDFs of the spatial parameters.

1-d and 2-d marginal PDFs of the spatial parameters (ζup−dip,ζdown−dip,ζfree in Extended Data Fig. 2a) describing (a) frictional domains for a model where we assume the 1738-1829 velocity field is attributed to steady frictional behaviour on the Sunda megathrust followed by (b) the occurrence of a long-lived transient slip event (SSE) from 1829-1861. The SSE is estimated to occur between ζup and ζbot with an average slip rate of Vtrans (mm/yr) (we normalize this by the plate rate Vpl). (See Methods for a more detailed description of all parameters). c, We show the joint distribution of SSE slip rate and the along-dip location where this slip occurred. The darker colours show a higher value of the PDF; the red line in the 1-d marginal PDFs is the maximum aposteriori estimate.

Extended Data Fig. 5 Snapshots through time of a frictional instability on a velocity strengthening fault.

Snapshots through time of a frictional instability on a velocity strengthening fault. A steady-state creeping fault was perturbed early in the simulation (t = 50 yrs) by a pore-fluid expulsion event and allowed to evolve. In this simulation we do not allow additional weakening from pore-pressure recovery on the fault. The colors represent different time periods (t = 190 to 230 yrs) - from the initial acceleration of the SSE (blue) until the instability is arrested and the fault resumes creeping at its steady rate velocity (yellow). The SSE nucleates at the 12–14 km position on the simulated fault, as the fault is trying to recover to its steady state creep rate. However, an overshoot of slip rates occurs leading to a pulse of high slip rate at the center of the simulated fault. The transition from creep at below 10−10 m/s to the accelerated slip pulse of ∼ 10−8 m/s occurs in a short period of time (1-2 yrs). This instability is then damped out and is smeared over the available fault area over 10–15 years.

Supplementary information

Supplementary Information

Two sections of supplementary text and Supplementary Figs. 1–3.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Mallick, R., Meltzner, A.J., Tsang, L.L.H. et al. Long-lived shallow slow-slip events on the Sunda megathrust. Nat. Geosci. 14, 327–333 (2021). https://doi.org/10.1038/s41561-021-00727-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41561-021-00727-y

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing