The structural and metamorphic evolution of the lower crust has direct effects on the lithospheric response to plate tectonic processes involved in orogeny, including subsidence of sedimentary basins, stability of deep mountain roots and extension of high-topography regions. Recent research shows that before orogeny most of the lower crust is dry, impermeable and mechanically strong1. During an orogenic event, the evolution of the lower crust is controlled by infiltration of fluids along localized shear or fracture zones. In the Bergen Arcs of Western Norway, shear zones initiate as faults generated by lower-crustal earthquakes. Seismic slip in the dry lower crust requires stresses at a level that can only be sustained over short timescales or local weakening mechanisms. However, normal earthquake activity in the seismogenic zone produces stress pulses that drive aftershocks in the lower crust2. Here we show that the volume of lower crust affected by such aftershocks is substantial and that fluid-driven associated metamorphic and structural transformations of the lower crust follow these earthquakes. This provides a ‘top-down’ effect on crustal geodynamics and connects processes operating at very different timescales.
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Jamtveit, B., Austrheim, H. & Putnis, A. Disequilibrium metamorphism of stressed lithosphere. Earth Sci. Rev. 154, 1–13 (2016).
Ben-Zion, Y. & Lyakhovsky, V. Analysis of aftershocks in a lithospheric model with seismogenic zone governed by damage rheology. Geophys. J. Int. 165, 197–210 (2006).
Chen, W. P. & Molnar, P. Focal depths of intracontinental and intraplate earthquakes and their implication for the thermal and mechanical properties of the lithosphere. J. Geophys. Res. 88, 4183–4214 (1983).
Jackson, J. Strength of the continental lithosphere: time to abandon the jelly sandwich? GSA Today 12, 4–9 (2002).
Rudnick, R. L. & Fountain, D. M. Nature and composition of the continental lower crust. Rev. Geophys. 33, 267–309 (1995).
Copley, A., Avouac, J.-P., Hollingsworth, J. & Leprince, S. The 2001 M W 7.6 Bhuj earthquake, low fault friction and the upper crustal support of plate driving forces in India. J. Geophys. Res. 116, B08405 (2011).
Craig, T. J., Copley, A. & Jackson, J. Thermal and tectonic consequences of India underthrusting Tibet. Earth Planet. Sci. Lett. 353–354, 231–239 (2012).
Austrheim, H. & Boundy, T. M. Pseudotachylytes generated during seismic faulting and eclogitization of the deep crust. Science 265, 82–83 (1994).
John, T. & Schenk, V. Interrelations between intermediate-depth earthquakes and fluid flow within subducting oceanic plates: constraints from eclogite facies pseudotachylytes. Geology 34, 557–560 (2006).
Moecher, D. P. & Steltenpohl, M. G. Direct calculation of rupture depth for an exhumed paleoseismogenic fault from mylonitic pseudotachylyte. Geology 37, 999–1002 (2009).
Kohlstedt, D. L., Evans, B. & Mackwell, S. J. Strength of the lithosphere—constraints imposed by laboratory experiments. J. Geophys. Res. 100, 17587–17602 (1995).
Ellis, S. & Stöckhert, B. Elevated stresses and creep rates beneath the brittle-ductile transition caused by seismic faulting in the upper crust. J. Geophys. Res. 109, B05407 (2004).
Hawemann, F., Mancktelow, N. S., Wex, S., Camacho, A. & Pennaccioni, G. Pseudotachylyte as field evidence for lower crustal earthquakes during the intracontinental Petermann Orogeny (Musgrave Block, Central Australia). Solid Earth Discuss. (submitted); preprint at https://doi.org/10.5194/se-2017-123 (2018).
Andersen, T. B., Mair, K., Austrheim, H., Podladchikov, Y. Y. & Vrijmoed, J. C. Stress release in exhumed intermediate and deep earthquakes determined from ultramafic pseudotachylite. Geology 36, 995–998 (2008).
Hillers, G., Ben-Zion, Y. & Mai, P. M. Seismicity on a fault controlled by rate- and state dependent friction with spatial variations of the critical slip distance. J. Geophys. Res. 111, B01403 (2006).
Jiang, J. & Lapusta, N. Connecting depth limits of interseismic locking, microseismicity, and large earthquakes in models of long-term fault slip. J. Geophys. Res. 122, 6491–6523 (2017).
Bingen, B., Davis, W. J. & Austrheim, H. Zircon U-Pb geochronology in the Bergen arc eclogites and their Proterozoic protoliths, and implications for the pre-Scandian evolution of the Caledonides in western Norway. Geol. Soc. Am. Bull. 113, 640–649 (2001).
Bhowany, K. et al. Phase equilibria modelling constraints on P-T conditions during fluid catalysed conversion of granulite to eclogite in the Bergen Arcs, Norway. J. Metamorph. Geol. 36, 315–342 (2018).
Austrheim, H. et al. Microstructural records of seismic slip. Sci. Adv. 3, e1602067 (2017).
Mitchell, T. M., Toy, V., Di Toro, G., Renner, J. & Sibson, R. H. Fault welding by pseudotachylyte formation. Geology 44, 1059–1062 (2016).
Ben-Zion, Y. Collective behavior of earthquakes and faults: continuum-discrete transitions, progressive evolutionary changes and different dynamic regimes. Rev. Geophys. 46, RG4006 (2008).
Ben-Zion, Y. & Ampuero, J.-P. Seismic radiation from regions sustaining material damage. Geophys. J. Int. 178, 1351–1356 (2009).
Ben-Zion, Y. & Zhu, L. Potency-magnitude scaling relations for southern California earthquakes with 1.0<ML<7.0. Geophys. J. Int. 148, F1–F5 (2002).
Edwards, B., Allmann, B., Fah, D. & Clinton, J. Automatic computation of moment magnitudes for small earthquakes and the scaling of local to moment magnitude. Geophys. J. Int. 183, 407–420 (2010).
Båth, M. Lateral inhomogeneities in the upper mantle. Tectonophysics 2, 483–514 (1965).
Zaliapin, I. & Ben-Zion, Y. Y. Earthquake clusters in southern California. I: Identification and stability. J. Geophys. Res. 118, 2847–2864 (2013).
Zaliapin, I. & Ben-Zion, Y. A global classification and characterization of earthquake clusters. Geophys. J. Int. 207, 608–634 (2016).
McNamara, D. E. et al. Source modeling of the 2015 M W 7.8 Nepal (Gorkha) earthquake sequence: implications for geodynamics and earthquake hazards. Tectonophysics 714–715, 21–30 (2017).
Wells, D. L. & Coppersmith, K. J. New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bull. Seismol. Soc. Am. 84, 974–1002 (1994).
Putnis, A., Jamtveit, B. & Austrheim, H. Metamorphic processes and seismicity: the Bergen Arcs as a natural laboratory. J. Petrol. 58, 1871–1898 (2017).
Yardley, B. W. D. The role of water in the evolution of the continental crust. J. Geol. Soc. Lond. 166, 585–600 (2009).
Munz, I. A., Yardley, B. W. D., Banks, D. & Wayne, D. Deep penetration of sedimentary fluids in basement rocks from Southern Norway—evidence from hydrocarbon and brine inclusions in quartz veins. Geochim. Cosmochim. Acta 59, 239–254 (1995).
Austrheim, H. Fluid and deformation induced metamorphic processes around Moho beneath continent collision zones: Examples from the exposed root zone of the Caledonian mountain belt, W-Norway. Tectonophysics 609, 620–635 (2013).
Rybacki, E. & Dresen, G. Deformation mechanism maps for feldspar rocks. Tectonophysics 382, 173–187 (2004).
Azuma, S., Katayama, I. & Nakakuki, T. Rheological decoupling at the Moho and implications to Venusian tectonics. Sci. Rep. 4, 4403 (2014).
Tullis, J. & Yund, R. The brittle–ductile transition in feldspar aggregates. An experimental study. Int. Geophys. 51, 89–117 (1992).
This project has been supported by the European Union’s Horizon 2020 Research and Innovation Programme under ERC Advanced Grant Agreement number 669972, ‘Disequilibrium Metamorphism’ (‘DIME’; to B.J.), and by the Norwegian Research Council grant number 250661 (‘HADES’; to F.R.). Y.B.-Z. acknowledges support from the National Science Foundation (grant EAR-1722561). The paper benefited from discussions with and comments by I. Zaliapin, J. Jackson, A. Putnis, S. Schmalholz, S. Xu, P. Meakin and J. Platt.
Nature thanks B. Yardley and the other anonymous reviewer(s) for their contribution to the peer review of this work.
The authors declare no competing interests.
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Jamtveit, B., Ben-Zion, Y., Renard, F. et al. Earthquake-induced transformation of the lower crust. Nature 556, 487–491 (2018). https://doi.org/10.1038/s41586-018-0045-y
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