Abstract
Large earthquakes are thought to release strain on previously locked faults. However, the details of how earthquakes are initiated, grow and terminate in relation to pre-seismically locked and creeping patches is unclear1,2,3,4. The 2015 Mw 7.8 Gorkha, Nepal earthquake occurred close to Kathmandu in a region where the prior pattern of fault locking is well documented5. Here we analyse this event using seismological records measured at teleseismic distances and Synthetic Aperture Radar imagery. We show that the earthquake originated northwest of Kathmandu within a cluster of background seismicity that fringes the bottom of the locked portion of the Main Himalayan Thrust fault (MHT). The rupture propagated eastwards for about 140 km, unzipping the lower edge of the locked portion of the fault. High-frequency seismic waves radiated continuously as the slip pulse propagated at about 2.8 km s−1 along this zone of presumably high and heterogeneous pre-seismic stress at the seismic–aseismic transition. Eastward unzipping of the fault resumed during the Mw 7.3 aftershock on 12 May. The transfer of stress to neighbouring regions during the Gorkha earthquake should facilitate future rupture of the areas of the MHT adjacent and updip of the Gorkha earthquake rupture.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Schurr, B. et al. Gradual unlocking of plate boundary controlled initiation of the 2014 Iquique earthquake. Nature 512, 299–302 (2014).
Loveless, J. P. & Meade, B. J. Spatial correlation of interseismic coupling and coseismic rupture extent of the 2011 Mw = 9.0 Tohoku-oki earthquake. Geophys. Res. Lett. 38, L17306 (2011).
Yue, H. et al. The 5 September 2012 Nicoya, Costa Rica Mw 7.6 earthquake rupture process from joint inversion of high-rate GPS, strong-motion, and teleseismic P wave data and its relationship to adjacent plate boundary interface properties. J. Geophys. Res. 118, 5453–5466 (2013).
Kaneko, Y., Avouac, J. P. & Lapusta, N. Towards inferring earthquake patterns from geodetic observations of interseismic coupling. Nature Geosci. 3, 363–369 (2010).
Ader, T. et al. Convergence rate across the Nepal Himalaya and interseismic coupling on the Main Himalayan Thrust: Implications for seismic hazard. J. Geophys. Res. 117, B04403 (2012).
Pandey, M. R., Tandukar, R. P., Avouac, J. P., Lave, J. & Massot, J. P. Interseismic strain accumulation on the Himalaya crustal ramp (Nepal). Geophys. Res. Lett. 22, 751–754 (1995).
M7.8–36 km E of Khudi, Nepal. USGS (2015); http://earthquake.usgs.gov/earthquakes/eventpage/us20002926#general_summary
Lavé, J. & Avouac, J. P. Active folding of fluvial terraces across the Siwaliks Hills, Himalayas of central Nepal. J. Geophys. Res. 105, 5735–5770 (2000).
M7.3–19 km SE of Kodari, Nepal. USGS (2015); http://earthquake.usgs.gov/earthquakes/eventpage/us20002ejl#general_summary
Nabelek, J. et al. Underplating in the Himalaya-Tibet collision zone revealed by the Hi-CLIMB Experiment. Science 325, 1371–1374 (2009).
Lemonnier, C. et al. Electrical structure of the Himalaya of Central Nepal: High conductivity around the mid-crustal ramp along the MHT. Geophys. Res. Lett. 26, 3261–3264 (1999).
Bilham, R. et al. GPS measurements of present-day convergence across the Nepal Himalaya. Nature 386, 61–64 (1997).
Ishii, M., Shearer, P. M., Houston, H. & Vidale, J. E. Extent, duration and speed of the 2004 Sumatra-Andaman earthquake imaged by the Hi-Net array. Nature 435, 933–936 (2005).
Ji, C., Wald, D. & Helmberger, D. V. Source Description of the 1999 Hector Mine, California Earthquake, Part I: Wavelet Domain Inversion Theory and Resolution Analysis. Bull. Seismol. Soc. Am. 92, 1192–1207 (2002).
Cattin, R. & Avouac, J. P. Modeling mountain building and the seismic cycle in the Himalaya of Nepal. J. Geophys. Res. 105, 13389–13407 (2000).
Ide, S., Imanishi, K., Yoshida, Y., Beroza, G. C. & Shelly, D. R. Bridging the gap between seismically and geodetically detected slow earthquakes. Geophys. Res. Lett. 35, L10305 (2008).
Lay, T. et al. Depth-varying rupture properties of subduction zone megathrust faults. J. Geophys. Res. 117, B04311 (2012).
Mugnier, J. L. et al. Structural interpretation of the great earthquakes of the last millennium in the central Himalaya. Earth Sci. Rev. 127, 30–47 (2013).
Ambraseys, N. N. & Douglas, J. Magnitude calibration of north Indian earthquakes. Geophys. J. Int. 159, 165–206 (2004).
Bilham, R. Location and magnitude of the 1833 Nepal earthquake and its relation to the rupture zones of contiguous great Himalayan earthquakes. Curr. Sci. 69, 101–128 (1995).
Lavé, J. et al. Evidence for a great medieval earthquake (approximate to 1100 AD) in the Central Himalayas, Nepal. Science 307, 1302–1305 (2005).
Kumar, S. et al. Paleoseismic evidence of great surface-rupture earthquakes along the Indian Himalaya. J. Geophys. Res. 111, B03304 (2006).
Sapkota, S. N. et al. Primary surface ruptures of the great Himalayan earthquakes in 1934 and 1255. Nature Geosci. 6, 71–76 (2013).
Bollinger, L. et al. Estimating the return times of great Himalayan earthquakes in eastern Nepal: Evidence from the Patu and Bardibas strands of the Main frontal thrust. J. Geophys. Res. 119, 7123–7163 (2014).
Lapusta, N., Rice, J. R., Ben-Zion, Y. & Zheng, G. T. Elastodynamic analysis for slow tectonic loading with spontaneous rupture episodes on faults with rate- and state-dependent friction. J. Geophys. Res. 105, 23765–23789 (2000).
Bürgmann, R. et al. Interseismic coupling and asperity distribution along the Kamchatka subduction zone. J. Geophys. Res. 110, B07405 (2005).
Rajendran, C. P., John, B. & Rajendran, K. Medieval pulse of great earthquakes in the central Himalaya: Viewing past activities on the frontal thrust. J. Geophys. Res. 120, 1623–1641 (2015).
Bilham, R. & Wallace, K. Future Mw > 8 earthquakes in the Himalaya: Implications from the 26 Dec 2004 Mw = 9.0 earthquake on India’s eastern plate margin. Geol. Surv. India 85, 1–14 (2005).
Yule, D., Dawson, S., Lave, J., Sapkota, S. & Tiwari, D. AGU Fall Meeting Abstract #S33C-05 (AGU, 2006).
Rajaure, S. et al. Pandey. Double difference relocation of local earthquakes in the Nepal Himalaya. J. Nepal Geol. Soc. 46, 133–142 (2013).
Vandecar, J. C. & Crosson, R. S. Determination of teleseismic relative phase arrival times using multi-channel cross-correlation and least-squares. Bull. Seismol. Soc. Am. 80, 150–169 (1990).
Meng, L. S., Inbal, A. & Ampuero, J. P. A window into the complexity of the dynamic rupture of the 2011 Mw 9 Tohoku-Oki earthquake. Geophys. Res. Lett. 38, L00G07 (2011).
Meng, L., Ampuero, J. P., Sladen, A. & Rendon, H. High-resolution backprojection at regional distance: Application to the Haiti M7.0 earthquake and comparisons with finite source studies. J. Geophys. Res. 117, B04313 (2012).
Meng, L. S., Ampuero, J. P., Luo, Y. D., Wu, W. B. & Ni, S. D. Mitigating artifacts in back-projection source imaging with implications for frequency-dependent properties of the Tohoku-Oki earthquake. Earth Planets Space 64, 1101–1109 (2012).
De Zan, F. & Guarnieri, A. M. TOPSAR: Terrain observation by progressive scans. IEEE Trans. Geosci. Remote Sens. 44, 2352–2360 (2006).
Wegmuller, U. & Werner, C. in Proc. Third ERS Symp. Space Service Environment Vol. III, 1687–1692 (Special Publications 414, ESA, 1997).
Michel, R., Avouac, J. P. & Taboury, J. Measuring ground displacements from SAR amplitude images: Application to the Landers earthquake. Geophys. Res. Lett. 26, 875–878 (1999).
Wang, T., Jonsson, S. & Hanssen, R. F. Improved SAR Image Coregistration Using Pixel-Offset Series. IEEE Geosci. Remote Sens. Lett. 11, 1465–1469 (2014).
Jonsson, S., Zebker, H., Segall, P. & Amelung, F. Fault slip distribution of the 1999 Mw 7.1 Hector Mine, California, earthquake, estimated from satellite radar and GPS measurements. Bull. Seismol. Soc. Am. 92, 1377–1389 (2002).
Bamler, R. & Eineder, M. Accuracy of differential shift estimation by correlation and split-bandwidth interferometry for wideband and Delta-k SAR systems. IEEE Geosci. Remote Sens. Lett. 2, 151–155 (2005).
Tinti, E., Bizzarri, A. & Cocco, M. Modeling the dynamic rupture propagation on heterogeneous faults with rate- and state-dependent friction. Ann. Geophys. 48, 327–345 (2005).
Mahesh, P. et al. One-dimensional reference velocity model and precise locations of earthquake hypocenters in the Kumaon-Garhwal Himalaya. Bull. Seismol. Soc. Am. 103, 328–339 (2013).
Acknowledgements
Sentinel-1A data are provided by the European Space Agency. T.W. thanks J. Kim from SMU for help in processing the SAR data. We also thank R. Bürgmann for comments on an earlier version of this study. J.-Ph.A. thanks the BP Foundation and the Royal Society for support.
Author information
Authors and Affiliations
Contributions
J.-Ph.A. coordinated the research and wrote the article. L.M. and J.-P.A. carried out the back-projection. S.W. carried out the finite source modelling. T.W. carried out the SAR offset measurements. All authors contributed to the interpretation and writing of the article.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
Supplementary Information (PDF 1203 kb)
Rights and permissions
About this article
Cite this article
Avouac, JP., Meng, L., Wei, S. et al. Lower edge of locked Main Himalayan Thrust unzipped by the 2015 Gorkha earthquake. Nature Geosci 8, 708–711 (2015). https://doi.org/10.1038/ngeo2518
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/ngeo2518
This article is cited by
-
Unraveling the role played by a buried mud diapir: alternative model for 2016 Mw 6.4 MeiNong earthquake in southwestern Taiwan
Geoscience Letters (2024)
-
Tectonic significance of the 2021 Lamjung, Nepal, mid-crustal seismic cluster
Earth, Planets and Space (2023)
-
The break of earthquake asperities imaged by distributed acoustic sensing
Nature (2023)
-
Structural evidences of active tectonics along Himalayan Frontal Thrust of northwest Himalaya: A case study along Kumia river section, Nainital, India
Journal of Earth System Science (2023)
-
Fractal Characteristics of the Seismic Swarm Succeeding the 2015 Gorkha Earthquake, Nepal
Indian Geotechnical Journal (2023)