Abstract
The near-fault GNSS records of strong-ground movement are the most sensitive for defining the fault rupture. Here, two unpublished GNSS records are studied, a near-fault-strong-motion station (NAGA) and a distant station in a poorly covered area (PYRA). The station NAGA, located above the Gorkha fault, sensed a southward displacement of almost 1.7 m. The PYRA station that is positioned at a distance of about 150 km from the fault, near the Pyramid station in the Everest, showed static displacements in the order of some millimeters. The observed displacements were compared with the calculated displacements of a finite fault model in an elastic halfspace. We evaluated two slips on fault models derived from seismological and geodetic studies: the comparison of the observed and modelled fields reveals that our displacements are in better accordance with the geodetic derived fault model than the seismologic one. Finally, we evaluate the yearly strain rate of four GNSS stations in the area that were recording continuously the deformation field for at least 5 years. The strain rate is then compared with the strain released by the Gorkha earthquake, leading to an interval of 235 years to store a comparable amount of elastic energy. The three near-fault GNSS stations require a slightly wider fault than published, in the case of an equivalent homogeneous rupture, with an average uniform slip of 3.5 m occurring on an area of 150 km × 60 km.
Similar content being viewed by others
References
Ader, T., Avouac, J.-P., Liu-Zeng, J., Lyon-Caen, H., Bollinger, L., Galetzka, J., et al. (2012). Convergence rate across the Nepal Himalaya and interseismic coupling on the Main Himalayan Thrust: implications for seismic hazard. Journal of Geophysical Research, 117, B04403. doi:10.1029/2011JB009071.
Arora, B. R., Bansal, B. K., Prajapati, S. K., Sutur, A. K., & Nayak, S. (2017). Seismotectonics and seismogenesis of M w 7.8 Gorkha Earthquake and its Aftershocks. Journal of Asian Earth Sciences, 133, 2–11. doi:10.1016/j.jseaes.2016.07.018.
Avouac, J.-P., Meng, L., Wei, S., Wang, T., & Ampuero, J.-P. (2015). Lower edge of locked main Himalayan thrust unzipped by the 2015 Gorkha earthquake. Nature Geoscience, 8, 708–711. doi:10.1038/ngeo2518.Battaglia.
Battaglia, M., Cervelli, P. F., & Murray, J. R. (2013). dMODELS: a MATLAB software package for modeling crustal deformation near active faults and volcanic centers. Journal of Volcanology and Geothermal Research, 254, 1–4.
Böhm, J., Werl, B., & Schuh, H. (2006). Troposphere mapping functions for GPS and very long baseline interferometry from European Centre for Medium-Range Weather Forecasts operational analysis data. Journal of Geophysical Research: Solid Earth, 111, B02406. doi:10.1029/2005JB003629.
Caporali, A., Braitenberg, C., & Massironi, M. (2005). Geodetic and hydrological aspects of the Merano earthquake of 17 July 2001. Journal of Geodynamics, 39, 317–336.
Chaulagain, H., Rodrigues, H., Silva, V., Spacone, E., & Varum, H. (2015). Seismic risk assessment and hazard mapping in Nepal. Natural Hazards, 78(1), 583. doi:10.1007/s11069-015-1734-6.
Cheloni, D., D’Agostino, N., D’Anastasio, E., Avallone, A., Mantenuto, S., Giuliani, R., et al. (2010). Coseismic and initial post-seismic slip of the 2009 M w 6.3 L’Aquila earthquake, Italy, from GPS measurements. Geophysical Journal International, 181(3), 1539–1546.
DeMets, C., Gordon, R. G., Argus, D. F., & Stein, S. (1990). Current plate motions. Geophysical Journal International, 101, 425–478.
DeMets, C., Gordon, R. G., Argus, D. F., & Stein, S. (1994). Effect of the recent revisions to the geomagnetic reversal timescale. Geophysical Research Letters, 21, 2191–2194.
Denolle, M. A., Fan, W., & Shearer, P. M. (2015). Dynamics of the 2015 M 7.8 Nepal earthquake. Geophysical Research Letters, 42, 7467–7475. doi:10.1002/2015GL065336.
Devoti, R., Zuliani, D., Braitenberg, C., Fabris, P., & Grillo, B. (2015). Hydrologically induced slope deformations detected by GPS and clinometric surveys in the Cansiglio Plateau, Southern Alps. Earth and Planetary Science Letters, 419, 134–142.
Fan, W., & Shearer, P. M. (2015). Detailed rupture imaging of the 25 April 2015 Nepal earthquake using teleseismic P waves. Geophysical Research Letters, 42, 5744–5752.
Fu, Y., & Freymueller, J. T. (2012). Seasonal and long-term vertical deformation in the Nepal Himalaya constrained by GPS and GRACE measurements. Journal of Geophysical Research, 117, B03407. doi:10.1029/2011JB008925.
Fu, Y., Freymueller, J. T., & Jensen, T. (2012). Seasonal hydrological loading in southern Alaska observed by GPS and GRACE. Geophysical Research Letters, 39, L15310. doi:10.1029/2012GL052453.
Galetzka, J., Melgar, D., Genrich, J. F., Geng, J., Owen, S., Lindsey, E. O., et al. (2015). Slip pulse and resonance of the Kathmandu Basin during the 2015 Gorkha earthquake, Nepal. Science, 349, 1091–1095.
Grandin, R., Vallée, M., Satriano, C., Lacassin, R., Klinger, Y., Simoes, M., et al. (2015). Rupture process of the M w = 7.9 2015 Gorkha earthquake (Nepal): insights into Himalayan megathrust segmentation. Geophysical Research Letters, 42, 8373–8382.
Gualandi, A., Avouac, J-P., Galetzka, J., Genrich, J.F., Blewitt, G., Adhikari,L.B., Koirala, B.P., Gupta, R., Upreti, B.N., Pratt-Sitaula, B., Liu-Zeng, J. (2016). Pre- and post- seismic deformation related to the 2015, M w7.8 Gorkha earthquake, Nepal, Tectonophysics, in press, doi:10.1016/j.tecto.2016.06.014.
Mencin, D., Bendick, R., Upreti, B. N., Adhikari, D. P., Gajurel, A. P., Bhattarai, R.R., Shrestha, H.R., Bhattarai, T. N., Mananadhar, N., Galetzka, J., Knappe, E., Pratt-Sitaula, B., Aoudia, A., Bilham, R. (2016). Himalayan strain reservoir inferred from limited afterslip following the Gorkha earthquake, Nature Geoscience, 9, 533-537, doi:10.1038/ngeo2734.
Molnar, P. (1979). Earthquake recurrence intervals and plate tectonics. Bulletin of the Seismological Society of America, 29, 211–229.
Okada, Y. (1985). Surface deformations due to shear and tensile faults in a halfspace. Bull. Seism. Soc. Am., 75(4), 1135–1154.
Rajendran, K., & Rajendran, C. P. (2011). Revisiting the earthquake sources in the Himalaya: perspectives on past seismicity. Tectonophysics, 504(1–4), 75–88.
Savage, J. C. (1983). A dislocation model of strain accumulation and release at a subduction zone. Journal of Geophysical Research, 88, 4984–4996.
Shen, Z.-K., Jackson, D. D., & Ge, B. X. (1996). Crustal deformation across and beyond the Los Angeles basin from geodetic measurements. Journal of Geophysical Research, 101(B12), 27957–27980.
Shin, Y. H., Shum, C. K., Braitenberg, C., Lee, S. M., Na, S.-H., Choi, K. S., et al. (2015). Moho topography, ranges and folds of Tibet by analysis of global gravity models and GOCE data. Scientific Reports, 5, 1–7. doi:10.1038/srep11681.
Sreejith, K. M., Sunil, P. S., Agrawal, R., Saji, A. P., Ramesh, D. S., & Rajawat, A. S. (2016). Coseismic and early postseismic deformation due to the 25 April 2015, M w 7.8 Gorkha, Nepal, earthquake form InSAR and GPS measurements. Geophysical Research Letters, 43, 3160–3168.
Thapa, D. R., & Guoxin, W. (2013). Probabilistic seismic hazard analysis in Nepal. Earthquake Engineering and Engineering Vibration, 12, 577–586.
Toda, S., Stein, R.S., Reasenberg, P.A., Dieterich, J.H. (1998). Stress transferred by the M w = 65 Kobe, Japan, shock: Effect on aftershocks and future earthquake probabilities. J Geophys Res 103(24), 543–24,565.
Toda, S., Stein, R.S., Sevilgen, V., Lin, J. (2011). Coulomb 3.3 Graphic-rich deformation and stress-change software for earthquake, tectonic, and volcano research and teaching—user guide. U.S. Geological Survey Open-File Report. http://pubs.usgs.gov/of/2011/1060/. Accessed 10 Dec 2016.
UNAVCO (2016) ftp://data-out.unavco.org/pub/rinex, http://www.unavco.org/data/gps-gnss/data-access-methods/dai2/app/dai2.html#. Accessed 10 Dec 2016.
USGS. (2016). Event page M7.8–36 km E of Khudi, Nepal. https://earthquake.usgs.gov/earthquakes/eventpage/us20002926#executive. Accessed 10 Dec 2016.
Wang, K., & Fialko, Y. (2015). Slip model of the 2015 M w 7.8 Gorkha (Nepal) earthquake from inversions of ALOS-2 and GPS data. Geophysical Research Letters, 42, 7452–7458.
Acknowledgements
Niraji Manandhar is gratefully thanked for providing GNSS data for the Nagarkot station. Gianpietro Verza from EvK2-CNR is acknowledged for giving meteorological data. We acknowledge the UNAVCO consortium for the GNSS data of the stations KIT3, KKN4, LAHZ, TPLJ, and CHLM. The reviewers are kindly acknowledged for their fruitful comments that contributed in improving the quality of the paper.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Morsut, F., Pivetta, T., Braitenberg, C. et al. Strain Accumulation and Release of the Gorkha, Nepal, Earthquake (M w 7.8, 25 April 2015). Pure Appl. Geophys. 175, 1909–1923 (2018). https://doi.org/10.1007/s00024-017-1639-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00024-017-1639-2