skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Dominant Controls of Downdip Afterslip and Viscous Relaxation on the Postseismic Displacements Following the Mw7.9 Gorkha, Nepal, Earthquake

Journal Article · · Journal of Geophysical Research. Solid Earth
DOI:https://doi.org/10.1002/2017JB014366· OSTI ID:1479332
ORCiD logo [1];  [2];  [1];  [1];  [1];  [3]
  1. China Earthquake Administration, Wuhan (China)
  2. Univ. of California, Berkeley, CA (United States)
  3. National Earthquake Infrastructure Service, Beijing (China)

Here, we analyze three-dimensional GPS coordinate time series from continuously operating stations in Nepal and South Tibet and calculate the initial 1 year postseismic displacements. We first investigate models of poroelastic rebound, afterslip, and viscoelastic relaxation individually and then attempt to resolve the trade-offs between their contributions by evaluating the misfit between observed and simulated displacements. We compare kinematic inversions for distributed afterslip with stress-driven afterslip models. The modeling results show that no single mechanism satisfactorily explains near- and far-field postseismic deformation following the Gorkha earthquake. When considering contributions from all three mechanisms, we favor a combination of viscoelastic relaxation and afterslip alone, as poroelastic rebound always worsens the misfit. The combined model does not improve the data misfit significantly, but the inverted afterslip distribution is more physically plausible. The inverted afterslip favors slip within the brittle-ductile transition zone downdip of the coseismic rupture and fills the small gap between the mainshock and largest aftershock slip zone, releasing only 7% of the coseismic moment. Our preferred model also illuminates the laterally heterogeneous rheological structure between India and the South Tibet. The transient and steady state viscosities of the upper mantle beneath Tibet are constrained to be greater than 1018 Pa s and 1019 Pa s, whereas the Indian upper mantle has a high viscosity ≥1020 Pa s. The viscosity in the lower crust of southern Tibet shows a clear trade-off with its southward extent and thickness, suggesting an upper bound value of ~8 × 1019 Pa s for its steady state viscosity.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1479332
Journal Information:
Journal of Geophysical Research. Solid Earth, Vol. 122, Issue 10; ISSN 2169-9313
Publisher:
American Geophysical UnionCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 66 works
Citation information provided by
Web of Science

References (92)

Nonlinear strain buildup and the earthquake cycle on the San Andreas Fault journal July 1983
Dynamics of Izmit Earthquake Postseismic Deformation and Loading of the Duzce Earthquake Hypocenter journal February 2002
Underplating in the Himalaya-Tibet Collision Zone Revealed by the Hi-CLIMB Experiment journal September 2009
Time-Dependent Distributed Afterslip on and Deep below the Izmit Earthquake Rupture journal February 2002
GPS deformation in a region of high crustal seismicity: N. Cascadia forearc journal April 2002
Seismicity and one-dimensional velocity structure of the Himalayan collision zone: Earthquakes in the crust and upper mantle journal January 2006
Geodetic imaging of late postseismic lower crustal flow in Tibet journal October 2014
Current shortening across the Himalayas of Nepal journal April 2004
The long-term strength of continental lithosphere: “jelly sandwich” or “crème brûlée”? journal January 2006
Long-term growth of the Himalaya inferred from interseismic InSAR measurement journal September 2012
Lithospheric rheology constrained from twenty-five years of postseismic deformation following the 1989 M 6.9 Loma Prieta earthquake journal February 2016
GPS measurements of present-day convergence across the Nepal Himalaya journal March 1997
Mantle Flow Beneath a Continental Strike-Slip Fault: Postseismic Deformation After the 1999 Hector Mine Earthquake journal September 2001
Fault stability inferred from granite sliding experiments at hydrothermal conditions journal April 1991
Coseismic and early postseismic deformation due to the 25 April 2015, M w 7.8 Gorkha, Nepal, earthquake from InSAR and GPS measurements journal April 2016
Implications for elastic energy storage in the Himalaya from the Gorkha 2015 earthquake and other incomplete ruptures of the Main Himalayan Thrust journal December 2017
Earthquake focal depths, effective elastic thickness, and the strength of the continental lithosphere journal January 2000
Coseismic and postseismic deformation due to the 2007 M 5.5 Ghazaband fault earthquake, Balochistan, Pakistan : 2007 M5.5 GHAZABAND FAULT EARTHQUAKE journal May 2015
Subduction of the Indian lithosphere beneath the Tibetan Plateau and Burma journal September 2008
Surface Deformation and Lower Crustal Flow in Eastern Tibet journal May 1997
Post-earthquake ground movements correlated to pore-pressure transients journal July 2003
The crustal viscosity gradient measured from post-seismic deformation: A case study of the 1997 Manyi (Tibet) earthquake journal October 2012
Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake journal January 2016
A comprehensive model of postseismic deformation of the 2004 Sumatra–Andaman earthquake deduced from GPS observations in northern Sumatra journal July 2014
Great Himalayan earthquakes and the Tibetan plateau journal November 2006
On the mechanics of earthquake afterslip journal January 1991
Frictional Properties on the San Andreas Fault near Parkfield, California, Inferred from Models of Afterslip following the 2004 Earthquake journal September 2006
A mixed seismic–aseismic stress release episode in the Andean subduction zone journal December 2015
Post-earthquake relaxation using a spectral element method: 2.5-D case journal May 2014
Postseismic deformation due to the M w 6.0 2004 Parkfield earthquake: Stress-driven creep on a fault with spatially variable rate-and-state friction parameters journal January 2009
Coseismic and postseismic slip of the 2011 magnitude-9 Tohoku-Oki earthquake journal June 2011
From Geodetic Imaging of Seismic and Aseismic Fault Slip to Dynamic Modeling of the Seismic Cycle journal May 2015
Rapid afterslip following the 1999 Chi-Chi, Taiwan Earthquake: RAPID AFTERSLIP FOLLOWING THE EARTHQUAKE journal August 2002
Coseismic and Initial Postseismic Deformation from the 2004 Parkfield, California, Earthquake, Observed by Global Positioning System, Electronic Distance Meter, Creepmeters, and Borehole Strainmeters journal September 2006
Poroelasticity: Efficient modeling of strongly coupled, slow deformation processes in a multilayered half‐space journal March 2003
ITRF2008: an improved solution of the international terrestrial reference frame journal February 2011
Convergence rate across the Nepal Himalaya and interseismic coupling on the Main Himalayan Thrust: Implications for seismic hazard: COUPLING ON THE MHT journal April 2012
Rheology of the Lower Crust and Upper Mantle: Evidence from Rock Mechanics, Geodesy, and Field Observations journal May 2008
Frictional Afterslip Following the 2005 Nias-Simeulue Earthquake, Sumatra journal June 2006
Line‐of‐sight displacement from ALOS‐2 interferometry: M w 7.8 Gorkha Earthquake and M w 7.3 aftershock journal August 2015
Afterslip (and only afterslip) following the 2004 Parkfield, California, earthquake journal January 2007
Geological implications of a permeability-depth curve for the continental crust journal January 1999
Interseismic coupling on the main Himalayan thrust: INTERSEISMIC COUPLING ON THE MHT journal July 2015
Steady-state laboratory flow laws alone fail to explain postseismic observations journal November 2010
Lower edge of locked Main Himalayan Thrust unzipped by the 2015 Gorkha earthquake journal August 2015
Crustal rheology of the Himalaya and Southern Tibet inferred from magnetotelluric data journal November 2005
Postseismic deformation in Pakistan after the 8 October 2005 earthquake: Evidence of afterslip along a flat north of the Balakot-Bagh thrust journal January 2011
Active shortening within the Himalayan orogenic wedge implied by the 2015 Gorkha earthquake journal August 2016
Density distribution of the India plate beneath the Tibetan plateau: Geophysical and petrological constraints on the kinetics of lower-crustal eclogitization journal December 2007
Lower crustal relaxation beneath the Tibetan Plateau and Qaidam Basin following the 2001 Kokoxili earthquake: Kokoxili lower crustal relaxation journal September 2011
Postseismic relaxation and aftershocks journal January 2007
Strength of the continental lithosphere: Time to abandon the jelly sandwich? journal January 2002
The mechanism of partial rupture of a locked megathrust: The role of fault morphology journal August 2016
Crustal strength in central Tibet determined from Holocene shoreline deflection around Siling Co journal August 2015
Plate Motion of India and Interseismic Strain in the Nepal Himalaya from GPS and DORIS Measurements journal March 2006
Earthquakes and friction laws journal January 1998
Post-seismic motion following the 1997 Manyi (Tibet) earthquake: InSAR observations and modelling journal June 2007
Exhumation, crustal deformation, and thermal structure of the Nepal Himalaya derived from the inversion of thermochronological and thermobarometric data and modeling of the topography journal January 2010
Postseismic deformation following the 1999 Chi-Chi earthquake, Taiwan: Implication for lower-crust rheology: CHI-CHI POSTSEISMIC DEFORMATION journal December 2012
Seasonal and long-term vertical deformation in the Nepal Himalaya constrained by GPS and GRACE measurements: GPS/GRACE VERTICAL DEFORMATION IN NEPAL journal March 2012
A precise velocity field of tectonic deformation in China as inferred from intensive GPS observations journal May 2012
Tandem afterslip on connected fault planes following the 2008 Nima-Gaize (Tibet) earthquake journal January 2010
Modeling afterslip and aftershocks following the 1992 Landers earthquake journal January 2007
Coseismic and post-seismic activity associated with the 2008 Mw 6.3 Damxung earthquake, Tibet, constrained by InSAR journal November 2013
Dominant role of tectonic inheritance in supercontinent cycles journal February 2011
Stress-dependent power-law flow in the upper mantle following the 2002 Denali, Alaska, earthquake journal December 2006
Probing the lithospheric rheology across the eastern margin of the Tibetan Plateau journal June 2014
Elastic thickness of the Himalayan–Tibetan orogen estimated from the fan wavelet coherence method, and its implications for lithospheric structure journal January 2015
Thermal and tectonic consequences of India underthrusting Tibet journal November 2012
Transient rheology of the uppermost mantle beneath the Mojave Desert, California journal October 2003
Focal depths and fault plane solutions of earthquakes under the Tibetan Plateau journal January 1983
Earthquake distribution in southern Tibet and its tectonic implications journal January 2008
Slip model of the 2015 M w 7.8 Gorkha (Nepal) earthquake from inversions of ALOS‐2 and GPS data journal September 2015
Co- and postseismic deformation of the 28 March 2005 Nias M w 8.7 earthquake from continuous GPS data journal January 2006
Tomographic evidence for wholesale underthrusting of India beneath the entire Tibetan plateau journal June 2005
Postseismic relaxation in Kashmir and lateral variations in crustal architecture and materials journal June 2015
Asthenosphere rheology inferred from observations of the 2012 Indian Ocean earthquake journal October 2016
Towards inferring earthquake patterns from geodetic observations of interseismic coupling journal April 2010
Himalayan strain reservoir inferred from limited afterslip following the Gorkha earthquake journal June 2016
Active structures of the Himalayan-Tibetan orogen and their relationships to earthquake distribution, contemporary strain field, and Cenozoic volcanism journal June 2009
Evidence of fluid-filled upper crust from observations of postseismic deformation due to the 1992 M w 7.3 Landers earthquake : POSTSEISMIC DEFORMATION DUE TO LANDERS EARTHQUAKE journal August 2004
Crustal deformation on the Chinese mainland during 1998–2014 based on GPS data journal January 2015
Seasonal variations of seismicity and geodetic strain in the Himalaya induced by surface hydrology journal February 2008
Afterslip and viscoelastic relaxation following the 2011 Tohoku-oki earthquake ( M w 9.0) inferred from inland GPS and seafloor GPS/Acoustic data journal January 2015
Poroelastic rebound along the Landers 1992 earthquake surface rupture journal December 1998
Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation journal December 2001
What can GPS data tell us about the dynamics of post-seismic deformation? journal December 2003
Kinematics of the India-Eurasia collision zone from GPS measurements journal January 1999
Postseismic Rebound in Fault Step-Overs Caused by Pore Fluid Flow journal August 1996
Crustal deformation across and beyond the Los Angeles basin from geodetic measurements journal December 1996
Co-seismic displacements associated with the 2015 Nepal <italic>M</italic><sub>w</sub>7.9 earthquake and <italic>M</italic><sub>w</sub>7.3 aftershock constrained by Global Positioning System Measurements journal October 2015
Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal journal August 2015

Cited By (10)

Role of Lower Crust in the Postseismic Deformation of the 2010 Maule Earthquake: Insights from a Model with Power-Law Rheology journal January 2019
Anomalous transients in GPS measurements due to induced changes in local site conditions journal July 2019
Changes in Groundwater Level Possibly Encourage Shallow Earthquakes in Central Australia: The 2016 Petermann Ranges Earthquake journal March 2019
Source Characteristics of the 2017 Ms 7.0 Jiuzhaigou, China, Earthquake and Implications for Recent Seismicity in Eastern Tibet journal May 2019
Interseismic and Postseismic Shallow Creep of the North Qaidam Thrust Faults Detected with a Multitemporal InSAR Analysis journal July 2019
Logarithmic Model Joint Inversion Method for Coseismic and Postseismic Slip: Application to the 2017 Mw 7.3 Sarpol Zahāb Earthquake, Iran journal November 2019
Transient High Strain Rate During Localized Viscous Creep in the Dry Lower Continental Crust (Lofoten, Norway) journal October 2019
Constraints on the Geometry and Frictional Properties of the Main Himalayan Thrust Using Coseismic, Postseismic, and Interseismic Deformation in Nepal journal February 2020
Audit of stored strain energy and extent of future earthquake rupture in central Himalaya journal November 2018
Interseismic and Postseismic Shallow Creep of the North Qaidam Thrust Faults Detected with a Multitemporal InSAR Analysis text January 2019

Figures / Tables (16)


Similar Records

Inferred rheological structure and mantle conditions from postseismic deformation following the 2010 Mw 7.2 El Mayor-Cucapah Earthquake
Journal Article · Mon Dec 18 00:00:00 EST 2017 · Geophysical Journal International · OSTI ID:1479332

Statistical tests of simple earthquake cycle models: Testing Earthquake Cycle Models
Journal Article · Fri Sep 23 00:00:00 EDT 2016 · Geophysical Research Letters · OSTI ID:1479332

Near-fault measurement of postseismic slip associated with the 1989 Loma Prieta, California, earthquake
Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Geophysical Research Letters (American Geophysical Union); (USA) · OSTI ID:1479332