Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal
Abstract
Detailed geodetic imaging of earthquake ruptures enhances our understanding of earthquake physics and associated ground shaking. The 25 April 2015 moment magnitude 7.8 earthquake in Gorkha, Nepal was the first large continental megathrust rupture to have occurred beneath a high-rate (5-hertz) Global Positioning System (GPS) network. We used GPS and interferometric synthetic aperture radar data to model the earthquake rupture as a slip pulse ~20 kilometers in width, ~6 seconds in duration, and with a peak sliding velocity of 1.1 meters per second, which propagated toward the Kathmandu basin at ~3.3 kilometers per second over ~140 kilometers. The smooth slip onset, indicating a large (~5-meter) slip-weakening distance, caused moderate ground shaking at high frequencies (>1 hertz; peak ground acceleration, ~16% of Earth's gravity) and minimized damage to vernacular dwellings. Whole-basin resonance at a period of 4 to 5 seconds caused the collapse of tall structures, including cultural artifacts.
Additional Information
© 2015 American Association for the Advancement of Science. Received for publication 25 May 2015. Accepted for publication 29 July 2015. Published online 6 August 2015. The GPS data are available from the UNAVCO website. The InSAR data are available at http://topex.ucsd.edu/nepal/. The Nepal Geodetic Array was funded by Caltech and DASE (to J.-P.A.) and by the Gordon and Betty Moore Foundation, through grant GBMF 423.01 to the Caltech Tectonics Observatory; support was maintained by NSF grant EAR-1345136. A. Miner and the Pacific Northwest Geodetic Array (PANGA) at CWU are thanked for technical assistance with the construction and operation of the Tribhuvan University (TU)–CWU network. Additional funding for the TU-CWU network came from the United Nations Development Programme and the Nepal Academy for Science and Technology. The high-rate data were recovered thanks to (i) a rapid intervention funded by NASA (USA) and the Department of Foreign International Development (UK) and (ii) engineering services provided by UNAVCO via the GAGE (Geodesy Advancing Geosciences and EarthScope) Facility, with support from NSF and NASA under NSF Cooperative Agreement no. EAR-1261833. We also thank Trimble Navigation and the Vaidya family for supporting the rapid response. The accelerometer record at KATNP was provided by USGS. We thank A. Nathan (U.S. Embassy in Kathmandu), S. Hough, D. Given, I. Flores, and J. Luetgert for contributions to the installation of this station. Research at UC–Berkeley was funded by the Gordon and Betty Moore Foundation through grant GBMF 3024. A portion of this work was carried out at JPL under a contract with the NASA. The GPS data were processed by the Advanced Rapid Imaging and Analysis Center for Natural Hazards (JPL) and the Scripps Orbit and Permanent Array Center. The effort at the Scripps Institution of Oceanography was funded by NASA grants NNX14AQ53G and NNX14AT33G. Advanced Land Observing Satellite–2 data were provided by the Japan Aerospace Exploration Agency under investigations 1148 and 1413. J.-P.A. thanks the Royal Society for support. We thank D. Dreger for discussion and W. Mooney for comments. J.-P.A led the study and wrote the article. D.M. performed the kinematic modeling and wrote the article. Y.B. supervised the high-rate data processing and wrote the article. J.Ga. led the field operations. J.Ge. conducted the high-rate data processing. S.O., A.M., W.S., and J.F.G. conducted the low-rate data analysis to estimate coseismic offsets. E.O.L. and X.X. conducted the InSAR data processing. L.B. helped to organize the field operations. All other authors contributed to building and servicing the GPS stations and to the post-earthquake data recovery. All authors edited the article.Attached Files
Supplemental Material - aac6383-Galetzka-SM-movie-S1.mp4
Supplemental Material - aac6383-Galetzka-SM.pdf
Files
Additional details
- Alternative title
- Slip pulse and resonance of Kathmandu basin during the 2015 Mw 7.8 Gorkha earthquake, Nepal imaged with geodesy
- Eprint ID
- 58975
- Resolver ID
- CaltechAUTHORS:20150721-170858547
- DOI
- 10.1126/science.aac6383
- Caltech
- DASE
- GBMF 423.01
- Gordon and Betty Moore Foundation
- EAR-1345136
- NSF
- United Nations Development Programme
- Nepal Academy for Science and Technology
- Department of Foreign International Development (UK)
- EAR-1261833
- NSF
- GBMF 3024
- Gordon and Betty Moore Foundation
- NASA/JPL/Caltech
- NNX14AQ53G
- NASA
- NNX14AT33G
- NASA
- 1148
- Japan Aerospace Exploration Agency (JAXA)
- 1413
- Japan Aerospace Exploration Agency (JAXA)
- Royal Society
- Created
-
2015-08-06Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory, Division of Geological and Planetary Sciences