Fault slip model of 2013 Lushan Earthquake retrieved based on GPS coseismic displacements

Abstract

Lushan Earthquake (~M _w 6.6) occurred in Sichuan Province of China on 20 April 2013, was the largest earthquake in Longmenshan fault belt since 2008 Wenchuan Earthquake. To better understand its rupture pattern, we focused on the influences of fault parameters on fault slips and performed fault slip inversion using Akaike’s Bayesian Information Criterion (ABIC) method. Based on GPS coseismic data, our inverted results showed that the fault slip was mainly confined at depths. The maximum slip amplitude is about 0.7 m, and the scalar seismic moment is about 9.47×10¹⁸ N·m. Slip pattern reveals that the earthquake occurred on the thrust fault with large dip-slip and small strike-slip, such a simple fault slip represents no second sub-event occurred. The Coulomb stress changes (ΔCFF) matched the most aftershocks with negative anomalies. The inverted results demonstrated that the source parameters have significant impacts on fault slip distribution, especially on the slip direction and maximum displacement.

Keywords

Lushan Earthquake / slip distribution / GPS coseismic data / source parameter

References

[1] Akaike H., . Barnardo J. M., DeGroot M. H., Lindley D. V., . Likelihood and the Bayes Procedure. Bayesian Statistics. Valencia University Press, Valencia., 1980, 143-166.

[2] Bro R. D., Jong S. D. A Fast Non-Negativity- Constrained Least Squares Algorithm. Journal of Chemometrics, 1997, 11(5): 393-401.

[3] Chen W. W., Wang D. C., Wei S. J. A Study on the Uncertainties of the Centroid Depth of the 2013 Lushan Earthquake from Teleseimic Body Wave Data. Earthquake Science, 2013, 26(3/4): 161-168.

[4] Duputel Z., Agram P. S., Simons M., . Accounting for Prediction Uncertainty when Inferring Subsurface Fault Slip. Geophysical Journal International, 2014, 197(1): 464-482.

[5] Duputel Z., Rivera L., Fukahata Y., . Uncertainty Estimations for Seismic Source Inversions. Geophysical Journal International, 2012, 190(2): 1243-1256.

[6] Feng W., Li Z., Elliott J. R., . The 2011 Mw 6.8 Burma Earthquake: Fault Constraints Provided by Multiple SAR Techniques. Geophysical Journal International, 2013, 195(1): 650-660.

[7] Geophysical Research Letters, 2003, 30 6

[8] Fukahata Y., Wright T. J. A Non-Linear Geodetic Data Inversion Using ABIC for Slip Distribution on a Fault with an Unknown Dip Angle. Geophysical Journal International, 2008, 173(2): 353-364.

[9] Funning G. J. Surface Displacements and Source Parameters of the 2003 Bam (Iran) Earthquake from Envisat Advanced Synthetic Aperture Radar Imagery. Journal of Geophysical Research, 2005, 110 B9 B09406

[10] Funning G. J., Fukahata Y., Yagi Y., . A Method for the Joint Inversion of Geodetic and Seismic Waveform Data Using ABIC: Application to the 1997 Manyi, Tibet, Earthquake. Geophysical Journal International, 2014, 196(3): 1564-1579.

[11] Funning G. J., Parsons B., Wright T. J. Fault Slip in the 1997 Manyi, Tibet Earthquake from Linear Elastic Modelling of InSAR Displacements. Geophysical Journal International, 2007, 169(3): 988-1008.

[12] Görgün E. Source Characteristics and Coulomb Stress Change of the 19 May 2011 Mw 6.0 Simav-Kütahya Earthquake, Turkey. Journal of Asian Earth Sciences, 2014, 87: 79-88.

[13] Han L. B., Zeng X. F., Jiang C. S., . Focal Mechanisms of the 2013 Mw 6.6 Lushan, China Earthquake and High-Resolution Aftershock Relocations. Seismological Research Letters, 2014, 85(1): 8-14.

[14] Hao J. L., Ji C., Wang W. M., . Rupture History of the 2013 Mw 6.6 Lushan Earthquake Constrained with Local Strong Motion and Teleseismic Body and Surface Waves. Geophysical Research Letters, 2013, 40(20): 5371-5376.

[15] He P., Wen Y. M., Xu C. J., . The Large Aftershocks Triggered by the 2011 Mw 9.0 Tohoku-Oki Earthquake, Japan. Journal of Asian Earth Sciences, 2013, 74: 1-10.

[16] Jiang Z. S., Wang M., Wang Y. Z., . GPS Constrained Coseismic Source and Slip Distribution of the 2013 Mw 6.6 Lushan, China, Earthquake and Its Tectonic Implications. Geophysical Research Letters, 2014, 41(2): 407-413.

[17] Jónsson S., Zebker H., Segall P., . Fault Slip Distribution of the 1999 Mw 7.1 Hector Mine, California, Earthquake, Estimated from Satellite Radar and GPS Measurements. Bulletin of the Seismological Society of America, 2002, 92(4): 1377-1389.

[18] King G. C., Stein R. S., Lin J. Static Stress Changes and the Triggering of Earthquakes. Bulletin of the Seismological Society of America, 1994, 84(3): 935-953.

[19] Lin J., Stein R. S. Stress Triggering in Thrust and Subduction Earthquakes and Stress Interaction between the Southern San Andreas and nearby Thrust and Strike-Slip Faults. Journal of Geophysical Research, 2004, 109 B2 B02303

[20] Liu C. L., Zheng Y., Ge C., . Rupture Process of the Ms 7.0 Lushan Earthquake, 2013. Science China: Earth Sciences, 2013, 56(7): 1187-1192.

[21] Miao M., Zhu S. B. The Static Coulomb Stress Change of the 2013 Lushan Ms 7.0 Earthquake and Its Impact on the Spatial Distribution of Aftershocks. Acta Seismologica Sinica, 2013, 35(5): 619-631.

[22] Minson S. E., Simons M., Beck J. L. Bayesian Inversion for Finite Fault Earthquake Source Models I—Theory and Algorithm. Geophysical Journal International, 2013, 194(3): 1701-1726.

[23] Okada Y. Surface Deformation due to Shear and Tensile Faults in a Half-Space. Bulletin of the Seismological Society of America, 1985, 75(4): 1135-1154.

[24] Pollitz F. F. Coseismic Deformation from Earthquake Faulting on a Layered Spherical Earth. Geophysical Journal International, 1996, 125(1): 1-14.

[25] Sun W. K., Okubo S., Vanícek P. Global Displacements Caused by Point Dislocations in a Realistic Earth Model. Journal of Geophysical Research, 1996, 101 B4 8561

[26] Toda S. Forecasting the Evolution of Seismicity in Southern California: Animations Built on Earthquake Stress Transfer. Journal of Geophysical Research, 2005, 110 B5 B05S16

[27] Toda S., Lin J., Meghraoui M., . 12 May 2008 M= 7.9 Wenchuan, China, Earthquake Calculated to Increase Failure Stress and Seismicity Rate on Three Major Fault Systems. Geophysical Research Letters, 2008, 35 17 L17305

[28] Toda S., Stein R. S., Lin J. Widespread Seismicity Excitation Throughout Central Japan Following the 2011 M=9.0 Tohoku Earthquake and Its Interpretation by Coulomb Stress Transfer. Geophysical Research Letters, 2011, 38 7 L00G03

[29] Wang R., Lorenzo-Martín F., Roth F. Computation of Deformation Induced by Earthquakes in a Multi-Layered Elastic Crust—FORTRAN Programs EDGRN/EDCMP. Computers & Geosciences, 2003, 29(2): 195-207.

[30] Wessel P., Smith W. H. F. New, Improved Version of Generic Mapping Tools Released. Eos, Transactions American Geophysical Union, 1998, 79 47 579

[31] Weston J., Ferreira A. M. G., Funning G. J. Systematic Comparisons of Earthquake Source Models Determined Using InSAR and Seismic Data. Tectonophysics, 2012, 532–535: 61-81.

[32] Wright T. J., Lu Z., Wicks C. Constraining the Slip Distribution and Fault Geometry of the Mw 7.9, 3 November 2002, Denali Fault Earthquake with Interferometric Synthetic Aperture Radar and Global Positioning System Data. Bulletin of the Seismological Society of America, 2004, 94(6B): S175-S189.

[33] Xu C. J., Liu Y. M., Wen Y. M., . Coseismic Slip Distribution of the 2008 Mw 7.9 Wenchuan Earthquake from Joint Inversion of GPS and InSAR Data. Bulletin of the Seismological Society of America, 2010, 100(5B): 2736-2749.

[34] Xu C. J., Wang L. Y. Progress of Joint Inversion of Geodetic and Seismological Data for Seismic Source Rupture Process. Geomatics and Information Science of Wuhan University, 2010, 35(4): 457-462.

[35] Xu X. W., Wen X. Z., Han Z. J., . Lushan^MS 7.0 Earthquake: A Blind Reserve-Fault Event. Chinese Science Bulletin, 2013, 3437-3443.

[36] Yabuki T., Matsu’ura M. Geodetic Data Inversion Using a Bayesian Information Criterion for Spatial Distribution of Fault Slip. Geophysical Journal International, 1992, 109(2): 363-375.

[37] Yagi Y., Fukahata Y. Introduction of Uncertainty of Green’s Function into Waveform Inversion for Seismic Source Processes. Geophysical Journal International, 2011, 186(2): 711-720.

[38] Yagi Y., Fukahata F. Importance of Covariance Components in Inversion Analyses of Densely Sampled Observed Data: An Application to Waveform Data Inversion for Seismic Source Processes. Geophysical Journal International, 2008, 175: 215-221.

[39] Zeng X. F., Yan L., Han L. B., . The Lushan Ms 7.0 Earhtquake on 20 April 2013: A High-Angle Thrust Event. Chinese Journal of Geophysics, 2013, 56(4): 1418-1424.

[40] Zhang Y., Chen Y., Xu L. Rupture Process of the Lushan 4.20 Earthquake and Preliminary Analysis on the Disaster-Causing Mechanism. Chinese Journal of Geophysiscs, 2013, 56(4): 1408-1411.

[41] Zhang Y., Wang R. J., Chen Y. T., . Kinematic Rupture Model and Hypocenter Relocation of the 2013 Mw 6.6 Lushan Earthquake Constrained by Strong-Motion and Teleseismic Data. Seismological Research Letters, 2014, 85(1): 15-22.

[42] Zhao Z., Fan J., Zheng S. H. Precision Determination of the Crustal Structure and Hypocentral Locations in the Longmenshan Thrust Nappe Belt. Acta Seismologica Sinica, 1997, 19: 615-622.