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Comparisons of Co-Seismic Gravity Changes between GRACE Observations and the Predictions from the Finite-Fault Models for the 2012 Mw = 8.6 Indian Ocean Earthquake Off-Sumatra
Authors: Armin Rahimi
Abstract:The Gravity Recovery and Climate Experiment (GRACE) has been a very successful project in determining math redistribution within the Earth system. Large deformations caused by earthquakes are in the high frequency band. Unfortunately, GRACE is only capable to provide reliable estimate at the low-to-medium frequency band for the gravitational changes. In this study, we computed the gravity changes after the 2012 Mw8.6 Indian Ocean earthquake off-Sumatra using the GRACE Level-2 monthly spherical harmonic (SH) solutions released by the University of Texas Center for Space Research (UTCSR). Moreover, we calculated gravity changes using different fault models derived from teleseismic data. The model predictions showed non-negligible discrepancies in gravity changes. However, after removing high-frequency signals, using Gaussian filtering 350 km commensurable GRACE spatial resolution, the discrepancies vanished, and the spatial patterns of total gravity changes predicted from all slip models became similar at the spatial resolution attainable by GRACE observations, and predicted-gravity changes were consistent with the GRACE-detected gravity changes. Nevertheless, the fault models, in which give different slip amplitudes, proportionally lead to different amplitude in the predicted gravity changes.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1130573Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 595
 Duputel, Z., H. Kanamori, V. C. Tsai, L. Rivera, L. Meng, J-P. Ampuero, and J. Stock, (2012). “The 2012 Sumatra great earthquake sequence”, Earth and Planetary Science Letters, 351–352, 247–257.
 Wei S. (Caltech, Sumatra 2012). April/11/2012 (Mw8.6), Sumatra. “Source Models of Large Earthquakes”. http://www.tectonics.caltech.edu/slip_history/2012_Sumatra/index.html, last accessed July 1, 2013.
 Shao, G., X. Li and C. Ji (UCSB, Sumatra 2012). ”Preliminary Result of the Apr 11, 2012 Mw8.64 sumatra Earthquake”,http://www.geol.ucsb.edu/faculty/ji/big_earthquakes/2012/04/10/sumatra.html,last accessed August 19, 2013.
 Hayes G., (NEIC, Sumatra 2012) “Preliminary Result of the Apr 11, 2012 Mw8.6 Earthquake Off the West Coast of Northern Sumatra”, http://earthquake.usgs.gov/earthquakes/eqinthenews/2012/usc000905e/finite_fault.php,last accessed August 19, 2013.
 Yue, H, T. Lay and K. D. Koper (2012), “En Echelon and Orthogonal Fault Ruptures of the 11 April 2012 Great Intraplate Earthquakes”. Nature, 490, 245-249, doi:10.1038/nature11492.
 Han, S.-C., R. Riva, J. Sauber, and E. Okal, (2013). “Source parameter inversion for recent great earthquakes from a decade-long observation of global gravity fields”, J. Geophys. Res. Solid Earth, 118, 1240–1267, doi:10.1002/jgrb.50116.
 Han, S.-C., J. Sauber, and F. Pollitz (2015), “Co-seismic compression/dilatation and viscoelastic uplift/subsidence following the 2012 Indian Ocean earthquakes quantified from satellite gravity observations”, Geophys. Res. Lett., 42, 3764–3722, doi:10.1002/2015GL063819.
 Cheng, M., Tapley, B. D., (2004). “Variations in the Earth’s Oblateness during the Past 28 Years”. J. Geophys. Res., 109:B09402. doi: 10.1029/2004JB003028
 Chen, J. L., Wilson, C. R., Tapley, B. D., Grand, S., (2007). “GRACE detects co-seismic and post-seismic deformation from the Sumatra-Andaman earthquake.” Geophys. Res. Lett., 34(13).
 Jekeli, C., (1981). “Alternative methods to smooth the Earth’s gravity field”, Technical Report 327, Geodetic Science, Ohio State Univ., Columbus, OH.
 Wahr J, Molenaar M, Bryan F (1998) “Time variability of the Earth’s gravity field: hydrological and oceanic effects and their possible detection using GRACE”. J Geophys Res 103(B12):30205–30229.
 Wang, L., Shum, C. K., Jekeli, C., (2012a). “Gravitational gradient changes following the 2004 December 26 Sumatra-Andaman Earthquake inferred from GRACE”. Geophysical Journal International, 191(3), 1109–1118. doi: 10.1111/j.1365-246X.2012.05674.x.
 Wang R, Lorenzo MF, Roth F (2006) “PSGRN/PSCMP a new code for calculating co-and post-seismic deformation, geoid and gravity changes based on the viscoelastic-gravitational dislocation theory”. Comput Geosci 32:527–541. doi:10.1016/j.cageo.2005. 08.006.
 Hoechner A, Sobolev SV, Einarsson I, Wang RJ (2011) “Investigation on afterslip and steady state and transient rheology based on post-seismic deformation and geoid change caused by the Sumatra 2004 earthquake”. Geochem Geophys Geosyst 12:Q07010. doi:10.1029/2010GC003450.
 Sun, W. K., Fu, G. Y., Okubo, S., (2010). “Co-seismic Gravity Changes Computed for a Spherical Earth Model Applicable to GRACE Data. Gravity, Geoid and Earth Observation”, International Association of Geodesy Symposia, 135: 11–17. doi: 10.1007/978-3-642-10634-7_2.
 Sun, W. K., Okubo, S., Fu, G. Y, et al., (2009). “General Formulations of Global Co-seismic Deformations Caused by an Arbitrary Dislocation in a Spherically Symmetric Earth Model-Applicable to Deformed Earth Surface and SpaceFixed Point”. Geophys. J. Int., 177(3): 817–833. doi: 10.1111/j. 1365-246X.2009.04113.x.
 Sun W, Zhou X, (2012). “Co-seismic deflection change of the vertical caused by the 2011 Tohoku-Oki earthquake (Mw 9.0)”. Geophys J Int 189:937–955. doi:10.1111/j.1365-246X.2012.05434.x.
 Li J, Chen JL, Zhang ZZ, (2014). “Seismologic applications of GRACE time-variable gravity measurements”. Earthq Sci 27(2):229–245, doi:10.1007/s11589-014-0072-1.
 Wang, L., Shum, C. K., Simons, F. J., Tassara, A., Erkan, K., Jekeli, C., Braun, A., Kao, C., Lee, H., Yuan, D-N. (2012b) “Co-seismic slip of the 2010 Mw 8.8 Great Maule, Chile, earthquake quantified by the inversion of GRACE observations”. Earth and Planetary Science Letters, 335-336, 167-179. doi: 10.1016/j.epsl.2012.04.044.