Abstract
Large earthquakes cause observable changes in the Earth’s gravity field, which have been detected by the Gravity Recovery and Climate Experiment (GRACE). Since most previous studies focus on the detection of near-field gravity effects, this study provides the results from the medium- to far-field gravity changes caused by the 2004 Sumatra-Andaman earthquake that are recorded within GRACE monthly solutions. Utilizing a spherical-earth dislocation model we documented that large-scale signals predominate in the global field of the coseismic gravity changes caused by the earthquake. After removing the near-field effects, the coseismic gravity changes show a negative anomaly feature with an average magnitude of −0.18×10−8 m·s−2 in the region ranging ∼40° from the epicenter, which is considered as the “medium field” in this study. From the GRACE data released by Center for Space Research from August 2002 to December 2008, we retrieved the large-scale gravity changes smoothed with 3 000 km Gaussian filter. The results show that the coseismic gravity changes detected by GRACE in the medium field have an average of (−0.20±0.06)×10−8 m·s−2, which agrees with the model prediction. The detection confirms that GRACE is sensitive to large-scale medium-field coseismic gravitational effects of mega earthquakes, and also validates the spherical-earth dislocation model in the medium field from the perspective of satellite gravimetry.
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References
Bettadpur S (2007). Gravity Recovery and Climate Experiment Level -2 Gravity Field Product User Handbook. Rep. GRACE 327-734, Cent. For Space Res., Austin, Texas, 18pp.
Chambers D P (2006). Observing seasonal steric sea level variations with GRACE and satellite altimetry. J Geophys Res111: C03010, doi:10.1029/2005JC002914.
Chen J L, Wilson C R, Tapley B D and Grand S (2007). GRACE detects coseismic and postseismic deformation from the Sumatra-Andaman earthquake. Geophys Res Lett34: L13302, doi:10.1029/2007GL030356.
Cheng M and Tapley B D (2004). Variations in the Earth’s oblateness during the past 28 years. J Geophys Res109: B09402, doi:10.1029/2004JB003028.
de Linage C, Rivera L, Hinderer J, Boy J P, Rogister Y, Lambotte S and Biancale R (2009). Separation of coseismic and postseismic gravity changes for the 2004 Sumatra-Andaman earthquake from 4.6 yr of GRACE observations and modelling of the coseismic change by normalmodes summation. Geophys J Int176: 695–714, doi:10.1111/j.1365-246X.2008.04025.x.
Han S C, Sauber J and Luthcke S (2010). Regional gravity decrease after the 2010 Maule (Chile) earthquake indicates large-scale mass redistribution. Geophys Res Lett37: L23307, doi:10.1029/2010GL045449.
Han S C, Sauber J and Riva R (2011). Contribution of satellite gravimetry to understanding seismic source processes of the 2011 Tohoku-Oki earthquake. Geophys Res Lett38: L24312, doi:10.1029/2011GL049975.
Han S C, Shum C K, Bevis M, Ji C and Kuo C Y (2006). Crustal dilatation observed by GRACE after the 2004 Sumatra-Andaman earthquake. Science313(5787): 658–666, doi:10.1126/science.1128661.
Heki K and Matsuo K (2010). Coseismic gravity changes of the 2010 earthquake in central Chile from satellite gravimetry. Geophys Res Lett37: L24306, doi:10.1029/2010GL045335.
Li J and Shen W B (2011). Investigation of the co-seismic gravity field variations caused by the 2004 Sumatra-Andaman earthquake using monthly GRACE data. Journal of Earth Science22: 280–291, doi:10.1007/s12583-011-0181-x.
Matsuo K and Heki K (2011). Coseismic gravity changes of the 2011 Tohoku-Oki earthquake from satellite gravimetry. Geophys Res Lett38: L00G12, doi:10.1029/2011GL049018.
Sun W, Okubo S, Fu G and Araya A (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 space-fixed point. Geophys J Int177: 817–833, doi: 10.1111/j.1365-246X.2009.04113.x.
Sun W and Zhou X (2012). Coseismic deflection change of the vertical caused by the 2011 Tohoku-Oki earthquake (MW9.0). Geophys J Int189: 937–955, doi:10.1111/j.1365-246X.2012.05434.x.
Wahr J, Molenaar M and Bryan F (1998). Time variability of the Earth’s gravity field: Hydrologicalandoceanic effects and their possible detection using GRACE. J Geophys Res103(B12): 30 205–30 229.
Wang L, Shum C K, Simons F J, Tapley B and Dai C (2012). Coseismic and postseismic deformation of the 2011 Tohoku-Oki earthquake constrained by GRACE gravimetry. Geophys Res Lett39: L07301, doi:10.1029/2012GL051104.
Zhou X, Sun W and Fu G (2011). Gravity satellite GRACE detects coseismic gravity changes caused by 2010 MW 8.8 Chile earthquake. Chinese J Geophys54(7): 1 745–1 749, doi:10.3969/j.issn.0001-5733.2011.07.007 (in Chinese with English abstract).
Zhou X, Sun W, Zhao B, Fu G, Dong J and Nie Z (2012). Geodetic observations detecting coseismic displacements and gravity changes caused by the MW=9.0 Tohoku-Oki earthquake. J Geophys Res117: B05408, doi:10.1029/2011JB008849.
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Li, J., Shen, W. GRACE detection of the medium- to far-field coseismic gravity changes caused by the 2004 MW9.3 Sumatra-Andaman earthquake. Earthq Sci 25, 235–240 (2012). https://doi.org/10.1007/s11589-012-0849-z
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DOI: https://doi.org/10.1007/s11589-012-0849-z
Key words
- GRACE
- medium- to far-field
- coseismic gravity change
- 2004 Sumatra-Andaman earthquake
- spherical-Earth dislocation model