Quantification of Tsunami Bathymetry Effect on Finite Fault Slip Inversion

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• 作者：Quentin Bletery ; Anthony Sladen ; Bertrand Delouis…
• 刊名：Pure and Applied Geophysics
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：172
• 期：12
• 页码：3655-3670
• 全文大小：7,882 KB
• 参考文献：Bletery , Q., A. Sladen , B. Delouis , M. Vallée , J.-M. Nocquet , L. Rolland , J. Jiang (2014), A detailed source model for the Mw9.0 Tohoku-Oki earthquake reconciling geodesy, seismology and tsunami records. Journal of Geophysical Research: Solid Earth, doi: 10.-002/-014JB011261 .
  Delouis , B., D. Giardini , P. Lundgren, and J. Salichon (2002), Joint inversion of InSAR, GPS, teleseismic, and strong-motion data for the spatial and temporal distribution of earthquake slip: Application to the 1999 Izmit mainshock, Bulletin of the Seismological Society of America, 92 (1), 278-99, doi:10.-785/-120000806 .
  FRITZ , H.M., Phillips , D.A., Okayasu , A., Shimozono , T., Liu , H., Mohammed , F., Skanavis , V., Synolakis , C.E., Takahashi , T. (2012), The 2011 Japan tsunami current velocity measurements from survivor videos at Kesennuma Bay using LiDAR, Geophys. Res. Lett., 39, L00G23, doi:10.-029/-011GL050686 .
  Fujiwara , T., S. Kodaira , T. No , Y. Kaiho , N. Takahashi , Y. Kaneda (2011), The 2011 Tohoku-Oki Earthquake: Displacement Reaching the Trench Axis, Science 334, 6060, 10.-126/?science.-211554 .
  Gusman , A. R., Y. Tanioka , S. Sakai , H. Tsushima (2012), Source model of the great 2011 Tohoku earthquake estimated from tsunami waveforms and crustal deformation data, Earth and Planetary Science Letters 341-em class="EmphasisTypeItalic ">344, 234-em class="EmphasisTypeItalic ">242, 10.-016/?j.?epsl.-012.-6.-06 .
  Hayes , G. P., D. J. WALD , and R. L. Johnson (2012), Slab1. 0: A three-dimensional model of global subduction zone geometries, Journal of Geophysical Research: Solid Earth (19782012), 117 (B1).
  Hill , E.M., J.C. Borrero , Z. Huang , Q. Qiu , P. Banerjee , D.H. Natawidjaja , P. Elosegui , H.M. Fritz , B.W. Suwargadi , I.R. Pranantyo , L. Lin , K.A. Macpherson , V. Skanavis , C.E. Synolakis , and K. Sieh (2012), The 2010 Mw 7.8 Mentawai earthquake: Very shallow source of a rare tsunami earthquake determined from tsunami field survey and near-field GPS, Journal of Geophysical. Reseearch: Solid Earth, 117, B06402, doi:10.-029/-012JB009159 .
  Hooper , A., et al. (2013), Importance of horizontal seafloor motion on tsunami height for the 2011 Mw = 9.0 tohoku-oki earthquake, Earth and Planetary Science Letters, 361, 469-79, doi:10.-016/?j.?epsl.-012.-1.-13 .
  Kajiura , K. (1963), The leading wave of a tsunami, Bulletin of the Earthquake Research Institute, 41 (33), 535-71.
  Kanamori H. (1972), Mechanism of tsunami earthquakes, Phys. Earth Planet. Interiors, 6, 346-59.
  Kato , A., and T. Igarashi (2012), Regional extent of the large coseismic slip zone of the 2011 Mw 9.0 Tohoku-Oki earthquake delineated by on-fault aftershocks, Geophysical Research Letters, 39 (15), n/an/a, doi:10.-029/-012GL052220 .
  Koketsu , K., Y. Yokota , N. Nishimura , Y. Yagi , S. I. Miyazaki , K. Satake , and T. Okada (2011), A unified source model for the 2011 Tohoku earthquake, Earth and Planetary Science Letters, 310 (34), 480-87, doi:10.-016/?j.?epsl.-011.-9.-09 .
  Kido , M., Y. Osada , H. Fujimoto , R. Hino , Y. Ito (2011), Trench-normal variation in observed seafloor displacements associated with the 2011 Tohoku-Oki earthquake, Geophysical Research Letters 38, 24, doi:10.-029/-011GL050057 .
  Lay , T., Y. Yamazaki , C. J. Ammon , K. F. Cheung , and H. Kanamori (2011), The 2011 Mw 9.0 off the pacific coast of Tohoku earthquake: Comparison of deep-water tsunami signals with finite-fault rupture model predictions, Earth, planets and space, 63 (7), 797801.
  Maeda , T., T. Furumura , S. Sakai , and M. Shinohara (2011), Significant tsunami observed at ocean-bottom pressure gauges during the 2011 off the pacific coast of Tohoku earthquake, Earth, Planets and Space, 63 (7), 803808.
  Mansinha L. and D. E. Smylie (1971), The displacement fields of inclined faults, Bulletin of the Seismological Society of America, 61 (5), 1433-440.
  Melgar , D., and Y. Bock (2013), Near-field tsunami models with rapid earthquake source inversions from land- and ocean-based observations: The potential for forecast and warning, Journal of Geophysical Research: Solid Earth, 118 (11), 2013JB010,506, doi:10.-002/-013JB010506 .
  Minson , S. E., M. Simons , J. L. Beck , F. Ortega , J. Jiang , S. E. Owen , A. W. Moore , A. Inbal , and A. Sladen (2014), Bayesian inversion for finite fault earthquake source models II the 2011 great Tohoku-Oki, japan earthquake, Geophys. J. Int., 198(2), 922-44, doi: 10.-093/?gji/?ggu170 .
  Moreno M. S., J. Bolte , J. Klotz and D. Melnick (2009), Impact of megathrust geometry on inversion of coseismic slip from geodetic data: Application to the 1960 Chile earthquake, GRL, doi:10.-029/-009GL039276 ).
  Nettles , M., G. Ekstrom , and H.?C. Koss (2011), Centroid-moment-tensor analysis of the 2011 off the Pacific coast of Tohoku earthquake and its larger foreshocks and aftershocks, Earth Planets Space, 63(7), 519-23.
  Okada , Y. (1985), Surface deformati
• 作者单位：Quentin Bletery (1)
  Anthony Sladen (1)
  Bertrand Delouis (1)
  Lionel Mattéo (1)
  
  1. CNRS, IRD, Observatoire de la C?te d’Azur, Géoazur UMR 7329, Univ. Nice Sophia Antipolis, 250 rue Albert Einstein, Sophia Antipolis, 06560, Valbonne, France
  
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geophysics and Geodesy
  
• 出版者：Birkh盲user Basel
• ISSN：1420-9136

文摘

The strong development of tsunami instrumentation in the past decade now provides observations of tsunami wave propagation in most ocean basins. This evolution has led to the wide use of tsunami data to image the complexity of earthquake sources. In particular, the 2011 M_w9.0 Tohoku-Oki earthquake is the first mega-event for which such a tsunami instrumentation network was available with an almost complete azimuthal coverage. Source inversion studies have taken advantage of these observations which add a lot of constrain on the solutions, especially in the shallow part of the fault models where other standard data sets tend to lack resolution: while on-land data are quite insensitive to slip on the often-distant shallow part of a subduction fault interface, tsunami observations are directly sensitive to the shallowest slip. And it is in this shallow portion that steep bathymetry combined with horizontal motion, the so-called bathymetry effect, can contribute to the tsunami excitation, in addition to the direct vertical sea-bottom deformation. In this study, we carefully investigate the different steps involved in the calculation of this bathymetry effect, from the initial sea-floor deformation to the prediction of the tsunami records, and evaluate its contribution across the main subduction zones of the world. We find that the bathymetry effect locally exceeds 10 % of the tsunami excitation in all subduction zones and 25 % in those known to produce the largest tsunami, either from mega- or tsunami- earthquakes. We then show how the bathymetry effect can modify the tsunami wave predictions, with time shifts of the wavefront and amplitudes sometimes varying by a factor of two. If the bathymetry effect can have a strong impact on the simulated tsunami, it will also affect the solution of the finite-fault slip inversion. We illustrate this later aspect in the case of the Tohoku-Oki earthquake. We find that not accounting for the bathymetry effect will not necessarily cause strong variations in the spatial extent of the inferred coseismic rupture but can severely distort the solution. We also find that the bathymetry effect improves the consistency of the slip model inverted from tsunami data with seafloor geodesy observations, implying that taking the bathymetry effect into account reduces the epistemic uncertainties on tsunami modeling. Implementing this easily quantifiable effect in the tsunami early warning system could thus lead to improved estimates of the tsunami impact across ocean basins. Electronic supplementary materialThe online version of this article (doi:10.-007/?s00024-015-1113-y) contains supplementary material, which is available to authorized users.