Source parameter inversion for recent great earthquakes from a decade-long observation of global gravity fields
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In this paper, the authors quantify gravity changes after great earthquakes present within the 10-year long time series of monthly Gravity Recovery and Climate Experiment (GRACE) gravity fields using spherical harmonic normal-mode formulation, the respective source parameters of moment tensor and double-couple were estimated.Abstract:
We quantify gravity changes after great earthquakes present within the 10 year long time series of monthly Gravity Recovery and Climate Experiment (GRACE) gravity fields. Using spherical harmonic normal-mode formulation, the respective source parameters of moment tensor and double-couple were estimated. For the 2004 Sumatra-Andaman earthquake, the gravity data indicate a composite moment of 1.2?×?1023?N?m with a dip of 10°, in agreement with the estimate obtained at ultralong seismic periods. For the 2010 Maule earthquake, the GRACE solutions range from 2.0 to 2.7?×?1022?N?m for dips of 12°–24° and centroid depths within the lower crust. For the 2011 Tohoku-Oki earthquake, the estimated scalar moments range from 4.1 to 6.1?×?1022?N?m, with dips of 9°–19° and centroid depths within the lower crust. For the 2012 Indian Ocean strike-slip earthquakes, the gravity data delineate a composite moment of 1.9?×?1022?N?m regardless of the centroid depth, comparing favorably with the total moment of the main ruptures and aftershocks. The smallest event we successfully analyzed with GRACE was the 2007 Bengkulu earthquake with M0?~?5.0?×?1021?N?m. We found that the gravity data constrain the focal mechanism with the centroid only within the upper and lower crustal layers for thrust events. Deeper sources (i.e., in the upper mantle) could not reproduce the gravity observation as the larger rigidity and bulk modulus at mantle depths inhibit the interior from changing its volume, thus reducing the negative gravity component. Focal mechanisms and seismic moments obtained in this study represent the behavior of the sources on temporal and spatial scales exceeding the seismic and geodetic spectrum.read more
Citations
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Improved methods for observing Earth's time variable mass distribution with GRACE using spherical cap mascons
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Broad plumes rooted at the base of the Earth's mantle beneath major hotspots
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References
More filters
Journal ArticleDOI
Preliminary reference earth model
TL;DR: In this paper, a large data set consisting of about 1000 normal mode periods, 500 summary travel time observations, 100 normal mode Q values, mass and moment of inertia have been inverted to obtain the radial distribution of elastic properties, Q values and density in the Earth's interior.
Book
Quantitative seismology : theory and methods
Keiiti Aki,Paul Richards +1 more
TL;DR: This work has here attempted to give a unified treatment of those methods of seismology that are currently used in interpreting actual data and develops the theory of seismic-wave propagation in realistic Earth models.
Journal ArticleDOI
The 2011 Magnitude 9.0 Tohoku-Oki Earthquake: Mosaicking the Megathrust from Seconds to Centuries
Mark Simons,Sarah E. Minson,Anthony Sladen,Anthony Sladen,F. Ortega,Junle Jiang,Susan Owen,Lingsen Meng,Jean-Paul Ampuero,Shengji Wei,Risheng Chu,Donald V. Helmberger,Hiroo Kanamori,Eric A. Hetland,Angelyn Moore,Frank Webb +15 more
TL;DR: Detailed geophysical measurements reveal features of the 2011 Tohoku-Oki megathrust earthquake and suggest the need to consider the potential for a future large earthquake just south of this event.
Journal ArticleDOI
GGM02 - An Improved Earth Gravity Field Model from GRACE
Byron D. Tapley,John C Ries,Srinivas Bettadpur,Don P. Chambers,Minkang Cheng,Francis Condi,Brian Gunter,Zhigui Kang,Peter Nagel,R. Pastor,T. Pekker,S. R. Poole,Furun Wang +12 more
TL;DR: A new generation of Earth gravity field models called GGM02 are derived using approximately 14 months of data spanning from April 2002 to December 2003 from the Gravity Recovery And Climate Experiment (GRACE) as discussed by the authors.