東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Global Full-Waveform Tomography Usin...

French, Scott Winfield.

FindBook

Google Book

Amazon

博客來

Global Full-Waveform Tomography Using the Spectral Element Method: New Constraints on the Structure of Earth's Interior.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Global Full-Waveform Tomography Using the Spectral Element Method: New Constraints on the Structure of Earth's Interior./
作者:	French, Scott Winfield.
面頁冊數:	173 p.
附註:	Source: Dissertation Abstracts International, Volume: 76-02(E), Section: B.
Contained By:	Dissertation Abstracts International76-02B(E).
標題:	Geophysics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3640432
ISBN:	9781321258929

Global Full-Waveform Tomography Using the Spectral Element Method: New Constraints on the Structure of Earth's Interior.
French, Scott Winfield.

Global Full-Waveform Tomography Using the Spectral Element Method: New Constraints on the Structure of Earth's Interior. - 173 p.

Source: Dissertation Abstracts International, Volume: 76-02(E), Section: B.

Thesis (Ph.D.)--University of California, Berkeley, 2014.

This item must not be sold to any third party vendors.

The radially anisotropic shear-velocity structure of the earth's mantle provides a critical window on the interior dynamics of the planet, with isotropic variations interpretable in terms of thermal and compositional heterogeneity and anisotropy in terms of flow. Indeed, more than 30 years after the advent of global seismic tomography, many open questions remain regarding the dual roles of temperature and composition in shaping mantle convection, as well as interactions between different dominant scales of convective phenomena. To this end, we use full-waveform inversion of the long-period teleseismic wavefield to image radially anisotropic shear-wave velocity at the scale of the entire globe. In particular, we use a technique which we have termed the "hybrid" waveform-inversion approach, which combines the accuracy and generality of the spectral finite element method (SEM) for forward modeling of the global wavefield, with non-linear asymptotic coupling theory for efficient inverse modeling. This hybrid technique helps considerably in making SEM-based global waveform inversion tractable, as it allows for the use of a rapidly converging Gauss-Newton scheme for optimization of the underlying seismic model. We take additional steps to reduce the cost of these inversions using novel techniques for treatment of the earth's crust. Namely, naive modeling of thinly layered crustal structure can lead to an overly restrictive time-stability condition in the SEM, which in turn drives up the cost these simulations. Instead, taking advantage of the physics of long-period wave propagation, we introduce alternative parameterizations of crustal structure which appear identical to the wavefield, but relax these constraints on stability.

ISBN: 9781321258929Subjects--Topical Terms:

535228
Geophysics.

Global Full-Waveform Tomography Using the Spectral Element Method: New Constraints on the Structure of Earth's Interior.
LDR:03877nmm a2200301 4500 001 2061182
005 20150929074121.5
008 170521s2014 ||||||||||||||||| ||eng d
020 $a 9781321258929
035 $a (MiAaPQ)AAI3640432
035 $a AAI3640432
040 $a MiAaPQ $c MiAaPQ
100 1 $a French, Scott Winfield. $3 3175414
245 1 0 $a Global Full-Waveform Tomography Using the Spectral Element Method: New Constraints on the Structure of Earth's Interior.
300 $a 173 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-02(E), Section: B.
500 $a Adviser: Barbara Romanowicz.
502 $a Thesis (Ph.D.)--University of California, Berkeley, 2014.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a The radially anisotropic shear-velocity structure of the earth's mantle provides a critical window on the interior dynamics of the planet, with isotropic variations interpretable in terms of thermal and compositional heterogeneity and anisotropy in terms of flow. Indeed, more than 30 years after the advent of global seismic tomography, many open questions remain regarding the dual roles of temperature and composition in shaping mantle convection, as well as interactions between different dominant scales of convective phenomena. To this end, we use full-waveform inversion of the long-period teleseismic wavefield to image radially anisotropic shear-wave velocity at the scale of the entire globe. In particular, we use a technique which we have termed the "hybrid" waveform-inversion approach, which combines the accuracy and generality of the spectral finite element method (SEM) for forward modeling of the global wavefield, with non-linear asymptotic coupling theory for efficient inverse modeling. This hybrid technique helps considerably in making SEM-based global waveform inversion tractable, as it allows for the use of a rapidly converging Gauss-Newton scheme for optimization of the underlying seismic model. We take additional steps to reduce the cost of these inversions using novel techniques for treatment of the earth's crust. Namely, naive modeling of thinly layered crustal structure can lead to an overly restrictive time-stability condition in the SEM, which in turn drives up the cost these simulations. Instead, taking advantage of the physics of long-period wave propagation, we introduce alternative parameterizations of crustal structure which appear identical to the wavefield, but relax these constraints on stability.
520 $a We approach this imaging problem in an iterative fashion, hoping to learn something about the earth's interior at each step. First, we present our work focused on the upper mantle and transition zone (≤ 800km depth) in the form of the global model SEMum2, discussing both its development and general properties. Second, we take a detailed look at novel structures in SEMum2 - namely, never-before-seen low-velocity structures in the upper mantle beneath the ocean basins, showing intriguing correlations with other geophysical observables (e.g. absolute plate motions and the geoid). Third, we move on to imaging of the whole mantle, examining the relationships between different scales of convective phenomena in the upper and lower mantle, and particularly those previously seen in SEMum2. Finally, we discuss novel computational aspects of our work, focusing specifically on applications of the partitioned global address-space model of parallel computation to the large-scale data-driven calculations underlying our hybrid inversion approach.
590 $a School code: 0028.
650 4 $a Geophysics. $3 535228
690 $a 0373
710 2 $a University of California, Berkeley. $b Earth and Planetary Science. $3 3175415
773 0 $t Dissertation Abstracts International $g 76-02B(E).
790 $a 0028
791 $a Ph.D.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3640432