Integrated geophysical studies of continental transforms
- 出版日期：2007
- 页数：1 online resource.
- 第一责任说明：Neda Bundalo.
- 分类号：a247 ; a630
- ISBN：9780549206569(e-book) :
MARC全文
62h0047176 20131202151301.0 cr an |||||||| 131023s2007 a fsbm |000|0 eng | 3279585 9780549206569(e-book) : CNY371.35 NGL eng NGL a247 ; a630 Bundalo, Neda. Integrated geophysical studies of continental transforms [electronic resource] : San Andreas and Alpine Faults / Neda Bundalo. 2007 1 online resource. Description based on online resource; title from title page (viewed Oct. 23, 2013) Thesis (Ph.D.)--University of Houston, 2007. Includes bibliographical references. Continental transform margins are broad, complex regions dominated by strike-slip motion that mark the boundary between lithospheric plates. To better understand plate interactions at continental transforms, variations in crustal and upper mantle structure along the San Andreas transform margin have been investigated using gravity, magnetic and seismic data. Two-dimensional 2D) and three-dimensional 3D) gravity models have been constructed to analyze the distribution of density along the plate margin. In addition, analyses of gravity and magnetic anomalies and their enhancements have been used to map the spatial distribution of tectonics blocks involved in the development of the transform margin. In northern and central California, 2D gravity models constrained by regional seismic reflection and refraction data profiles have been developed. In southern California, the distribution of crustal elements is such that a 3D modeling approach is more appropriate. The 3D gravity model was constructed using the geometry of the Southern California Earthquake Center 3D seismic velocity model version 3. For both types of gravity models, density values were obtained from seismic P-wave density conversions. For northern and central California, results of this study are consistent with evolutionary models that assume no remnant subducted Farallon slab beneath North America. In particular, the results agree well with the predictions of the dynamic slab model that assume magmatic underplating and metamorphic changes in lower crust. For southern California, the 3D gravity model, and distribution of gravity and magnetic anomalies are consistent with a plate capture model during the early stages of plate boundary development. Residuals in the 3D gravity model of the crust and uppermost mantle, however, suggest that the recent development has been more complicated. Spatially coherent residual gravity highs indicate a high density body at depths ＞ 50 km beneath the San Gabriel Mountains that is interpreted to be lithospheric mantle down-welling produced during the past 5 My as a compressional component developed along the Big bend of the San Andreas fault in response changes in relative plate motion. A similar phenomenon has been observed along the oblique convergent Alpine Fault plate boundary in New Zealand. Geophysicz ; San Andreas Fault (Calif.) ; Faults (Geology) ; Prospecting California. ; California. ; Geophysical methods. Electronic dissertations local. aInternet resource. aCN b010001 http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=IBkZ9JOb5Cg%3d 010001 Bs2751 rCNY371.35 ; h1 bs1312