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

Simultaneous inversion of 3D velocit...

Preston, Leiph Alexander.

FindBook

Google Book

Amazon

博客來

Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia./
作者:	Preston, Leiph Alexander.
面頁冊數:	113 p.
附註:	Source: Dissertation Abstracts International, Volume: 64-11, Section: B, page: 5415.
Contained By:	Dissertation Abstracts International64-11B.
標題:	Geophysics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3111122

Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia.
Preston, Leiph Alexander.

Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia. - 113 p.

Source: Dissertation Abstracts International, Volume: 64-11, Section: B, page: 5415.

Thesis (Ph.D.)--University of Washington, 2003.

We develop and apply a non-linear inversion of direct and wide-angle reflection travel times for 3-D P-wave velocity structure, earthquake hypocenters, and reflector geometry under NW Washington focusing on the structure of the subducting Juan de Fuca plate. The first-arrival travel times are derived from both active-source experiments and from local earthquakes. The reflection arrivals were picked from data collected during the 1998 Wet SHIPS active-source experiment, which consisted of air-gun sources within the inland water-ways of NW Washington and SW British Columbia to land-based stations. Our inversion procedure reduces the well-known trade-off between reflector position and the velocities above it by the combination of simultaneous inversion and adequate crossing paths. We interpret the wide-angle reflector as the Moho of the subducting Juan de Fuca slab. The relocated intraslab earthquakes separate into two groups: those located up-dip of the 45km reflector depth contour generally lie below the reflector in material whose velocity exceeds 7.7km/s, placing them within the subducting mantle, while those down-dip of this contour occur within material whose velocities are 6.8–7.5km/s, placing them within subducted oceanic crust. We interpret these groups of earthquakes as resulting from serpentine dehydration in the subducted mantle and the basalt to eclogite transformation in the subducted crust. We have performed velocity checkerboard, slab velocity resolution, and parameter sensitivity tests to estimate our ability to resolve the relationship among the reflector, intraslab hypocenters, and slab velocity structure. These tests indicate we have the necessary resolvability and can distinguish the relative locations among the velocities, reflector, and intraslab hypocenters within the subducting slab to ±2km. The occurrence of events within the subducted mantle geometrically allows for larger magnitude earthquakes than could occur if they were confined to the oceanic crust. Additionally, the large amplitude of the reflected arrivals relative to direct arrivals suggests that slab reflections should be included in strong ground motion studies. The release of fluids attendant with the basalt to eclogite transformation have observable consequences which may be related to recent discoveries of slow slip events, tremor events, and a serpentinized mantle wedge.Subjects--Topical Terms:

535228
Geophysics.

Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia.
LDR:03287nmm 2200253 4500 001 1859418
005 20041014084351.5
008 130614s2003 eng d
035 $a (UnM)AAI3111122
035 $a AAI3111122
040 $a UnM $c UnM
100 1 $a Preston, Leiph Alexander. $3 1947076
245 1 0 $a Simultaneous inversion of 3D velocity structure, hypocenter locations, and reflector geometry in Cascadia.
300 $a 113 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-11, Section: B, page: 5415.
500 $a Chair: Kenneth C. Creager.
502 $a Thesis (Ph.D.)--University of Washington, 2003.
520 $a We develop and apply a non-linear inversion of direct and wide-angle reflection travel times for 3-D P-wave velocity structure, earthquake hypocenters, and reflector geometry under NW Washington focusing on the structure of the subducting Juan de Fuca plate. The first-arrival travel times are derived from both active-source experiments and from local earthquakes. The reflection arrivals were picked from data collected during the 1998 Wet SHIPS active-source experiment, which consisted of air-gun sources within the inland water-ways of NW Washington and SW British Columbia to land-based stations. Our inversion procedure reduces the well-known trade-off between reflector position and the velocities above it by the combination of simultaneous inversion and adequate crossing paths. We interpret the wide-angle reflector as the Moho of the subducting Juan de Fuca slab. The relocated intraslab earthquakes separate into two groups: those located up-dip of the 45km reflector depth contour generally lie below the reflector in material whose velocity exceeds 7.7km/s, placing them within the subducting mantle, while those down-dip of this contour occur within material whose velocities are 6.8–7.5km/s, placing them within subducted oceanic crust. We interpret these groups of earthquakes as resulting from serpentine dehydration in the subducted mantle and the basalt to eclogite transformation in the subducted crust. We have performed velocity checkerboard, slab velocity resolution, and parameter sensitivity tests to estimate our ability to resolve the relationship among the reflector, intraslab hypocenters, and slab velocity structure. These tests indicate we have the necessary resolvability and can distinguish the relative locations among the velocities, reflector, and intraslab hypocenters within the subducting slab to ±2km. The occurrence of events within the subducted mantle geometrically allows for larger magnitude earthquakes than could occur if they were confined to the oceanic crust. Additionally, the large amplitude of the reflected arrivals relative to direct arrivals suggests that slab reflections should be included in strong ground motion studies. The release of fluids attendant with the basalt to eclogite transformation have observable consequences which may be related to recent discoveries of slow slip events, tremor events, and a serpentinized mantle wedge.
590 $a School code: 0250.
650 4 $a Geophysics. $3 535228
690 $a 0373
710 2 0 $a University of Washington. $3 545923
773 0 $t Dissertation Abstracts International $g 64-11B.
790 1 0 $a Creager, Kenneth C., $e advisor
790 $a 0250
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3111122