نتایج جستجو برای: mantle and moho

تعداد نتایج: 16831278  

2002
M. Ravi Kumar D. S. Ramesh Joachim Saul Dipankar Sarkar Rainer Kind

[1] Analysis of receiver functions from an eight-station network on the Saudi Arabian shield indicates that the Moho depths vary between 35–38 km. The crust appears to be rather felsic in nature as evidenced by Poisson’s ratios of 0.25–0.27. A prominent negative phase following the Moho conversion is suggestive of a zone of velocity inversion. Indication of mantle stratification is observed ben...

ژورنال: فیزیک زمین و فضا 2020

Receiver functions are usually used to detect Ps converted waves and are especially useful to picture seismic discontinuities in the crust and upper mantle. In this study, the P receiver function technique beneath the west Iran is used to map out the lateral variation of the Moho boundary. The teleseismic data (Mb ≥5.5, epicentral distance between 30˚-95˚) recorded from 2004 to 2016 at 17 perma...

1998
F. Waldhauser E. Kissling J. Ansorge

We present a new approach to determine the 3-D topography and lateral continuity of seismic interfaces using 2-D-derived controlled-source seismic reflector data. The aim of the approach is to give the simplest possible structure consistent with all reflector data and error estimates. We define simplicity of seismic interfaces by the degree of interface continuity (i.e. shortest length of offse...

2002
Vadim Levin Jeffrey Park Mark Brandon Jonathan Lees Valerie Peyton Evgenii Gordeev Alexei Ozerov

Teleseismic receiver functions (RFs) from a yearlong broadband seismological experiment in Kamchatka reveal regional variations in the Moho, anisotropy in the supra-slab mantle wedge, and, along the eastern coast, Ps converted phases from the steeply dipping slab. We analyze both radialand transverse-component RFs in bin-averaged epicentral and backazimuthal sweeps, in order to detect Ps moveou...

2004
Heather R. DeShon Susan Y. Schwartz

[1] Characterizing the hydration state of the forearc mantle wedge yields valuable information on frictional stability at the downdip edge of subduction megathrusts. Simultaneous inversion of Pand S-wave arrival times collected as part of the Costa Rica Seismogenic Zone Experiment yields 1D and 3D Pand S-wave velocity models (VP and VS) for the Nicoya Peninsula segment of the Middle America Tre...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشکده علوم زمین سازمان زمین شناسی و اکتشافات مع 1390

the neogene intrusion masses in the noudeh-enghelab area located to the north of sabzevar ophiolite have cut the late cretaceous ophiolitic rocks, sedimentary- volcanic and eocene volcanic rocks and have been covered by pliocene and quaternary deposits. the margin is of lava with basalt, phyric andesite-basalt and andesite and the central parts (dome shaped) composed of phyric andesite-trachyan...

2007
STEVEN R. BRATT SEAN C. SOLOMON CLIFFORD H. THURBER

We present models for the structure of the crust and upper mantle beneath lunar impact basins from an inversion of gravity and topographic data from the nearside of the moon. All basin models display a thinner crust and an elevated Moho beneath the central basin region compared to surrounding areas, a signature of the processes of basin excavation and mantle uplift during collapse of the transi...

2014
Shintaro Azuma Ikuo Katayama Tomoeki Nakakuki

Plate tectonics is largely responsible for material and heat circulation in Earth, but for unknown reasons it does not exist on Venus. The strength of planetary materials is a key control on plate tectonics because physical properties, such as temperature, pressure, stress, and chemical composition, result in strong rheological layering and convection in planetary interiors. Our deformation exp...

2004
E. O. WALSH

Thermobarometry suggests that ultrahigh-pressure (UHP) to high-pressure (HP) rocks across the Western Gneiss Region ponded at the Moho following as much as 100 km of exhumation through the mantle and before exhumation to the upper crust. Eclogite across the c. 22 000 km study area records minimum pressures of c. 8–18 kbar and temperatures of c. 650–780 C. One orthopyroxene eclogite yields an UH...

2003
A. M. READING B. L. N. KENNETT M. C. DENTITH

The deep crustal and upper mantle structure of the Yilgarn Craton is investigated in this study using receiver-function analysis of teleseismic earthquake records from temporary stations. Two lines of stations were deployed, the main transect ran between Perth and Kalgoorlie, and a second line of stations ran across the east Yilgarn Craton 200 km to the north of Kalgoorlie. The broadband instru...

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