Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Body waves."”.
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Determination of earthquake source parameters from inversion of body waves
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984.
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Near-receiver scattering of teleseismic body waves in layered crust-mantle models having irregular interfaces.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1970.
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Development of the Spectral-Analysis-of-Body-Waves (SABW) method for downhole seismic testing with boreholes or penetrometers
… ratios, especially in the case of shear waves which arrive later in the time record. To avoid picking reference points, a cross-correlation method is sometimes applied to determine travel times of the seismic waves, especially in traditional downhole testing. One benefit of the …
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Upper-mantle velocity structure beneath the western Philippine Sea plate from body waves, surface waves, and SCS reverberations
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996.
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Seismic effects of the Caloris basin impact, Mercury
… formed as a consequence of focused seismic waves generated by the massive impact event. In this paper, we revisit the antipodal seismic focusing effects of the Caloris impact by developing physically consistent structure models for Mercury and parameterized seismic source models for the …
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Analyses and Applications of Seismic Surface Waves Using Machine Learning Algorithm
Surface waves are energetic signal components in the seismic inversion for near-surface elastic properties. However, they are noise components in reflection seismology in hydrocarbon exploration. Detecting and outlining the region of surface waves in seismic gathers facilitates either their …
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APPROXIMATE VS. PURELY NUMERICAL APPROACHES FOR FULL WAVEFORM MODELLING OF GLOBAL EARTH STRUCTURE
… on the global seismic forward modelling of body and surface waveforms in realistic 3-D Earth models using approximate and purely numerical methods. Firstly, we investigate two techniques: (i) the Born approximation, which should be valid for media with weak heterogeneity; and, (ii) the full …
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Seismic Evidence for Layering at the Core-Mantle Boundary
… ends of the frequency spectrum - high-frequency body waves and long-period normal modes. Before applying body waves to the CMB, this thesis first addresses the problem of ellipticity corrections for seismic phases such that they can be applied correctly to any seismic phase in any planetary …
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ΧΑΡΑΚΤΗΡΙΣΤΙΚΕΣ ΠΑΡΑΜΕΤΡΟΙ ΣΕΙΣΜΙΚΗΣ ΠΗΓΗΣ ΜΕ ΤΗ ΜΕΘΟΔΟ ΤΗΣ ΑΝΤΙΣΤΡΟΦΗΣ ΤΩΝ ΚΥΜΑΤΩΝ ΧΩΡΟΥ: ΕΛΛΑΔΑ ΚΑΙ Η ΕΥΡΥΤΕΡΗ ΠΕΡΙΟΧΗ ΤΗΣ
… AN INVERSION TECHNIQUE OF TELESEISMIC BODY WAVES WAS USED FORRECORDINGS AT 30-90. RECORDING FROM 12-16 STATIONS OF P AND SH WAVEFORMS HAVE BEEN INVERTED SIMULTANEOUSLY, TO GIVE FOCAL MECHANISMS, SOURCE DURATION, RAPTURE COMPLEXITY, SEISMIC MOMENT AND STRESS DROP. FIVE AREAS HAVE BEEN …
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Numerical modeling, suppression, and imaging of elastic wave scattering by near-surface heterogeneities
… the scatterer locations. Moreover, the scattered waves consist mostly of body waves scattered to surface waves and are, generally, as large as, or larger than, the reflections. These scattered waves often obscure weak primary reflections and can severely degrade the image quality. The results …
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Digital filters and applications to seismic detection and discrimination
… in which digital filters are applied to seismic body waves to i) try to determine whether the first arrival is up or down on a seismogram corrupted with microseismic noise, 2) increase signal-to-noise ratio on seismograms where noise has almost obliterated signal 3) assign polarity to each of two …
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Body and surface wave ambient noise seismic interferometry across the Salton Sea Geothermal Field, California
… successfully that contained strong surface waves at 0.4-2.5 Hz, an order of magnitude below the corner frequency of the geophones, and modest body waves at 22-30 Hz, which are generally more difficult to obtain due to the need for many large, well-distributed subsurface sources. The virtual …
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Studies on earthquake location and source determination using coda waves
… result from scattering and focus on early onset body waves to model earthquake location and source properties. A recent technique known as coda wave interferometry utilises the cross correlation of coda waves to constrain changes in source properties between earthquake pairs. This thesis focuses …
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Studies on earthquake location and source determination using coda waves
… result from scattering and focus on early onset body waves to model earthquake location and source properties. A recent technique known as coda wave interferometry utilises the cross correlation of coda waves to constrain changes in source properties between earthquake pairs. This thesis focuses …
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New insights into the differential rotation of the inner core
Time-dependent travel times of seismic waves traversing the inner core (IC) from repeating earthquakes provided compelling evidence for an IC differential motion. In this dissertation, we conducted a systematic search for strong repeating earthquakes in the last three decades to examine the global …
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Velocity and anisotropy structure of the Icelandic crust - An ambient seismic noise analysis
Measuring the travel times of seismic waves is one of the most important tools for uncovering Earth’s structure and dynamics. In recent years, the discovery that surface wave dispersion could be estimated from ambient noise has introduced new possibilities into the field of seismic imaging, such as …
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Advanced analysis of complex seismic waveforms to characterize the subsurface Earth structure
This thesis includes three major parts, (1) Body wave analysis of mantle structure under the Calabria slab, (2) Spatial Average Coherency (SPAC) analysis of microtremor to characterize the subsurface structure in urban areas, and (3) Surface wave dispersion inversion for shear wave velocity …
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Shallow and deep deformation in northern Apennines region using seismological data
… allowing the use in the inversion of surface waves [and not only of the body waves as the Centroid Moment Tensor (Dziewonski et al., 1981) one] allow to determine seismic source parameters for earthquakes with magnitude as small as 4.0. We applied this tool in the Northern Apennines and …
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Global Structure of the Mantle Transition Zone Discontinuities and Site Response Effects in the Atlantic and Gulf Coastal Plain
… The finite-frequency sensitivities of SS waves and precursors are calculated based on a single-scattering (Born) approximation and can be used for data selection. The new global models show a number of smaller-scale features that were absent in back-projection models. Good correlation …
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Combining body wave tomography, surface wave inversion, seismic interferometry and laboratory measurements to characterize the black shales on Bornholm at different scales
… In the laboratory measurements the seismic body waves were recorded for different pressure and temperature stages. Therefore, samples of different depths of the Alum Shale were available from one of the scientific boreholes at the study location. The measured velocities have a high variance …
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