| Autor: |
A.H. Kocaoglu, L.T. Long, J. Martin |
| Rok vydání: |
2000 |
| Předmět: |
|
| Zdroj: |
13th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems. |
| DOI: |
10.3997/2214-4609-pdb.200.2000_005 |
| Popis: |
Surface-wave group-velocity tomography provides an efficient way to measure the shallow S-wave structure at waste sites and other areas where measurements are not advisable directly above the structure. In this technique, measurements are made only on the boundary of a test area. The wavelength and area dimensions determine the depth of resolution. For example, structures in the depth range of 1 to 8 m may be interpreted from 16 to 48 Hz surface waves traversing a 30 m square. Given sufficiently dense record traces, the horizontal resolution is limited principally by wavelength. A 40 Hz wave will resolve structures less than 2 m in diameter near the surface. Unlike phase velocity measurements (e.g. SASW) corrections for energy delays introduced by the instrument response and geophone ground coupling are required for accurate velocity determination. The multiple filter technique is used to determine group arrival times and their uncertainties at individual frequencies. The SIRT algorithm is used to obtain a tomographic image of the group velocity at each frequency. The images for individual frequencies can be used to interpret geologic structure, or they can be combined to generate group-velocity dispersion curves and their associated S-wave structure for any position in the test area. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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