Podrobnosti záznamu

Název
    SEISMIC MEASUREMENTS ON A ROCK MASSIF SURFACE AT SHORT DISTANCES
Autor
    Lokajicek, Tomas
    Rudajev, Vladimir
    Vilhelm, Jan
    Zivor, Roman
Jazyk
    anglicky
Typ dokumentu
    článek v periodiku
Zdrojový dokument - seriál
    Acta Geodynamica et Geomaterialia
Svazek/č.
    Roč. 9, č. 2
Strany
    11
Rok
    2012
Výraz tezauru
    repeatability of measurement
    seismic P- and S-waves
    seismic source
    velocity measurement
Klíčové slovo
    DISTANCES
    MASSIF
    MEASUREMENTS
    ROCK
    SEISMIC
    SHORT
    SURFACE
Abstrakt (anglicky)
   Various geotechnical tasks require the knowledge of rock properties, e.g., of elastic moduli, fracture systems, inhomogeneities, etc. Seismic measurements usually provide these parameters. To describe the detailed properties of small rock volumes, it is necessary to use high-frequency signals and suitable registration systems. Seismic measurements are carried out directly on rock surfaces. Although the conditions, under which measurements are carried out, seem to be simple and convenient, practical measurements themselves are often complicated. The various measuring systems, including seismic sources and seismic receivers used for different base lengths, are discussed in this paper. It was found that, for the repeatability of measurements, the fixing of the sensors with plaster plays most significant role. Repeatability of hammer blow as seismic source is adversely affected namely by signal amplitude triggering. Pencil lead breaking tests with lead 1 and 6 mm in diameter were found as
   suitable for testing of the high-frequency measuring systems. Measuring directly on the rock massif surface is different compared to exploration seismic measurements. Due to absence of a low-velocity layer it necessary to use a special choice of mutual orientation of sources and receivers. Polarization analysis may be advantageous to identify the arrival of P and S seismic waves. It was also found that the rock massif behaves as a narrow frequency-band pass filter. For exciting frequencies of 0.1 and 1 MHz the transmitted signal displayed the same frequency of 25 kHz at a distance of 1.1 m.
Přispěvatel
    UK Praha, Přírodovědecká fakulta
Kód přispěvatele
    UK, PřF
Zdrojový formát
    R
Datum importu
    27. 4. 2014