R. Herbst et al., SEISMIC SOURCES FOR SHALLOW INVESTIGATIONS - A FIELD COMPARISON FROM NORTHERN GERMANY, Journal of applied geophysics, 38(4), 1998, pp. 301-317
Citations number
9
Categorie Soggetti
Geosciences, Interdisciplinary","Mining & Mineral Processing
A field test of 14 seismic P-wave sources was designed to show the cap
abilities of several sources for shallow subsurface investigations in
the quaternary landscapes of Northern Germany. The sources included ac
celerated dropped weights, shallow blasts, a shotgun using blank cartr
idges and controlled signal sources. Local changes in subsurface condi
tions showed a strong influence on the recorded data: so it proved nec
essary to record up to 120 shots per source in order to Set representa
tive results and to compare not only single shot records but stacked s
ections as well. Reducing the geophone spacing to 1 m, it became possi
ble to trace very local features like fluctuations in travel times or
in the recorded amplitudes. The amplitude spectra of the recorded trac
es indicated energy at frequencies up to 200 Hz and showed remarkable
spatial changes due to different subsurface conditions near the receiv
er locations. Changes in signal form and amplitude due to compacting e
ffects were visible in the first four impacts of strong sources. (C) 1
998 Elsevier Science B.V.