|
Detailed Reference Information |
MacBeth, C. and Snieder, R. (1989). Scattering of high-frequency surface waves in Scotland. Journal of Geophysical Research 94: doi: 10.1029/88JB03702. issn: 0148-0227. |
|
High-frequency (≤5Hz) coda waves for velocities of arrival less than 3 km/s, recorded on vertical component instruments and generated from a local earthquake in Scotland, are analyzed to ascertain their cause. The adaption of existing velocity models and scattering from near-surface irregularities in Scotland such as mountains and lochs are considered as possible causes of the observed behavior. The former mechanism is not feasible, as it implies a significant alteration of the velocities in the upper 2 km crust, contradicting previous seismic surveys in the area. An analysis of the effects of scattering is performed using a formalism derived from the Born approximation. The scattered wave field is computed for interactions between first six Rayleigh and Love modes. The general character of the synthetic seismograms for these scattered waves agrees with the observations on a qualitative basis. The apparent absence of the fundamental mode energy from the records is also explained by the synthetic seismograms. The calculations imply that scatterers with a scale length of less than 300 m are applicable to these data from the northernmost stations but around 2 km for the more southern areas. It is thought that the scale length relates to the size of a region on the slopes of the mountains or lochs where there is a sharp gradient. This study emphasises the effectiveness of linear scattering theory in accounting, on a qualitative basis for many of the observed features of the apparently complex coda waves. ¿ American Geophysical Union 1989 |
|
|
|
BACKGROUND DATA FILES |
|
|
Abstract |
|
|
|
|
|
Keywords
Seismology, Surface waves and free oscillations, Seismology, General or miscellaneous, Seismology, Continental crust, Information Related to Geographic Region, Europe |
|
Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
|
|
|