Open AccessModal synthesis of high‐frequency waves in Scotland
Author(s) -
MacBeth C. D.,
Panza G. F.
Publication year - 1989
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1989.tb04456.x
Subject(s) - seismogram , coda , seismology , geology , dispersion (optics) , modal , fault (geology) , mode (computer interface) , crust , synthetic seismogram , shock (circulatory) , event (particle physics) , scattering , rayleigh wave , aftershock , series (stratigraphy) , seismic wave , surface wave , geophysics , physics , optics , computer science , medicine , paleontology , chemistry , quantum mechanics , polymer chemistry , operating system
Summary. Local recordings on the 1974 LISPB array of a shock from an earthquake series in NW Scotland show a well developed Sg ‐wavegroup and higher mode coda. Using the results of previous work on the group velocity dispersion of the higher mode surface waves, a synthetic seismogram study is carried out to obtain a revised estimate of the depth of the event and investigate the nature of the rupture process. High‐frequency (up to 5 Hz) synthetic seismograms are constructed using a modal summation technique. These indicate that a fault model consisting of a single rupture is inconsistent and that a more appropriate description consists of two components. The main component corresponds to an event at a depth of 10 km and the other a weaker ‘source’ acting at 0.5 km. This result may be interpreted as a double event (both sources occurring on the pre‐existing Strathconan fault with a lateral separation of about 2 km) or a consequence of scattering from buried heterogeneities in the upper crust.