The earthquake in Vatnafjöll, 25 May 1987 (M = 5.8), was the largest earthquake in south Iceland since 1912 (M = 7), and it was one of the first earthquakes recorded on a local network of strong-motion acceleration recorders. In this study, the strong-motion records are used to obtain an estimate of the source parameters and the attenuation of high-frequency waves. The source parameters are obtained by fitting the data by a dislocation source model combined with an exponential model for the attenuation. The root-mean-squared acceleration is also estimated and compared to predicted values using the source parameters. The source parameters estimated here (M0 = 8.2 × 1024 dyn-cm, r = 4.6 km, Δσ = 38 bars, Δu = 36 cm, Td = 3 sec) and estimated moment magnitude (Mw = 5.9) agree well with values obtained previously from teleseismic waves and strain-meter data. Estimates of path-averaged crustal shear-wave quality factors give results in the range Q = 128 to 425, and k = 0.05 sec for the spectral decay parameter, confirming recent measurements of higher crustal Q for this region than in earlier studies.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.