Some Figures Concerning South Iceland

Seismograms

- Fig. 1 Transverse-horizontal component record section of a local
earthquake showing clear shear waves. (PostScript version).
(LDEO AH format seismograms).

Velocity Structures

- Fig. 1 Traveltimes, phase velocities and their ratio for P and S waves from local
earthquakes. (PostScript version).

- Fig. 2 SIST experiment compressional velocity 1D model.
(PostScript version). (Table).

Shear Wave Splitting

- Fig. 1 Horizontal-component seismograms of local earthquakes
showing shear wave splitting. Columns 1 and 3 show original data, columns 2 and 4 after
rotation and time shift as given in figure. Bar is 1s long. (PostScript version).

- Fig. 2 Seismogram os a local earthquake recorded on station
HEI in the western volcanic zone of southwest Iceland. Two horizontal comonents (rotated
to N40E and N130E) and the vertical component are shown. Note that clear splitting of the
S wave. (PostScript version).

Polarization analysis

- Fig. 1 Apparent angle of incidence of the P wave of local
earthquakes vs. earthquake depth. (PostScript version).

Attenuation

- Fig. 1 P wave and S wave mplitudes vs. range for shallow (< 5 km)
local earthquakes, compared to a model with an upper later with Qs=50 overlaying a halfspace
with Qs=300. (PostScript version).

- Fig. 2 Frequency dependence of attenuation seems to be small.
(PostScript version).

- Fig. 3.Results of 1D inversion of the variation of quality
factor with depth. (Top) Compressional wave quality factor; (Bottom) Inversion results,
quality factor vs. depth for a 1-D model with 4 km thick laters. The path averaged quality
factor data (circles) and predictions (squares) are also shown, plotted at the maximum
depth of penetration of the ray. (PostScript).
(Table).

- Fig. 4. Quality factors in the upper 4 km of crust, from
an inversion of microearthquake data. (Top) Map showing data microearthquake hypocenters
(circles) and stations (triangles). (Middle) Compressional wave quality factors; (Bottom)
Shear wave quality factors. (PostScript).

- FIg. 5. Compressional and shear wave quality factor ratios.
Path averaged observations (squares), surface layer inversion results (circles), Qs=1.4Qp
(solid line), Qs=Qp (dotted line). (PostScript).

Katla Undershooting

- Fig. 1Two record sections from Katla Undershooting
Experiment that show delayed P waves and S-wave shadows. (PostScript).

- Fig. 2Image of P-wave velocity beneath Latla Volcano (inset shows velocity perturbation from reference structure). (PostScript).

Miscellaneous

- Fig. 1.Northern Mid-Atlantic Ridge and Iceland.

- Fig. 2.Map of Iceland. (PostScript).

- Fig. 3.Locations of various refraction profiles. (PostScript).