Surface wave waveform anomalies at the Saudi Seismic Network

This paper describes surface wave waveforms observed at the Saudi Arabian S eismic Network. We identify records corresponding to events occuring in the Kuril Islands region as anomalous and discuss possible causes for the wave form distortions. Most likely, tile waveform anomalies are caused by constr uctive and destructive interference of laterally refracted wave packets. So me waveform anomalies are probably of instrumental origin and we suspect a calibration error for the vertical component at station RIYD. For station A FIF, we find a significant clockwise rotation of the horizontal components with respect to geographic North by approximately 4 degrees.