| Author(s) | A.M. AI-Amri*, P. Davis**, M. S. AI-Amri***, A. A Gharib* and |
| Affiliation | *Sei.fmic Studies Center. King Saud University. Riyadh. Saudi Arabia ** Institute (!f Geophysics and Planetary Physics. Univer.fity of CalitcJrnia. San Diexo ***IAGR. King A.bdulaziz City for Science and Technology. Riyadh. Saudi Arabia |
| Title | Seismic Characteristics of RAYN / GSN Station, |
| Source | Journal of King Saud University. Science. Volume 11, No 2. (1999/1419) |
| Abstract | The IRISIIDA station RA YN. Saudi Arabia is one of the newest stations in the IRIS Global Seismographic Network (GSN). Ambient seismic ground noise levels and minimum detectable magnitudes were estimated for this station. Noise conditions showed that RA YN station was very quiet with noise levels near the USGS Low Noise Model for frequencies higher than 0.1 Hz. At lower frequencies, the horizontal components showed increased noise levels, possibly due to instrumental characteristics. High frequency (1Hz) noise varied as much as 10 dB between day and night Seasonal noise levels also varied, with April to June being the quietest and with October to December being the nosiest months. Slight changes in peak microseism frequency also occurred seasonally. Generally, noise levels were quietest at night and noisiest during morning and early afternoon, as expected for cultural noise. The most significant variations occurred at frequencies above I Hz. Minimum detectable magnitudes were estimated for RAYN using the observed noise levels over I Hz. The mb detection threshold for the distance range of 5 -lOdegreesisaboutmb=2.7-3.0assuminga signal-to-noise ratio of 3 dB or better. The magnitude estimates increase with increasing frequency. |
