Saudi Arabian Broadband Array

Summary

Introduction

From November 1995 to March 1997 a total of nine broadband temporary stations were deployed across the Saudi Arabian shield. These stations consisted of STS-2 seismometers recorded continuously at 40 sps on REFTEK dataloggers. All installations were at bedrock sites. The results from our field deployment of nine portable broadband stations suggest that sites in the Arabian shield are extremely quiet. Using data sections selected randomly during the deployment, noise studies showed that most stations were exceptionally quiet with noise levels near the USGS Peterson (1993) 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 ( > 1 Hz) noise varied as much as 10 dB between day and night for some stations (RAYN, TAIF) while more isolated stations (HALM) were constant. Seasonal noise levels also varied, with April to June being the quietest months. Slight changes in peak microseism frequency also occurred seasonally. The quietest stations were HALM, RAYN, AFIF and UQSK, all of which were located in central Saudi Arabia and showed noise levels near the low noise model for frequencies between 0.1 and 4 HZ. The optimal site for a new station would be near HALM as it was both quiet and showed very little diurnal variation due to cultural noise.

The low noise at these stations also contributes to the very low detection threshold of events with mb = 3.5 at distances from 10 to 100 degrees. These stations appear to be among the best sites in the world for the properties of detection thresholds and ground noise levels. Seismograms from sources 10 degrees from the center of the network have unique characteristics which can be used to identify the source regions. Zagros events have a clear Pn and Sn arrivals with an observable Lg. Shallow events from the Arabian Sea have clear P, S, and surface waves but no discernible Lg phases. From the opposite direction, aftershocks from the Gulf of Aqaba have very weak P and S waves with very strong Lg phases.

Station Map

Station map

Station List

(table version)

sta   ondate   offdate   lat   lon   elev   staname   statype   refsta   dnorth   deast   
AFIF   1995001   -1   23.931   43.04   1.116   Afif, Saudi Arabia   ss   HALM   121.2775   -129.8206   
BISH   1995001   1996071   19.9228   42.6901   1.379   Bisha, Saudi Arabia   ss   HALM   -324.0641   -170.17   
HALM   1995001   -1   22.8454   44.3173   0.93   Hadabat Al-Mahri, Saudi Arabia   ss   HALM   0   0   
RANI   1995001   -1   21.3116   42.7761   1.001   Raniyah, Saudi Arabia   ss   HALM   -169.7276   -159.6634   
RAYN   1995001   1996160   23.522   45.5008   0.792   Ar-Rayn, Saudi Arabia   ss   HALM   75.7196   120.6603   
RAYN   1996161   -1   23.5225   45.5032   0.631   Ar-Rayn, Saudi Arabia   ss   HALM   75.7772   120.9045   
RIYD   1996069   -1   24.722   46.643   0.717   Riyadh, Saudi Arabia   ss   HALM   210.5587   234.9251   
SODA   1995001   -1   18.2921   42.3769   2.876   Al-Soda, Saudi Arabia   ss   HALM   -505.0186   -205.0602   
TAIF   1996150   -1   21.281   40.349   2.05   Taif, Saudi Arabia   ss   HALM   -168.5365   -411.1522   
UQSK   1996161   -1   25.789   42.36   0.95   Uqlat Squoor, Saudi Arabia   ss   HALM   328.6509   -196.0379   

Total: 10

Channel List

(table version)

sta   chan   ondate   chanid   offdate   ctype   edepth   hang   vang   descrip   
AFIF   BHE   1995001   2082   -1   n   -0   90   90   -   
AFIF   BHN   1995001   2083   -1   n   -0   0   90   -   
AFIF   BHZ   1995001   2084   -1   n   -0   0   0   -   
BISH   BHE   1995001   2085   1996071   n   -0   90   90   -   
BISH   BHN   1995001   2086   1996071   n   -0   0   90   -   
BISH   BHZ   1995001   2087   1996071   n   -0   0   0   -   
HALM   BHE   1995001   2088   -1   n   -0   90   90   -   
HALM   BHN   1995001   2089   -1   n   -0   0   90   -   
HALM   BHZ   1995001   2090   -1   n   -0   0   0   -   
RANI   BHE   1995001   2091   -1   n   -0   90   90   -   
RANI   BHN   1995001   2092   -1   n   -0   0   90   -   
RANI   BHZ   1995001   2093   -1   n   -0   0   0   -   
RAYN   BHE   1995001   2094   1996160   n   -0   90   90   -   
RAYN   BHE   1996161   2095   1997032   n   0   90   90   -   
RAYN   BHN   1995001   2096   1996160   n   -0   0   90   -   
RAYN   BHN   1996161   2097   1997032   n   0   0   90   -   
RAYN   BHZ   1995001   2098   1996160   n   -0   0   0   -   
RAYN   BHZ   1996161   2099   1997032   n   0   0   0   -   
RIYD   BHE   1996069   2100   -1   n   -0   90   90   -   
RIYD   BHN   1996069   2101   -1   n   -0   0   90   -   
RIYD   BHZ   1996069   2102   -1   n   -0   0   0   -   
SODA   BHE   1995001   2103   -1   n   -0   90   90   -   
SODA   BHN   1995001   2104   -1   n   -0   0   90   -   
SODA   BHZ   1995001   2105   -1   n   -0   0   0   -   
TAIF   BHE   1996150   2106   -1   n   -0   90   90   -   
TAIF   BHN   1996150   2107   -1   n   -0   0   90   -   
TAIF   BHZ   1996150   2108   -1   n   -0   0   0   -   
UQSK   BHE   1996161   2109   -1   n   -0   90   90   -   
UQSK   BHN   1996161   2110   -1   n   -0   0   90   -   
UQSK   BHZ   1996161   2111   -1   n   -0   0   0   -   

Total: 30

Selected References

URL: http://eqinfo.ucsd.edu/deployments/saudi_arabia.php [Last updated: 2015-10-22 (295) 23:07:43 UTC]