| Author(s) | A. M. AI-Amri, B.T. Punsalan and E. A. Uy |
| Affiliation | Seismic Studies Center, King Saud University, Riyadh, Saudi Arabia |
| Title | Magnitude Calibration of the Seismographic Sub-network in NW Saudi Arabia |
| Source | Journal of King Saud University. Science. Volume 12, No 1. (2000/1420) |
| Abstract | Two magnitude formulas to be applied in seismic parameter determinations were developed for the seismographic sub-network in NW Saudi Arabia: ML = Log (A / T) + 3.4 Log D + 2.55 and .Mc = 2.55 Log (t) - 2.15. These formulas were empirically determined through magnitude calibration of the amplitude and total trace duration data ~m the seismic stations of the network. The relationship found between coda magnitude (Mc). duration, and tlistance indicates negligible correction factor for epicentral distance of earthquake events less than 1000 km from the network making it compatible to use with the adapted local magnitude scale (ML) for better estimate of earthquake magnitude values. These findings make the twp magnitude scales supplementary to each other and their complimentary roles could possibly cover a wider area in the observation of earthquake events in the eastern Mediterranean region. Both magnitude scales give good fits with standard error of 0.16 for ML and 0.12 for Mc. Other useful relations were also empirically determined between corresponding calculated values from the two magnitude scales and the observed body-wave magnitude values. These were: ML = 0.9] mb + 0.39 and Mc = 0.89 mb + 0.48 which can be applied for counter-checking and verifitations of calculations when either one is known. |
