Magnitude Estimation Based on Integrated Amplitude and Frequency Content of the Initial P Wave in Earthquake Early Warning Applied to Tehran, Iran

To optimize magnitude estimation for the earthquake early warning system around the Tehran region, different amplitude-and frequency-based parameters, that is, predominant period (tau(max)(p)), characteristic period (tau(c)), log-average period (tau(log)), and peak displacement (P-d) were analyzed in this article. All parameters were calculated directly from seismic records, with an epicentral distance less than 150 km, and within the initial 3 s of the P waves. The analysis of earthquakes in the 2.4 < M-L< 4.9 magnitude range verified that the result of tau(max)(p) showed a consistent trend as compared with the global observations, and provided a robust estimate of magnitude for the dataset used in this research. In comparison with worldwide observations, the calculated P-d and tau(c) were underestimated, and there was no scaling relationship with the tau(log) parameter. When combined with the global observations from Japan, Taiwan, and Italy, the results of P-d and tc for the Tehran region produced optimized results.