Magnitude estimation using the covered areas of strong ground motion in earthquake early warning

Abstract

We collected the strong‐motion accelerograms with peak ground acceleration (PGA) larger than 100 Gal (1 Gal = 1.0 cm/s2) from large crustal earthquakes in Taiwan recorded by the Taiwan Strong Motion Instrumentation Program (TSMIP) stations to find an empirical relationship between the area of high PGA and the corresponding earthquake magnitude. We found that the logarithms of the areas inside the PGA contours have a linear relation to the corresponding earthquake magnitudes. We propose that this relationship might be able to rapidly define the earthquake magnitude while providing sufficient seismic station coverage and might have practical application in earthquake early warning (EEW) and rapid reporting systems. The proposed magnitude estimation method is directly related to the level of strong surface shaking and is inherently suitable for the purpose of the EEW and rapid reporting systems.