Magnitude determination using strong ground‐motion attenuation in earthquake early warning

We use 1661 strong‐motion accelerograms with peak ground acceleration (PGA) larger than 80 Gal (1 Gal = 1.0 cm/s2) from 77 earthquakes recorded by the Taiwan Strong Motion Instrumentation Program (TSMIP) stations to derive a strong‐motion attenuation relationship. This relationship can be used to dynamically define a “Mpga magnitude” for earthquakes using earthquake locations determined by earthquake early warning process. The Mpga magnitude using this strong‐motion attenuation relationship corresponds well with Mw given a sufficient number of PGA readings. MEMS (Micro Electro Mechanical Systems) acceleration sensor could be widely used for ground motion monitoring purposes. Thus, we propose that once a large earthquake has begun, that we might be able to use strong, near‐field (tens of kilometers) PGA values to quickly estimate the earthquake's magnitude, which would improve earthquake early warning.