Magnitude estimation using the first three seconds P‐wave amplitude in earthquake early warning 论文

摘要

Pd is the peak amplitude of displacement in the first three seconds after the arrival of the P wave. We investigated the attenuation of Pd with the hypocentral distance R in southern California as a function of magnitude M , and obtained the following relationship: log ( P d ) = −3.463 + 0.729 × M − 1.374 × log ( R ) ± 0.305. Given an earthquake location determined by the P ‐wave arrival times at stations close to the epicenter, this relationship can be used to define a so‐called “ Pd magnitude” of earthquakes. Our result shows that for earthquakes in southern California the Pd magnitudes agree with the catalog magnitudes with a standard deviation of 0.18 for events less than magnitude 6.5. Therefore, Pd is a robust measurement for estimating the magnitudes of earthquakes and has practical application in earthquake early warning systems.