William L. Ellsworth Shunta Noda 2016 <p><span>We introduce a new scaling relation between earthquake magnitude (</span><i>M</i><span>) and a characteristic of initial </span><i>P</i><span> wave displacement. By examining Japanese K-NET data averaged in bins partitioned by&nbsp;</span><i>M_w</i><span> and hypocentral distance, we demonstrate that the </span><i>P</i><span> wave displacement briefly displays similar growth at the onset of rupture and that the departure time (</span><i>T</i>_dp<span>), which is defined as the time of departure from similarity of the absolute displacement after applying a band-pass filter, correlates with the final </span><i>M</i><span> in a range of 4.5 ≤ </span><i>M_w</i><span> ≤ 7. The scaling relation between </span><i>M</i>_w<span> and </span><i>T</i>_dp&nbsp;<span>implies that useful information on the final </span><i>M</i><span> can be derived while the event is still in progress because </span><i>T</i>_dp<span> occurs before the completion of rupture. We conclude that the scaling relation is important not only for earthquake early warning but also for the source physics of earthquakes.</span></p> application/pdf 10.1002/2016GL070069 en American Geophysical Union Scaling relation between earthquake magnitude and the departure time from P wave similar growth article