A New Seismic Phase to Detect Mid‐Mantle Scatterers

Abstract Small‐scale mid‐mantle heterogeneities (<100 km) are revealed by various short‐period seismic waves with different sampling paths. Here, using dense stations in China, we present the observations of a new phase that arrives as PP precursor. This arrival represents P‐wave scattered at PdpP (“d” indicates depth heterogeneity) and appears two forms: (a) wave train increasing slowness from P/P diff to slowness; (b) single unique between P slowness. Waveform modeling results suggest both types signals can be simultaneously generated lower mantle scatterers scales larger than 20 km, situated close source region. Furthermore, focusing on Fiji‐Tonga earthquakes, locate series 800–1,350 km may related Pacific slab subducting along Tonga‐Kermadec trench.