Comparison of broadband and short-period seismic waveform stacks: Implications for upper-mantle discontinuity structure

摘要: Stacks of short-period and broadband seismic waveforms from four deep (h > 550 km) earthquakes in South America recorded California exhibit small amplitude signals between the direct P surface-reflected pP phases. The anomalous variable slownesses these stacks, as well differences stacks suggest that weak arrivals originate by reflection laterally varying structure mantle near subduction zone. only consistently producing near-source near-receiver reflections is “410 km” discontinuity, which varies depth ±10 km, has an impedance contrast comparable with predicted reference Earth models.