Fig. 2: Travel time analysis.
From: Ultra-low-velocity anomaly inside the Pacific Slab near the 410-km discontinuity
a Arrival times of the first-arriving refracted wave (solid circles) and the direct wave (open circles). The measurements are shown in black, and cyan for the RR’ and SS’ paths, respectively. See also Supplementary Fig. 2. Note a reduced velocity of 10.1 km/s is applied to the time axis. b The traveltime difference between the direct wave and the refracted wave. The y-axis indicates the turning depth of the refracted wave, converted from the corresponding epicentral distance in (a) using a fast-matching ray-tracing method19 with model FWEA18 for SS’ to the left in cyan and RR’ to the right in black.
