Fig. 2

Observed and synthetic record sections. The observed (a) and computed (b) record sections of a Fiji-Tonga event recorded at the European stations. The arrivals of S2KS, S3KS, S4KS, S5KS, and S6KS are clearly visible. When aligned on S3KS arrivals, S4KS and S5KS waves are systematically delayed relative to PREM across the entire array. In this example, d t ³⁻², d t ⁴⁻³, and d t ⁵⁻³ are anomalous by about +1.2 s