Fig. 2.

Sampling and analyses scheme of tephra layers. The sampling of tephra layers was adapted to their appearance and recognition (a–d). Cryptotephra, which was not indicated by sediment proxy data, was detected by sampling of intervals determined based on stratigraphic or chronological assessment (a). Cryptotephra, which was detected by anomalies in sediment proxy data, was treated as illustrated in (b). Thin tephra layers and lenses or patches of tephra were sampled as illustrated in (c). Massive tephra layers were sampled as shown in (d). The treatment of cryptotephra is adapted from the protocol of Blockley, et al.³⁵.