Creating a Reliability-Weighted Vertical Motion Dataset of the Sunda Shelf, Towards a Harmonized Workflow Using Local Datapoints.

Sea level cycles influenced land bridge formation and island connectivity throughout the Pleistocene, including the Sunda Shelf in SE Asia. Shelf-wide paleogeographic models are often based on few local observations and assumptions of tectonic uniformity. This study, using the Sunda Shelf as innovative example, compiles all published local vertical motion (VM) rates, assigns a reproducible reliability index – that accounts for methodological rigor, temporal precision, spatial accuracy, and source credibility – to each individual datapoint, and produces a harmonized VM raster. Our database synthesizes 93 VM datapoints, from 13 published sources of petrochemical exploration wells, fossil coral reef analysis, and seismostratigraphic proxies of varying spatial and temporal scales. Major tectonic boundaries, sedimentary basins, and structural zones were incorporated as barriers, while support points were added to steer interpolation in data poor areas. The created VM raster is a ready-to-use input for paleogeographic relative sea-level models, such as tabs (De Groeve et al., 2025). This study highlights the possibility and importance of a harmonized VM workflow to allow for intercomparison of paleogeographic studies and unlock the continental coastlines of Earth’s past.