Estimating sediment transport in rivers using seismic detections

Rocks and sand carried in a river's flows, which bump, grind, and scrape against the riverbed, are an important force in driving topographic change by controlling riverbed erosion and incision rates over long time scales. Sediment transport observations collected worldwide have typically been sparse, infrequent, or inconsistent, even within some of the world's most important rivers. In mountainous rivers, where sediment‐driven erosion is an even more important force than in low‐lying watersheds, even basic measurements are often nonexistent. Tsai et al. seek to alleviate this sparsity of data by introducing a method to use seismic wave detections to estimate basic sediment transport information. The authors' model uses data on the high‐frequency, low‐amplitude seismic waves that are produced every time a rock or pebble settles out of the river's flows and hits the riverbed. When combined with measurements of the sediment grain size distribution collected in the field, the seismic signals allowed the authors to estimate the number of grains of each size, the total sediment mass, and the velocity of the rock‐riverbed collision.