Detrital in situ and meteoric Beryllium 10 measurements from samples taken before and after Hurricane Maria in Dominica

Tropical islands, including many in island arcs, are susceptible to recurring disturbances from extreme storms. To test whether such storms bias isotopic indicators of long-term erosion, we measured 10Be in samples collected before and after Hurricane Maria (2017, category five) from Dominica, an andesitic island in the Caribbean. Populations of before- and after-storm concentrations of 10Be are indistinguishable (n = 7 for in situ, n = 11 for meteoric); however, individual sample sites replicate less well with isotopic concentrations in samples taken before and after the storm varying by an average of 12%. These data suggest that processes controlling the depth and amount of near-surface erosion on Dominica during extreme storms are stochastic. Erosion rates determined from in situ 10Be are low compared to similarly steep and wet areas (median = 0.082 mm/yr, n = 12) and appear to be controlled by orographic precipitation.