Shallow subduction erosion

Basal erosion is a prevalent process at subduction zones and plays an important role in the mass balance of global plate tectonics. In contradiction with the theoretical expectation that basal erosion requires high basal friction and hence compression in the upper plate, extensional faulting is commonly observed in submarine wedges that undergo such erosion. Here we propose a model to explain this apparent paradox in terms of stress fluctuations during earthquake cycles. 

In this model, basal erosion occurs during large earthquakes when the shallow, rate-strengthening part of the plate interface strengthens and its overlying wedge weakens, but extension occurs during interseismic relaxation of wedge stress. 

The mechanics of basal erosion provide important information on the nature of the updip limit of the megathrust seismogenic zone in margins dominated by basal erosion.

This work was published on Geology:

Wang, K., Y. Hu, R. von Huene, & N. Kukowski (2010), Interplate earthquakes as a driver of shallow subduction erosion, Geology, 38(5), 431-434, doi: 10.1130/G30597.1. Link