Salt marsh subsurface deposits (0-4 rn depth) in Netarts Bay, a small coastal lagoon of northern Oregon, record six events of marsh burial in the last several thousand years. Five of the buried marsh surfaces show sharp, nonerosional upper contacts with either anomalous sand layers (tsunami deposits) or tidal fiat mud deposits. These sequences indicate episodic, abrupt subsidence of the marsh surfaces to low intertidal levels. In contrast, lower marsh contacts with underlying intertidal muds are gradafional, indicating gradual uplift and development of the marsh. Three in&pendent measures of deposit elevation relative to mean tidal level (percent organics, diatom assemblages, and percent eolian sand) have been used to estimate vertical displacements of marsh surfaces. Abrupt subsidence displacements of 1-1.5 rn alternate with gradual uplift displacements of the order of 0.5-1.0 m. The vertical tectonic movements are interpreted to reflect coseismic strain release (abrupt subsidence) following interseismic strain accumulation (gradual uplift), associated with interplate coupling between the Juan de Fuca Plate and the North American plate in the Cascadia subduction zone. Recurrence intervals between subsidence events range from possibly less than 300 years to at least 1000 years, with the last dated event likely occurring 300-400 radiocgbon years before present (RCYBP). Significant x'•C age overlaps of at least four subsidence events recorded at Netarts and reported for southern Washington and other northern