This dataset consists of nine tables that include radiocarbon dates, Cesium-137 activity, grain size measurements, and scanning X-ray fluorescence element intensity counts.

This dataset consists of sample descriptions and radiocarbon age data from coastal environments on Montague Island, Alaska, analyzed at the National Ocean Sciences Accelerator Mass Spectrometry Facility.

This dataset consists of sample descriptions and radiocarbon age data from coastal environments on Montague Island, Alaska, analyzed at the National Ocean Sciences Accelerator Mass Spectrometry Facility.

This data set is a point shapefile representing tsunami deposits within the Seaside, Oregon region obtained by Brooke Fiedorowicz and Curt Peterson in 1997 and Bruce Jaffe, Curt Peterson, and Robert Peters in 2004. The geospatial dataset were derived from spreadsheets provided by Bruce Jaffe.

This data set is a point shapefile representing tsunami deposits within the Seaside, Oregon region obtained by Brooke Fiedorowicz and Curt Peterson in 1997 and Bruce Jaffe, Curt Peterson, and Robert Peters in 2004. The geospatial dataset were derived from spreadsheets provided by Bruce Jaffe.

This dataset presents radiocarbon data from 87 samples from sediment cores collected in southern Cascadia (offshore northern California) aboard the M/V Bold Horizon in September-October 2019. Sample ages were determined by the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility and the W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (KCCAMS) facility at the University of California, Irvine (UCI).

This dataset presents radiocarbon data from 87 samples from sediment cores collected in southern Cascadia (offshore northern California) aboard the M/V Bold Horizon in September-October 2019. Sample ages were determined by the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility and the W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (KCCAMS) facility at the University of California, Irvine (UCI).

The following report summarizes the dating results from Bradley Lake, Oregon. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and datingrelated calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.

The USGS Powell Center Cascadia earthquake hazards working group compiled published onshore and offshore paleoseismic data along the Cascadia subduction zone, spanning sites from Vancouver Island to the Mendocino triple junction. Evidence for megathrust rupture includes coastal land-level change, tsunami inundation, onshore shaking proxies such as landslides or liquefaction, and offshore shaking proxies such as marine turbidites. The quality of paleoseismic data for megathrust rupture along the Cascadia subduction zone collected over the past three decades varies because analytical capabilities and data collection methodologies have evolved. Thus, as part of the compilation, we also present a ranking scheme to assess the quality of age estimates and evidence for great megathrust rupture. With the age ranking scheme, we ask: "How well is a proposed paleoseismic event dated?" based on the materials and methods used. With the evidence ranking scheme, we ask: "How confident are we that a proposed event is, in fact, the result of a Cascadia megathrust rupture?" based on the sedimentological characteristics, correlation, and mapping. The evidence ranking scheme also helps to evaluate possible alternative mechanisms for creating paleoseismic evidence such as crustal fault, intraslab, or distant tsunamigenic earthquake.

The USGS Powell Center Cascadia earthquake hazards working group compiled published onshore and offshore paleoseismic data along the Cascadia subduction zone, spanning sites from Vancouver Island to the Mendocino triple junction. Evidence for megathrust rupture includes coastal land-level change, tsunami inundation, onshore shaking proxies such as landslides or liquefaction, and offshore shaking proxies such as marine turbidites. The quality of paleoseismic data for megathrust rupture along the Cascadia subduction zone collected over the past three decades varies because analytical capabilities and data collection methodologies have evolved. Thus, as part of the compilation, we also present a ranking scheme to assess the quality of age estimates and evidence for great megathrust rupture. With the age ranking scheme, we ask: "How well is a proposed paleoseismic event dated?" based on the materials and methods used. With the evidence ranking scheme, we ask: "How confident are we that a proposed event is, in fact, the result of a Cascadia megathrust rupture?" based on the sedimentological characteristics, correlation, and mapping. The evidence ranking scheme also helps to evaluate possible alternative mechanisms for creating paleoseismic evidence such as crustal fault, intraslab, or distant tsunamigenic earthquake.