Data Compilations
The paleoseismology records displayed in the CRESCENT CPAL Viewer are drawn from the USGS Powell Center Cascadia earthquake hazards working group’s published compilation of onshore and offshore paleoseismic data along the Cascadia Subduction Zone.
Primary source¶
USGS ScienceBase catalog entry:
Compiled onshore and offshore paleoseismic data along the Cascadia Subduction zone
The USGS entry is the authoritative source for the underlying data, methodology, age-ranking scheme, evidence-ranking scheme, and full field metadata. Users looking for details about how a specific record was evaluated or the sedimentological / analytical basis for a given entry should consult the ScienceBase page directly.
About the compilation¶
The Powell Center 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 (e.g. landslides, liquefaction)
Offshore shaking proxies (e.g. marine turbidites)
The quality of paleoseismic data for megathrust rupture varies because analytical capabilities and data collection methodologies have evolved over the past three decades. The compilation therefore includes two ranking schemes:
Age ranking — “How well is a proposed paleoseismic event dated?” based on the materials and methods used.
Evidence ranking — “How confident are we that a proposed event is, in fact, the result of a Cascadia megathrust rupture?” based on sedimentological characteristics, correlation, and mapping. The evidence ranking also helps evaluate alternative mechanisms such as crustal fault, intraslab, or distant tsunamigenic earthquakes.
In the CPAL Viewer¶
The CPAL Viewer surfaces this compilation as four record-type layers (coastal deformation, marine shaking, terrestrial shaking, tsunami), each downloadable in a condensed GeoJSON form. For the full compilation metadata, age/evidence ranking definitions, and the underlying source publications, always refer to the USGS ScienceBase entry linked above.