Data from: Deformed submarine terraces in Puget Sound, Pacific Northwest indicate only one M > ~7.5 earthquake on the Seattle fault zone in the past 11,000 years
Data files
Jan 30, 2026 version files 2.97 MB
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bathymetric_datasets.xlsx
14.29 KB
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profiles.zip
2.95 MB
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README.md
6.16 KB
Abstract
Seafloor terraces around ~50 m depth are abundant beneath Puget Sound. These terraces have been attributed to a sea-level lowstand ca. 11 ka. Depths to the terraces across upper plate faults in Puget Sound can be used as a record for tectonic deformation since that time.
The data consist of bathymetric and seismic reflection data from Puget Sound, Washington, USA. They have been interpreted to show an upward offset in bathymetric terraces across the Seattle fault zone. This data repository includes the following files necessary to reproduce these results:
basemap.pdf: Bathymetric and topographic map of the study area (central Puget Sound, USA) showing the location of bathymetric profiles and fault zones used in the study.
bathymetric_datasets.xlsx: Spreadsheet describing all public bathymetric datasets used in the study.
profiles.zip: Text files of bathymetric profiles used in the study. Each profile consists of a distance and depth extracted from the bathymetric files listed in dataset 2.
picks.xlsx: Spreadsheet that identifies each bathymetric profile, the x-y coordinate location and measured depth for each profile's bathymetric terrace and the uncertainties and propagated error for each depth.
images.pdf: PDF document showing locations and images for the two seismic reflection profiles used in the study, plus explanations for each image. See the Methods section for a description of the collection of these profiles.
Dataset DOI: 10.5061/dryad.wh70rxx2v
Description of the data and file structure
This dataset consists of supporting data for the manuscript "Deformed submarine terraces in Puget Sound, USA indicate only one M > ~7.5 earthquake on the Seattle fault zone in the past 11,000 years." Seafloor terraces around ~50 m depth are abundant beneath Puget Sound. These terraces have been attributed to a sea-level lowstand ca. 11 ka. Depths to the terraces across upper plate faults in Puget Sound can be used as a record for tectonic deformation since that time.
The data consist of bathymetric and seismic reflection data from Puget Sound, Washington, USA. They have been interpreted to show an upward offset in bathymetric terraces across the Seattle fault zone.
Files and variables
File: bathymetric_datasets.xlsx
Description: This spreadsheet lists all of the public bathymetric datasets used in this study and includes links to each dataset. The datasets are listed in order of use (highest resolution on top). The first three rows of the dataset are text descriptions; the fourth row are column headers (described below).
- File name: Name of the bathymetric dataset assigned by NOAA
- Grid size: Size in meters of the bathymetric grid. Most datasets consist of multiple layers with different grid sizes covering different depths. Each layer is a row.
- General location: General description of the dataset location in Puget Sound
- Year: Year of dataset publication
- Vertical datum: Vertical datum that depths are referenced to
- Tide station: Tide station for the vertical datum
- Horizontal datum: Horizontal reference datum
- Projection: Map projection
- Scale: Scale of the map
- Full file name: Full file name
- Website: Hyperlink to dataset
File: basemap.pdf
Description: This map of central Puget Sound, USA, shows locations of the bathymetric profiles used in this study, as well as major fault zones.
File: picks.xlsx
Description: This spreadsheet provides x-y locations for each terrace used in the study, as well as measured depths to each terrace. Depth uncertainty is listed and calculated for each measurement. Profiles are listed from north to south and keyed to the filenames in profiles.zip. The data in each field were measured from the associated bathymetric slope profile. All depths are measured in meters (m) below mean lower low water (MLLW). The first three rows of the dataset are descriptive text; the fourth row are column headers (described below).
- North to south index: Profile index number; numbered from north to south, first on the east side of Puget Sound, then on the west.
- Terrace index: Index number for each terrace
- Profile file name: Name of profile file in profiles.zip
- y (NAD83 UTM 10N): UTM coordinates for the back edge of the terrace
- x (NAD83 UTM 10N): UTM coordinates for the back edge of the terrace
- East or west side of Puget Sound: Whether the terrace lies on the east or west side of Puget Sound (east/west)
- Location relative to SFZ (zone of mapped faults): Whether the terrace is north of the zone of mapped SFZ faults (north), south of the zone of mapped faults (south), within the zone of mapped faults (in), or whether publications disagree about whether faults exist around the location of the terrace (testable)
- Descriptive location: Brief description of the terrace location with respect to onshore landmarks.
- Identifier for which terrace tread is imaged in profile, numbered by increasing depth ("2" is the terrace studied herein): Numbers indicating whether the profile shows a terrace adjacent to the modern shoreline (1), and/or a terrace around 50 m depth (2), or both.
- Environment: Inferred geologic feature at the terrace, inferred from surrounding topography and bathymetry. Only populated for notable examples.
- Confidence that there is a terrace (high, med, low): Author's confidence that the profile shows a terrace and not other features, only populated for notable examples.
- Comments: Author's comments about the profile or the pick.
- Anomaly?: Descriptive text if pick is anomalous
- Distance from Alki Point (km): Distance in kilometers of the picked terrace back edge from Alki Point.
- Bathymetric error (m): Error of the bathymetric dataset at the picked terrace back edge.
- Depth picked at shoreline angle inflection point by EJD (m): Depth in meters of the terrace back edge, picked manually by the author.
- Picking error assigned by EJD (m): Error in meters of the pick location assigned by the author.
- Seaward edge of terrace depth (m): Depth in meters of the deepest extent of the terrace
- Depth of base of steeper slope above terrace (m): Depth in meters of the slope above the terrace (i.e., the shallowest depth of the terrace)
- Propagated error UP (m): Error in meters of picked terrace depth calculated by formally propagating bathymetric error, picking error, and 0.3 m of measurement error in the comparative dataset. The terrace inner edge could be at the picked depth or as shallow as this value.
- Propagated error DOWN (m): Error in meters of picked terrace depth calculated by formally propagating bathymetric error, picking error, up to 3 m of sediment cover, and 0.3 m of measurement error in the comparative dataset. The terrace inner edge could be at the picked depth or as deep as this value.
File: images.pdf
Description: This provides images and maps with locations of seismic reflection data used in this study.
File: profiles.zip
Description: This .zip folder includes one text file for each bathymetric profile used in the study. The first column is a measured distance along the profile (starting at 0 at the landward edge of the profile) measured in meters (m); the second column is a depth measured in meters (m) below mean lower low water (MLLW).
Dataset 5 (images.pdf) shows images from two seismic reflection surveys collected in Puget Sound, USA:
2019 CHIRP seismic reflection survey
This survey was collected by the authors in October, 2019 aboard the R/V Weelander, a 15 ft vessel operated by the University of Washington School of Oceanography. The survey was collected with an ultra-high resolution, 2-16 kHZ Edgetech 216s CHIRP system and crossed Elliott Bay, the Duwamish Waterway, and terraces offshore Bainbridge Island. Data were processed using a standard CHIRP processing workflow that included heave correction and conversion to envelope. After processing, the data were collected in an interpretation project along with complementary datasets using the IHS Kingdom Suite software. Two-way travel time in seconds was converted to depth using a constant velocity of 1500 m/s. Depths were not tide-corrected, and we do not use absolute depths in this study.
1982 minisparker legacy data
This survey was collected in 1982 by Dr. Mark Holmes and others aboard the R/V Onar at the University of Washington School of Oceanography. A cruise map and paper scrolls showing the data were produced and were encountered by the authors in the files of the University of Washington School of Oceanography.