Port Profile Map Information
The following list indicates the types of data available for some of the ports in "Port Profiles". For definitions of each data type, click on the words below.- Aerial Photography
- Topography
- Nautical Charts
- Relative Earthquake Hazard
- Liquefaction Potential
- Landslide Potential
- Geology
- Faults
- Critical Habitat
- Shoreline Land Use
- Tsunami Inundation
Aerial Photography
The aerial photographs used in this project are United States Geologic Survey (USGS) Digital Orthophotos (DOQs). Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. They serve a variety of purposes, from interim maps to field references for earth science investigations and analyses. For this project, the DOQs are used as base maps to overlay other data.
Topography
The topographic maps provided in this project are also from the USGS. One of the most widely used of all maps is the USGS topographic map. The feature that most distinguishes topographic maps from maps of other types is the use of contour lines to portray the shape and elevation of the land. Topographic maps render the three-dimensional ups and downs of the terrain on a two-dimensional surface. Topographic maps usually portray both natural and man-made features. They show and name works of nature including mountains, valleys, plains, lakes, rivers, and vegetation. They also identify the principal works of man, such as roads, boundaries, transmission lines, and major buildings. The wide range of information provided by topographic maps makes them extremely useful for this project, especially in identifying areas above and below tsunami inundation levels, and areas with steep gradients.
Nautical Charts
NOAA Nautical Charts provide graphical portrayal of the marine environment. A chart is a working document used
by the mariner both as a "road map" and worksheet and is essential for safe navigation. In conjunction with
supplemental navigational aids, it is used to lay out courses and navigate ships by the shortest and most economically safe route. A chart shows the
nature and form of the coast, the depths of the water and general character and configuration of the sea bottom,
locations of dangers to navigation, the rise and fall of the tides, locations of man-made aids to navigation,
and the characteristics of Earth's magnetism. For this project, the NOAA Nautical Charts are used both as a base
map to overlay data, and to identify harbor channels and depths.
Landslide Maps
These maps were produced from a subset of the data set "Relative Earthquake Hazard," developed by the Oregon Department of Geology and Mineral Industries (DOGAMI). Absolute landslide potential is not depicted by these maps; rather, they should be used to gain a general idea of those areas with landslide potential. Landslide maps were developed for all urban areas studied by DOGAMI (for a description of how locations were determined see Relative Earthquake Hazard Maps). Existing maps of landslide occurrence were used to determine landslide potential. For those areas without landslide information already mapped, aerial photography was used to determine areas of recent or historic landslide events. Slope data were then derived from USGS 30-meter Digital Elevation Models (DEM). Landslide potential for urban areas was determined by assessing slope data from the DEMs and existing landslide maps. Classification of landslide potential as high, medium, or low was developed by DOGAMI geologists. Generally, those areas with slopes of greater than 25 percent were classified as high, areas with a slope of 5 percent to 25 percent were classified as medium, and those areas with slopes below 5o were classified as low.
Liquefaction Maps
These maps were produced from a subset of the data set "Relative Earthquake Hazard," developed by DOGAMI. Absolute liquefaction potential is not depicted by these maps; rather, they should be used to gain a general idea of those areas with liquefaction potential. Liquefaction maps were developed for all urban areas studied by DOGAMI (for a description of how locations were determined see Relative Earthquake Hazard Maps). Liquefaction potential was examined by investigating the age and grain size of each sediment unit, thickness of the unit, and the sheer-wave velocity of the unit. Liquefaction potential was then classified as high, medium, low, or none for each urban area. DOGAMI geologists determined this classification.
Relative Earthquake Hazard Maps
These maps were produced from the data set "Relative Earthquake Hazard," collected by DOGAMI. These maps do not depict the absolute earthquake hazard at any particular site. This data set was developed by analysis of the behavior of the soils for each urban area depicted. Areas were classified as having a high, medium, low, or very low relative earthquake hazard. Those areas classified as having a high relative earthquake hazard exhibited one or more of the following characteristics: high ground amplification potential, high liquefaction potential, existing landslides, or slopes greater than 25 percent. For a detailed description of DOGAMI's process in developing the Relative Earthquake Hazard data set, see the metadata below.
DOGAMI's Development of Relative Earthquake Hazard Data Set
Urban areas in western Oregon were selected by DOGAMI to participate in the development of relative earthquake hazard maps. Selection of urban areas was determined by three criteria: population greater than 4,000; located in Uniform Building Code (UBC) Seismic Zone 3 or 4; and a determination that the area was not likely to be subject to future, detailed hazard mapping programs. The extent of each area to be mapped was determined by applying a 1 kilometer buffer to the Urban Growth Boundary (UGB) of each location. The first step taken by DOGAMI to develop the relative earthquake hazard maps was to investigate the geology of each location. This investigation was conducted by using the most recent geologic maps for the area and aerial photography. The types of materials present and their locations were then plotted on United States Geological Survey (USGS) Digital Raster Graphs (DRG). Water well data were then used to facilitate determination of the thickness of overburden material (loose sediments overlying bedrock) to a depth of approximately 100 feet. Both data was then used to develop a surface model using geographic information system (GIS) software. These models were then reviewed by local geologists from each area to determine if the data were reasonable and consistent.
Next, existing maps of landslide occurrence were used to determine landslide potential. For those areas without landslide information already mapped, aerial photography was used to determine areas of recent or historic landslide events. Slope data were then derived from USGS 30-meter Digital Elevation Models (DEM). The next step involved examining the ground- shaking amplification for each area; sediment thickness and stiffness were the two variables used to determine amplification effects. Liquefaction potential for each area was the final factor examined. Liquefaction potential was determined by investigating the age and grain size of each sediment unit, thickness of the unit, and the sheer-wave velocity of the unit. Finally, the relative earthquake hazard maps for each urban area were developed by a composite of the above-mentioned factors (soil type and thickness, landslide potential, amplification, and liquefaction). For a more detailed description of the process see the relative earthquake hazard metadata developed by DOGAMI.
Geology
This data set represents geology in Oregon. The data were developed by the USGS National Mapping Division Western Division.
Faults
This data set developed by the USGS shows all known faults in Oregon.
Critical Habitats
Critical habitats is a data set that represents estuary habitats defined by the Oregon Fish and Wildlife department. Polygons are coded to represent a hierarchical habitat structure.
Shoreline Land Use
Shoreline land use is a data set that represents land use as defined by Oregon counties. The following classes are used: forest, exclusive farm use, family farm, recreation, rural residential, urban residential, commercial, industrial, water dependent/related, public, and conservation.
Tsunami Inundation
The tsunami inundation line is part of a series of U.S. Geological Survey quadrangle-based tsunami hazard maps that were produced to implement Senate Bill 379, passed by the 1995 Oregon legislature and enacted into law as Oregon Revised Statutes (ORS) 455.446 and 455.447. The red line represents the upper limit of area expected to be covered by floodwater from a tsunami caused by a magnitude 8.8 undersea earthquake. The area within the green line is above the area expected to be covered by floodwater from a tsunami caused by a magnitude 8.8 undersea earthquake. These areas are surrounded by the tsunami inundation zone.