This map depicts three distinct types of Geologic Hazards.
Earthquake Hazards shows the two most likely earthquake scenarios for our area -- Cascadia Subduction Zone M9.0 and Portland Hills Fault M6.8 earthquakes, Perceived Shaking and Damage Potential, from DOGAMI OFR-18-02.
Steep Slopes are polygons representing slopes greater than or equal to 20% in the Portland Bureau of Environmental Services topographic watershed boundary area. Derived from 2014, reclassified, 1' resolution LiDAR bare-earth digital elevation model (DEM). All slopes average over a horizontal distance of 15'. Minimum area of contiguous slope is approximately 1/2 acre. Polygons were created, generalized and smoothed in ArcGIS 10.3.1 and ArcGIS Pro.
DOGAMI Landslide Inventory consists of polygons delineating landslide deposits (including debris flow fans and talus extent), from DOGAMI IMS-57.