Geologic hazard areas shall be classified according to the criteria in this section.
A. Landslide Hazard Areas: Landslide hazard areas are classified as class I, class II, or class III as follows:
1. Class I/High: Areas of greater than thirty percent (30%) slope with soils designated by SCS as moderate, severe or very severe erosion hazard.
2. Class II/Moderate: Areas of fifteen percent (15%) to thirty percent (30%) slopes with soils designated by the SCS as moderate or severe erosion hazard.
3. Class III/Low: Areas with slopes less than fifteen percent (15%). Class III/low hazard areas are not designated critical areas, and are exempt from critical areas review.
B. Erosion Hazard Areas: Erosion hazard areas are classified as class I, class II, or class III as follows:
1. Class I/High Hazard: All sites classified with soil types designated as "severe" or "very severe" erosion hazard.
2. Class II/Moderate Hazard: All sites classified with soil types designated as "moderate" erosion hazard.
3. Class III/Low Hazard: All sites classified with soil types designated by the department of agriculture soil conservation service (SCS) as having "no" or "slight" erosion hazard. Class III/low erosion hazard areas are not designated critical areas, and are exempt from critical areas review.
C. Seismic Hazard Areas: Seismic hazard areas are classified as class I or class II as follows:
1. Class I/High Hazard: All areas with lands designated as alluvium and recessional outwash surficial geologic units (as identified in "Groundwater Occurrence And Stratigraphy Of Unconsolidated Deposits, Central Pierce County, WA, Water Supply Bulletin #22, Plates One And Two, U.S. Dept. Of Interior, Geological Survey, Water Resources Division"), or slopes greater than thirty percent (30%).
2. Class II/Low Hazard: All other sites with a lower risk geological classification. Class II/low seismic hazard areas are not designated critical areas, and are exempt from critical areas review.
D. Volcanic Hazard Areas: The classification system for defining areas at risk to volcanic hazards from Mount Rainier is as follows:
1. Class I/High Hazard: Valley floor areas in which there could be a high degree of danger from mudflows of similar magnitude to the electron mudflow (as identified in "map showing potential hazards from future eruptions of Mount Rainier, WA, USGS").
2. Class II/Moderate Hazard: Valley floor areas which could be covered by a mudflow as large as the electron mudflow, in valleys in which mudflows have been relatively frequent (as identified in "map showing potential hazards from future eruptions of Mount Rainier, WA, USGS").
3. Class III/Low Hazard: Valley floor areas which could be covered by a mudflow of similar magnitude to the electron mudflow, in valleys where mudflows have been relatively infrequent, and areas in the other valleys which might be subject to flooding (as identified in "map showing potential hazards from future eruptions of Mount Rainier, WA, USGS"). Class III/low volcanic hazard areas are not designated critical areas, and are exempt from critical areas review. (Ord. 806, 6-30-2005)