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Layer: Soil_Landslide_Groups (ID:0)

View In:   Map Viewer

Name: Soil_Landslide_Groups

Display Field: Name

Type: Feature Layer

Geometry Type: esriGeometryPolygon

Description:

This dataset includes both the soil amplification classes and the landslide susceptible geologic groups. Soil amplification classification, or ground motion amplification potential, is a rating that represents the National Earthquake Hazards Reduction Program (NEHRP) class assigned to the geologic map units within the study area (FEMA 2003). These ratings are based on the NEHRP classification scheme, defined by the average speed at which a shear-wave propagates through the upper 30-meters of a geologic profile. There are 6 separate classes, hard rock (A), rock (B), very dense soil and soft rock (C), stiff soils (D), soft soils (E), and soils requiring site-specific evaluation (F). Geologic units used for assigning NEHRP classes were obtained from combining multiple published geologic maps. Linework amendments were performed in areas of high soil amplification potential, mainly areas of alluvium and unmapped landslide deposits. Areas composed of artificial fill and landslides were classified as ‘F’ given that they require site-specific analysis. The landslide susceptible geologic group data is an intermediary classification used to produce the landslide susceptibility data. Based on their geotechnical characteristics, geologic units are divided into A) Strongly Cemented Rocks, B) Weakly Cemented Rocks and Soils, and C) Argillaceous Rocks. These factors relate to the unit’s general geotechnical properties such as strength, but also to depositional setting and unit history. Group C includes existing landslides.



Copyright Text: This work was funded on behalf of Regional Disaster Preparedness Organization with an Urban Area Security Initiative grant for the Portland Metropolitan Region.

Min. Scale: 0

Max. Scale: 0

Default Visibility: true

Max Record Count: 2000

Supported query Formats: JSON, geoJSON, PBF

Use Standardized Queries: True

Extent:

Drawing Info:

HasZ: true

HasM: true

Has Attachments: false

Has Geometry Properties: true

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Object ID Field: OBJECTID

Unique ID Field:

Global ID Field:

Type ID Field: LS_Class

Fields:
Types:

Is Data Versioned: false

Has Contingent Values: false

Supports Rollback On Failure Parameter: true

Last Edit Date: 5/21/2021 8:19:15 PM

Schema Last Edit Date: 5/21/2021 8:19:15 PM

Data Last Edit Date: 5/21/2021 8:19:15 PM

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