Metadata: Identification_Information: Citation: Citation_Information: Originator: Edwin L. Harp Originator: Randall W. Jibson Publication_Date: 1995 Title: Inventory of landslides triggered by the 1994 Northridge, California earthquake Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 95-213 Other_Citation_Details: Digital files of landslide map can be accessed off of the greenwood server both as HPGL2 graphics files and ARC/INFO GIS files. Online_Linkage: http://pubs.usgs.gov/of/1995/ofr-95-0213/ Description: Abstract: The 17 January 1994 Northridge, California, earthquake (M=6.7) triggered more than 11,000 landslides over an area of about 10,000 km². Most of the landslides were concentrated in a 1,000-km² area that includes the Santa Susana Mountains and the mountains north of the Santa Clara River valley. We mapped landslides triggered by the earthquake in the field and from 1:60,000-scale aerial photography provided by the U.S. Air Force and taken the morning of the earthquake; these were subsequently digitized and plotted in a GIS-based format, as shown on the accompanying maps (which also are accessible via Internet). Most of the triggered landslides were shallow (1-5 m), highly disrupted falls and slides in weakly cemented Tertiary to Pleistocene clastic sediment. Average volumes of these types of landslides were less than 1,000 m³, but many had volumes exceeding 100,000 m³. Many of the larger disrupted slides traveled more than 50 m, and a few moved as far as 200 m from the bases of steep parent slopes. Deeper ( >5 m) rotational slumps and block slides numbered in the hundreds, a few of which exceeded 100,000 m³ in volume. The largest triggered landslide was a block slide having a volume of 8X10E06 m³. Triggered landslides damaged or destroyed dozens of homes, blocked roads, and damaged oil-field infrastructure. Analysis of landslide distribution with respect to variations in (1) landslide susceptibility and (2) strong shaking recorded by hundreds of instruments will form the basis of a seismic landslide hazard analysis of the Los Angeles area. Purpose: This extensive database will allow quantitative modeling of the relation between strong ground shaking, landslide susceptibility, and landslide distribution. The area of the greatest landslide concentration currently is undeveloped, but many parts of this area in the Santa Susana Mountains are slated for future dense residential development. We anticipate using the data and modeling results from the Northridge earthquake to produce regional maps of earthquake-induced landslide hazards that can be used to make informed decisions regarding development in the areas most susceptible to seismically triggered landsliding. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1995 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -119.17 East_Bounding_Coordinate: -118.13 North_Bounding_Coordinate: 34.75 South_Bounding_Coordinate: 34.0 Access_Constraints: none Use_Constraints: none Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Harp, Edwin L Contact_Organization: USGS-GEO-CRG-GHZ Contact_Address: Address_Type: mailing and physical address Address: Mail Stop 966, USGS P.O. Box 25046 City: Lakewood State_or_Province: CO Postal_Code: 80225 Country: US Contact_Voice_Telephone: 303-273-8557 Contact_Electronic_Mail_Address: harp@usgs.gov Keywords: Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: geology Theme_Keyword: landslides Theme_Keyword: maps and atlases Theme_Keyword: landslide susceptibility assessment Theme_Keyword: geospatial datasets Theme: Theme_Keyword_Thesaurus: National Geologic Map Database Catalog themes, augmented Theme_Keyword: 3400 - Graphical Theme_Keyword: 3100 - Vector Theme_Keyword: 3110 - ESRI Theme_Keyword: 3112 - export Theme_Keyword: 3430 - HPGL Theme_Keyword: 1500 - Hazards Theme_Keyword: 1501 - Earthquakes Theme_Keyword: 1503 - Landslides Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Categories Theme_Keyword: geoscientificInformation Place: Place_Keyword_Thesaurus: Augmented FIPS 10-4 and FIPS 6-4 Place_Keyword: f06037 = Los Angeles Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/1995/ofr-95-0213/plate1.gif Browse_Graphic_File_Description: GIF of landslide deposits in the Northridge, California area Browse_Graphic_File_Type: GIF Data_Set_Credit: David Keefer and Ray Wilson of the U.S. Geological Survey assisted in the post-earthquake reconnaissance efforts and in defining the landslide limits. John Michael and Art Tarr of the U.S. Geological Survey helped construct the digital landslide map. Al Barrows and Pam Irvine of the California Division of Mines and Geology, and Robert Larson of Los Angeles County provided useful information on the location and nature of many landslides triggered by the earthquake. Data_Quality_Information: Logical_Consistency_Report: The Northridge earthquake provided an unprecedented amount of data for studying the distribution and effects of landslides triggered by an earthquake in an urban area. Detailed field investigations to document earthquake-triggered landslides, which were initiated the day of the earthquake, are continuing. In the first several days following the earthquake, we drove outward from the epicentral area in all directions to locate areas of concentrated landsliding and to find the farthest extent of landsliding, which is defined by small rock and soil falls from very susceptible slopes such as steep road and stream cuts. High-altitude aerial photography (nominal scale 1:60,000) of the epicentral region was flown by the U.S. Air Force within hours of the earthquake, and we mapped fresh landslides visible on these photos to provide a detailed inventory of ground failures triggered by the earthquake. We mapped more than 11,000 individual landslides on 1:24,000-scale U.S.G.S. topographic base maps. The photos show all but the smallest slope failures and some that were hidden within deep shadows on the north sides of steep slopes. Completeness_Report: Landslides as small as 1-2 m across are visible where the slopes were sunlit;where slopes were partly shaded, slides about 5-10 m across are the smallest that could be resolved; thus, the inventory is not complete. However, our field observations indicate that south-facing slopes in most of the landslide area generally are steeper and produced far more landslides than north-facing slopes. Therefore, landslides on north-facing slopes that are not visible on the photos because of shadows probably account for only a small proportion of the total landslides. From our field investigations we estimate that we missed no more than about 20 percent of the landslides that exceeded 5 m in maximum dimension and no more than 50 percent of those smaller than 5 m. In terms of area, however, we estimate that we have mapped more than 90 percent of the area covered by triggered landslides, because most of the landslides that are not visible on the photos are small. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: We estimate that location accuracy of landslides mapped from the airphotos to the paper base maps is generally within 10 m and no worse than 20 m. When the paper maps were registered on the digitizer, the computer calculated the root-mean-square (RMS) error in the base-map registration, which averaged 3.6 m and ranged from 0.2 to 10.4 m. Thus, landslide locations plotted on plates 1 and 2 are generally accurate within about 15 m and are no more than 30 m mislocated. Lineage: Process_Step: Process_Description: We manually digitized the landslides mapped on the 1:24,000-scale base maps using the Arc/Info geographic information system (GIS). Landslides triggered by the earthquake are plotted as solid polygons on the digital inventory maps (plates 1 and 2). Process_Date: 1994-1995 Process_Step: Process_Description: Creation of original metadata record Process_Date: 20000829 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peter N Schweitzer Contact_Organization: U.S. Geological Survey, ER Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: Mail Stop 954 12201 Sunrise Valley Drive City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: 703-648-6533 Contact_Facsimile_Telephone: 703-648-6252 Contact_Electronic_Mail_Address: pschweitzer@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: vector Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Transverse Mercator Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -117.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000 False_Northing: -4000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: Ordinate_Resolution: Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: LANDSLIDE.PAT Entity_Type_Definition: Locations of landslides Entity_Type_Definition_Source: OFR-95-0213 Attribute: Attribute_Label: SLIDE Attribute_Definition: Location of landslides Attribute_Definition_Source: OFR-95-0213 Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 0 Enumerated_Domain_Value_Definition: Corresponds to polygons in which landslides are not found, such as inliers Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 1 Enumerated_Domain_Value_Definition: Corresponds to label points within landslide polygons Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Information Services Contact_Address: Address_Type: mailing Address: Box 25286, Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80255-0046 Country: USA Contact_Voice_Telephone: 1-888-ASK-USGS Contact_Facsimile_Telephone: 1-303-202-4695 Contact_Electronic_Mail_Address: infoservices@usgs.gov Resource_Description: US Geological Survey Open File Report 95-0213 Distribution_Liability: This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ARCE Format_Version_Number: 7.x Format_Information_Content: Landslide map File_Decompression_Technique: No compression applied Transfer_Size: 3.0 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/1995/ofr-95-0213/downloads/landslide.e00.Z Fees: none Metadata_Reference_Information: Metadata_Date: 20160205 Metadata_Review_Date: 20000831 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Peter N Schweitzer Contact_Organization: USGS Midwest Area Contact_Position: Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/ Contact_Address: Address_Type: mailing address Address: Mail Stop 954 12201 Sunrise Valley Dr City: Reston State_or_Province: VA Postal_Code: 20192-0002 Country: USA Contact_Voice_Telephone: 703-648-6533 Contact_Facsimile_Telephone: 703-648-6252 Contact_Electronic_Mail_Address: pschweitzer@usgs.gov Metadata_Standard_Name: Content for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998