20231002 13333200 1.0 TRUE 150000000 5000 FGDC Ridgecrest 2021 Surface Rupture Mapping Senior Engineering Geologist, Earthquake Fault Zoning Unit California Geological Survey, Seismic Hazards Program 715 P Street MS 1901 Sacramento CA 95814 SHMP@conservation.ca.gov US (916) 322-1019 Essential Facility Review Unit Manager GIS and Publications Unit Supervisor 2024-01-31T00:00:00 Recommended Citation: California Geological Survey . 2024, Special Report #257: Surface Rupture Mapping of the Ridgecrest Earthquake Sequence 2019 M6.4 and M7.1 on Lidar and Associated Imagery, Sacramento, CA. Department of Conservation, California Geological Survey. Accessed [Day] [Month] [Year] CGS California Geological Survey Ridgecrest Rupture Mapping LiDAR Surface Rupture Mapping This surface rupture mapping dataset aims to create a complete surface rupture map for the entire extent of the Ridgecrest Earthquake Sequence utilizing high-resolution lidar and aerial orthoimagery from Hudnut et al. (2020). Using accurately georeferenced and uniform basemaps, this mapping improves the location accuracy for fault rupture features and will aid in the future creation of Alquist-Priolo Earthquake Fault Zones. <DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="text-align:Justify;margin:0 0 0 0;"><SPAN><SPAN>The </SPAN></SPAN><SPAN STYLE="font-style:italic;"><SPAN>M</SPAN></SPAN><SPAN STYLE="font-style:italic;"><SPAN>W</SPAN></SPAN><SPAN><SPAN> 6.4 and </SPAN></SPAN><SPAN STYLE="font-style:italic;"><SPAN>M</SPAN></SPAN><SPAN STYLE="font-style:italic;"><SPAN>W</SPAN></SPAN><SPAN><SPAN> 7.1 2019 Ridgecrest Earthquake Sequence produced complex surface rupture and ground deformation along two distinct fault zones with mapped rupture lengths extending 18 km and 50 km, respectively. Immediate post-earthquake field reconnaissance allowed for efficient flight-line planning for the simultaneous collection of medium- to high-resolution aerial lidar (25 to 80 pulses per square meter (ppsm), respectively) and airborne optical imagery along the rupture (Hudnut et al., 2020). We produced a comprehensive surface rupture map using orthoimages and hillshades derived from these data, documenting visible features with qualitative descriptions and an associated catalog of attributes. We mapped the full extent of surface rupture at a consistent digital screen scale (1:300 – 1:500), the largest scale at which imagery resolution is not degraded. This allowed for centimeter-scale features to be resolved, although mapping using orthoimagery was somewhat limited by image resolution, variable image quality, and time available to map at a large scale. Both fault zones consist of primary fault strands with linear cracks continuous along strike, broad regions of distributed fractures, and well-defined scarps as high as 3 m. The mapping approach was designed to capture the width of these rupture zones and zones of cracking and to characterize the rupture’s expression through varying terrain, such as hillslopes, fan surfaces, and relatively flat playa surfaces. These aerial lidar and orthoimagery datasets allow for comprehensive and uniform documentation of surface rupture and ground deformation features and are complementary with previous mapping datasets. Features mapped in our dataset generally have greater location accuracy and more specificity to fine-scale expression when compared with previous mapping datasets. Whereas our mapping does capture deformation in previously undocumented areas, it can be less comprehensive compared with ground-based and geodetic observations in the near-field. Our dataset of surface rupture features will be potentially useful for longer term, geomorphic-based fault evaluation as we continue to learn from mapping of earthquake ruptures that are the primary evidence of large &gt;</SPAN></SPAN><SPAN STYLE="font-style:italic;"><SPAN>M</SPAN></SPAN><SPAN STYLE="font-style:italic;"><SPAN>W</SPAN></SPAN><SPAN> 6.0 earthquakes. Characterizing zones of deformation for the 2019 Ridgecrest Earthquake Sequence, important for improving fault displacement and seismic hazard assessment and understanding fault mechanics, benefits from a paired approach using both high-resolution lidar and orthoimagery in addition to established ground-based collection methods.</SPAN></P></DIV></DIV></DIV> <DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 0 0;"><SPAN>LICENSE AGREEMENT: (c) 2023 California Department of Conservation, California Geological Survey. All rights reserved. No part of these data may be reproduced, transmitted, or distributed in any form or by any means, electronic or mechanical for any purpose, without the express written permission of the California Geological Survey except under the following conditions: 1) Personal use; 2) For publication in a report, in unmodified form, cite on figure or in text as "Reproduced with permission, California Geological Survey and (3) for publication in a report in modified form; cite on figure or in text as "Modified from California Geological Survey, Special Report #257: Surface Rupture Mapping of the Ridgecrest Earthquake Sequence 2019 M6.4 and M7.1 on Lidar and Orthoimagery</SPAN><SPAN STYLE="text-decoration:underline;"><SPAN>.</SPAN></SPAN></P><P><SPAN /></P></DIV></DIV></DIV> external 0f206e0c884459fa051c704035acff18885cbee1 Senior Engineering Geologist, Earthquake Fault Zoning Unit California Geological Survey, Seismic Hazards Program 715 P Street MS 1901 Sacramento CA 95814 SHMP@conservation.ca.gov US (916) 322-1019 Essential Facility Review Unit Manager GIS and Publications Unit Supervisor True Senior Engineering Geologist, Earthquake Fault Zoning Unit 0 3310 0 0 Ridgecrest Ridgecrest Trona Kern County San Bernardino County California USA Ridgecrest Earthquake Sequence Surface Rupture Lidar Mapping Special Report Imagery Mapping Orthoimagery Senior Engineering Geologist, Earthquake Fault Zoning Unit California Geological Survey, Seismic Hazards Program 715 P Street MS 1901 Sacramento CA 95814 SHMP@conservation.ca.gov US (916) 322-1019 Essential Facility Review Unit Manager GIS and Publications Unit Supervisor Senior Engineering Geologist, Earthquake Fault Zoning Unit 20240109 <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>LICENSE AGREEMENT: (c) 2023 California Department of Conservation, California Geological Survey. All rights reserved. No part of these data may be reproduced, transmitted, or distributed in any form or by any means, electronic or mechanical for any purpose, without the express written permission of the California Geological Survey except under the following conditions: 1) Personal use; 2) For publication in a report, in unmodified form, cite on figure or in text as "Reproduced with permission, California Geological Survey and (3) for publication in a report in modified form; cite on figure or in text as "Modified from California Geological Survey, Special Report #257: Surface Rupture Mapping of the Ridgecrest Earthquake Sequence 2019 M6.4 and M7.1 on Lidar and Orthoimagery.</SPAN></P></DIV></DIV></DIV> <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN><SPAN>Access_Constraints: Because digital data are easily altered, cities, counties, and others who use this file are advised to obtain the file directly from the Department of Conservation, California Geological Survey. </SPAN></SPAN></P></DIV></DIV></DIV> Process_Description: Mapping of the Ridgecrest Earthquake Sequence surface ruptures and ground deformation was done to primarily catalog features that are directly tectonic in origin, i.e., features that display horizontal and vertical displacement. We mapped surface rupture to capture the primary faults and secondary ground deformation features (off-fault ground deformation), allowing for more qualitative descriptions of these features and an extensive catalog of metadata for both the Paxton Ranch and Salt Wells Valley fault zones. All mappers mapped surface rupture and ground deformation mapping at predominantly 1:500 scale while also creating a catalog of qualitative attributes for each feature. Features were initially mapped on the lidar base with the orthoimagery subsequently used to ensure all visible features were captured, especially those closest to the primary ruptures and for features with minimal to no horizontal displacement. Additionally, the orthoimagery was used to verify the attribute confidence for the feature. The dataset contains fault traces derived from lidar and aerial orthoimagery collected after the 2019 Ridgecrest M6.4 and M7.1 earthquakes. The topographic base map, which was included on the published map, is not included. Horizontal_Positional_Accuracy_Report: No systematic control surveys have been conducted to characterize the positional accuracy of the fault traces. The processes used to generate these data span a wide range of techniques including digitizing on lidar derived shaded relief base maps and aerial orthoimagery from Hudnut et al. (2020). The data have been interpreted and mapped as accurately as possible given the type of source data, and the time, staff, and technology available at the time of mapping. Digital GIS files are provided as ESRI feature services Type Lineaments: For lidar-based mapping. Faults are features clearly identifiable as surface ruptures, and typically have vertical relief. Lineaments are linear features that are mappable but have greater origin uncertainty. Examples might include bedrock and geomorphic features where the geologist cannot determine if the linear feature ruptured during the earthquake. Fractures are not typically assigned when interpreting lidar data, because these features lack vertical relief or, are typically below the resolution of lidar to resolve, but are visible on optical imagery. Faults: For imagery-based mapping: Faults meets the same criteria as described above for lidar-based mapping. The geologist may also use other criteria such as en echelon stepping patterns of rupture to assign the features as faults. Lineaments are the same as described above. Fractures are mappable cracks where it is uncertain if there is displacement (other than an opening mode). CGS Text 254 ExistenceConfidence The surface rupture and ground deformation mapping is on lidar and optical orthoimagery, so default is “certain”. If there is some indication the feature could be a scan artifact (e.g., lidar “corduroy”, then linework is assigned as “questionable”. CGS Text 50 IdentityConfidence This field is related to the “Type” field. Certain: Identity of feature can be determined using relevant observations and scientific judgement. Faults will have a “certain” identity confidence and there is reasonable confidence in credibility of this interpretation. Questionable: Identity of feature cannot be determined using relevant observations and scientific judgement. There is low confidence in the credibility of this interpretation and will typically be associated with lineaments and fractures and/or pre-existing features. CGS Text 50 Scarp Used to indicate if fault rupture has a vertical component of slip (either real or apparent) and denoted by a “Y” or “N” CGS Text 10 ScarpFacingDirection One of the either cardinal/ordinal directions (e.g., N, NE, E, SE, S, SW, W, NW) CGS Text 10 Label Feature associated with either the Paxton Ranch Fault Zone or the Salt Wells Valley Fault Zone. (This attribute is generalized and not intended to assign origin of a feature to a specific event) CGS Text 50 InterpretationSourceID Refers to basemap upon which features were mapped. National Center for Airborne Laser Mapping (NCALM) Lidar dataset or NCALM orthoimagery, both from Hudnut et al. (2020) Notes: Text for additional information and descriptions specific to the feature. CGS Text 50