Geologic Mapping for Landscape Resiliency in California, Oregon, and Washington
Quaternary Geology map of Santa Cruz Island
Marine Terraces of Anacapa Island
Quaternary geology map of Santa Rosa Island
Correlation of Map Units
This project uses geologic and geomorphic mapping in the context of societally relevant problems in the Earth’s critical zone. Leveraging interdisciplinary research ties and interagency collaborations, it utilizes remote sensing data, corroborated with field observations, to determine i) the spatial distribution of geomorphic processes and ages of Quaternary deposits in the context of active tectonics, landsliding, and ecosystem function in California in collaboration with the National Park Service and ii) the record of earthquake-triggered terrestrial Quaternary landslides in the west. Working with land-use manager partners, our research aims to answer the following questions for readily applied science:
Where in the landscape are Quaternary materials and where are they geomorphically active?
What are their sources, rates of deposition with respect to frequency and magnitude, and thresholds for re-mobilization and associated hazards?
This project is supported by the National Cooperative Geologic Mapping Program and Landslide Hazards Program.
Science Issues and Relevance:
Active geomorphic processes, surface erosion, and landslides
Mapping the distribution of earth materials is essential to understanding the location, timing, and magnitude of surface-water availability, ecosystem function, and erosion hazards. Bedrock and Quaternary surficial maps provide different information for analyzing processes that span the surface and subsurface. Supplemental geomorphic process maps, expressing modes of sediment transport tied to triggering functions, can be used to estimate future mobilization thresholds. Additionally, efforts to estimate 3D thickness, with refinements of deposit architecture and material properties, elucidate potential landslide volumes and potential runout lengths.
Active Tectonics
Constraining connectivity between faults, past displacement rates, and cumulative displacements are critical to modeling future deformation and relative hazard to life and property. While most existing geologic maps focus on fault deformation in bedrock, providing context for long-term deformation patterns and mineral resources, knowledge of Quaternary fault activity is critical to estimate hazard and risk. Opportunities exist to map offset of Quaternary materials associated with on- and off-fault deformation patterns. Quaternary surficial mapping, at scales commensurate with fault-displaced materials, coupled with robust numerical dating campaigns will refine frequency/magnitude relations.
Surface and Ground Water
As industrial, agricultural, and residential demands continue to stress available resources, surface water and groundwater reserves will be in higher demand. Understanding the spatial distribution of earth materials is critical to forecasting where water reserves exist. Quaternary surficial maps, including unit thicknesses, could inform estimates of transmissivity and water delivery rates. Albeit, thin-skinned, this avenue can enrich geologic maps with 3-D data.
Post-event response
In the wake of natural disasters, decision makers have timely needs for accurate earth science information. Improving the collection of potentially time-sensitive, spatially relevant data for map representation of source and inundation areas for immediate planning and extrapolation to future events is high-visibility science. Map-based interpretations promote richer interpretations of geomorphic indicators of pre-historic ground ruptures, multi-disciplinary research, integrated assessments, predictive modeling, and knowledge transfer to land managers.
Methodology to Address Issues:
Geologic Maps and associated Geodatabases
Although this project generates traditional Quaternary surficial geologic maps, it also forges new directions demonstrating the utility of geomorphic transport process mapping. This new mapping will address topical research problems with collaborating partners. Mapping strategies will employ remotely sensed image analysis, field control for characteristic map units, stratigraphic, paleontologic, geochronological, and geochemical studies. Maps will be released on scale-appropriate base materials such as high-resolution, lidar-derived topography.
Watershed Erosion Rates
Mapping the geomorphic processes, coupled with monitoring the erosion rates and modeling the sediment budget, locates and quantifies the sediment sources and sediment flux from a watershed. We can estimate the magnitude and recurrence interval of erosion-causing events. The resulting products enable community members and relevant stakeholders to make informed decisions about how to efficiently protect resources to maintain long-term viability.
Structure from Motion to estimate ground-deformation
Structure from Motion (SfM) from fixed wing or UAV platforms provides a cost-effective means to rapidly acquire imagery that can be transformed to digital topography using photogrammetry. The inherent high spatial and temporal resolution of coupled imagery and topography, as well as potential for time series data, allow for enhanced mapping of deposits and joining them to transport mechanisms (wind, rain, etc.). Target areas include constraining crustal deformation associated with tectonics and deep-seated landsliding. Such an approach is essential to responding to post-event natural disaster recovery missions, as the UAV platform can be used to generate both imagery and topography for process mapping.
Results
1. Quaternary Geologic Mapping of Channel Islands National Park (CHIS)
Tectonics
Located in the western Transverse Range (WTR) of California, Channel Islands National Park (CHIS) is part of the active broad San Andreas transform plate margin with dramatic Neogene and Quaternary transpressional faulting, folding, and clockwise vertical-axis rotations of crustal blocks. Geologically youthful manifestations of tectonism include regions of concentrated seismicity and recent to active crustal uplift, associated basinal subsidence, and local drainage capture. Significant seismic hazard exists, exemplified by the 2018 M 5.3 earthquake south of Santa Cruz Island that triggered coastal landslides.
Surface Water Availability
Repeat surveys of surface-water distribution conducted by NPS-CHIS scientists reveal spring and sink points that correlate with geologic contacts and faults juxtaposing rocks and deposits with contrasting hydrologic properties. Spatial correlations between independent geologic and hydrologic mapping provide the opportunity to evaluate causal mechanisms for surface water presence in the water-limited landscape and assist restoration efforts.
Ecosystem Restoration
Disturbance caused by heavy grazing, introduction of non-native vegetation, and associated erosion complicates NPS land management. Grazing of native vegetation on steep slopes resulted in significantly increased erosion rates and, in some cases, complete stripping of hillslope soil. Presently, endemic vegetation is competing with non-natives, especially shrubs and grasses, or has been completely replaced by invasive species. The Channel Islands are unique in that the grazing ungulates have been removed and the landscape is now managed for conservation with concomitant restoration efforts.
Big Sur Coast Landslides
Faulting and associated uplift in the Santa Lucia Range of central California has generated steep, high-relief hillslopes with abundant active landslides supplying sediment to the adjacent national marine sanctuary in the Pacific Ocean and impacting California State Hwy. 1. The 2017 Mud Creek landslide closed Hwy. 1 for 15 months with a present cost of \$54 million to re-open the road. Hwy. 1, the only transportation artery along the coast has an average daily traffic count of ~ 4000. Closures have been common since its inauguration in 1937, with long-term deep-seated landslide-induced closures occurring in years of heavy rainfall. Structure from Motion (SfM) was used to estimate the timing of deformation and volume of the Mud Creek landslide.
2. Evaluating the record of earthquake-triggered terrestrial Quaternary landslides
The western states of Washington, Oregon, and California face a myriad of landslide hazards ranging from Cascadia subduction zone megathrust earthquakes in the north, shallow crustal earthquakes along the latitudinal extent, and heavy precipitation in the form of atmospheric river events. Additional hazard potential in mountainous landscapes is posed by deep, large-volume landslides, as they can form valley-wide dams that lead to outburst flooding which can harm downstream communities (and significantly alter the sediment transport and storage along river networks).
Our goals are to understand the:
- influence of rock type on landslide character, size, and kinematics, and
- connection between rainfall or earthquake recurrence magnitude and inter-event time, seismic ground motion, and landslide occurrence.
The expansion of high-resolution topographic data with lidar (light detection and ranging) provides an opportunity to identify and characterize large landslides and their morphologic characteristics. Maps of Quaternary landslides constrain their sources, runout inundation, spatial distribution and relative age. Such information helps determine recurrence intervals of landslides relative to topographic signatures and earth materials. Our work strengthens the linkages between earthquakes, storms, material properties of bedrock and regolith, and long-runout landslide occurrences. Additionally, our techniques combine field investigations, morphological analyses, stability modeling, and geotechnical material testing to better understand patterns in landslide initiation and mobility.
We address the following questions:
- What records of pre-historic, Cascadia megathrust and crustal fault earthquakes still exist in the landscape, and what can we learn from these deposits and landforms?
- Are larger landslides more prone to reactivation from a future M9 subduction event?
- Are secondary hazards such as landslide-dam outburst floods possible?
- What growth potential exists for entraining down valley deposits along the transport path?
Landslide runout characteristics strongly influence landslide hazard and risk. The extent of sediment inundation significantly impacts water quality, infrastructure security, and human safety. As such, we develop methods and software tools to model downslope debris-flow growth from landslide source areas through channel networks to depositional setting.
View the Grfin Tools model software release here:
Grfin Tools—Software Package and Runtime Documentation for Users | U.S. Geological Survey
This project uses geologic and geomorphic mapping in the context of societally relevant problems in the Earth’s critical zone. Leveraging interdisciplinary research ties and interagency collaborations, it utilizes remote sensing data, corroborated with field observations, to determine i) the spatial distribution of geomorphic processes and ages of Quaternary deposits in the context of active tectonics, landsliding, and ecosystem function in California in collaboration with the National Park Service and ii) the record of earthquake-triggered terrestrial Quaternary landslides in the west. Working with land-use manager partners, our research aims to answer the following questions for readily applied science:
Where in the landscape are Quaternary materials and where are they geomorphically active?
What are their sources, rates of deposition with respect to frequency and magnitude, and thresholds for re-mobilization and associated hazards?
This project is supported by the National Cooperative Geologic Mapping Program and Landslide Hazards Program.
Science Issues and Relevance:
Active geomorphic processes, surface erosion, and landslides
Mapping the distribution of earth materials is essential to understanding the location, timing, and magnitude of surface-water availability, ecosystem function, and erosion hazards. Bedrock and Quaternary surficial maps provide different information for analyzing processes that span the surface and subsurface. Supplemental geomorphic process maps, expressing modes of sediment transport tied to triggering functions, can be used to estimate future mobilization thresholds. Additionally, efforts to estimate 3D thickness, with refinements of deposit architecture and material properties, elucidate potential landslide volumes and potential runout lengths.
Active Tectonics
Constraining connectivity between faults, past displacement rates, and cumulative displacements are critical to modeling future deformation and relative hazard to life and property. While most existing geologic maps focus on fault deformation in bedrock, providing context for long-term deformation patterns and mineral resources, knowledge of Quaternary fault activity is critical to estimate hazard and risk. Opportunities exist to map offset of Quaternary materials associated with on- and off-fault deformation patterns. Quaternary surficial mapping, at scales commensurate with fault-displaced materials, coupled with robust numerical dating campaigns will refine frequency/magnitude relations.
Surface and Ground Water
As industrial, agricultural, and residential demands continue to stress available resources, surface water and groundwater reserves will be in higher demand. Understanding the spatial distribution of earth materials is critical to forecasting where water reserves exist. Quaternary surficial maps, including unit thicknesses, could inform estimates of transmissivity and water delivery rates. Albeit, thin-skinned, this avenue can enrich geologic maps with 3-D data.
Post-event response
In the wake of natural disasters, decision makers have timely needs for accurate earth science information. Improving the collection of potentially time-sensitive, spatially relevant data for map representation of source and inundation areas for immediate planning and extrapolation to future events is high-visibility science. Map-based interpretations promote richer interpretations of geomorphic indicators of pre-historic ground ruptures, multi-disciplinary research, integrated assessments, predictive modeling, and knowledge transfer to land managers.
Methodology to Address Issues:
Geologic Maps and associated Geodatabases
Although this project generates traditional Quaternary surficial geologic maps, it also forges new directions demonstrating the utility of geomorphic transport process mapping. This new mapping will address topical research problems with collaborating partners. Mapping strategies will employ remotely sensed image analysis, field control for characteristic map units, stratigraphic, paleontologic, geochronological, and geochemical studies. Maps will be released on scale-appropriate base materials such as high-resolution, lidar-derived topography.
Watershed Erosion Rates
Mapping the geomorphic processes, coupled with monitoring the erosion rates and modeling the sediment budget, locates and quantifies the sediment sources and sediment flux from a watershed. We can estimate the magnitude and recurrence interval of erosion-causing events. The resulting products enable community members and relevant stakeholders to make informed decisions about how to efficiently protect resources to maintain long-term viability.
Structure from Motion to estimate ground-deformation
Structure from Motion (SfM) from fixed wing or UAV platforms provides a cost-effective means to rapidly acquire imagery that can be transformed to digital topography using photogrammetry. The inherent high spatial and temporal resolution of coupled imagery and topography, as well as potential for time series data, allow for enhanced mapping of deposits and joining them to transport mechanisms (wind, rain, etc.). Target areas include constraining crustal deformation associated with tectonics and deep-seated landsliding. Such an approach is essential to responding to post-event natural disaster recovery missions, as the UAV platform can be used to generate both imagery and topography for process mapping.
Results
1. Quaternary Geologic Mapping of Channel Islands National Park (CHIS)
Tectonics
Located in the western Transverse Range (WTR) of California, Channel Islands National Park (CHIS) is part of the active broad San Andreas transform plate margin with dramatic Neogene and Quaternary transpressional faulting, folding, and clockwise vertical-axis rotations of crustal blocks. Geologically youthful manifestations of tectonism include regions of concentrated seismicity and recent to active crustal uplift, associated basinal subsidence, and local drainage capture. Significant seismic hazard exists, exemplified by the 2018 M 5.3 earthquake south of Santa Cruz Island that triggered coastal landslides.
Surface Water Availability
Repeat surveys of surface-water distribution conducted by NPS-CHIS scientists reveal spring and sink points that correlate with geologic contacts and faults juxtaposing rocks and deposits with contrasting hydrologic properties. Spatial correlations between independent geologic and hydrologic mapping provide the opportunity to evaluate causal mechanisms for surface water presence in the water-limited landscape and assist restoration efforts.
Ecosystem Restoration
Disturbance caused by heavy grazing, introduction of non-native vegetation, and associated erosion complicates NPS land management. Grazing of native vegetation on steep slopes resulted in significantly increased erosion rates and, in some cases, complete stripping of hillslope soil. Presently, endemic vegetation is competing with non-natives, especially shrubs and grasses, or has been completely replaced by invasive species. The Channel Islands are unique in that the grazing ungulates have been removed and the landscape is now managed for conservation with concomitant restoration efforts.
Big Sur Coast Landslides
Faulting and associated uplift in the Santa Lucia Range of central California has generated steep, high-relief hillslopes with abundant active landslides supplying sediment to the adjacent national marine sanctuary in the Pacific Ocean and impacting California State Hwy. 1. The 2017 Mud Creek landslide closed Hwy. 1 for 15 months with a present cost of \$54 million to re-open the road. Hwy. 1, the only transportation artery along the coast has an average daily traffic count of ~ 4000. Closures have been common since its inauguration in 1937, with long-term deep-seated landslide-induced closures occurring in years of heavy rainfall. Structure from Motion (SfM) was used to estimate the timing of deformation and volume of the Mud Creek landslide.
2. Evaluating the record of earthquake-triggered terrestrial Quaternary landslides
The western states of Washington, Oregon, and California face a myriad of landslide hazards ranging from Cascadia subduction zone megathrust earthquakes in the north, shallow crustal earthquakes along the latitudinal extent, and heavy precipitation in the form of atmospheric river events. Additional hazard potential in mountainous landscapes is posed by deep, large-volume landslides, as they can form valley-wide dams that lead to outburst flooding which can harm downstream communities (and significantly alter the sediment transport and storage along river networks).
Our goals are to understand the:
- influence of rock type on landslide character, size, and kinematics, and
- connection between rainfall or earthquake recurrence magnitude and inter-event time, seismic ground motion, and landslide occurrence.
The expansion of high-resolution topographic data with lidar (light detection and ranging) provides an opportunity to identify and characterize large landslides and their morphologic characteristics. Maps of Quaternary landslides constrain their sources, runout inundation, spatial distribution and relative age. Such information helps determine recurrence intervals of landslides relative to topographic signatures and earth materials. Our work strengthens the linkages between earthquakes, storms, material properties of bedrock and regolith, and long-runout landslide occurrences. Additionally, our techniques combine field investigations, morphological analyses, stability modeling, and geotechnical material testing to better understand patterns in landslide initiation and mobility.
We address the following questions:
- What records of pre-historic, Cascadia megathrust and crustal fault earthquakes still exist in the landscape, and what can we learn from these deposits and landforms?
- Are larger landslides more prone to reactivation from a future M9 subduction event?
- Are secondary hazards such as landslide-dam outburst floods possible?
- What growth potential exists for entraining down valley deposits along the transport path?
Landslide runout characteristics strongly influence landslide hazard and risk. The extent of sediment inundation significantly impacts water quality, infrastructure security, and human safety. As such, we develop methods and software tools to model downslope debris-flow growth from landslide source areas through channel networks to depositional setting.
View the Grfin Tools model software release here:
Grfin Tools—Software Package and Runtime Documentation for Users | U.S. Geological Survey