Science Center Objects

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 coastal California, ii) the discharge of land-based pollutants, such as sediment and nutrients, degrading coral reef ecosystems in the Hawaiian Islands,and iii) the record of earthquake-triggered terrestrial Quaternary landslides in the west. Working with land-use manager partners, answers to the following questions should result in 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? 

                     How do rates of erosion and deposition change in response to tectonics, climate, and human activities?

Science Issue 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.

 

Adjustment of tension in infiltrometer to measure post-fire recovery.

Research Geologist Jonathan Perkins adjusting tension in infiltrometer to evaluate post-fire recovery conditions in the Pepperwood Preserve, Santa Rosa, CA following the October 2017 Tubbs Fire to better understand how landscapes heal after wildfire. 

(Credit: Jonathan Stock, USGS/GMEG. Courtesy: Jonathan Stock)

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.

Geologist standing on steep outcrop on island

Research Geologist Scott Minor searching for fossils on uplifted marine terrace on San Miguel Island, Channel Islands National Park, CA. 

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

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 mission as the UAV platform can be used to generate both imagery and topography for process mapping.

Geologists holding plane and camera

Research Geologists Elisabeth Haddon and Skye Corbett mounting camera to UAV for flight of Big Sur deep-seated landslides.

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

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.

Two geologists pointing out faulted rocks

Research Geologists Scott Minor and David Bedford pointing out Santa Rosa Island fault in the Channel Island National Park, CA

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

Surface Water Availability

Recent 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.

Geologist using instrument to test rock permeability

Research Geologist Scott Minor testing rock permeability along the Santa Rosa Island fault in the Channel Island National Park, CA. Surface water, a limited resource, is partially controlled by contrasting permeabilities of rock juxtaposed by faulting. 

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

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.

Instruments in and above ground to monitor rainfall and soil moisture

Instrument array to monitor fog, rainfall, and soil moisture on Santa Rosa Island, Channel Islands National Park, CA. The study is evaluating the effectiveness of plants and fog to modulate soil moisture in the root zone to advise on ecosystem restoration strategies.

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

Geologist using instrument to measure soil infiltration

Research Geologist Jonathan Perkins measuring soil infiltration in vegetation recovery area on Santa Rosa Island, Channel Islands National Park, CA

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

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 suppling sediment to the adjacent national marine sanctuary in the Pacific Ocean and impacting California 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.

Geologist using GPS with tripod to measure landslide displacement

Research Geologist Mark Reid monitoring landslide displacement along Big Sur Coast using campaign-style differential GPS measurements. Paul's slide shown here intermittently closes CA State Highway 1. 

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

Aerial image showing landslide deformation

Aerial image of lateral margin of Big Sur landslide highlighted by recent asphalt patches in road. Note how asphalt patches align with vegetation break upslope of the road. Image obtained by UAV, truck for scale in hairpin curve.

(Credit: Kevin Schmidt, USGS/GMEG. Courtesy: Kevin Schmidt)

2. Geomorphic Process Mapping, Monitoring and Modeling to Non-Point Source Erosion Impacting Coral Reef Health in the Hawaiian Islands

Coral reef ecosystems, and the fishing and tourism industries they support, depend on clean waters. Fine sediment pollution from nearshore watersheds threatens these economies across the Hawaiian Islands. The terrestrial sediment sources are largely unknown and vary by location due to geology and land-use history. To effectively mitigate sediment pollution, it is critical to know where the sediment is coming from, how fast it erodes, and when it moves. These questions are either unanswered or unquantified, and relevant to stakeholders trying to mitigate the problem. USGS, in collaboration with federal and local partners, is working in watersheds across the Hawaiian Islands to: 1) map geomorphic processes generating fine sediment, 2) monitor erosion rates, 3) determine thresholds for sediment mobilization, and 4) determine the likely frequency of triggering events. The products delivered provide data stakeholders use to make informed mitigation decisions.

Geologist taking notes of erosion on Hawai'i

Research Geologists Corina Cerovski-Darriau and Jonathan Stock measure how, when, and where erosion occurs in Pelekane to understand the sources of fine sediment polluting the coastal waters of West Hawai'i

(Credit: Juli Rose, The Nature Conservancy. Courtesy: Kevin Schmidt)

Geologists placing anemometer in ground

USGS Research Geologist Jonathan Stock and student contractor Madison Douglas install an anemometer to measure wind conditions at one of hte monitoring sites in Pelekane.

(Credit: Corina Cerovski-Darriau, USGS/GMEG. Courtesy: Corina Cerovski-Darriau)

3. Evaluating the record of earthquake-triggered terrestrial Quaternary landslides

The Pacific Northwest and Coastal California face a myriad of landslide hazards ranging from subduction zone megathrust earthquakes in the north, shallow crustal earthquakes along the central and southern California coast, and heavy precipitation in the form of atmospheric river events across much of the region. However, our understanding of the terrestrial landscape response to these events is lacking. In collaboration with academic colleagues, personnel are convening a series of workshops through USGS Powell Center to integrating geological and geophysical datasets to understand subduction zone earthquake recurrence and hazards.