Here we present new observations of two different interactions between aeolian ridges and boulder... more Here we present new observations of two different interactions between aeolian ridges and boulder fields on Mars that provide insight into past wind conditions. First, an analysis of ridge and boulder interactions at two test sites in Proctor Crater and an additional site ~430 km to the northeast shows that ridge geometry can be affected by changes in surface roughness elements generated by boulder fields. Second, a detailed examination of some of the boulder fields found that individual boulders can generate multi‐armed ‘wakes’ that have no clear proxy on Earth. The ridge/boulder dynamics suggest that transverse aeolian ridges acted as roughness during their development, indicating that they formed at a length scale greater than wind ripples. The boulder wakes seem to represent an unusual interaction between flow separation and pre‐exiting ridges; why this pattern is not observed on Earth remains uncertain.
ABSTRACT Morphological characteristics of cirques have been studied for decades; however, no repe... more ABSTRACT Morphological characteristics of cirques have been studied for decades; however, no repeatable set of metrics has been derived that can consistently identify them. Perhaps more importantly, there is no consensus definition of the form that distinguishes cirques and clusters of cirques from non-cirques. In our approach, we use Shuttle Radar Topography Mission (SRTM) digital elevation models (DEMs) in a Convolutional Neural Network (CNN) framework to identify cirques in 20 mountain ranges globally. We extracted bounding boxes of cirques in 19 of these study areas and used them to develop a training set for a cirque identification model. The trained model was applied to the Sierra Nevada California to assess whether this algorithmic approach derived from a global dataset could produce consistent results in complex terrain with mutually interacting cirque forms. Using commonalities revealed using this approach, we find that there is a basic, recognizable and morphometrically quantifiable cirque form. This approach can be used to automate the identification of cirque locations and to guide the quantification of cirque form independent of the subjective definitions of individual workers. The approach can also be used to understand cirque form under different environmental conditions, including similar forms on Mars.
We examine the coseismic influence of the 5 July 2019, MW7.1 Ridgecrest and the 24 June 2020 MW5.... more We examine the coseismic influence of the 5 July 2019, MW7.1 Ridgecrest and the 24 June 2020 MW5.8 Owens Lake earthquakes on rockfall distributions in two undisturbed high-altitude areas of the southern Sierra Nevada Mountains, California, USA. These events occurred within the geologically recent (<2 Mya) Walker Lane/eastern California shear zone. While both study areas are characterized as plutonic, the Owens Lake event largely affected terrain that was formerly glaciated and oversteepened while the Ridgecrest event affected non-glaciated terrain. Our inventory of rockfall locations was derived from analysis of Sentinel-2 images acquired just prior to and immediately after the events. This difference mapping approach using readily-available Sentinel-2 imagery allows for rapid rockfall and landslide mapping. GIS analysis shows that even though the total area assessed for both earthquakes was similar (~1500 km2), the significantly lower magnitude Owens Lake event produced nearly t...
The original version of this Article contained an error in the fifth sentence of the third paragr... more The original version of this Article contained an error in the fifth sentence of the third paragraph of the "Introduction" section which incorrectly read 'We applied metrics that easily differentiate networked morphologies by (1) the number of vertices per cell and (2) the number of cells per vertex (Fig. 2d, e).' The correct version adds '(nodal degree)' after 'number of cells per vertex'.
MSL ChemCam RMI rover imagery and HiRISE orbital data are utilized to interpret the formation pro... more MSL ChemCam RMI rover imagery and HiRISE orbital data are utilized to interpret the formation processes and the sedimentary architecture of the Peace Vallis fan.
Transverse aeolian ridges – enigmatic Martian features without a proven terrestrial analog – are ... more Transverse aeolian ridges – enigmatic Martian features without a proven terrestrial analog – are increasingly important to our understanding of Martian surface processes. However, it is not well understood how the relationships between different ridges evolve. Here we present a hypothesis for the development of complex hexagonal networks from simple linear forms by analyzing HiRISE images from the Mars Reconnaissance Orbiter. We identify variable morphologies which show the presence of secondary ridges, feathered transverse aeolian ridges and both rectangular and hexagonal networks. We propose that the formation of secondary ridges and the reactivation of primary ridge crests produces sinuous networks which then progress from rectangular cells towards eventual hexagonal cells. This morphological progression may be explained by the ridges acting as roughness elements due to their increased spatial density which would drive a transition from two-dimensional bedforms under three-dimens...
The presence of buried glacial ice and putative extinct rock glaciers in Mars’ equatorial regions... more The presence of buried glacial ice and putative extinct rock glaciers in Mars’ equatorial regions has implications for understanding its climate history and sensitivity to changes in insolation and has significant implications for past global redistribution of the water ice cryosphere. We quantify the morphology of rock glacier- “like” features on the northern slopes of Aeolis Mons (known also as Mount Sharp) within Gale crater and use this information to evaluate a possible rock glacier origin for these forms. Detailed morphometric evaluation of cross and long profiles of these lobate features, which exhibit higher slopes at their heads, lower slopes at their distal edge, and a convex upward cross-sectional profile and oversteepened sides, resembles active terrestrial rock glaciers. However, the absence of a chevron wrinkle pattern and sublimation features could indicate extensive aeolian reworking and the lack of deflation could indicate a higher rock to ice mixture. The lack of c...
Introduction: The history of fluvial activity in Gale Crater has been examined by numerous author... more Introduction: The history of fluvial activity in Gale Crater has been examined by numerous authors [recently 1-3]. The Peace Vallis (PV) channel and alluvial fan received the most attention due to the proximity to the MSL (Curiosity) landing site. An initial watershed area (or catchment) of about 1000 km2 that may drain to the Peace Vallis (PV) fan was identified [1]. The determination that an upper PV fan unit may be substantially younger than the majority of deltas and fan surfaces in Gale has led us to begin reexamining the upper PV channel network and watershed [4]. Although new HiRISE images have helped with the interpretations, coverage is still very limited, there are no HiRISE stereo pairs, and the lack of HiRISE DEMs makes quantitative analysis difficult. However, the following observations and preliminary interpretations seem plausible: 1. Fluvial modification occurred over a large amount of time; a hierarchy of channel cutting and inverted channel deposition both above an...
Introduction: The Jezero crater has been selected to be the destination for the Mars 2020 rover i... more Introduction: The Jezero crater has been selected to be the destination for the Mars 2020 rover in early 2021. One of the primary goals of the Mars 2020 mission is to identify locations within or near the landing ellipse that could have high biosignature preservation potential. The rover would then seek these locations and cache samples for return and analysis on the Earth. It is therefore vital to locate areas near or in the landing ellipse utilizing orbitally derived imagery. Solar and cosmogenic radiation destroys organic molecules after prolonged exposure at the Martian surface, however fresh outcrops (<100ma) re-exposed by aeolian dominated erosion provide potential sites where biosignatures could have been protected and made recently available for sampling. This and previous work [1] tests the parallel scarp retreat model that would expose fresh outcrops. Previous work on analyzing aeolian dominated erosion by mapping meter-scale scarp orientation [1] returned a distributio...
Introduction: An automated methodology for identifying boulders in High Resolution Imaging Scienc... more Introduction: An automated methodology for identifying boulders in High Resolution Imaging Science Experiment (HiRISE) [1] images via ArcGIS was developed for this study. The workflow enables the measurement of important boulder characteristics (area, length, width, elevation, transport distance), and geospatial statistical metrics (density, autocorrelation, and clustering). Understanding these properties is important for broadly two reasons: 1) boulders and large clasts pose a challenge to the traversability of terrain for both rovers and future human missions [2]–[5], and 2) boulders are important for understanding the sedimentologic, aeolian, and erosional processes at work on a surface [6]–[12]. Methods: This study had four objectives: 1) Accessibility for varied levels of experience with geographic information systems (GIS) software and programming, 2) application to almost any HiRISE image with boulder features, 3) effective discrimination between boulders and other features, ...
Here we present new observations of two different interactions between aeolian ridges and boulder... more Here we present new observations of two different interactions between aeolian ridges and boulder fields on Mars that provide insight into past wind conditions. First, an analysis of ridge and boulder interactions at two test sites in Proctor Crater and an additional site ~430 km to the northeast shows that ridge geometry can be affected by changes in surface roughness elements generated by boulder fields. Second, a detailed examination of some of the boulder fields found that individual boulders can generate multi‐armed ‘wakes’ that have no clear proxy on Earth. The ridge/boulder dynamics suggest that transverse aeolian ridges acted as roughness during their development, indicating that they formed at a length scale greater than wind ripples. The boulder wakes seem to represent an unusual interaction between flow separation and pre‐exiting ridges; why this pattern is not observed on Earth remains uncertain.
ABSTRACT Morphological characteristics of cirques have been studied for decades; however, no repe... more ABSTRACT Morphological characteristics of cirques have been studied for decades; however, no repeatable set of metrics has been derived that can consistently identify them. Perhaps more importantly, there is no consensus definition of the form that distinguishes cirques and clusters of cirques from non-cirques. In our approach, we use Shuttle Radar Topography Mission (SRTM) digital elevation models (DEMs) in a Convolutional Neural Network (CNN) framework to identify cirques in 20 mountain ranges globally. We extracted bounding boxes of cirques in 19 of these study areas and used them to develop a training set for a cirque identification model. The trained model was applied to the Sierra Nevada California to assess whether this algorithmic approach derived from a global dataset could produce consistent results in complex terrain with mutually interacting cirque forms. Using commonalities revealed using this approach, we find that there is a basic, recognizable and morphometrically quantifiable cirque form. This approach can be used to automate the identification of cirque locations and to guide the quantification of cirque form independent of the subjective definitions of individual workers. The approach can also be used to understand cirque form under different environmental conditions, including similar forms on Mars.
We examine the coseismic influence of the 5 July 2019, MW7.1 Ridgecrest and the 24 June 2020 MW5.... more We examine the coseismic influence of the 5 July 2019, MW7.1 Ridgecrest and the 24 June 2020 MW5.8 Owens Lake earthquakes on rockfall distributions in two undisturbed high-altitude areas of the southern Sierra Nevada Mountains, California, USA. These events occurred within the geologically recent (<2 Mya) Walker Lane/eastern California shear zone. While both study areas are characterized as plutonic, the Owens Lake event largely affected terrain that was formerly glaciated and oversteepened while the Ridgecrest event affected non-glaciated terrain. Our inventory of rockfall locations was derived from analysis of Sentinel-2 images acquired just prior to and immediately after the events. This difference mapping approach using readily-available Sentinel-2 imagery allows for rapid rockfall and landslide mapping. GIS analysis shows that even though the total area assessed for both earthquakes was similar (~1500 km2), the significantly lower magnitude Owens Lake event produced nearly t...
The original version of this Article contained an error in the fifth sentence of the third paragr... more The original version of this Article contained an error in the fifth sentence of the third paragraph of the "Introduction" section which incorrectly read 'We applied metrics that easily differentiate networked morphologies by (1) the number of vertices per cell and (2) the number of cells per vertex (Fig. 2d, e).' The correct version adds '(nodal degree)' after 'number of cells per vertex'.
MSL ChemCam RMI rover imagery and HiRISE orbital data are utilized to interpret the formation pro... more MSL ChemCam RMI rover imagery and HiRISE orbital data are utilized to interpret the formation processes and the sedimentary architecture of the Peace Vallis fan.
Transverse aeolian ridges – enigmatic Martian features without a proven terrestrial analog – are ... more Transverse aeolian ridges – enigmatic Martian features without a proven terrestrial analog – are increasingly important to our understanding of Martian surface processes. However, it is not well understood how the relationships between different ridges evolve. Here we present a hypothesis for the development of complex hexagonal networks from simple linear forms by analyzing HiRISE images from the Mars Reconnaissance Orbiter. We identify variable morphologies which show the presence of secondary ridges, feathered transverse aeolian ridges and both rectangular and hexagonal networks. We propose that the formation of secondary ridges and the reactivation of primary ridge crests produces sinuous networks which then progress from rectangular cells towards eventual hexagonal cells. This morphological progression may be explained by the ridges acting as roughness elements due to their increased spatial density which would drive a transition from two-dimensional bedforms under three-dimens...
The presence of buried glacial ice and putative extinct rock glaciers in Mars’ equatorial regions... more The presence of buried glacial ice and putative extinct rock glaciers in Mars’ equatorial regions has implications for understanding its climate history and sensitivity to changes in insolation and has significant implications for past global redistribution of the water ice cryosphere. We quantify the morphology of rock glacier- “like” features on the northern slopes of Aeolis Mons (known also as Mount Sharp) within Gale crater and use this information to evaluate a possible rock glacier origin for these forms. Detailed morphometric evaluation of cross and long profiles of these lobate features, which exhibit higher slopes at their heads, lower slopes at their distal edge, and a convex upward cross-sectional profile and oversteepened sides, resembles active terrestrial rock glaciers. However, the absence of a chevron wrinkle pattern and sublimation features could indicate extensive aeolian reworking and the lack of deflation could indicate a higher rock to ice mixture. The lack of c...
Introduction: The history of fluvial activity in Gale Crater has been examined by numerous author... more Introduction: The history of fluvial activity in Gale Crater has been examined by numerous authors [recently 1-3]. The Peace Vallis (PV) channel and alluvial fan received the most attention due to the proximity to the MSL (Curiosity) landing site. An initial watershed area (or catchment) of about 1000 km2 that may drain to the Peace Vallis (PV) fan was identified [1]. The determination that an upper PV fan unit may be substantially younger than the majority of deltas and fan surfaces in Gale has led us to begin reexamining the upper PV channel network and watershed [4]. Although new HiRISE images have helped with the interpretations, coverage is still very limited, there are no HiRISE stereo pairs, and the lack of HiRISE DEMs makes quantitative analysis difficult. However, the following observations and preliminary interpretations seem plausible: 1. Fluvial modification occurred over a large amount of time; a hierarchy of channel cutting and inverted channel deposition both above an...
Introduction: The Jezero crater has been selected to be the destination for the Mars 2020 rover i... more Introduction: The Jezero crater has been selected to be the destination for the Mars 2020 rover in early 2021. One of the primary goals of the Mars 2020 mission is to identify locations within or near the landing ellipse that could have high biosignature preservation potential. The rover would then seek these locations and cache samples for return and analysis on the Earth. It is therefore vital to locate areas near or in the landing ellipse utilizing orbitally derived imagery. Solar and cosmogenic radiation destroys organic molecules after prolonged exposure at the Martian surface, however fresh outcrops (<100ma) re-exposed by aeolian dominated erosion provide potential sites where biosignatures could have been protected and made recently available for sampling. This and previous work [1] tests the parallel scarp retreat model that would expose fresh outcrops. Previous work on analyzing aeolian dominated erosion by mapping meter-scale scarp orientation [1] returned a distributio...
Introduction: An automated methodology for identifying boulders in High Resolution Imaging Scienc... more Introduction: An automated methodology for identifying boulders in High Resolution Imaging Science Experiment (HiRISE) [1] images via ArcGIS was developed for this study. The workflow enables the measurement of important boulder characteristics (area, length, width, elevation, transport distance), and geospatial statistical metrics (density, autocorrelation, and clustering). Understanding these properties is important for broadly two reasons: 1) boulders and large clasts pose a challenge to the traversability of terrain for both rovers and future human missions [2]–[5], and 2) boulders are important for understanding the sedimentologic, aeolian, and erosional processes at work on a surface [6]–[12]. Methods: This study had four objectives: 1) Accessibility for varied levels of experience with geographic information systems (GIS) software and programming, 2) application to almost any HiRISE image with boulder features, 3) effective discrimination between boulders and other features, ...
Uploads
Papers by Louis Scuderi