Douglas J. Jerolmack
· Edmund J. and Louise W. Kahn Endowed Term Professor of Earth and Environmental Science Professor of Mechanical Engineering and Applied MechanicsVerifiedUniversity of Pennsylvania · Civil and Environmental Engineering
Active 2001–2026
About
Douglas Jerolmack, Ph.D., is the Principal Investigator and the Edmund J. and Louise W. Kahn Endowed Term Professor of Earth and Environmental Science (EES) at the University of Pennsylvania. His research focuses on Earth and environmental sciences, with particular emphasis on understanding the dynamics of natural systems. As a professor, he contributes to advancing knowledge in these fields through his leadership in research and education.
Research topics
- Physics
- Computer Science
- Mechanics
- Materials science
- Artificial Intelligence
- Composite material
- Geology
- Chemical physics
- Mathematics
- Geotechnical engineering
- Chemical engineering
- Biology
- Archaeology
- Psychology
- Condensed matter physics
- Geomorphology
- Ecology
- Engineering
- Chemistry
- Geography
- Nanotechnology
- Statistical physics
- Communication
- Thermodynamics
Selected publications
Zenodo (CERN European Organization for Nuclear Research) · 2026-03-01
datasetOpen accessThis is for Data and Materials for the manuscript "Legged Autonomous Surface Science In Analogue Environments (LASSIE): Making Every Robotic Step Count in Planetary Exploration"
Fracture geometry and topology and their spectral signatures at OxiaPlanum, Mars
2026-03-14
articleOpen accessThe European Space Agency (ESA) Rosalind Franklin rover Mission (RFM) is expected to land at Oxia Planum, Mars in 2030. Orbital spectral data and imagery reveal layered, clay-rich sedimentary deposits, often overlain by or interbedded with a dark, more resistant rock rich in mafic minerals [e.g., 1, 2]. The 1:30k scale geologic map of the landing site [1] associates two geologic units to their VNIR color and fracture spacing; Apuzzo et al. [3] studied directional statistics of fractures in selected regions of interest. However, complete quantitative fracture metrics over the RFM landing area are not yet available. Since at least 35% of the landing site is covered by fractures [3], a comprehensive study of fractures, and the composition of their hosting bedrock, is critical for elucidating whether formation mechanism, alteration history, and/or mineralogy vary across the Oxia Planum site.Here, we present fracture density (number of fractures/m^2) and topological connectivity of fractures within an unbiased collection of 33 approximately 500x500 m square windows spaced along transects over the center of the predicted landing footprint of the RFM. Multiple windows overlap with Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral cubes for which Fe,Mg-clay abundance has been qualitatively estimated [2]. Fractures are mapped manually as linear segments in QGIS software, using visual interpretation of High Resolution Imaging Science Experiment (HiRISE) images (0.3 m/px) in the red spectral range. We map at 1:1250 scale resulting in a minimum resolvable fracture length of about five pixels, or 1.5 m. The NetworkGT QGIS software plugin [4] is used to extract node connectivity, fracture orientations, and fracture lengths.Topological analysis of node types and fracture-bounded polygon shapes is then leveraged to aid in interpreting (1) changes in fracture behavior across previously mapped unit boundaries, and (2) formation mechanisms of the fracture networks, following [5]. We also compare fracture mapping within and outside specific clay-rich areas of interest [2, 6] to determine if they have unique mechanical or formation characteristics. Preliminary analysisindicates that fracture density is often higher within more clay-rich areas, and that the majority of mapped fractures are “I-node”, meaning they terminate without connecting to another fracture. Where fractures do connect, three- and four-sided polygon shapes dominate. We compare these findings with previous topological network characterization [e.g., 5] to enhance our interpretation of the possible scenarios of formation and current unit composition at Oxia Planum, considering topological characteristics will better constrain our understanding of past aqueous activity. Our results will support the better selection of analog materials for terrestrial drill testing before mission launch, and help inform drill site selection when the rover reaches Mars’ surface.References: [1] Fawdon et al. (2024) Journal of Maps 20, 2302361. [2] Brossier et al. (2022) Icarus 386, 115114. [3] Apuzzo et al. (2025) PSS 267, 106169. [4] Nyberg et al. (2018) Geosphere 14(4) 10.1130/GES01595.1. [5] Silver et al. (2025) PNAS 22 (10) e2411738122. [6] Altieri et al. (2026), this conference.Acknowledgements: This work is funded by the Italian Space Agency (ASI) [Grant ASI-INAF n. 2023–3–HH.0].
Zenodo (CERN European Organization for Nuclear Research) · 2026-03-01
datasetOpen accessThis is for Data and Materials for the manuscript "Legged Autonomous Surface Science In Analogue Environments (LASSIE): Making Every Robotic Step Count in Planetary Exploration"
Climate extremes and urbanization drive flood tipping points at the city–river interface
npj natural hazards. · 2026-02-25 · 1 citations
articleOpen accessAbstract Hurricane Ida struck the U.S. East Coast in August 2021, driving the Schuylkill River in Philadelphia to a record discharge nearly 100 times its average flow. Ida exposes the growing challenge of predicting urban flooding arising from coupled rainfall–runoff and river–tide–landscape interactions that coarse models cannot resolve. Here, we address this gap with a street-resolving flood model that integrates LiDAR-derived terrain, bathymetric surveys, and land-use-based surface friction across Philadelphia’s watershed to reproduce Ida’s flood. We show that soil saturation, impervious surfaces, and fragmented infrastructure amplify pluvial flooding, increasing exposure in both low- and high-income communities. Scenario simulations reveal a flood tipping point: for river return periods exceeding 100 years, the inundated area grows logarithmically, with an additional 2–7% increase in flooding when peak discharge coincides with high tide and up to $$\sim$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> </mml:math> 15% under projected sea-level rise by 2100. As extreme rainfall intensifies and return periods shorten, this tipping point will be crossed more often, demanding integrated forecasting and adaptive planning in vulnerable, low-lying, rapidly urbanizing regions.
ArXiv.org · 2026-02-21
articleOpen accessRobot-aided exploration of planetary surfaces is essential for understanding geologic processes, yet many scientifically valuable regions, such as Martian dunes and lunar craters, remain hazardous due to loose, deformable regolith. We present a scout-rover cooperation framework that expands safe access to such terrain using a hybrid team of legged and wheeled robots. In our approach, a high-mobility legged robot serves as a mobile scout, using proprioceptive leg-terrain interactions to estimate regolith strength during locomotion and construct spatially resolved terrain maps. These maps are integrated with rover locomotion models to estimate traversal risk and inform path planning. We validate the framework through analogue missions at the NASA Ames Lunar Simulant Testbed and the White Sands Dune Field. Experiments demonstrate (1) online terrain strength mapping from legged locomotion and (2) rover-specific traversal-risk estimation enabling safe navigation to scientific targets. Results show that scout-generated terrain maps reliably capture spatial variability and predict mobility failure modes, allowing risk-aware path planning that avoids hazardous regions. By combining embodied terrain sensing with heterogeneous rover cooperation, this framework enhances operational robustness and expands the reachable science workspace in deformable planetary environments.
arXiv (Cornell University) · 2026-03-20
preprintOpen accessThe ability to efficiently and effectively explore planetary surfaces is currently limited by the capability of wheeled rovers to traverse challenging terrains, and by pre-programmed data acquisition plans with limited in-situ flexibility. In this paper, we present two novel approaches to address these limitations: (i) high-mobility legged robots that use direct surface interactions to collect rich information about the terrain's mechanics to guide exploration; (ii) human-inspired data acquisition algorithms that enable robots to reason about scientific hypotheses and adapt exploration priorities based on incoming ground-sensing measurements. We successfully verify our approach through lab work and field deployments in two planetary analog environments. The new capability for legged robots to measure soil mechanical properties is shown to enable effective traversal of challenging terrains. When coupled with other geologic properties (e.g., composition, thermal properties, and grain size data etc), soil mechanical measurements reveal key factors governing the formation and development of geologic environments. We then demonstrate how human-inspired algorithms turn terrain-sensing robots into teammates, by supporting more flexible and adaptive data collection decisions with human scientists. Our approach therefore enables exploration of a wider range of planetary environments and new substrate investigation opportunities through integrated human-robot systems that support maximum scientific return.
Open MIND · 2026-02-21
preprintRobot-aided exploration of planetary surfaces is essential for understanding geologic processes, yet many scientifically valuable regions, such as Martian dunes and lunar craters, remain hazardous due to loose, deformable regolith. We present a scout-rover cooperation framework that expands safe access to such terrain using a hybrid team of legged and wheeled robots. In our approach, a high-mobility legged robot serves as a mobile scout, using proprioceptive leg-terrain interactions to estimate regolith strength during locomotion and construct spatially resolved terrain maps. These maps are integrated with rover locomotion models to estimate traversal risk and inform path planning. We validate the framework through analogue missions at the NASA Ames Lunar Simulant Testbed and the White Sands Dune Field. Experiments demonstrate (1) online terrain strength mapping from legged locomotion and (2) rover-specific traversal-risk estimation enabling safe navigation to scientific targets. Results show that scout-generated terrain maps reliably capture spatial variability and predict mobility failure modes, allowing risk-aware path planning that avoids hazardous regions. By combining embodied terrain sensing with heterogeneous rover cooperation, this framework enhances operational robustness and expands the reachable science workspace in deformable planetary environments.
Zenodo (CERN European Organization for Nuclear Research) · 2026-03-01
datasetOpen accessThis is for Data and Materials for the manuscript "Legged Autonomous Surface Science In Analogue Environments (LASSIE): Making Every Robotic Step Count in Planetary Exploration"
Climate Extremes at the City–River Interface: Insights from the Philadelphia-Schuylkill System
2025-02-07
preprintOpen accessHurricane Ida struck the U.S. East Coast in August 2021, pushing the Schuylkill River in Philadelphia to a record discharge nearly 100 times larger than its average flow. As one of the most severe disasters of the 21st century, Ida exemplifies the increasing frequency and intensity of extreme hydrometeorological events under climate change. Predicting urban flood pathways remains challenging due to the complex interplay of rainfall-runoff and river–tide–landscape interactions. To address this, we developed a high-resolution (street-resolved) flood model integrating LiDAR terrain data, bathymetric surveys, and land use-based surface friction across Philadelphia. We find that impervious surfaces and fragmented infrastructure exacerbate pluvial flooding and localized waterlogging, increasing exposure for both low- and high-income communities. Scenario-based simulations reveal a tipping point: a logarithmic increase in inundation areas for return periods above 100 years, and 2-7% additional flooding when peak discharge coincides with high tide—rising to up to 15% under projected sea level rise by 2100. Our findings underscore the compounding impacts of climate extremes in urban river systems and the need for integrated forecasting and adaptive planning—particularly in vulnerable, low-lying, and rapidly urbanizing regions worldwide.
Unified Granular Intrusion Dynamics for Planetary Materials
2025-10-02
articleOpen accessSenior authorGranular friction μ is a sensitive and poorly understood function of packing fraction ϕ. Every granular material has a distinct critical volume fraction ϕc that delineates two mechanical deformation modes – compaction for ϕ &lt; ϕc, and dilation for ϕ &gt; ϕc. Here we examine the relation(s) between friction and packing fraction, using quasi-static penetration tests in materials ranging from glass beads to highly heterogeneous lunar regolith simulant. Noncohesive materials collapse onto a master curve that relates changes in friction to the distance from ϕc, confirming that the handoff from compaction to dilation is a phase transition. The mechanical distinction between compaction and dilation regimes is highlighted with the addition of cohesive dust – relevant for lunar regolith – which has little effect for ϕ &lt; ϕc, but drastically enhances strength for ϕ &gt; ϕc. Our simple model improves predictions of granular resistance to intrusion, which can help to explore and manipulate soils on Earth and regolith on other planets. A reanalysis of Apollo era lunar penetration tests demonstrates the promise of our approach.
Recent grants
NSF · $179k · 2012–2015
Collaborative research: Linking scales of geomorphology and solute transport in river corridors
NSF · $139k · 2008–2011
NSF · $213k · 2008–2013
Frequent coauthors
- 54 shared
Paulo E. Arratia
- 47 shared
K. E. Herkenhoff
Astrogeology Science Center
- 47 shared
J. P. Grotzinger
California Institute of Technology
- 46 shared
R. Greeley
Arizona State University
- 44 shared
L. A. Soderblom
United States Geological Survey
- 44 shared
David A. Fike
- 43 shared
W. H. Farrand
Space Science Institute
- 43 shared
P. R. Christensen
Arizona State University
Education
- 2006
PhD, Geophysics, EAPS
Massachusetts Institute of Technology
- 2001
B.S., Environmental Engineering
Drexel University
Awards & honors
- Edmund J. and Louise W. Kahn Endowed Term Professor of Earth…
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