PRF2022—Progressive Failure of Brittle Rocks
Flat Rock, North Carolina, USA | 20–24 June 2022
Highland Lake Inn and Resort
Apply to Attend
Submit a ~250 word abstract, or fill out the Participation Form if you don't plan to present.
Design by Ken Lambla, Marek Ranis, Missy Eppes—an art-science collaboration funded
in part by NSF EAR#1839148.
Dr. Matthew Brain, Dept. of Geography, Durham University, email@example.com
Prof. Martha-Cary (Missy) Eppes, Dept. of Geography & Earth Sciences, University of
North Carolina at Charlotte, firstname.lastname@example.org
Dr. Kerry Leith, GNS Science, New Zealand, email@example.com
Dr. Alex Rinehart, Earth and Environmental Science, New Mexico Tech, Alex.Rinehart@nmt.edu
- GSA Quaternary Geology and Geomorphology Division
- GSA Environmental and Engineering Geology Division
- GSA Soil and Soil Processes Division
- GSA Planetary Geology Division
What: A five-day conference with diverse keynote speakers, talks, posters, discussions,
mentoring, and a one-day field trip.
Why: To foster a more robust and multidisciplinary understanding of the
interdependencies of rock fracture and surface processes, hazards, infrastructure decay, weathering, and
Who: Geomorphologists, rock physicists, stone heritage preservationists, geotechnical
engineers, critical zone scientists, and planetary geologists.
Where: Self-contained in a picturesque mountain retreat located in the Blue Ridge
Mountains of west-central North Carolina, USA. Comfortable indoor and outdoor seating areas, walking
trails, canoes, and swimming facilities will be available.
Table Rock, South Carolina, USA: A typical granite “bald” and Blue Ridge
escarpment landscape of the conference location, located just over the state line from Flat Rock,
North Carolina, USA. Photo by JJ Fowler, vanzeppelin.com.
The progressive growth of fractures in rock directly impacts virtually all natural earth-surface systems
and components of the built environment that involve rock. As rocks fracture in response to
environmental, tectonic, and topographic forces and factors, that crack growth itself changes rock
strength, porosity, and permeability. In turn, these changes impact natural processes and society. For
example, the stability of slopes, excavations, tunnels, and boreholes are all intimately linked to these
changes, as is the management of aging infrastructure, the conservation of our archaeological heritage,
and the assessment of hazard risks related to phenomena like landslides and rockfalls. Crack growth also
impacts the overall evolution of the critical zone, governing rates and modes of earth-surface processes
ranging from CO2 cycling to regolith production and hillslope sediment supply to bedrock
Thus, there is substantial societal and scientific motivation for understanding rock fracture, the role
it plays across a range of time and space scales, and for identifying key controls on its morphology,
mechanisms, rates, and processes. However, the factors (e.g., climate, material properties, stresses,
and water availability and chemistry) that drive or limit fracture growth itself—as well its
manifestation and impacts over time—remain poorly characterized across a broad array of disciplines.
We hope this Penrose Conference, which we are calling PRF2022, can illustrate a pathway forward for
filling the many knowledge gaps related to rock fracture overall, but particularly with respect to
progressive rock failure (PRF). There is a burgeoning appreciation that crack growth in the natural and
built environment is non-linear, most commonly progressing as slow, climate dependent,
subcritical deformation (i.e., PRF; Eppes and Keanini, 2017), which at times accelerates toward
rapid and hazardous critical failure without obvious forewarning. Yet, the potentially central
role that PRF may play in all fracture-related systems has been largely unrecognized or misconceived
across both surface-process and engineering applications. Geomorphologists studying natural rock
fracture have largely overlooked the knowledge and concepts to be derived from rock physics and
engineering research on PRF, and engineers and rock physicists have remained largely unaware of the
potential applications and validations that might be possible via the study of PRF in natural
landscapes. PRF2022 seeks to bring together these communities for lively discussions and data analysis
centered around testing and considering the assertion that virtually all natural rock fracture is
dominated by—or at least predicated on—PRF.
This conference aims to transcend traditional disciplinary divides in the study of rock fracture—and its
impacts—in both natural and applied research. We hope PRF2022 will enable attendees to understand and
catalogue the applicability of PRF to fracture problems within their own disciplines by addressing the
following types of questions:
- If mechanical weathering, critical zone fracture, infrastructure decay, and hazards are at least
partially occurring via PRF, what are the implications? How can we quantify the extent to which PRF
is, or is not, a dominant process in natural landscapes and built stone infrastructure?
- If environment controls both stress and crack-tip PRF processes, what are the ramifications
for the study of how past and ongoing climate change impacts rock fracture and any processes
impacted by rock fracture processes?
- What is the impact of varying surface chemistry, moisture, and temperature conditions on the
presence, rates, and morphological manifestation of PRF and thus the processes that it influences?
- What does it mean for mechanical weathering and “erodibility” if only the smallest of stresses are
needed to grow fractures? What are the relative roles of constant low-level stress generators versus
infrequent large-stress generators?
- How do relationships between crack growth rates and fracture spacing (density/intensity) under PRF
differ from relationships between fracture spacing and critical failure strength?
- How might experimental studies of microcrack growth be relevant over geologic time scales where
material properties change as rocks are exposed under different—and changing—climatic regimes?
Specifically, by encouraging attendance by practitioners from a range of disciplines, PRF2022 will:
- Provide a platform to identify complementary data/observations/approaches (e.g., experimental vs.
field, short time vs. deep time, modeling, etc.);
- Identify new scientific and commercial funding opportunities through new collaborations (e.g.,
bringing geomorphology and stone heritage investigators into engineering or mechanics studies and
- Reveal key datasets (e.g., long-term data that can validate experiments or vice versa); and
- Lay out a framework for the future evaluation of PRF in the context of a full range of both academic
and applied questions.
The pier at Highland Lake Inn and Resort, Flat Rock, North Carolina, USA. Photo by
We plan to kick off this Penrose Conference with a “PRF primer and Q&A” that will ensure all
attendees are on the same page with respect to the basic concepts and vocabulary of PRF; this will also
free up time normally used for “background” for all presentations. Primer topics will be determined with
input from attendees. It is expected that most attendees will be novices with respect to some aspects of
the conference (e.g., PRF, fracture mechanics, surface processes, engineering, etc.). The underlying
commonality will be that rock fracture is of interest.
We will organize daily talks, posters, and discussions around:
2. Laboratory simulations;
3. Numerical modeling;
4. Fracture in a changing climate;
5. Scale linkages; and
6. Applications: From landscapes to hazard management.
Throughout the conference, we will schedule smaller discussions particularly aimed at early-career
researchers and attendees from groups underrepresented in the geosciences. These discussions will be
facilitated by an allocated mentor (conference convenor and/or a keynote speaker), allowing discussion
of key themes in a friendly, supportive setting.
The mid-conference field excursion will consider both natural-system and applied aspects of PRF evident
in the landscape and how the resultant hazards are managed, focusing on mass wasting features in the
Hickory Nut Gorge, cutting into the impressive Blue Ridge Escarpment of western North Carolina. We hope
the field trip will contextualize concepts discussed during the conference, demonstrating the
significance and challenges of understanding the role that PRF plays in infrastructure degradation,
hazards, and landscape evolution.
Field Trip Leaders
Rick Wooten, P.G., North Carolina Geological Survey (retired)
Bart Cattanach, P.G., North Carolina Geological Survey
David Korte, Ph.D., P.G., North Carolina Geological Survey
Jennifer Bauer, P.G., Appalachian Landslide Consultants
Philip Prince, Ph.D., Appalachian Landslide Consultants
Cheryl Waters-Tormey, Ph.D., Western Carolina University
Karl Wegmann, Ph.D, L.G., L.E.G., North Carolina State University
International Advisory Board and Keynote Speakers
These scientists are aiding the Penrose Conference conveners in identifying diverse attendees, providing
keynote addresses, and acting as mentors.
Professor Erik Eberhardt, University of British Colombia. Recipient of the Canadian
Geotechnical Society’s 2013 John A. Franklin Award for outstanding technical contributions to rock
mechanics and the 2017 Thomas Roy Award for outstanding contributions to engineering geology.
Dr. Stephen Laubach, University of Texas at Austin. Distinguished lecturer for the
American Association of Petroleum Geologists (2010–2011) and Society of Petroleum Engineers (2003–2004)
and GSA Fellow (2016).
Dr. Jill Marshall, University of Arkansas. Winner of the 2018 American Geophysical Union
(AGU) Luna B. Leopold Young Scientist Award for significant and outstanding contributions that advance
knowledge about earth- and planetary-surface processes.
Professor Phil Meredith, University College London. Winner of the 2016 European
Geophysical Union Louis Néel Medal for his contributions to rock physics and geomechanics and for his
role in stimulating international collaboration and interdisciplinary research.
Dr. Seulgi Moon, University of California Los Angeles. Recipient of the Gabilan Stanford
Graduate Fellowship at Stanford University, and holder of an NSF Career Award for her work on fractures
Professor Laura Pyrak-Nolte, Purdue University. President of the International Society
of Porous Media (InterPore; 2019–2021); president of the American Rock Mechanics Association
(2017–2019); recipient of the Society of Exploration Geophysicists 2020 Reginald Fessenden Award; fellow
of the American Association for Advancement of Science, AGU, and American Rock Mechanics Association.
Professor Heather Viles, University of Oxford. Co-director of the Engineering and
Physical Sciences Research Council Centre for Doctoral Training in Science and Engineering in Art,
Heritage and Archaeology; honorary professor at the Institute of Sustainable Heritage, University
College London; leader of the Oxford University Heritage Network.
PRF2022 plans to host ~75 in-person participants. Attendees will make their own travel arrangements. The
anticipated registration fee (~US$1000, but possibly less depending on additional sponsorship) will
cover all meals and lodging (nights of 19–23 June) and pre-arranged transportation from (19 June) and to
Charlotte (24 June).
An application form link will be available via the GSA Penrose Conference website (https://www.geosociety.org/penrose) and the meeting
website (www.prf2022.org) starting in October 2021. Applications will require a
provisional presentation/poster title and/or a brief summary of research interests and work related to
the conference themes. Attendees are not required make a presentation to participate. Successful
applicants will be notified 15 Feb. 2022, and registration—which will require an abstract if
presenting—will close 15 Mar. 2022.
A key goal the conference is to maximize inclusion and diversity. We encourage participation from, and
will provide some financial support for, a range of international, gender, BIPOC, LGBTQIA, early-career
stage, and other underrepresented groups. To further foster a sense of belonging and a welcoming and
inclusive atmosphere, we will be implementing a mentoring scheme for any attendee who wants a mentor. An
artist in residence will also attend the conference, and resultant artwork will provide a key
communication tool with the public and among scientists. All participants will be expected to observe
the GSA Code of Ethics and the Events Code of Conduct throughout the meeting.
Eppes, M-C., and Keanini, R., 2017, Mechanical weathering and rock erosion by
climate‐dependent subcritical cracking: Reviews of Geophysics, v. 55, no. 2, p. 470–508.