At the Crater Workshop in May 19-22, 2015, we discussed numerous issues related to using impact craters to understand solar system processes. An outcome of this is that we would like to take advantage of an offer to create a special issue of the Meteoritics & Planetary Science journal with a submission deadline of some time in 2016. Both Stuart Robbins and Catherine Plesko (the co-conveners of the Workshop) will be guest Editors.

This page is meant for collecting ideas for papers. Please follow the template style already in use for a paper subject, title, description, and if you would like to be an author on the paper. If you are the first to suggest it, you can be first author. If you are not the first to suggest it, check with the persons already listed as being interested before claiming to be first author.

If you are not Wiki-savvy, there are a lot of online guides to doing this, but if you're really stuck, contact Stuart: stuart@boulder.swri.edu

Copy the below text to create a new paper entry, and put it under the double-equal signs for the type of paper:

Template Paper

Tentative Title: [Put text here]

Persons Interested: [Put text here, adding your name to the end of the list if there is one]

Brief Summary / Purpose: [Put explanation of the paper and rationale here.]

Introduction / Overview Paper

Tentative title: [None right now]

Persons Interested: Stuart Robbins, Catherine Plesko [probably locked at these two]

Brief Summary / Purpose: The purpose of this paper would be to introduce the journal issue and review what was discussed at this conference. This would emphasize the many issues raised at the conference on which the later papers in this issue are based, including: What are the known unknowns and perhaps unknown unknowns, what are sources of uncertainty that we tend to take into account (counting errors) versus don't take into account (e.g., researcher variability), what do we need to answer some of our most pressing questions (e.g., lunar samples that are dated from a known surface to better calibrate the lunar flux which is the key to the rest of the solar system), reliance on old statistical techniques which may be "good enough" but not completely "correct" given what we know now and the modern tools available, ... . This paper would also emphasize that you cannot do crater counts without a geologic context / interpretation, for each intent changes how areas are mapped, counted, and what you can derive (e.g., doing crater counts on a crater floor without understanding that it's a sand trap).

Review Papers

Future Lunar Exploration

Tentative title: The Moon: Fundamental Key to Understanding Solar System History

Persons Interested: [various persons, suggest: Jim Head], Stuart Robbins [not 1st/lead], F. Scott Anderson

Brief Summary / Purpose: The first day or two of the workshop underlined the need to return to the moon to get samples to really "nail down" the lunar chronology function. Presentations at the LEAG and other -EAG meetings, white papers in the decadal survey (next one in 2023), are all good, but a paper here can underscore that as well. We should come up with a short list of key sites to go to to answer this, potentially including international participation. We need to present a coherent message, recommend place(s) that is/are unambiguous and uncomplicated, and include recommended infrastructure. Emphasize that transporting the lunar chronology to other solar system bodies has advanced in recent decades with better and hopefully more accurate dynamical models, especially within the inner solar system.

Secondary Craters

Tentative title: The Issue of Secondary Craters on Planetary Surfaces

Persons Interested: Beau Bierhaus, Stuart Robbins, Kelsi Singer, Wes Watters

Brief Summary / Purpose: The excellent review paper of McEwen & Bierhaus (2006) is still great as an introduction to secondary craters, but in the decade since that work was published, we have learned a lot more about secondary craters from observational and analytical studies. Populations of secondary craters globally on different bodies (Robbins and Hynek, 2014; Bierhaus (thesis)), studies of individual primary craters and the secondary crater fields they generate (Singer, Zanetti, others), and other work has advanced this field to the point that a new review paper is warranted.

Progress and Importance of Measuring Current Impact Rate

Tentative title: [None Yet]

Persons Interested: McEwen, Daubar, Williams, [various persons, suggest: Hartmann, Robinson, Speyerer...]

Brief Summary / Purpose: Progress in (and the importance of) understanding the current impact rate, and a review of efforts to do so on Earth, Moon, and Mars, and the latest results. Synthesize Moon/Mars rates and compare with each other and established production functions and chronology.

Can we date very young surfaces?

Tentative Title: Can we date very young surfaces?

Persons Interested: J-P Williams, M. Palucis, I. Daubar, M. Kirchoff [Put text here, adding your name to the end of the list if there is one]

Brief Summary / Purpose: Can we date very young surfaces? What extra things do we have to take into account (seismic shaking, atmospheric loss (Mars), secondaries, target properties MUCH more, etc.).

Measuring Enough Craters

Tentative Title: Measuring Enough Craters

Persons Interested: M. Palucis [Put text here, adding your name to the end of the list if there is one]

Brief Summary / Purpose: [Put explanation of the paper and rationale here.]

Automated detections

Tentative Title: A review on Crater Detection Algorithms

Persons Interested: Pedro Pina, Jorge S. Marques, Wes Watters, Brian Encke

Brief Summary / Purpose: The detection performance by automated means has increased substantially in the last decade, as well as the number and diversity of methods employed. It seems to be the right time to make a comprehensive evaluation of the methods employed with a quantification of the performances achieved (to permit comparisons, a conversion to the same quantities will be performed). Other aspects like the type of planetary surface, the characteristics of the sensor, the environmental conditions at the time of acquisition or the inferior dimensional limit of detection will be further detailed and analyzed. The current strengths and limitations of the methods, with the identification of the aspects requiring stronger development efforts, will be highlighted. The possibility of gathering the CDA outputs with other characteristics of the craters (morphologies, degradation or preservation status, …) will be analyzed. Suggestions for creating benchmark datasets for testing the CDA and the necessity of disposing of the same evaluation framework will be also discussed.

Crater Saturation

Tentative Title: Understanding Crater Saturation

Persons Interested: Michelle Kirchoff [Suggested: Clark Chapman, Bill Hartmann, Simone Marchi, Jim Richardson]

Brief Summary / Purpose: It has been decades since a good review of what crater saturation (and equilibrium) potentially looks like in the solar system, along with the arguments for and against the occurrence of saturation throughout the solar system. I propose this paper as a review of the current state of knowledge on this topic and the tools used to study it.

Tools / Recommendations Papers

Best Practices Recommendation for Data Presentation and Archiving

Tentative title: Communicating Crater Work to the World: Recommendations for Data Display and Archiving

Persons Interested: Stuart Robbins, Jamie Riggs, Michelle Kirchoff [various persons, suggest: Carolyn van der Bogart]

Brief Summary / Purpose: The 1979 Crater Analysis Techniques Working Group published guidelines, but they were based on technology available at the time, and they are viewed by some as antiquated so should no longer be followed. We propose to submit a paper that would provide guidelines that should be uniformly followed by the crater community to both display data in papers and archive it. Recommendations may include:

Ensuring all data are displayed as both cumulative and R-plots, at a minimum.
Ensuring all mapping regions are included in the paper, at a minimum.
Should we be putting error bars on the horizontal (diameter) axis?
How many craters are "enough" to analyze?
Recommend including original shapefiles and/or high-resolution images of mapped regions as Supplemental Material.
Strongly recommend including CSV ASCII file of, at a minimum, crater latitude, longitude, and diameter used for that study, while including in README documentation the version/era of the coordinate system in which the data were gathered.

This paper would also refer to the related paper in this volume on data display that suggests versions of the probability density function / survival function for data display. It should also reference the latest NASA guidelines on compliance with public data policy for taxpayer-funded research, and that inherently "our" data are the publics' data, and we should be more open to sharing it.

Understanding Crater-Based Model Ages

Tentative title: Assigning and Understanding Crater-Based Model Ages and Uncertainties

Persons Interested: [Someone 1st], Stuart Robbins, Michelle Kirchoff [various persons, suggest: Greg Michael, Clark Chapman, etc.]

Brief Summary / Purpose: A lot of controversy arose over how to properly estimate the model age of a surface from craters. The interpretation of age and uncertainties from cumulative counts versus incremental, how to use all the data as opposed to those in a single bin, etc. needs more discussion, and if we're somewhat confused (or disagree on how to do it), certainly those outside our field will be confused, too. We need to agree on a single or small set of recommended practices for assigning these and their associated uncertainties. This would be closely linked to - though probably different from - the stats paper on comparing and fitting crater population data with/to models. Inherent uncertainty in the individual crater diameter measurements themselves should also play some role in this.

On Measuring Enough Craters

Tentative title: When Is Enough Enough?— Effects of Choosing Areas for Crater Counts

Persons Interested: [Someone 1st] [various persons, suggest: Carolyn van der Bogart, Nicholas Warner, Bill Hartmann, Clark Chapman, Jamie Riggs, Marisa Palucis], Stuart Robbins

Brief Summary / Purpose: Choosing a large enough area on which to identify impact craters, understanding spatial sampling to do a proper "nested" crater-counting approach, accounting for properties of doing small-area counts like the (single) largest crater(s) and their related resurfacing, etc., has advanced a lot in just the last few years. A review paper that presents a best practices of these techniques is needed to summarize a lot of this work.

Crater Geometry

Tentative title: [Determination of Crater Depth/Diameter Ratios: Insights from High-Resolution Digital Elevation Models]

Persons Interested: P. J. Mouginis-Mark, J. M. Boyce and V. L. Sharpton

Brief Summary / Purpose: Historically, crater depth/diameter ratios have been determined from shadow lengths or altimetric measurements made at single points on the rim and crater floor. Often these measurements missed the highest point on the rim crest and/or failed to find the lowest point on the floor. The availability of new high-resolution digital elevation models changes this situation, as the topographic variability of the rim crest, the height variability of the rim above the pre-impact surface, and the elevation of the deepest point of the crater floor can now be accurately determined. We will document this new method using lunar and Martian craters in the diameter range 5 - 40 km, and discuss the results in the context of earlier studies as well as the implications for other planetary bodies (Mercury, Venus and outer planet satellites).

More "Stats"-Focused Papers

Data Display

Tentative title: To Bin or Not to Bin Crater Data, and the Proper Assignment of Uncertainties and Confidence on Counted Crater Observations

Persons Interested: Brian Weaver, Stuart Robbins, Joe Hilbe, Jamie Riggs, Michelle Kirchoff

Brief Summary / Purpose: Binning crater data is inherently smoothing the data, and it comes with its own biases and foibles (bin size? bin starting location? independent error bars?). This paper would be divided into two main "recommendations" sections, one on recommended binning methods if one were to bin, and the other recommending that we use a survival function approach in which each datum is plotted as its own point. For each section, a discussion of how to more rigorously assess uncertainties and confidences on the data would be addressed that goes beyond Poisson statistics.

Comparing Crater Data with Models

Tentative title: On the Fitting of Production Functions to Crater Population Data and Determining Statistically Significant Deviations for Interpretation of Geological Processes

Persons Interested: Brian Weaver, Stuart Robbins, Joe Hilbe, Michelle Kirchoff

Brief Summary / Purpose: Fitting the vertical offset of a production function model to observed crater data is often something of an art form. There are more statistically rigorous ways to do this, assign confidence in it, and therefore assign age, using all of the data available to us. Additionally, we can use these confidences to describe at what point an observed population deviates from the model, given an a priori confidence threshold, and then use that for our geophysical interpretations.

Understanding Individual Researcher Bias

Tentative title: Crater Counting Repeatability and Reproducibility

Persons Interested: [Various, possibly Robbins as 1st on this too, maybe? anyone else?] Jamie Riggs

Brief Summary / Purpose: Potential paper doing a follow-up on Robbins et al. (2014) which compared 8 expert crater researchers identifying craters independently with their own tools on two different LROC images. If there are enough additional persons who calibrate on these in that time, a follow-up paper could be written that gets more into understanding differences in how we identify impacts, including potentially people trained within the same group (e.g. Hiesinger - van der Bogart group).

Using Spatial Statistics in Crater Analyses

Tentative title: Using Spatial Statistics in Crater Analyses

Persons Interested: Michelle Kirchoff [Suggest: Jamie Riggs, Beau Bierhaus]

Brief Summary / Purpose: Discuss the use of spatial statistics in different crater studies, such as secondaries, saturation, and potentially understanding resurfacing, etc. Emphasize how it can be a partner tool to SFDs. Present methodology and correct usage.

Craters for "Beginners"

Tentative title: ?

Persons Interested: Margaret Landis, Stuart Robbins, Michelle Kirchoff [various persons, suggest:Nadine Barlow]

Brief Summary / Purpose: For someone who is just starting out in crater counting (or needs a refresher), a summary of the current tools available, current field standard plots (i.e. telling people to go read the 1979 paper), how to pick images to count on, saturation and some 'common sense' that scientists outside of the crater age dating subfield may not know about crater techniques. (Added by Stuart:) Something similar to the Melosh book page that explains how to interpret SFDs -- I think some guide either in this paper or as part of a different one to explain how common geologic processes affect crater SFDs would be good.

Other Papers

Ideas:

Identifying impact craters given what we know about morphology, preservation, geologic context, etc.
Chronology related:
- What is the shape of the chronology function?
- Are production functions "reasonably" well constrained at this point?
- Any way to get beyond 3.92 Ga?
- Any way to tell if there are discontinuities?
- Latest dynamical work that may help us.
- Has the lunar flux changed, and if so, how? And can we tell? -- Michelle interested in this one, but could it potentially be part of one of the current papers (e.g., date very young surfaces)?
- Can we date very young surfaces? What extra things do we have to take into account (seismic shaking, atmospheric loss (Mars), secndaries, target properties MUCH more, etc.).
Production function related:
- How do we address variations?
- How do you even start to assign uncertainties in the PFs based on target properties, analyst bias, etc.?
- Inner vs outer solar system? Huge variations within the outer solar system (Saturn vs Jupiter, etc. -- Strom (1987))
Review paper on current state of citizen science efforts? What is needed from it for our community to "trust" the results?
Review paper on current state of automated crater detection efforts? Morphology classification efforts?
Review paper on degradation processes, how they vary on different solar system bodies?
Review paper on utilizing non-"visible" datasets in crater studies. What are their limits? How do we include and use big buried "signatures" in interpreting geology, ages, large secondaries, etc.? For chronology, they push us further back in time. If you can separate the surface from the buried population, you can get a timing difference that has a lot of geological implications, and we're getting to an area that we haven't gotten to before: Depth structure.
Review paper on current state of knowledge on crater saturation? Warning about NAC-scale images?
How do you determine the minimum crater size in pixels, and what's the inherent uncertainty there? How do you fit curves/lines to data or estimate errors?
More Community Outreach:
- How do we communicate challenges and "under"-estimated uncertainties on overall ages, etc.?
- How do we account for audience? *WE* kinda know what we mean, but others in other fields don't!
- How do we communicate to other fields the implicit uncertainties that are not reflected in quoted error bars?
Kelsi: I like the idea of a review paper on the effect various scaling assumptions has on your final answer/age dating etc., but I won't have time to lead this - happy to be an interested person though :).

MAPS Special Edition Document

Contents