Using HiRISE Digital Elevation Models to Investigate the Peripheral Peak Ring Morphology in the Martian Impact Crater Tooting
Bibliographic record
Abstract
Introduction: Examination of MOC, MOLA HRSC, THEMIS, and most recently HiRISE data reveal the presence of partial or completely collapsed rims in some Martian impact craters. These collapse features have been named Peripheral Peak Rings (PPR) [1]. The 29km diameter impact crater Tooting is an excellent example of a young, largely uneroded complex impact crater which contains a PPR. By generating digital elevation models (DEM’s) from HiRISE stereo data, detailed topographical information was obtained about the PPR in this crater. These data assisted in reconstructing the original rim of the Tooting crater before PPR formation, and allowed for the development of a robust PPR formation model. Peripheral Peak Ring Formation: PPR are blocks from the crater rim that separated and slid downwards across the terraced zone until stopping near the crater floor. PPR form when the crater rim wall, after conventional slumping to form the terraced zone overlying the slump blocks (in the case of a complex crater), fails. PPR can be differentiated from the outermost terrace zone based on morphology. Whereas the slump blocks that form the terraces show downward displacement consistent with normal faulting, PPR undergo displacement that is mostly lateral, across the tops of the terraces (in the case of complex craters). This causes the tops of some PPR to be higher in elevation than the resulting crater rim, a phenomenon not seen in terraces. Examples of well developed PPR have been observed in simple craters as well, and most PPR have shapes that fit back into the depletion zone which once held them. Impact Crater Tooting: The Tooting Impact crater is located at 23.4oN, 207.5°E (Figure 1). MouginisMark and Garbiel determined the age of Tooting to be between 0.4 and 1.7Myr [2]. Figure 1 shows the well developed monolithic PPR in the NW portion of the crater. Tooting has recently been almost completely covered by HiRISE stereo pairs which allow for the generation of Digital Elevation Models having sub meter resolution. DEM Generation: DEM’s were generated from stereo pairs having a maximum resolution of 25cm/pixel using stereo workstations and BAE’s SOCET SET® photogrammetry software (see Acknowledgements). Using the USGS processing sequence, generated HiRISE DEM’s were controlled to the MOLA DEM and groundtracks for absolute orientation. This results in an absolute error of the DEM’s overall position in the X and Y direction of 50-100m. The absolute error in the Z direction for an entire DEM would be limited to the error in MOLA measurements, which in the case of steep topography, can be on the order of 10% of the elevation change within the 160m MOLA sample window (≈9m on a slope of 30°). [3].
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".