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Journal articles on the topic 'Crater morphology'

Author: Grafiati
Published: 28 June 2021
Last updated: 5 February 2022

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1

Hu, Bo, Song Lin Ding, Christopher Lim, Milan Brandt, and John Mo. "Measurement of Polycrystalline Diamond Craters in Electrical Discharge Machining." Applied Mechanics and Materials 664 (October 2014): 304–9. http://dx.doi.org/10.4028/www.scientific.net/amm.664.304.

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The electrical discharge grinding method is widely used to machine polycrystalline diamond tools because diamond is the hardest material and the traditional abrasive grinding method leads to high tool wear rate. The aim of this study was to find a method to precisely measure the individual diamond crate morphology during the electrical discharge process. A 3D microscopy with the focus-variation technique was chosen to obtain the stereolithography file of the polycrystalline diamond craters. The measurements were shown that the polycrystalline diamond crater morphology is more complex than that of normal tungsten carbide material. This finding can help build more accurate model of polycrystalline crater formation during electrical discharge process.
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2

Badr, Sarah, Georges Gauthier, and Philippe Gondret. "Crater jet morphology." Physics of Fluids 28, no. 3 (March 2016): 033305. http://dx.doi.org/10.1063/1.4943160.

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3

Li, B., Z. C. Ling, J. Zhang, J. Chen, C. Q. Liu, and X. Y. Bi. "GEOLOGICAL MAPPING OF LUNAR CRATER LALANDE: TOPOGRAPHIC CONFIGURATION, MORPHOLOGY AND CRATERING PROCESS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W1 (July 25, 2017): 77–83. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w1-77-2017.

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Highland crater Lalande (4.45° S, 8.63° W; D = 23.4 km) is located on the PKT area of the lunar near side, southeast of Mare Insularum. It is a complex crater in Copernican era and has three distinguishing features: high silicic anomaly, highest Th abundance and special landforms on its floor. There are some low-relief bulges on the left of crater floor with regular circle or ellipse shapes. They are ~ 250 to 680 m wide and ~ 30 to 91 m high with maximum flank slopes > 20°. There are two possible scenarios for the formation of these low-relief bulges which are impact melt products or young silicic volcanic eruptions. According to the absolute model ages of ejecta, melt ponds and hummocky floor, the ratio of diameter and depth, similar bugle features within other Copernican-aged craters and lack of volcanic source vents, we hypothesized that these low-relief bulges were most consistent with an origin of impact melts during the crater formation instead of small and young volcanic activities occurring on the crater floor. Based on Kaguya TC ortho-mosaic and DTM data produced by TC imagery in stereo, geological units and some linear features on the floor and wall of Lalande have been mapped. Eight geological units are organized by crater floor units: hummocky floor, central peak and low-relief bulges; and crater wall units: terraced walls, channeled and veneered walls, interior walls, mass wasting areas, blocky areas, and melt ponds. These geological units and linear features at Lalande provided us a chance to understand some details of the cratering process and elevation differences on the floor. We evaluated several possibilities to understand the potential causes for the observed elevation differences on the Lalande's floor. We proposed that late-stage wall collapse and subsidence due to melt cooling could be the possible causes of observed elevation differences on the floor.
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Wang, Y., X. Tong, H. Xie, M. Jiang, Y. Huang, S. Liu, X. Xu, Q. Du, Q. Wang, and C. Wang. "CRATER DETECTION USING TEXTURE FEATURE AND RANDOM PROJECTION DEPTH FUNCTION." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-3-2020 (August 3, 2020): 603–8. http://dx.doi.org/10.5194/isprs-annals-v-3-2020-603-2020.

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Abstract. In this paper, a novel automatic crater detection algorithm (CDA) based on traditional texture feature and random projection depth function has been proposed. By using traditional texture feature, mathematical morphology is used to identify crater initially. To further reduce the false detection rate, random projection depth function is used. For this purpose, firstly, gray level co-occurrence matrix and a novel grade level co-occurrence matrix are both used to further obtain the texture features of these candidate craters. Secondly, based on the above collected features, random projection depth function is used to refine the crater candidate detection results. LRO Narrow Angle Camera (NAC) mosaic images (1 m/pixel) and Wide-angle Camera (WAC) mosaic images (100 m/pixel) are used to test the accuracy of proposed method. The experimental results indicate our proposed method is robust to detect craters located in different terrains.
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Hardy, Stuart. "Discrete Element Modelling of Pit Crater Formation on Mars." Geosciences 11, no. 7 (June 24, 2021): 268. http://dx.doi.org/10.3390/geosciences11070268.

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Pit craters are now recognised as being an important part of the surface morphology and structure of many planetary bodies, and are particularly remarkable on Mars. They are thought to arise from the drainage or collapse of a relatively weak surficial material into an open (or widening) void in a much stronger material below. These craters have a very distinctive expression, often presenting funnel-, cone-, or bowl-shaped geometries. Analogue models of pit crater formation produce pits that typically have steep, nearly conical cross sections, but only show the surface expression of their initiation and evolution. Numerical modelling studies of pit crater formation are limited and have produced some interesting, but nonetheless puzzling, results. Presented here is a high-resolution, 2D discrete element model of weak cover (regolith) collapse into either a static or a widening underlying void. Frictional and frictional-cohesive discrete elements are used to represent a range of probable cover rheologies. Under Martian gravitational conditions, frictional-cohesive and frictional materials both produce cone- and bowl-shaped pit craters. For a given cover thickness, the specific crater shape depends on the amount of underlying void space created for drainage. When the void space is small relative to the cover thickness, craters have bowl-shaped geometries. In contrast, when the void space is large relative to the cover thickness, craters have cone-shaped geometries with essentially planar (nearing the angle of repose) slope profiles. Frictional-cohesive materials exhibit more distinct rims than simple frictional materials and, thus, may reveal some stratigraphic layering on the pit crater walls. In an extreme case, when drainage from the overlying cover is insufficient to fill an underlying void, skylights into the deeper structure are created. This study demonstrated that pit crater walls can exhibit both angle of repose slopes and stable, gentler, collapse slopes. In addition, the simulations highlighted that pit crater depth only provides a very approximate estimate of regolith thickness. Cone-shaped pit craters gave a reasonable estimate (proxy) of regolith thickness, whereas bowl-shaped pit craters provided only a minimum estimate. Finally, it appears that fresh craters with distinct, sharp rims like those seen on Mars are only formed when the regolith had some cohesive strength. Such a weakly cohesive regolith also produced open fissures, cliffs, and faults, and exposed regolith “stratigraphy” in the uppermost part of the crater walls.
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6

Zhao, Runchen, Qianyun Zhang, Hendro Tjugito, and Xiang Cheng. "Granular impact cratering by liquid drops: Understanding raindrop imprints through an analogy to asteroid strikes." Proceedings of the National Academy of Sciences 112, no. 2 (December 29, 2014): 342–47. http://dx.doi.org/10.1073/pnas.1419271112.

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When a granular material is impacted by a sphere, its surface deforms like a liquid yet it preserves a circular crater like a solid. Although the mechanism of granular impact cratering by solid spheres is well explored, our knowledge on granular impact cratering by liquid drops is still very limited. Here, by combining high-speed photography with high-precision laser profilometry, we investigate liquid-drop impact dynamics on granular surface and monitor the morphology of resulting impact craters. Surprisingly, we find that despite the enormous energy and length difference, granular impact cratering by liquid drops follows the same energy scaling and reproduces the same crater morphology as that of asteroid impact craters. Inspired by this similarity, we integrate the physical insight from planetary sciences, the liquid marble model from fluid mechanics, and the concept of jamming transition from granular physics into a simple theoretical framework that quantitatively describes all of the main features of liquid-drop imprints in granular media. Our study sheds light on the mechanisms governing raindrop impacts on granular surfaces and reveals a remarkable analogy between familiar phenomena of raining and catastrophic asteroid strikes.
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7

Lu, Yintao, Xiaoyong Xu, Xiwu Luan, Shu Jiang, Weimin Ran, Taotao Yang, Fuliang Lyu, Yingfang Zhou, and Zhili Yang. "Morphology, internal architectures, and formation mechanisms of mega-pockmarks on the northwestern South China Sea margin." Interpretation 9, no. 4 (September 1, 2021): T1043—T1058. http://dx.doi.org/10.1190/int-2020-0175.1.

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Pockmarks, as depression morphology related to fluid escape on the seafloor, are revealed by 3D seismic data on the northwestern South China Sea (SCS) margin. The pockmarks can be classified into two groups based on their various shapes in plan view: the circular group and the elongating group. These pockmarks in the study area could be defined as mega-pockmarks because their maximum diameters can reach to 7.5 km. They commonly develop more than one crater, which are called the central crater and the secondary crater. The seismic data illuminated their complicated internal architectures in the subsurface, as well as their evolution periods, such as the initiation stage, mature stage, and abandonment stage. According to the buried structures and their genesis mechanism, mega-pockmarks could be classified into linear faults-associated pockmarks and volcano-associated pockmarks. The linear fault-associated pockmarks root on the top Middle Miocene, where the linear faults are distributed. The linear faults on the top of fluid reservoir in Middle Miocene act as conduits for fluid seepage. The fluid seepage is driven by the break of balance between the hydrostatic and pore pressure. When the fluid seepage initiates, they will migrate along the linear faults, making the linear feature of pockmarks on the seafloor. Thermogenic gas from deep intervals and biogenic gas from shallow intervals may be fluid sources for the genesis of pockmarks. However, the volcanic activities control the genesis and evolution of volcano-associated pockmarks. Volcano-associated pockmarks root on the craters of volcanoes. The volcanoes underneath the pockmarks provide volcanic hydrothermal solutions, such as phreatomagmatic eruptions through the volcanic craters. The confined fluid seepages make the pockmarks exhibit a more circular shape on the seafloor. Long-term, multiepisode fluid expulsions generate the complicated internal architecture that leads to multicratered mega-pockmarks on the northwestern margin of SCS.
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8

Qiu, Yanyu, Songlin Yue, Mingyang Wang, Gan Li, Yihao Cheng, Zhangyong Zhao, and Zhongwei Zhang. "Experimental Investigation of the Crater Caused by Hypervelocity Rod Projectile Impacting on Rocks." Shock and Vibration 2020 (July 24, 2020): 1–11. http://dx.doi.org/10.1155/2020/9768745.

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To investigate the cratering effects of hypervelocity rod projectile impacting on rocks, a two-stage light gas gun was used to carry out 10 groups of small-scale experiments, whose velocity ranges from 1.5 km/s to 4.1 km/s. After each experiment, the morphology and size of the hypervelocity impacting crater were accurately obtained by using a device for image scanning. According to the morphology of the final crater, the impact crater can be divided into crushing area, spallation area, and radial crack area. Based on the experimental results of steel projectile vertical impacting on granite targets, the relationship between the depth and the diameter of the crater is analyzed, i.e., h/D≈0.1∼0.2; it shows that the depth of the crater is much smaller than the diameter of the crater, and the crater seems to be a shallow dish. The relation between the kinetic energy of the projectile and the size of the crater was discussed. With the increase of the projectile kinetic energy, it is uncertain whether the depth of the crater increases, but the volume of the crater will increase. Lastly, dimensionless analysis of the impact crater was carried out. Specifically, the limitations of point source solutions to hypervelocity rod projectile impact cratering have been proved, and there is no essential difference to calculate the final crater by using the energy scale or the momentum scale.
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9

Trang, David, Jeffrey J. Gillis-Davis, and Joseph M. Boyce. "Absolute model ages from lunar crater morphology." Journal of Geophysical Research: Planets 120, no. 4 (April 2015): 725–38. http://dx.doi.org/10.1002/2014je004639.

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10

Trego, Kent D. "Neptune's satellites: Implications from impact crater morphology." Earth, Moon and Planets 49, no. 1 (April 1990): 85–90. http://dx.doi.org/10.1007/bf00053998.

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11

Yalinewich, Almog, and Matthew E. Caplan. "Crater morphology of primordial black hole impacts." Monthly Notices of the Royal Astronomical Society: Letters 505, no. 1 (June 10, 2021): L115—L119. http://dx.doi.org/10.1093/mnrasl/slab063.

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ABSTRACT In this work, we propose a novel campaign for constraining relativistically compact massive compact halo object (MACHO) dark matter, such as primordial black holes (PBHs), using the Moon as a detector. PBHs of about 1019 to 1022 g may be sufficiently abundant to have collided with the Moon in the history of the Solar system. We show that the crater profiles of a PBH collision differ from traditional impactors and may be detectable in high-resolution lunar surface scans now available. Any candidates may serve as sites for in situ measurements to identify high-pressure phases of matter which may have formed near the PBH during the encounter. While we primarily consider PBH dark matter, the discussion generalizes to the entire family of MACHO candidates with relativistic compactness. Moreover, we focus on the Moon since it has been studied well, but the same principles can be applied to other rocky bodies in our Solar system without an atmosphere.
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12

Keller, H. U., C. Barbieri, D. Koschny, P. Lamy, H. Rickman, R. Rodrigo, H. Sierks, et al. "E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta." Science 327, no. 5962 (January 7, 2010): 190–93. http://dx.doi.org/10.1126/science.1179559.

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The European Space Agency’s Rosetta mission encountered the main-belt asteroid (2867) Steins while on its way to rendezvous with comet 67P/Churyumov-Gerasimenko. Images taken with the OSIRIS (optical, spectroscopic, and infrared remoteimaging system) cameras on board Rosetta show that Steins is an oblate body with an effective spherical diameter of 5.3 kilometers. Its surface does not show color variations. The morphology of Steins is dominated by linear faults and a large 2.1-kilometer-diameter crater near its south pole. Crater counts reveal a distinct lack of small craters. Steins is not solid rock but a rubble pile and has a conical appearance that is probably the result of reshaping due to Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) spin-up. The OSIRIS images constitute direct evidence for the YORP effect on a main-belt asteroid.
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13

Walter, Thomas R., Alexander Belousov, Marina Belousova, Tatiana Kotenko, and Andreas Auer. "The 2019 Eruption Dynamics and Morphology at Ebeko Volcano Monitored by Unoccupied Aircraft Systems (UAS) and Field Stations." Remote Sensing 12, no. 12 (June 18, 2020): 1961. http://dx.doi.org/10.3390/rs12121961.

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Vulcanian explosions are hazardous and are often spontaneous and direct observations are therefore challenging. Ebeko is an active volcano on Paramushir Island, northern Kuril Islands, showing characteristic Vulcanian-type activity. In 2019, we started a comprehensive survey using a combination of field station records and repeated unoccupied aircraft system (UAS) surveys to describe the geomorphological features of the edifice and its evolution during ongoing activity. Seismic data revealed the activity of the volcano and were complemented by monitoring cameras, showing a mean explosion interval of 34 min. Digital terrain data generated from UAS quadcopter photographs allowed for the identification of the dimensions of the craters, a structural architecture and the tephra deposition at cm-scale resolution. The UAS was equipped with a thermal camera, which in combination with the terrain data, allowed it to identify fumaroles, volcano-tectonic structures and vents and generate a catalog of 282 thermal spots. The data provide details on a nested crater complex, aligned NNE-SSW, erupting on the northern rim of the former North Crater. Our catalog of thermal spots also follows a similar alignment on the edifice-scale and is also affected by topography on a local scale. This paper provides rare observations at Ebeko volcano and shows details on its Vulcanian eruption style, highlighting the relevance of structural and morphologic control for the geometry of craters and tephra fallout as well as for structurally controlled geothermal activity.
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14

Hobbs, Steven W., David J. Paull, and Mary C. Bourke. "Aeolian processes and dune morphology in Gale Crater." Icarus 210, no. 1 (November 2010): 102–15. http://dx.doi.org/10.1016/j.icarus.2010.06.006.

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15

Morgan, Jo, Mike Warner, the Chicxulub Working Group, John Brittan, Richard Buffler, Antonio Camargo, Gail Christeson, et al. "Size and morphology of the Chicxulub impact crater." Nature 390, no. 6659 (December 1997): 472–76. http://dx.doi.org/10.1038/37291.

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16

Wallis, D., M. J. Burchell, A. C. Cook, C. J. Solomon, and N. McBride. "Azimuthal impact directions from oblique impact crater morphology." Monthly Notices of the Royal Astronomical Society 359, no. 3 (May 2005): 1137–49. http://dx.doi.org/10.1111/j.1365-2966.2005.08978.x.

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17

Baker, David M. H., and Lynn M. Carter. "Probing supraglacial debris on Mars 2: Crater morphology." Icarus 319 (February 2019): 264–80. http://dx.doi.org/10.1016/j.icarus.2018.09.009.

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18

Gurov, Eugene P., Christian Koeberl, and Anatoly Yamnichenko. "El'gygytgyn impact crater, Russia: Structure, tectonics, and morphology." Meteoritics & Planetary Science 42, no. 3 (March 2007): 307–19. http://dx.doi.org/10.1111/j.1945-5100.2007.tb00235.x.

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19

Kanmani Subbu, S., Janakarajan Ramkumar, and S. Dhamodaran. "Single Discharge of Dry µ-EDM on Silicon: Crater and Plasma Temperature Measurement." Advanced Materials Research 299-300 (July 2011): 1334–37. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.1334.

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To improve the performance of the Electric discharge machining (EDM) process it is of interest to characterize the plasma involved. Plasma temperature needs to be measured as an initial phase of plasma characterization. Non-contact optical emission spectroscopy has been used to measure the plasma temperature. The plasma temperature and crater morphology has been investigated for different energy conditions on Silicon in dry µ-EDM condition. The plasma temperature is calculated using line pair method and crater morphology analyzed by scanning electron microscope (SEM) and profilometer.
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20

Hanuš, J., M. Marsset, P. Vernazza, M. Viikinkoski, A. Drouard, M. Brož, B. Carry, et al. "The shape of (7) Iris as evidence of an ancient large impact?" Astronomy & Astrophysics 624 (April 2019): A121. http://dx.doi.org/10.1051/0004-6361/201834541.

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Context. Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V ~ 7–8) and large angular size of 0.33′′ during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100 Myr of the solar system’s collisional evolution. Aims. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. Methods. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE and earlier AO systems as inputs. We analyzed the SPHERE images and our model to infer the asteroid’s global shape and the morphology of its main craters. Results. We present the 3D shape, volume-equivalent diameter Deq = 214 ± 5 km, and bulk density ρ = 2.7 ± 0.3 g cm−3 of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20–40 km in diameter detected at several epochs, which we interpret as impact craters, and several additional crater candidates. Craters on Iris have depth-to-diameter ratios that are similar to those of analogous 10 km craters on Vesta. Conclusions. The bulk density of Iris is consistent with that of its meteoritic analog based on spectroscopic observations, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3 Gyr) impact. Iris’s shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities, and the absence of a substantial impact-induced regolith on Iris.
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21

Wei, Liang Jun, Song Peng, and Lin Lin Wang. "Investigation on the Surface Quality in Electrical Discharge Machining." Applied Mechanics and Materials 543-547 (March 2014): 3754–58. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.3754.

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By analyzing the geometry of craters in a single pulse, the model of surface roughness in EDM was established and the main factors impacting on surface roughness were analyzed. On the base of establishment of the roughness model, the effect of discharge parameters on surface roughness was investigated by the process test method during the process of aluminum alloy 2A12 in EDM. At the same time, surface morphology obtained by different discharge parameters was comparatively analyzed. The results show that the effect of peak current and pulse width on the surface roughness is more significant, the crater on the machined surface has larger size while using higher peak current and pulse width, but the number of discharge craters is reduced.
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22

Zhao, Jiantao, Zhenge Zhu, Yacheng Xu, Xueyong Song, Yufan Wang, Hao Peng, Ying Wang, Jinrong Zuo, Xuedao Shu, and Anmin Yin. "Nanosecond Laser Ablation of Ti–6Al–4V under Different Temperature." Applied Sciences 10, no. 13 (July 6, 2020): 4657. http://dx.doi.org/10.3390/app10134657.

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Multi-pulse nanosecond laser ablation of Ti–6Al–4V is a complex process. In this study, the effect of substrate temperature on the nanosecond laser ablation of Ti–6Al–4V was investigated. Morphology, diameter and depth of ablation craters were observed; ablation efficiency ω (μm3/mJ) was proposed to analyzes the ablation process. The results showed that, with the increasing of substrate temperature, the ablation craters’ diameter increased and depth decreased, while ω initially increased, but then decreased rapidly. Furthermore, with increasing pulse number, the depth of ablation crater increased linearly, while the growth of the diameter gradually slowed down and tended to be stable after the 16th irradiation. The above changes were different in details at different substrate temperatures.
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23

Chadwick, D. John, and Gerald G. Schaber. "Impact crater outflows on Venus: Morphology and emplacement mechanisms." Journal of Geophysical Research 98, E11 (1993): 20891. http://dx.doi.org/10.1029/93je02605.

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24

Bacon, Charles R., James V. Gardner, Larry A. Mayer, Mark W. Buktenica, Peter Dartnell, David W. Ramsey, and Joel E. Robinson. "Morphology, volcanism, and mass wasting in Crater Lake, Oregon." Geological Society of America Bulletin 114, no. 6 (June 2002): 675–92. http://dx.doi.org/10.1130/0016-7606(2002)114<0675:mvamwi>2.0.co;2.

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25

Schulze, H. P., R. Herms, H. Juhr, W. Schaetzing, and G. Wollenberg. "Comparison of measured and simulated crater morphology for EDM." Journal of Materials Processing Technology 149, no. 1-3 (June 2004): 316–22. http://dx.doi.org/10.1016/j.jmatprotec.2004.02.016.

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26

Klink, Andreas, Maximilian Holsten, and Lars Hensgen. "Crater morphology evaluation of contemporary advanced EDM generator technology." CIRP Annals 66, no. 1 (2017): 197–200. http://dx.doi.org/10.1016/j.cirp.2017.04.137.

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27

Tognon, Gloria, Riccardo Pozzobon, Matteo Massironi, and Sabrina Ferrari. "Geologic Mapping and Age Determinations of Tsiolkovskiy Crater." Remote Sensing 13, no. 18 (September 10, 2021): 3619. http://dx.doi.org/10.3390/rs13183619.

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Tsiolkovskiy is a ~200 km diameter crater presenting one of the few mare deposits of the lunar far side. In this work, we perform a geological study of the crater by means of morpho-stratigraphic and color-based spectral mappings, and a detailed crater counting age determination. The work aims at characterizing the surface morphology and compositional variation observed from orbital data including the Lunar Reconnaissance Orbiter Wide Angle Camera and Clementine UVVIS Warped Color Ratio mosaics, and attempts a reconstruction of the evolutionary history of the Tsiolkovskiy crater through both relative and absolute model age determinations. The results show a clear correlation between the geologic and spectral units and an asymmetric distribution of these units reflecting the oblique impact origin of the crater. Crater counts performed using the spectral units identified on the smooth crater floor returned distinct age ranges, suggesting the occurrence of at least three different igneous events, generating units characterized by particular compositions and/or degree of maturity. This work demonstrates the scientific value of Tsiolkovskiy crater for a better understanding of the volcanic evolution of the Moon and, in particular, of its far side.
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Newton, David E., Amy G. Ryan, and Luke J. Hilchie. "Competence and lithostratigraphy of host rocks govern kimberlite pipe morphology." Canadian Journal of Earth Sciences 55, no. 2 (February 2018): 130–37. http://dx.doi.org/10.1139/cjes-2017-0019.

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We use analogue experimentation to test the hypothesis that host rock competence primarily determines the morphology of kimberlite pipes. Natural occurrences of kimberlite pipes are subdivided into three classes: class 1 pipes are steep-sided diatremes emplaced into crystalline rock; class 2 pipes have a wide, shallow crater emplaced into sedimentary rock overlain by unconsolidated sediments; class 3 pipes comprise a steep-sided diatreme with a shallow-angled crater emplaced into competent crystalline rock overlain by unconsolidated sediments. We use different configurations of three analogue materials with varying cohesions to model the contrasting geological settings observed in nature. Pulses of compressed air, representing the energy of the gas-rich head of a kimberlitic magma, are used to disrupt the experimental substrate. In our experiments, the competence and configuration of the analogue materials control the excavation processes as well as the final shape of the analogue pipes: eruption through competent analogue strata results in steep-sided analogue pipes; eruption through weak analogue strata results in wide, shallow analogue pipes; eruption through intermediate strength analogue strata results in analogue pipes with a shallow crater and a steep-sided diatreme. These experimental results correspond with the shapes of natural kimberlite pipes, and demonstrate that variations in the lithology of the host rock are sufficient to generate classic kimberlite pipe shapes. These findings are consistent with models that ascribe the pipe morphologies of natural kimberlites to the competence of the host rocks in which they are emplaced.
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Chang, Qing Li, Yan Liu Yan, and Wan Kun. "Crater Structure and Photoluminescence of Porous Silicon." Advanced Materials Research 1120-1121 (July 2015): 179–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.179.

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Porous silicon (p-Si) was fabricated by single-groove electrochemical anodic etching method; the influence of large etching current density on the surface morphology was observed. And the surface microstructure and photoluminescence (PL) of p-Si were shown by scanning electron microscope (SEM) and PL spectra, respectively. The SEM image showed that a new microstructure was formed at the large current density etching area, which resembled a crater structure; and the area away from the crater appeared the porous structure. The comparison results of the PL spectra for the different areas indicated that PL of the crater area has a shorter wavelength.
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Prieur, N. C., T. Rolf, K. Wünnemann, and S. C. Werner. "Formation of Simple Impact Craters in Layered Targets: Implications for Lunar Crater Morphology and Regolith Thickness." Journal of Geophysical Research: Planets 123, no. 6 (June 2018): 1555–78. http://dx.doi.org/10.1029/2017je005463.

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Seo, Jooyeok, Sungho Nam, Hwajeong Kim, Donal D. C. Bradley, and Youngkyoo Kim. "Nano-crater morphology in hybrid electron-collecting buffer layers for high efficiency polymer:nonfullerene solar cells with enhanced stability." Nanoscale Horizons 4, no. 2 (2019): 464–71. http://dx.doi.org/10.1039/c8nh00319j.

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32

Gaudio, Pasquale, Roberto Montanari, Ekaterina Pakhomova, Maria Richetta, and Alessandra Varone. "Surface Morphology of Refractory Metals Submitted to a Single Laser Pulse." Materials Science Forum 1016 (January 2021): 1526–31. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1526.

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The work investigates refractory metals (bulk W, W produced via plasma spraying, W-1% La2O3 and Mo) of interest as plasma facing materials in future nuclear fusion reactors. They have been irradiated by a single Nd:YAG laser pulse to simulate the effects of transient thermal loads of high energy occurring in a tokamak under operative conditions and then examined by SEM observations. In all the materials the laser pulse induces a crater in the central area of laser spot surrounded by a ridge due to movement of molten metal while in a more external area a network of cracks is observed. Diameter and depth of the crater, ablated volume and morphological features of the surrounding area exhibit differences depending on the specific metal, its physical and microstructural characteristics which affect vaporization, melting and heat propagation from the irradiated spot.
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Villaça, Caio Vidaurre Nassif, Alvaro Penteado Crósta, and Carlos Henrique Grohmann. "Morphometric Analysis of Pluto’s Impact Craters." Remote Sensing 13, no. 3 (January 22, 2021): 377. http://dx.doi.org/10.3390/rs13030377.

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The scope of this work is to carry out a morphometric analysis of Pluto’s impact craters. A global Pluto digital elevation model (DEM) with a resolution of 300 m/px, created from stereoscopic pairs obtained by the New Horizons Mission, was used to extract the morphometric data of craters. Pluto’s surface was divided according to different morphometric characteristics in order to analyze possible differences in the impact dynamics and modification rate in each region. A Python code was developed, within the QGIS 3× software environment, to automate the process of crater outlining and collection of morphometric data: diameter (D), depth (d), depth variation, slope of the inner wall (Sw), diameter of the base (Db), and the width of the wall (Ww). Data have been successfully obtained for 237 impact craters on five distinct terrains over the west side of Sputnik Planitia on Pluto. With the collected data, it was possible to observe that craters near the equator (areas 3 and 4) are deeper than craters above 35°N (areas 1 and 2). Craters on the western regions (areas 2 and 3) contain the lowest depth values for a given diameter. The transition diameter from simple to complex crater morphology was found to change throughout the areas of study. Craters within areas 1 and 4 exhibit a transition diameter (Dt) of approximately 10 km, while Dt for craters within areas 3 and 5 the transitions occurs at 15 km approximately. The presence of volatile ices in the north and north-west regions may be the reason for the difference of morphometry between these two terrains of Pluto. Two hypotheses are presented to explain these differences: (1) The presence of volatile ices can affect the formation of craters by making the target surface weaker and more susceptible to major changes (e.g., mass waste and collapse of the walls) during the formation process until its final stage; (2) The high concentration of volatiles can affect the depth of the craters by atmospheric decantation, considering that these elements undergo seasonal decantation and sublimation cycles.
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34

Bunn, F. E., F. W. Thirkettle, and W. F. J. Evans. "Rapid motion of the 1989 Arctic ozone crater as viewed with TOMS data." Canadian Journal of Physics 69, no. 8-9 (August 1, 1991): 1087–92. http://dx.doi.org/10.1139/p91-167.

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The data from the NIMBUS-7 TOMS instrument were used to study the Arctic ozone layer in late winter and spring, 1989. This paper presents an analysis of TOMS total ozone values, to produce a picture of the morphology of the Arctic stratospheric ozone crater in winter–spring 1989. The Arctic crater formed in late January when the vortex moved off the pole to over Scandinavia. The TOMS data clearly show the Arctic ozone-crater feature over Scandinavia and the western Soviet Union, on February 2, 1989. It later moved south to Baffin Island and then, in March, down over Toronto, and eventually to western Canada, near Edmonton. A similar, unexpected, crater was present in the Antarctic fall, on March 15, 1989. This phenomenon is mainly produced by dynamic uplift, but there may be ozone depletion occurring as well owing to reduced temperatures.
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35

Silber, Elizabeth A., and Brandon C. Johnson. "Impact Crater Morphology and the Structure of Europa's Ice Shell." Journal of Geophysical Research: Planets 122, no. 12 (December 2017): 2685–701. http://dx.doi.org/10.1002/2017je005456.

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36

Bray, Veronica J., and Paul M. Schenk. "Pristine impact crater morphology on Pluto – Expectations for New Horizons." Icarus 246 (January 2015): 156–64. http://dx.doi.org/10.1016/j.icarus.2014.05.005.

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37

DUFRESNE, Anja, Michael H. POELCHAU, Thomas KENKMANN, Alex DEUTSCH, Tobias HOERTH, Frank SCHÄFER, and Klaus THOMA. "Crater morphology in sandstone targets: The MEMIN impact parameter study." Meteoritics & Planetary Science 48, no. 1 (January 2013): 50–70. http://dx.doi.org/10.1111/maps.12024.

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38

Basilevsky, A. T., and G. G. Michael. "Lunar Crater Ina: Analysis of the Morphology of Intracrater Landforms." Solar System Research 55, no. 1 (January 2021): 20–30. http://dx.doi.org/10.1134/s0038094621010020.

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39

STURKELL, ERIK F. F. "Resurge morphology of the marine Lockne impact crater, Jämtland, central Sweden." Geological Magazine 135, no. 1 (January 1998): 121–27. http://dx.doi.org/10.1017/s0016756897007875.

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In the Brunflo area of Jämtland, central Sweden, a Cambrian to Ordovician sedimentary sequence rests on a Proterozoic crystalline basement. The area lies just outside the site of the middle Ordovician Lockne impact, and it later experienced Caledonian overthrusting. The degree of Caledonian tectonization of the Palaeozoic varies, but an autochthonous Cambrian and Ordovician sequence apparently occurs in the greater part of the area, particularly in the north. The pre-impact sedimentary succession is 81 m thick in the autochthon, with the Middle Ordovician Furudal Limestone as uppermost member. Brunflo village is located just outside the crater, 8–9 km north of its centre, but the area was affected by the impact. The impact-generated ejecta and resurge deposits rest on a surface which cuts the sedimentary strata at a low angle. This surface cuts at progressively higher stratigraphic levels at increasing distance from the crater. According to observations in the autochthon the impact generated an erosion surface dipping 1–2° towards the crater centre. The sequence of events that shaped this surface began with bombardment with high-speed ejecta closely followed by resurging water. The resurge mixed ejecta clasts with the products of resurge erosion to form the resurge deposits. No rim wall can be traced at the Lockne impact structure, probably because a rim wall, if it formed, collapsed in the modification stage owing to local lithological conditions and because the remains of it were completely eroded in the resurge phase. It is suggested the rim wall formed in sedimentary strata with unlithified clays at their base, and that this clay was unable to support it.
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40

Zhang, Liao Yuan, Di Yu, Zhong Qing Shao, Shuo Wang, and Zhong Xiu Lv. "Study of Electrode Surface Characteristics under Short Single Pulse in Micro Ed-Milling." Applied Mechanics and Materials 395-396 (September 2013): 1057–61. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.1057.

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Laminated removal micro ED-Milling is a non-contact special processing technology, through electrode discharge removal in materials. Therefore, shape, size and overlapping degree of the discharge crater determine the surface roughness and surface morphology. Using the principle of electrode wears, through the experiment of Micro-EDM milling shallow groove under short single pulse, getting morphology of a single pulse discharge machining surface. And from the crater of morphological features analyses the different cause of formation, and contrasts in different electric parameters, the different of the electrode surface. For further analysis of the surface physical and mechanical performance changes to lay the foundation, and provides a way for the electrode material removal mechanism research and the calculation of the Single pulse discharge energy.
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41

Lasemi, Niusha, Günther Rupprechter, Gerhard Liedl, and Dominik Eder. "Near-Infrared Femtosecond Laser Ablation of Au-Coated Ni: Effect of Organic Fluids and Water on Crater Morphology, Ablation Efficiency and Hydrodynamic Properties of NiAu Nanoparticles." Materials 14, no. 19 (September 24, 2021): 5544. http://dx.doi.org/10.3390/ma14195544.

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Scanning electron microscopy (SEM) and profilometry of the crater morphology and ablation efficiency upon femtosecond laser ablation of Au-coated Ni targets in various fluids revealed a pronounced dependence on the ablation medium. For ethanol, a sufficient ablation efficiency was obtained, whereas for 2-butanol a higher efficiency indicated stronger laser–target interaction. Hierarchical features in the crater periphery pointed to asymmetrical energy deposition or a residual effect of the Coulomb-explosion-initiating ablation. Significant beam deviation in 2-butanol caused maximum multiple scattering at the crater bottom. The highest values of microstrain and increased grain size, obtained from Williamson–Hall plots, indicated the superposition of mechanical stress, defect formation and propagation of fatigue cracks in the crater circumference. For n-hexane, deposition of frozen droplets in the outer crater region suggested a femtosecond-laser-induced phase explosion. A maximum ablation depth occurred in water, likely due to its high cooling efficiency. Grazing incidence micro X-ray diffraction (GIXRD) of the used target showed residual carbon and partial surface oxidation. The produced nanoparticle colloids were examined by multiangle dynamic light scattering (DLS), employing larger scattering angles for higher sensitivity toward smaller nanoparticles. The smallest nanoparticles were obtained in 2-butanol and ethanol. In n-hexane, floating carbon flakes originated from femtosecond-laser-induced solvent decomposition.
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42

Evans, W. F. J., A. E. Walker, and F. E. Bunn. "The Arctic ozone crater in 1989." Canadian Journal of Physics 68, no. 10 (October 1, 1990): 1113–21. http://dx.doi.org/10.1139/p90-156.

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The presence of a thinned area or craterlike feature in the Arctic polar ozone layer during March, 1986 has been reported previously (Can. J. Phys. 67, 161 (1989)). In this paper the morphology of the reappearance of the crater from January to March, 1989 is described. It appeared over northern Europe in late January and moved over western Canada in late February. The minimum value of ozone in the crater floor had fallen from 300 DU (1 Dobson unit (DU) = 0.01 mm) in 1979 to a new low of less than 200 DU in 1989, which is similar to the thinned total ozone columns observed within the Antarctic ozone hole. Analysis of the available total ozone mapping spectrometer ozone measurements indicates that the crater could be explained by a combination of two mechanisms; a chemical process, which depleted the ozone concentrations at altitudes in the 14–22 km region, and a transport process, which shifted the altitude distribution of ozone upwards such as a vertical circulation cell. Although the Arctic ozone crater is similar in several aspects to the Antarctic ozone hole, there remain several differences; the issue is whether the crater and the hole are manifestations of the same phenomenon. We consider that the Arctic ozone crater is mainly produced by dynamic redistribution driven by tropospheric circulation features.
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43

Zhao, Song-Chuan, Rianne de Jong, and Devaraj van der Meer. "Raindrop impact on sand: a dynamic explanation of crater morphologies." Soft Matter 11, no. 33 (2015): 6562–68. http://dx.doi.org/10.1039/c5sm00957j.

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44

Mirdan, B. M., H. A. Jawad, D. Batani, V. Conte, T. Desai, and R. Jafer. "Surface morphology modifications of human teeth induced by a picosecond Nd:YAG laser operating at 532 nm." Laser and Particle Beams 27, no. 1 (January 15, 2009): 103–8. http://dx.doi.org/10.1017/s0263034609000159.

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AbstractThe interaction of an Nd:YAG laser, operating at 532 nm with 40 ps pulse duration, with human teeth was studied. The results show that teeth were significantly modified at an energy fluence of about 11 J/cm2. Various surface morphologies of enamel and dentine were recorded. Features on enamel include crater (conical form) in the central part and cauliflower morphology at the periphery, whereas on dentine the crater looks like a stretched dome between sharp edges. The behavior of the enamel-dentine junction area showed different morphology with respect to both tooth enamel and dentine alone. Finally, the junction channel showed a removal of collagen fibers and the formation of a needle-like bottom structure. Generally, this investigation showed that the picosecond Nd:YAG laser can ablate a tooth surface practically instantaneously, implying that large tooth surfaces can be processed in short time.
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45

Mascaraque-Ramírez, Carlos, and Patricio Franco. "Comparison between different methods for experimental analysis of surface integrity in die-sinking electro-discharge machining processes." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 234, no. 3 (September 18, 2019): 479–88. http://dx.doi.org/10.1177/0954405419876471.

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Advanced manufacturing techniques such as die-sinking electro-discharge machining have been introduced in different industries such as the naval, automotive and product manufacturing. The surface finish of the parts subjected to these processes is influenced by diverse factors related to geometrical parameters, electric circuit, lubrication system and materials. For that reason, this work is focused on the analysis of the surface morphology of machined part that can be achieved by electro-discharge machining, as a function of some of the main process parameters such as the current intensity and penetration depth. In this work, three different methods for experimental analysis of surface quality, based on the measuring of surface roughness, material profile ratio and crater diameter, were applied and compared. The experimental phase included tests with copper tools on AISI 316 stainless steel workpieces. The surface roughness and accumulated material profile were recorded using measurements made with a profilometer, and for the purpose of measuring the diameter of the craters, scanning electron microscopy technology was used. According to the results, crater diameter can be adopted as a better indicator to characterize the surface quality in electro-discharge machining, because it exhibits a clearer tendency as a function of current intensity and penetration depth.
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46

Craddock, Robert A., Lourenço Bandeira, and Alan D. Howard. "An Assessment of Regional Variations in Martian Modified Impact Crater Morphology." Journal of Geophysical Research: Planets 123, no. 3 (March 2018): 763–79. http://dx.doi.org/10.1002/2017je005412.

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47

Bart, Gwendolyn D. "The quantitative relationship between small impact crater morphology and regolith depth." Icarus 235 (June 2014): 130–35. http://dx.doi.org/10.1016/j.icarus.2014.03.020.

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48

Iglseder, H., and E. Igenbergs. "Crater morphology at impact velocities between 8 and 17 km/s." International Journal of Impact Engineering 10, no. 1-4 (January 1990): 271–80. http://dx.doi.org/10.1016/0734-743x(90)90065-4.

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49

Jenerowicz, M., and M. Banaszkiewicz. "ASTEROID (21) LUTETIA: SEMI-AUTOMATIC IMPACT CRATERS DETECTION AND CLASSIFICATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2 (May 30, 2018): 479–86. http://dx.doi.org/10.5194/isprs-archives-xlii-2-479-2018.

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The need to develop an automated method, independent of lighting and surface conditions, for the identification and measurement of impact craters, as well as the creation of a reliable and efficient tool, has become a justification of our studies. This paper presents a methodology for the detection of impact craters based on their spectral and spatial features. The analysis aims at evaluation of the algorithm capabilities to determinate the spatial parameters of impact craters presented in a time series. In this way, time-consuming visual interpretation of images would be reduced to the special cases. The developed algorithm is tested on a set of OSIRIS high resolution images of asteroid Lutetia surface which is characterized by varied landforms and the abundance of craters created by collisions with smaller bodies of the solar system.The proposed methodology consists of three main steps: characterisation of objects of interest on limited set of data, semi-automatic extraction of impact craters performed for total set of data by applying the Mathematical Morphology image processing (Serra, 1988, Soille, 2003), and finally, creating libraries of spatial and spectral parameters for extracted impact craters, i.e. the coordinates of the crater center, semi-major and semi-minor axis, shadow length and cross-section. The overall accuracy of the proposed method is 98&amp;thinsp;%, the Kappa coefficient is 0.84, the correlation coefficient is &amp;sim;&amp;thinsp;0.80, the omission error 24.11&amp;thinsp;%, the commission error 3.45&amp;thinsp;%. The obtained results show that methods based on Mathematical Morphology operators are effective also with a limited number of data and low-contrast images.
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BRAY, Veronica J., Gareth S. COLLINS, Joanna V. MORGAN, and Paul M. SCHENK. "The effect of target properties on crater morphology: Comparison of central peak craters on the Moon and Ganymede." Meteoritics & Planetary Science 43, no. 12 (December 2008): 1979–92. http://dx.doi.org/10.1111/j.1945-5100.2008.tb00656.x.

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