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LRO NAC oblique image of an example rolling boulder/rockfall on the slope of the South Massif in Taurus Littrow valley (mean slope angle of ∼25°), the Apollo 17 landing site (image taken toward the southeast). A bright landslide deposit is visible as well. The high emission angle illustrates the dramatic topography (oblique photograph): the South Massif is ∼2,300 m tall, that is, ∼500 m higher than the Grand Canyon is deep. An Apollo 17 Hasselblad image further illustrates the local topography (see inset, image taken toward the west). The marked rolling boulder/rockfall event occurred after the landslide. Boulder and track are marked in red; the circular insets show (sub)nadir LRO NAC close‐ups of the source and deposition regions. Due to the viewing geometry the scale bar only represents an approximation. Image credits: LROC/ASU/GSFC and NASA.
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The long‐ and short‐term drivers and transport mechanisms of lunar rockfalls are currently not well understood, but could provide valuable information about the geologic processes that still shape the surface of the Moon today. Here, we compare the global distribution of rockfalls with relevant geophysical data, such as seismic, topographic, therma...
Citations
... The absence of evident tube-related cracks could imply that most tubes are too small to produce cracks or that the cracks have been hidden using subsequent surface processes. The surface of the Moon continues to evolve to this day through a combination of impact gardening and seismic shaking (Bickel et al., 2021;Costello et al., 2018;Senthil Kumar et al., 2016). These may cover thin cracks or craters. ...
Evidence shows that lava tubes on the Moon, which constitute intriguing targets for exploration and long‐term habitation, could be much larger than terrestrial tubes. However, existing observation strategies cannot confidently constrain the exact dimensions of lunar tubes in anticipation of in situ exploration. We produced and analyzed numerical models of the elastic gravity‐induced deformation field around lunar lava tubes to determine where failure may occur on their internal surfaces and how the lunar surface above them may deform. This analysis suggests ways to determine tube dimensions from lunar surface morphological observations. The models predict extensive failure on the tube floors and roofs, leaving relatively small sections of pristine floor near the tube walls even if the tube itself may not collapse. The most extensive type of internal failure, tensile floor failure, depends on the tube shape. Additionally, the lunar surface around lava tubes develops cracks and subtle topographic bulges running parallel to the tube axis at distances proportional to the tube width. If observed, these could be used to determine the tube's width remotely. We examined several lunar sinuous rilles using orbital data to search for the surface features we expect near tubes. Linear cracks consistent with the presence of lava tubes are present on the possible extensions of three rilles: Rimae Mairan, Sharp, and Marius. Other locations did not show similar features, possibly because of the resolution of available data, tube depths, or surface degradation. However, surface or low‐altitude observations would be more sensitive to the expected structures.
... Rockfalls require the presence of topographic slopes as well as bedrock fragments or clasts in a suitable size that can be displaced. Rockfalls can also form on shallow slopes, as long as boulder displacement is driven-and maintained-by sufficiently energetic processes, such as ground acceleration caused by a seismic event or shaking from meteorite impact (Bickel, Aaron, et al., 2021). Clasts have to be detached from or have a weak connection to their parent rock mass before they can be displaced ( Figure 1, Figures S1, S2 in Supporting Information S1). ...
... Clasts have to be detached from or have a weak connection to their parent rock mass before they can be displaced ( Figure 1, Figures S1, S2 in Supporting Information S1). On the Moon, boulder dislodgement and displacement has been observed to be driven by impacts (Bickel, Aaron, et al., 2020;Hovland & Mitchell, 1973;Ikeda et al., 2022), tectonic activity (Kumar et al., 2013;Watters et al., 2019), and solar-driven thermal fatigue (Bickel, Aaron, et al., 2021;Titley, 1966). Here, the term 'driver' includes both triggers and causes of clast displacement. ...
... The maximum and mean clast sizes as reported by Roberts et al. (2012) for Cerberus Fossae are slightly larger than reported elsewhere, which is not reflected in our dataset, however ( Figure 2). Interestingly, the largest identified martian rockfall clast (∼9.2 m) is a factor of ∼3.5 smaller than the largest lunar rockfall clast (∼33.9 m) mapped by Bickel, Aaron, et al. (2021) and just slightly larger than the lunar mean clast size (∼7.8 m, Figure 3). The power law exponent of the martian clast size frequency distribution (SFD, 5.8) is smaller than for lunar clasts ( 3.8), indicating that there are (relatively) more small rockfalls on Mars than on the Moon (Figure 3). ...
Rockfalls are ubiquitous expressions of present‐day landscape evolution across the solar system. On Mars, their distribution has been proposed to indicate endo‐ and exogenic drivers, such as tectonic activity and solar‐driven thermal fatigue. Here, we present the first global catalog of 1,383 rockfall‐bearing locations on Mars, derived using MRO HiRISE images and a machine learning‐driven and human‐reviewed mapping approach. Rockfalls are documented between 82°N and 53°S, are heterogeneously distributed, and predominantly occur on the steep walls of craters and fossae. Globally, we do not observe a significant relation between rockfall abundance and terrain age, insolation, volatile abundance, wind speed, and impact or tectonic events, implying that rockfall drivers might act on varying spatiotemporal scales and differ across the planet—dissimilar to rockfalls on other bodies, like the Moon. Our results help characterize the current geologic processes that are shaping the surfaces of Mars and other solar system bodies today.
... This situation relates to numerous natural phenomena. For instance, many boulder-fall traces have been found on the slopes of the lunar surface [9][10][11][12]. Large boulders should slide or roll over the regolith layer to form those boulder-fall traces. ...
For floating on water, low density is the sole necessary factor. However, it has not been clarified how to floatingly drift on fluidized granular matter. Although this problem relates to various natural phenomena such as debris flow and lunar boulder-fall traces, fundamental aspects of the floating drift on granular flow have not been revealed. Therefore, the motion of a sphere on a vibrated granular slope is experimentally investigated in this study. As a result, we find that the sinking depth of the floating sphere can be explained by a modified buoyancy model. In addition, the downstream velocity of the drifting sphere can be understood by a force balance between flow-induced pushing force and frictional resistance force. This force balance results in a nonsteady but stable floating drift on the relaxing granular slope.
Published by the American Physical Society 2024
... Furthermore, their analysis of the relationship between the number of craters with boulder falls and the distance from the lobate scarps does not positively support the idea of a shallow moonquake causing the boulder falls. A similar discussion is given by Bickel et al. (2021). From another aspect, Duennebier and Sutton (1974b) discussed the topography degradation due to thermally induced stress on soil on downslopes. ...
In the 1970s, two types of seismometers were installed on the nearside of the Moon. One type is called the Long‐Period (LP) seismometer, which is sensitive below 1.5 Hz. The other is called the Short‐Period (SP) seismometer, whose sensitivity is high around 2–10 Hz. So far, more than 13,000 seismic events have been identified through analyzing the LP data, which allowed us to investigate lunar seismicity and its internal structure. On the other hand, most of the SP data have remained unanalyzed because they include numerous artifacts. This fact leads to the hypotheses that (a) we have missed lots of high‐frequency seismic events and (b) lunar seismicity could be underestimated. To verify these ideas, I conducted an analysis of the SP data. In the analysis, I denoised the original SP data and performed the event detections by comparing the spectral features between the cataloged high‐frequency events (such as shallow moonquakes) and the continuous SP data. Eventually, I discovered 22,000 new seismic events, including thermal moonquakes, impact‐induced events, and shallow moonquakes. Among these, I focused on analyzing shallow moonquakes—tectonic‐related quakes. Consequently, it turned out that there were 2.6 times more tectonic events than considered before. Furthermore, additional detections of shallow moonquakes enabled me to see the regionality in seismicity. Comparing three landing sites (Apollo 14, 15, and 16), I found that the Apollo 15 site was more seismically active than others. These findings can change the conventional views of lunar seismicity.
... We used images taken by the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) (Robinson, 2010;Robinson et al., 2010;Speyerer et al., 2012;Humm et al., 2016;Mahanti et al., 2016) to quantify the availability of boulders at the two sites of interest. The NAC images were obtained as EDR (Experimental Data Record) and processed using ISIS3 (Laura et al., 2023) to derive georeferenced images, following Bickel et al. (2021). The mapping of the boulders then was done using QGIS 2 version 2.18.28. ...
... We introduce a factor, which relates the cube of the longest diameter d long to the estimated volume of the boulder V b . The volume estimate is done by assuming the boulder to be an ellipsoid, as applied by Bickel et al. (2021). It can be assumed, that the height of the boulder corresponds to the smallest of the three axes (Demidov and Basilevsky, 2014). ...
Significant infrastructure is required to establish a long-term presence of humans on the lunar surface. In-situ resource utilization (ISRU) is a fundamental approach to ensure the viability of such construction. Here, we investigate the feasibility of constructing blast shields as one example of lunar infrastructure using unprocessed lunar boulders and an autonomous robotic excavator. First, we estimate the volume of unprocessed material required for the construction of blast shield segments. Secondly, we quantify the amount of available boulders in two exploration zones (located at the Shackleton-Henson Connecting Ridge and the Aristarchus Plateau pyroclastic deposit) using LRO NAC images and boulder size-frequency distribution laws. In addition, we showcase an alternative approach that relies on Diviner rock abundance data. Thirdly, we use a path planning algorithm to derive the distance, energy, and time required to collect local material and construct blast shield elements. Our results show that our construction method requires two orders of magnitudes less energy than alternative ISRU construction methods, while maintaining realistic mission time and payload capacity margins.
... Some of the surface features and structures that are found on the slopes derive from processes that occurred after the emplacement of the Light Mantle landslides. For example, as the survival time of boulder tracks is estimated to range up to 35 Ma (e.g., Arvidson et al., 1975;Hurwitz & Kring, 2016;Kumar et al., 2019), their presence on the NE-facing slope of the South Massif (e.g., Bickel et al. (2021); Figure 1c) is evidence that boulder falls have occurred after the younger Light Mantle landslide event. ...
... The presence of boulder tracks is considered evidence of recent processes that have mobilized boulders downhill, as boulders and their associated tracks are estimated to survive on the lunar surface up to 150-300 Ma (Basilevsky et al., 2013) and 35 Ma (e.g., Arvidson et al., 1975;Hurwitz & Kring, 2016;Kumar et al., 2019), respectively. The vicinity of boulder falls to lobate scarps, as well as to wrinkle ridges and graben, is attributed to recent lunar identify an increased spatial density of rockfalls in the proximity of tectonic structures, therefore concluding that impacts are the primary driver of lunar rockfall events, aided by solar-induced thermal fatigue of fractured bedrock (Bickel et al., 2021). In a study of boulder falls within Finsen crater, Ruj et al. (2022) concluded that ground shaking is needed to trigger boulder falls; however, it is not possible to discriminate between impact-induced and tectonic-induced ground shaking. ...
The South Massif and Taurus‐Littrow valley represent a unique area for understanding recent geological processes on the Moon. The presence of two recent overlapping landslide deposits, and boulder falls, suggests that repetitive instability has affected the north‐east facing slope of the South Massif. The presence of the young Lee‐Lincoln lobate scarp associated with a thrust fault suggests that seismic shaking may have been an important factor in triggering surface changes and mass‐wasting events in the area. In this work, we use the younger landslide deposit as a geomorphological marker. The age of the deposit, 70–110 Ma, is known due to the returned samples of the Apollo 17 mission, therefore allowing to set a time constraint to surface changes that have occurred since its emplacement. Here, we extend the body of evidence of slope deformation of the north‐east slope of the South Massif post‐dating the emplacement of the younger landslide deposit. We map boulder tracks, zones of disturbed regolith, summit and slope structures. We described their mutual relationships and their relationships with the topography and local tectonic structures. We identified features directly related to the local stress field, as well as features derived from gravitational adjustment following basal slope support removal due to reactivation of the ancient valley‐bounding fault in reverse mode associated with the Lee‐Lincoln thrust fault. Our interpretation favors a scenario in which recent tectonism, coupled with long‐lasting influence of the subsurface geometry, has caused continuous slope deformation of the South Massif.
... The impact destabilizes the slope by causing a mass movement and changing its morphological characteristics, makes the slopes gentler and the surface regolith layer thicker and results in degraded craters (Bickel et al., 2022;Ikeda et al., 2022;Chandnani and Herrick, 2023)]. The impact of micrometeorites (0.1-2 mm) can also degrade the surface of the rock and possibly cause the granule on the surface to separate triggered debris flow and gardening produced agglutinate formation and related cohesion increase (Soderblom, 1970;Hörz et al., 1971;Basilevsky et al., 2013;Bandfield et al., 2014;Bickel et al., 2021;Bickel et al., 2022;Ikeda et al., 2022). Impactrelated seismicity is shallow seismic, and tectonic activity can also be the cause of shallow seismic. ...
... The strength of thermal weathering depends on the size of the rock mass's particles and albedo and thermal inertia, and some research has found that the thin regolith cover would prevent the initiation of thermal fracturing (Molaro et al., 2017;Ruesch et al., 2020). Besides thermal fracturing, thermal moonquakes, which happen only in extremely dry sand with a smooth surface may be another mechanism driving lunar landslides (Linasay, 1976;Bickel et al., 2021). There are no affect factors like rainfall, melting snow, and frequent human activities of mass movements on the Moon compared to the mass movements on the Earth. ...
... This contributes to the lack of catalogs on a global scale including all kinds of mass movements, and the lack of knowledge about the spatial distribution and density of mass movements. Research by Bickel et al. (2021), Bickel et al. (2022) used a machine learning-driven approach to solve this major limitation of human-driven, mapped 28,101 flow features and 136,610 boulder tracks between 60°N and S. These works opened the door to a statistically sound, globalscale analysis of the spatial distribution, density, and drivers of rockfalls and granular flows. ...
The study of the lunar surface is a significant field in exploring the Moon. As a non-negligible geological process shaping the lunar surface, however, the mass movements on the Moon have not been deeply studied regarding all available datasets. In this paper, we report the results of the literature review and quantitative analysis of 965 articles retrieved from the Scopus, WoS, and Astrophysics Data System databases using keyword search terms between the years 1872 and 2022. The main findings show that the lunar mass movements are a lasting but recent prosperous research topic (since 2009). The top three influential journals in this area are Icarus, JGR, and P&SS. Robinson, Lucchitta, and Carr are the most three productive authors. California Institute of Technology, Arizona State University, and Johns Hopkins University are active institutions leading the lunar mass movements research, and the related institutions are mainly located in the United States, Russia, and China. Articles are primarily published in journals specializing in the fields of astronomy and physics. The index analysis of citation indicates the growth of the academic impact of articles about the lunar mass movements. This article summarizes the datasets, methods, and relevant parameters of lunar mass movements to facilitate future research, as well as discussing the limitations and trends in the field. In addition, four unsolved issues are proposed, including: 1) the lack of a comprehensive global database that records all types of landslides incidents; 2) the need for definite classification indicators to quantify the classification criteria for lunar mass movements; 3) the absence of a mathematical model to explain the triggering mechanism of mass movements on the Moon; and 4) the lack of quantitative indexes to evaluate the modification effect of mass movements on the lunar surface morphology. With the support of big data, the combination of artificial intelligence and traditional GIS methods is expected to become the main approach for addressing these issues such a bibliometric analysis can inspire future researchers by exploring the overall characteristics of the published literature on lunar mass movements.
... The Moon exhibits different types of mass wasting features (gullies, landslides, granular flows, and boulder falls or rock falls) globally, and these provide excellent opportunity for studying the origins of each of these features under lunar surface conditions (e.g., low-gravity, absence of atmosphere and dryness). The mass wasting features were reported from different parts of the Moon by Pike (1971), Howard (1973), Hovland and Mitchell (1973), Bart (2007), Kumar et al. (2013Kumar et al. ( , 2016Kumar et al. ( , 2019, Xiao et al. (2013), Brunetti et al. (2015), Kokelaar et al. (2017), Mohanty et al. (2020), and Bickel et al. (2020Bickel et al. ( , 2021Bickel et al. ( , 2022. The talus deposits, boulder trails (also known as boulder tracks), large-scale crater wall terraces with radial channels were reported from the Apollo photographs (Pike, 1971). ...
... Using automated rock fall detection algorithms, Bickel et al. (2020) reported the occurrence of 1,36,610 rock falls globally and attributed their origins predominantly to impact cratering processes. In another study, Bickel et al. (2021) interpreted that the origins of globally occurring boulder falls were due to impacts and solar-driven thermal fatigue, while only fewer boulder falls were traced around tectonic features and known shallow moonquake sites. Ikeda et al. (2022) suggested that the boulder falls in the Schrödinger and Lorentz basins were triggered by local impact events, rather than moonquakes. ...
... failure, from where numerous boulder falls have been identified (Bickel et al., 2021;Hurwitz & Kring, 2016;Schmitt & Cernan, 1973). Such region at the summit of the South Massif is characterized by low reflectance material, smoother than the surrounding terrains, that Hahn et al. (2019) interpret as impact melt from the Tycho impact event. ...
The Light Mantle landslide is a hypermobile landslide on the Moon. Apollo 17 astronauts collected a core sample of the top 60 cm of the Light Mantle deposit, which is currently being analyzed as part of the NASA's Apollo Next Generation Sample Analysis program. The origin of its hypermobility remains undetermined, as the proposed mechanisms are difficult to prove because of the lack of theoretical and experimental support and the scarcity of field data related to the internal structures of its deposit. Regardless of the emplacement mechanisms, it has been proposed that localized dynamic frictional weakening is responsible for the early stage instability that leads to catastrophic failure. Here, we conduct friction experiments under vacuum to investigate the viability of dynamic friction weakening in lunar analog anorthosite‐bearing gouges (i.e., rock powders). Our results show that localized dynamic friction weakening does not occur in these gouges at loading conditions where, instead, weakening is observed in other materials on Earth. Therefore, possibly other fluidization‐related mechanisms contributed to the initiation of the hypermobile Light Mantle landslide. Finally, we describe the microstructures formed in the experiments, including the presence of clast cortex aggregates. Preliminary investigation of the Light Mantle core samples (73001/73002) shows the presence of similar microstructures. Therefore, our microstructural observations will help the analysis and interpretation of the Apollo 17 core samples, as keys to insights about internal processes occurring during the emplacement of the landslide.
... The evidence includes for both landforms (Figure 1), the abundance of boulder fields and patches Valantinas & Schultz, 2020;Watters et al., 2019), a distinct crisp morphology (e.g., Watters et al., 2010;Williams et al., 2019), crosscutting of impact craters (Lu et al., 2019;Nypaver & Thomson, 2022;Watters et al., 2010), ages <1 Ga determined from CSFD methods (Lu et al., 2019;Valantinas et al., 2018;van der Bogert et al., 2018), shallow moonquakes , boulder falls (Senthil Kumar et al., 2016), and associated small meter-scaled graben (French et al., 2015;Valantinas & Schultz, 2020;Watters et al., 2012). The correlation between boulder falls and seismic activity, however, has been questioned recently (Bickel et al., 2021;Ikeda et al., 2022), highlighting the ongoing and early state of the study of recent tectonic activity. Late-stage global contraction is consistent with both an initially molten Moon (Binder & Gunga, 1985;Watters et al., 2019) and a near-surface magma ocean (Solomon, 1986;Solomon & Head, 1979;Watters et al., 2019), however, the magnitude of the late-stage stresses predicted in the totally molten Moon model is inconsistent with the population of small lobate thrust fault scarps (Watters et al., 2012. ...
The lithosphere of the Moon has been deformed by tectonic processes for at least 4 billion years, resulting in a variety of tectonic surface features. Extensional large lunar graben formed during an early phase of net thermal expansion before 3.6 Ga. With the emplacement of mare basalts at ∼3.9–4.0 Ga, faulting and folding of the mare basalts initiated, and wrinkle ridges formed. Lunar wrinkle ridges exclusively occur within the lunar Maria and are thought to be the result of superisostatic loading by dense mare basalts. Since 3.6 Ga, the Moon is in a thermal state of net contraction, which led to the global formation of small lobate thrust faults called lobate scarps. Hence, lunar tectonism recorded changes in the global and regional stress fields and is therefore an important archive for the thermal evolution of the Moon. Here, we mapped tectonic features in the non‐mascon basin Mare Tranquillitatis and classified these features according to their respective erosional states. This classification aims to provide new insights into the timing of lunar tectonism and the associated stress fields. We found a wide time range of tectonic activity, ranging from ancient to recent (3.8 Ga to <50 Ma). Early wrinkle ridge formation seems to be closely related to subsidence and flexure. For the recent and ongoing growth of wrinkle ridges and lobate scarps, global contraction with a combination of recession stresses and diurnal tidal stresses, as well as with a combination of South Pole‐Aitken ejecta loading and true polar wander are likely.
