نتایج جستجو برای: permanent gullies
تعداد نتایج: 62766 فیلتر نتایج به سال:
The current low temperatures and pressures at the martian surface are not conducive to the stability of liquid water; hence the discovery of recently active, fluvial-like gullies [1, 2] presents an apparent paradox: how can these fluvial landforms have occurred if water is not stable at the surface? To approach this problem we have compared the morphometric properties of gullies in various sett...
[1] Geomorphic evidence suggests that recent gullies on Mars were formed by fluvial activity. The Martian gully features are significant because their existence implies the presence of liquid water near the surface on Mars in geologically recent times. Irrespective of the ultimate source of the fluid carving the gullies, we seek to understand the behavior of this fluid after it reaches the Mart...
The origin of the martian gullies has been much debated since their discovery by the Mars Orbiter Camera (MOC, Malin, M.C., Edgett, K.S. [2000]. Science 288, 2330–2335). Several previous studies have looked at slope gradients in and around gullies, but none have used Digital Elevation Models (DEMs) from the High Resolution Imaging Science Experiment (HiRISE, McEwen, A.S., and 14 colleagues [200...
Introduction: The discovery of youthful gullies on Mars [1] provided strong evidence for short-duration flow of liquid water within the last several million years, an era not generally considered conducive to the stability of liquid water at the surface [2]. Given average conditions below the melting point for all of Mars and the apparent correlation between bed-rock layering and gully alcoves,...
Introduction Background and objectives Gully erosion is one of the destructive forms of soil erosions that may lead to a considerable volume of soil loss. This erosion type in addition to on-site and off-site effects has an important role in land degradation and forming in some watersheds. In this regard, due to gully erosion in some provinces of Iran such as Hormozgan, Bushehr, Fars, K...
This study systematically investigates the overburden movement and strata behavior at a fully-mechanized top coal caving (FMTCC) face in a thick coal seam in a loess-covered gullied region by field measurement and theoretical analysis. A comparative analysis was performed to examine how the attitude of surface gullies and the structure of overburden affect face support resistance. The character...
[1] High-resolution images from Chandrayaan-1 Terrain Mapping Camera and Lunar Reconnaissance Orbiter Camera reveal landslides and gully formation on the interior wall of a 7 km-diameter simple crater emplaced in Schrödinger basin on the farside of the Moon. These features occur on the steep upper crater wall, where the slope is ~35 . The gullies show a typical alcove-channel-fan morphology. So...
Field investigations and interpretations of high-resolution remote sensing images reveal geomorphic features of cumulative offsets and deflections of Holocene streams and gullies along the western 450-km segment of the Kunlun fault which triggered the 2001 Mw 7.8 Kunlun earthquake in the northern Tibetan Plateau. The streams and gullies developed on Holocene alluvial fans are sinistrally displa...
I present lunar landslides that bear a striking resemblance to some martian gullies, despite the lack of water on the Moon both today and in the past. This observation indicates that gully features can be formed via a dry landslide mechanism. Thus on Mars, morphology alone is insufficient to determine the mechanism of formation of these features. Introduction: In 2000, Malin and Edgett (1) repo...
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