Purpose The purpose of our study was to identify major hillslope sediment sources in a partially urbanized coastal watershed supporting salmonid habitat and to evaluate the use of physical and maximum entropy models in predicting sites of greatest concern. Questions include when and where increased runoff from trail and unpaved road surfaces has influenced patterns of landslides and gullies to ...

The surface of Mars is too cold and dry to permit stable liquid water, yet fresh, apparently water-carved gullies and seepage features have been identified in high-resolution imaging of canyon and crater walls by the Mars Global Surveyor spacecraft. Here, a model of nonequilibrium hydrological activity and liquid water cryovolcanism explains the paradoxical appearance and observed properties of...

The gully erosion presents spectral and spatial heterogeneity and altimetry variation. It is not a land use class, but an object and it can be mapped as a subclass, using OBIA. This study presents a methodology for delimitation of gullies in rural environments, based on image classification procedures. For such, two study areas were selected: one located in Minas Gerais, Brazil and another one ...

Introduction: Two main theories of gully formation on Mars exist depending on the source of water. One holds that water was released from the subsurface [1]. The other proposes that water is deposited as nearsurface ice or snow from the atmosphere and is subsequently melted by insolation [2-4]. In this paper we applied fractal theory to study a gully's head alcove in different orientations of a...

Liquid water is currently extremely rare on Mars, but was more abundant during periods of high obliquity in the last few millions of years. This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems. However, there are no direct estimates of the amount and frequency of liquid water generation during these periods. Here we determine debris-flow size, freq...

[1] Fresh gully-like features on Mars strongly suggest that fluid flowed on the surface in the recent past. Here we consider the possibility that CO2 vapor-supported flows formed the gullies. We find that neither condensed CO2 nor CO2 clathrate hydrate are likely to accumulate in significant quantities in the Martian crust. In addition, if condensed CO2 were present under lithostatic pressures,...