The oldest materials in the region appear to be radar dark plains with light mottling in places. ... more The oldest materials in the region appear to be radar dark plains with light mottling in places. These plains are cut by fractures and other tectonic features, as well as at least one sinuous channel that may be the result of lava erosion. Superimposed on these plains and the associated structural features is a 75 krn diameter impact crater which in turn has been buried by lavas erupted from the Mylitta Fluctus source area. This volcanic complex is associated with the massive lava flow field that extends northwards into Lavinia Planitia for some 800 km. Superimposed on the source area are numerous small shields of a few kilometres in diameter.
We are attempting to define the topographic resolution required to derive essential information f... more We are attempting to define the topographic resolution required to derive essential information for process-driven studies.
Sites on Mars with rocky geomorphic features interpreted to be lava flows, avalanches, talus cone... more Sites on Mars with rocky geomorphic features interpreted to be lava flows, avalanches, talus cones, rock glaciers, glacial moraines and fluvial outwash channels are the focus of interest for this project. For each site, image and topography datasets have been compiled that include Viking Orbiter, Mars Orbiter Laser Altimeter (MOLA), Mars Orbital Camera (MOC), Thermal Emission Imaging System (THEMIS), HRSC and most recently MRO CTX and HiRISE. To correctly interpret geomorphic and geologic features and their underlying processes the limitations of the imaging sensors used at Mars and any derived data products have had to be understood. From studies conducted at our terrestrial analog sites it has become clear that obtaining topographic data at the appropriate resolution is essential to provide the boundary conditions to quantify processes such as lava flows, landslides and fluvial activity on Mars. Airborne Laser Altimeter derived topography at ~1-2 m/pixel has been obtained for six ...
We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions rangin... more We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions ranging from basalt to rhyolite. At each site, we stretched a line across the flow surface then measured the length of each block cut by this line that were greater than 3-12cm (depending on composition). The measurements from each site were reduced to cumulative size frequency
Introduction. Olympus Mons is an immense (23 km height above base, 600-800 km wide) volcano locat... more Introduction. Olympus Mons is an immense (23 km height above base, 600-800 km wide) volcano located to the northwest of the Tharsis Rise on Mars. The volcanic edifice is partially bounded by an escarpment of height up to 10 km, known as the Olympus Mons basal scarp. Lobate deposits with rugged morphology (the Olympus Mons aureole deposits, abbreviated as OMAD) extend outwards from the base of the scarp for hundreds of kilometers, with greatest extents and widths to the northwest of the edifice. Formation of the OMAD has been attributed to mass movements related to failure of portions of the flanks of Olympus Mons [4] or to flows of material (perhaps subsequently eroded) derived and emplaced locally [5]. Formation of the basal scarp has been attributed to thrust faulting, , to the coalescence of massmovement-related headscarps [1-4], or as a consequence of subglacial volcano growth [11]. While the proximity of scarp segments to aureole lobes is suggestive of a causal relationship, the limited resolution of available datasets has made it difficult to conclusively prove such a link. However, new high-resolution datasets, including Mars Orbiter Laser Altimeter (MOLA) topography [12], offer the potential for vital new insights into the structure and evolution of the Olympus Mons edifice, scarp and aureole. Thus, we examine the structure of the basal scarp and OMAD, as revealed by MOLA topography, from the perspective of evaluation of flank failure scenarios.
Introduction: Debris flows and other forms of mass movement are significant geomorphic agents on ... more Introduction: Debris flows and other forms of mass movement are significant geomorphic agents on the terrestrial planets. Viking images revealed deposits that have been interpreted to be similar to terrestrial debris flows [1]. The term debris flow is used to denote a viscous to highly fluid form of rapid mass movement of granular solids, (vegetation and air) with flow properties that vary with water content, sediment size and sorting of particles. We have obtained high-precision topographic profiles and performed a sedimentological study over a debris flow near Graves Mill (38.24°N, 78.23°W) in Madison County, Virginia. Use of an empirical model in conjunction with these data constrain to first order the flow behavior during the emplacement of the Graves Mill debris flows, and provide a method to interpret debris flow emplacement on Mars [e.g. 1].
Traditional methods of landslide monitoring have normally employed ground based instrumentation t... more Traditional methods of landslide monitoring have normally employed ground based instrumentation that is either read directly, logged by computer or telemetered to a remote station. While such methods have shown excellent results they remain labour intensive and costly. Furthermore such equipment is frequently lost. In recent years the use of remotely sensed data for the detection and monitoring of landslides
Modified volcanic domes, referred to as collapsed margin domes, have diameters greater than those... more Modified volcanic domes, referred to as collapsed margin domes, have diameters greater than those of terrestrial domes and were therefore thought to have no suitable terrestrial analogue. Comparison of the collapsed debris using the Magellan SAR images with volcanic debris avalanches on Earth has revealed morphological similarities. Some volcanic features identified on the seafloor from sonar images have diameters similar to those on Venus and also display scalloped margins, indicating modification by collapse. Examination of the SAR images of collapsed dome features reveals a number of distinct morphologies to the collapsed masses. Ten examples of collapsed margin domes displaying a range of differing morphologies and collapsed masses have been selected and examined.
Voyager stereoimages of Euboea Montes, Io, indicate that this mountain formed when a large crusta... more Voyager stereoimages of Euboea Montes, Io, indicate that this mountain formed when a large crustal block was uplifted 10.5 kilometers and tilted by approximately 6 degrees. Uplift triggered a massive slope failure on the northwest flank, forming one of the largest debris aprons in the solar system. This slope failure probably involved relatively unconsolidated layers totaling approximately 2 kilometers in thickness, overlying a rigid crust (or lithosphere) at least 11 kilometers thick. Mountain formation on Io may involve localized deep-rooted thrust faulting and block rotation, due to compression at depth induced during vertical recycling of Io's crust.
The town of Machu Picchu, Peru, serves the >700 000 tourists visiting Machu Picchu annually. It h... more The town of Machu Picchu, Peru, serves the >700 000 tourists visiting Machu Picchu annually. It has grown threefold in population in the past two decades. Due to the limited low-lying ground, construction is occurring on the unstable valley slopes. Slopes range from <10 • on the valley floor to >70 • in the surrounding mountains. The town has grown on a delta formed at the confluence of the Alcamayo, Aguas Calientes and Vilcanota Rivers. Geohazards in and around the town of particular concern are 1) large rocks falling onto the town and/or the rail line, 2) flash flooding by any one of its three rivers, and 3) mudflows and landslides. A prototype early warning system that could monitor weather, river flow and slope stability was installed along the Aguas Calientes River in 2009. This has a distributed modular construction allowing components to be installed, maintained, salvaged, and repaired by local technicians. A diverse set of candidate power, communication and sensor technologies was evaluated. Most of the technologies had never been deployed in similar terrain, altitude or weather. The successful deployment of the prototype proved that it is technically feasible to develop early warning capacity in the town.
The oldest materials in the region appear to be radar dark plains with light mottling in places. ... more The oldest materials in the region appear to be radar dark plains with light mottling in places. These plains are cut by fractures and other tectonic features, as well as at least one sinuous channel that may be the result of lava erosion. Superimposed on these plains and the associated structural features is a 75 krn diameter impact crater which in turn has been buried by lavas erupted from the Mylitta Fluctus source area. This volcanic complex is associated with the massive lava flow field that extends northwards into Lavinia Planitia for some 800 km. Superimposed on the source area are numerous small shields of a few kilometres in diameter.
We are attempting to define the topographic resolution required to derive essential information f... more We are attempting to define the topographic resolution required to derive essential information for process-driven studies.
Sites on Mars with rocky geomorphic features interpreted to be lava flows, avalanches, talus cone... more Sites on Mars with rocky geomorphic features interpreted to be lava flows, avalanches, talus cones, rock glaciers, glacial moraines and fluvial outwash channels are the focus of interest for this project. For each site, image and topography datasets have been compiled that include Viking Orbiter, Mars Orbiter Laser Altimeter (MOLA), Mars Orbital Camera (MOC), Thermal Emission Imaging System (THEMIS), HRSC and most recently MRO CTX and HiRISE. To correctly interpret geomorphic and geologic features and their underlying processes the limitations of the imaging sensors used at Mars and any derived data products have had to be understood. From studies conducted at our terrestrial analog sites it has become clear that obtaining topographic data at the appropriate resolution is essential to provide the boundary conditions to quantify processes such as lava flows, landslides and fluvial activity on Mars. Airborne Laser Altimeter derived topography at ~1-2 m/pixel has been obtained for six ...
We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions rangin... more We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions ranging from basalt to rhyolite. At each site, we stretched a line across the flow surface then measured the length of each block cut by this line that were greater than 3-12cm (depending on composition). The measurements from each site were reduced to cumulative size frequency
Introduction. Olympus Mons is an immense (23 km height above base, 600-800 km wide) volcano locat... more Introduction. Olympus Mons is an immense (23 km height above base, 600-800 km wide) volcano located to the northwest of the Tharsis Rise on Mars. The volcanic edifice is partially bounded by an escarpment of height up to 10 km, known as the Olympus Mons basal scarp. Lobate deposits with rugged morphology (the Olympus Mons aureole deposits, abbreviated as OMAD) extend outwards from the base of the scarp for hundreds of kilometers, with greatest extents and widths to the northwest of the edifice. Formation of the OMAD has been attributed to mass movements related to failure of portions of the flanks of Olympus Mons [4] or to flows of material (perhaps subsequently eroded) derived and emplaced locally [5]. Formation of the basal scarp has been attributed to thrust faulting, , to the coalescence of massmovement-related headscarps [1-4], or as a consequence of subglacial volcano growth [11]. While the proximity of scarp segments to aureole lobes is suggestive of a causal relationship, the limited resolution of available datasets has made it difficult to conclusively prove such a link. However, new high-resolution datasets, including Mars Orbiter Laser Altimeter (MOLA) topography [12], offer the potential for vital new insights into the structure and evolution of the Olympus Mons edifice, scarp and aureole. Thus, we examine the structure of the basal scarp and OMAD, as revealed by MOLA topography, from the perspective of evaluation of flank failure scenarios.
Introduction: Debris flows and other forms of mass movement are significant geomorphic agents on ... more Introduction: Debris flows and other forms of mass movement are significant geomorphic agents on the terrestrial planets. Viking images revealed deposits that have been interpreted to be similar to terrestrial debris flows [1]. The term debris flow is used to denote a viscous to highly fluid form of rapid mass movement of granular solids, (vegetation and air) with flow properties that vary with water content, sediment size and sorting of particles. We have obtained high-precision topographic profiles and performed a sedimentological study over a debris flow near Graves Mill (38.24°N, 78.23°W) in Madison County, Virginia. Use of an empirical model in conjunction with these data constrain to first order the flow behavior during the emplacement of the Graves Mill debris flows, and provide a method to interpret debris flow emplacement on Mars [e.g. 1].
Traditional methods of landslide monitoring have normally employed ground based instrumentation t... more Traditional methods of landslide monitoring have normally employed ground based instrumentation that is either read directly, logged by computer or telemetered to a remote station. While such methods have shown excellent results they remain labour intensive and costly. Furthermore such equipment is frequently lost. In recent years the use of remotely sensed data for the detection and monitoring of landslides
Modified volcanic domes, referred to as collapsed margin domes, have diameters greater than those... more Modified volcanic domes, referred to as collapsed margin domes, have diameters greater than those of terrestrial domes and were therefore thought to have no suitable terrestrial analogue. Comparison of the collapsed debris using the Magellan SAR images with volcanic debris avalanches on Earth has revealed morphological similarities. Some volcanic features identified on the seafloor from sonar images have diameters similar to those on Venus and also display scalloped margins, indicating modification by collapse. Examination of the SAR images of collapsed dome features reveals a number of distinct morphologies to the collapsed masses. Ten examples of collapsed margin domes displaying a range of differing morphologies and collapsed masses have been selected and examined.
Voyager stereoimages of Euboea Montes, Io, indicate that this mountain formed when a large crusta... more Voyager stereoimages of Euboea Montes, Io, indicate that this mountain formed when a large crustal block was uplifted 10.5 kilometers and tilted by approximately 6 degrees. Uplift triggered a massive slope failure on the northwest flank, forming one of the largest debris aprons in the solar system. This slope failure probably involved relatively unconsolidated layers totaling approximately 2 kilometers in thickness, overlying a rigid crust (or lithosphere) at least 11 kilometers thick. Mountain formation on Io may involve localized deep-rooted thrust faulting and block rotation, due to compression at depth induced during vertical recycling of Io's crust.
The town of Machu Picchu, Peru, serves the >700 000 tourists visiting Machu Picchu annually. It h... more The town of Machu Picchu, Peru, serves the >700 000 tourists visiting Machu Picchu annually. It has grown threefold in population in the past two decades. Due to the limited low-lying ground, construction is occurring on the unstable valley slopes. Slopes range from <10 • on the valley floor to >70 • in the surrounding mountains. The town has grown on a delta formed at the confluence of the Alcamayo, Aguas Calientes and Vilcanota Rivers. Geohazards in and around the town of particular concern are 1) large rocks falling onto the town and/or the rail line, 2) flash flooding by any one of its three rivers, and 3) mudflows and landslides. A prototype early warning system that could monitor weather, river flow and slope stability was installed along the Aguas Calientes River in 2009. This has a distributed modular construction allowing components to be installed, maintained, salvaged, and repaired by local technicians. A diverse set of candidate power, communication and sensor technologies was evaluated. Most of the technologies had never been deployed in similar terrain, altitude or weather. The successful deployment of the prototype proved that it is technically feasible to develop early warning capacity in the town.
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Papers by Marko Bulmer