Recently, the use of unmanned aerial vehicles (UAVs) has increased in popularity across several industries. Most notable, however, is the impact that this technology has had in research at academic institutions worldwide. As the technology for UAVs has improved, with that comes easier to operate, more accessible equipment. UAVs have been used in various types of applications and are quickly becoming a preferred method of studying and analyzing a site. Currently, the most common use of a UAV is to monitor a location of interest to a researcher that is difficult to gain access to otherwise. The UAV can be altered to meet the needs of any given project and this versatility has contributed to their popularity. Often, they are equipped with a type of remote sensor that can gather information in the form of images, sounds, heat, or light. Once data has been gathered from a site, it is processed and modified, allowing it to be studied and analyzed. A process known as Structure from Motion (SfM) creates a 3D digital terrain model from camera images captured through the use of a UAV. SfM is a common method of processing the vast amount of images that are taken at a site and the 3D model that it creates is a helpful resource for analysis. These digital models, while useful, are oftentimes created at an unknown accuracy. This research presents a comparative study of the accuracies obtained when different parameters are applied during the SfM process. The results present a comparison of the time required to process a particular model and the accuracy that the model had. Depending on the application and type of project, a desired level of accuracy can be obtained in the presented amount of time. This particular study used a landslide as the site of interest and captured the imagery using a helicopter UAV.

Landslides represent a serious hazard to people and property in the Pacific Northwest. Currently, the factors leading to sudden catastrophic failure vs. gradual slow creeping are not well understood. Utilizing high-resolution monitoring techniques at a sub-annual temporal scale can help researchers better understand the mechanics of mass wasting processes and possibly lead to better mitigation of their danger. This research used historical imagery analysis, precipitation data, aerial lidar analysis, Structure from Motion (SfM) photogrammetry, terrestrial laser scanning (TLS), and hydrologic measurements to monitor displacement of the Silt Creek Landslide in the western Cascade Mountain Range in Linn County, Oregon. This landslide complex is ~4 km long by ~400 m wide. The lower portion of the landslide reactivated following failure of an internal scarp in June 2014. Precipitation was measured on site and historical precipitation data was determined from a nearby SNOTEL site. Analysis of aerial lidar data found that the internal scarp failure deposited around 1.00x106 m3 of material over an area of 1.20x105 m2 at the uppermost portion of the reactivated slide. Aerial lidar analysis also found that displacement rates on the slide surface were as high as 3 m/yr during the 2015 water year, which was the year immediately following the failure. At the beginning of the 2016 water year, very low altitude aerial images were collected and used to produce point cloud data, via SfM, of a deformed gravel road which spans a portion of the reactivated slide. The SfM data were complimentary to the aerial and TLS scans. The SfM point cloud had an average point density of >7500 points per square meter. The resulting cloud was manipulated in 3D software to produce a model of the road prior to deformation. This was then compared to the original deformed model. Average displacement found in the deformed gravel road was 7.5 m over the 17 months between the scarp failure and the collection of the images, or ~3 m/yr. TLS point clouds were collected quarterly over the course of the 2016 water year at six locations along the eastern margin of the reactivated portion of the landslide. These 3D point cloud models of the landslide surface had an average density of 175 points per square meter. Scans were georeferenced to UTM coordinates and relative alignment of the scans was accomplished by first using the iterative closest point algorithm to align stable, off-slide terrain, and then applying the same rigid body translation to the entire scan. This was repeated for each scan at each location. Landmarks, such as tree trunks, were then manually selected at each location and their coordinates were recorded from the initial scan and each successive scan to measure displacement vectors. Average annual displacement for the 2016 water year ranged from a maximum of 0.92 m/yr in the uppermost studied area of the slide, to a low of 0.1 m/yr at the toe. Average standard deviation of the vectors of features on stable areas was 0.039 m, corresponding to a minimum detectable displacement of about ±4 cm. Displacement totals decreased with increasing distance downslope from the internal scarp failure. Additionally, displacement tended to increase with increasing distance laterally onto the slide body away from the right margin at all locations except the uppermost, where displacement rates were relatively uniform for all landmarks. Volumetric discharge measurements were collected for Silt Creek in 2016 using salt dilution gauging and found that discharge in the upslope portion of the study area was ~1 m3/s and increased to ~1.6 m3/s in the downslope portion. Landslide displacement rates were found to be much lower during the 2016 water year than during the 2015 water year, despite higher precipitation. This suggests that the over-all displacement trend was decoupled from precipitation values. Displacement rates at all locations on the slide decreased with each successive scan period with some portions of the landslide stopping by autumn of 2016, suggesting the study captured the slide as it returned to a state of stability. The spatial and temporal pattern of displacement is consistent with the interpretation that the landslide reactivation was a response to the undrained load applied by the internal scarp failure. This finding highlights the importance of detailed landslide monitoring to improve hazard estimation and quantification of landslide mechanics. This study provides new evidence that supports previous research showing that internal processes within landslide complexes can have feedback relationships, combines several existing 3D measurement tools to develop a detailed landslide monitoring methodology, uses a novel approach to landslide surface deformation measurements using SfM, and suggests that landslide initiation models which rely heavily on precipitation values may not account for other sources of landslide activation.

The distribution of landslide type and age was analyzed to determine the causes and timing of landsliding, and to assess landslide hazards in the study area. 1173 landslides and zones of landsliding were mapped on 1:15,840 scale air photos and designated by their style of movement and age. Slides were assigned to one of four age classes based on their degree of m orphologic modification visible on air photos. Relative dating (RD) methods previously applied to glacial deposits were used to refine and calibrate the age classification. Eleven RD para meters were measured on 21 rockslide and 19 glacial deposits. Cluster analyses were run on the RD data set. Slides assigned to Age-Classes 4, 3+, and 2 tend to cluster with probable Pinedale, early Holocene, and Neoglacial-age moraines respectively. Cluster analyses indicate poor age resolution by the RD method from approximately early Altithermal to early Neoglacial time. Landslide age cannot be resolved in this study to a finer degree by the RD method than by the morphologic (air -photo) method. However, cluster analyses generally confirm age assignments and absolute age estimates of the four landslide age classes, despite limitations of the RD method such as boulder spalling, and variations in lithology, deposit type, and elevation/climate between sampled deposits. The temporal distribution of landslides indicates that mass movements may have occurred rather uniformly throughout Holocene time, with slightly higher rates of sliding during post-Altithermal time due to climatic effects associated with Neoglacial advances. Spatial analyses indicate that landslides cover 73% of the Cretaceous section. Development, such as logging and road construction, could trigger landsliding in the Cretaceous section. Landslides account for 15% and 10% of the outcrop areas of the Paleozoic and Triassic-Jurassic sections respectively. Debris flows and slump-earth flows dominate sliding in both sections, with minor numbers of rockslides present. Debris flows pose the greatest hazard in both sections. Fine-grained stratigraphic units have the highest landslide densities in both sections. The previous event locations define areas most susceptible to future sliding.

Thesis (M.A.)--Miami University, Dept. of Geography, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 67-72).

Submarine landslides can generate local tsunamis posing a hazard to human lives and coastal facilities. Two major related problems are: (i) quantitative estimation of tsunami hazard and (ii) early detection of the most dangerous landslides. This thesis focuses on both those issues by providing numerical modeling of landslide-induced tsunamis and by suggesting and justifying a new method for fast detection of tsunamigenic landslides by means of tiltmeters. Due to the proximity to the Sunda subduction zone, Indonesian coasts are prone to earthquake, but also landslide tsunamis. The aim of the GITEWS-project (German-Indonesian Tsunami Early Warning System) is to provide fast and reliable tsunami warnings, but also to deepen the knowledge about tsunami hazards. New bathymetric data at the Sunda Arc provide the opportunity to evaluate the hazard potential of landslide tsunamis for the adjacent Indonesian islands. I present nine large mass movements in proximity to Sumatra, Java, Sumbawa and Sumba, whereof the largest event displaced 20 km³ of sediments. Using numerical modeling, I compute the generated tsunami of each event, its propagation and runup at the coast. Moreover, I investigate the age of the largest slope failures by relating them to the Great 1977 Sumba earthquake. Continental slopes off northwest Europe are well known for their history of huge underwater landslides. The current geological situation west of Spitsbergen is comparable to the continental margin off Norway after the last glaciation, when the large tsunamigenic Storegga slide took place. The influence of Arctic warming on the stability of the Svalbard glacial margin is discussed. Based on new geophysical data, I present four possible landslide scenarios and compute the generated tsunamis. Waves of 6 m height would be capable of reaching northwest Europe threatening coastal areas. I present a novel technique to detect large submarine landslides using an array of tiltmeters, as a possible tool in future tsunami early warning systems. The dislocation of a large amount of sediment during a landslide produces a permanent elastic response of the earth. I analyze this response with a mathematical model and calculate the theoretical tilt signal. Applications to the hypothetical Spitsbergen event and the historical Storegga slide show tilt signals exceeding 1000 nrad. The amplitude of landslide tsunamis is controlled by the product of slide volume and maximal velocity (slide tsunamigenic potential). I introduce an inversion routine that provides slide location and tsunamigenic potential, based on tiltmeter measurements. The accuracy of the inversion and of the estimated tsunami height near the coast depends on the noise level of tiltmeter measurements, the distance of tiltmeters from the slide, and the slide tsunamigenic potential. Finally, I estimate the applicability scope of this method by employing it to known landslide events worldwide. / Submarine Erdrutsche können lokale Tsunamis auslösen und stellen somit eine Gefahr für Siedlungen an der Küste und deren Einwohner dar. Zwei Hauptprobleme sind (i) die quantitative Abschätzung der Gefahr, die von einem Tsunami ausgeht und (ii) das schnelle Erkennen von gefährlichen Rutschungsereignissen. In dieser Doktorarbeit beschäftige ich mich mit beiden Problemen, indem ich Erdrutschtsunamis numerisch modelliere und eine neue Methode vorstelle, in der submarine Erdrutsche mit Hilfe von Tiltmetern detektiert werden. Die Küstengebiete Indonesiens sind wegen der Nähe zur Sunda-Subduktionszone besonders durch Tsunamis gefährdet. Das Ziel des GITEWS-Projektes (Deutsch- Indonesisches Tsunami-Frühwarnsystem) ist es, schnell und verlässlich vor Tsunamis zu warnen, aber auch das Wissen über Tsunamis und ihre Anregung zu vertiefen. Neue bathymetrische Daten am Sundabogen bieten die Möglichkeit, das Gefahrenpotential von Erdrutschtsunamis für die anliegenden indonesischen Inseln zu studieren. Ich präsentiere neun große Rutschungereignisse nahe Sumatra, Java, Sumbawa und Sumba, wobei das größte von ihnen 20 km³ Sediment bewegte. Ich modelliere die Ausbreitung und die Überschwemmung der bei diesen Rutschungen angeregten Tsunamis. Weiterhin untersuche ich das Alter der größten Hanginstabilitäten, indem ich sie zu dem Sumba Erdbeben von 1977 in Beziehung setze. Die Kontinentalhänge im Nordwesten Europa sind für Ihre immensen unterseeischen Rutschungen bekannt. Die gegenwärtige geologische Situation westlich von Spitzbergen ist vergleichbar mit derjenigen des norwegischen Kontinentalhangs nach der letzten Vergletscherung, als der große Tsunamianregende Storegga-Erdrutsch stattfand. Der Einfluss der arktischen Erwärmung auf die Hangstabilität vor Spitzbergen wird untersucht. Basierend auf neuen geophysikalischen Messungen, konstruiere ich vier mögliche Rutschungsszenarien und berechne die entsprechenden Tsunamis. Wellen von 6 Metern Höhe könnten dabei Nordwesteuropa erreichen. Ich stelle eine neue Methode vor, mit der große submarine Erdrutsche mit Hilfe eines Netzes aus Tiltmetern erkannt werden können. Diese Methode könnte in einem Tsunami-Frühwarnsystem angewendet werden. Sie basiert darauf, dass die Bewegung von großen Sedimentmassen während einer Rutschung eine dauerhafte Verformung der Erdoberfläche auslöst. Ich berechne diese Verformung und das einhergehende Tiltsignal. Im Falle der hypothetischen Spitzbergen-Rutschung sowie für das Storegga-Ereignis erhalte ich Amplituden von mehr als 1000 nrad. Die Wellenhöhe von Erdrutschtsunamis wird in erster Linie von dem Produkt aus Volumen und maximaler Rutschungsgeschwindigkeit (dem Tsunamipotential einer Rutschung) bestimmt. Ich führe eine Inversionsroutine vor, die unter Verwendung von Tiltdaten den Ort und das Tsunamipotential einer Rutschung bestimmt. Die Genauigkeit dieser Inversion und damit der vorhergesagten Wellenhöhe an der Küste hängt von dem Fehler der Tiltdaten, der Entfernung zwischen Tiltmeter und Rutschung sowie vom Tsunamipotential ab. Letztlich bestimme ich die Anwendbarkeitsreichweite dieser Methode, indem ich sie auf bekannte Rutschungsereignisse weltweit beziehe.

The purpose of this study is to determine the most suitable remediation techniques via engineering geological assessment of the landslide that occurred during the construction of Artvin-Savsat Junction - Meydancik Provincial Road at Km: 12+200 in an active landslide area. For this purpose, the geotechnical parameters of the mobilized geological material which is colluvium along the sliding surface were determined by back analyses of the landslide at three geological sections. The landslide were then modeled along the most representative section of the study area by considering the landslide mechanism, the parameters determined from the geotechnical investigations, the size of the landslide and the location of the slip circle. In addition, pseudostatic stability analyses were performed comprising the earthquake potential of the site. The most suitable slope remediation technique was determined to be a combination of surface and subsurface conditions. A static analysis of the landslide shall also be performed through utilizing finite element analyses. The static analyses were compared with the inclinometer readings in the field to verify the direction of the movement. Consequently, shear strength parameters were specified as c = 0 kPa and f = 10&deg / for the landslide material and pre-stressed anchoring and rock buttressing were considered as a remediation method.

A numerical study aimed at probabilistically assessing the coastal hazard posed by tsunamis induced by one-dimensional submarine rigid landslides that experience translational failure is presented. The numerical model here utilized is the finite-difference recreation of a linear, fully dispersive mild-slope equation model for wave generation and propagation. This recreated model has the capability to simulate submarine landslides that detach into multiple rigid pieces as failure occurs. An ad-hoc formulation describing the combined space-time coherency of the landslide is presented. Monte Carlo simulations are employed, with an emphasis on the shoreward-traveling waves, to construct probability of exceedance curves for the maximum dimensionless wave height from which wave statistics can be extracted. As inputs to the model, eight dimensionless parameters are specified both deterministically in the form of parameter spaces and probabilistically with normal distributions. Based on a sensitivity analysis, the results of this study indicate that submarine landslides with large width to thickness ratios and coherent failure behavior are most effective in generating tsunamis. Failures modes involving numerous slide pieces that fail in a very compact fashion, however, were observed to induce bigger waves than more coherent landslides. Rapid weakening in tsunami generation potential for some of the parameter combinations suggests that the hazard posed by submarine landslide tsunamis is strongly dependent on source features and local conditions and is only of concern for landslides of substantial dimensions.

This thesis seeks to analyze the occurrence and behavior of rainfall-triggered landslides in coastal British Columbia. In particular, it focuses on the analysis of landslide temporal and spatial distributions occurrence and their magnitudes, and considers the major factors that influence regional landslide behavior. Implicit in the research is the understanding that the landscape of coastal BC is managed, and that landslides, in addition to occurring naturally may be caused by, and certainly impact, resources that are important to humankind. Underlying each chapter is the rationale that by better understanding the causes of, and controls on landslide occurrence and magnitude, we can reduce the impacts and lower the associated risk. Statistical magnitude-frequency relationships are examined in coastal BC. Observations suggest that landslides in coastal British Columbia tend to a larger size until about 10,000 m2 in total area. At this point larger landslides are limited by landscape controls according to a power law. Probabilistic regional hazard analysis is one logical outcome of magnitude-frequency analysis and a regional mass movement hazard map for Vancouver Island is presented. Physiographic controls on statistical magnitude-frequency distributions are examined using a cellular automata based model and results compare favorably to actual landslide behavior: modeled landslides bifurcate at local elevation highs, deposit mass preferentially where the local slopes decrease, find routes in confined valley or channel networks, and, when sufficiently large, overwhelm the local topography. The magnitude-frequency distribution of both the actual landslides and the cellular automata model follow a power law for magnitudes higher than 10,000 m2 - 20,000 m2 and show a flattening of the slope for smaller magnitudes. The results provide strong corroborative evidence for physiographic limitations related to slope, slope distance and the distribution of mass within landslides. The physiographic controls on landslide magnitude, debris flow mobility and runout behavior is examined using detailed field and air photograph analysis. The role of slope on deposition and scour is investigated and a practical method for estimating both entrainment and runout in the field, as well as in the GIS environment, is presented. Further controls on landslide mobility, including the role of gullies and stream channels, roads and benches and intact forests, are considered. The role of landslides in controlling landscape physiography is also examined. In particular, it is determined that moderate-sized landslides do the most work transporting material on hillslopes, defined by a work peak, and that magnitude varies based on local physiography and climate. Landslides that form the work peak are distinct from catastrophic landslides that are themselves formative and system resetting. The persistence time for debris slides/debris flows and rock slides/rock avalanches is calculated over six orders of magnitude and an event is considered catastrophic when it persists in the landscape ten times longer than the population of landslides that form the work peak. A detailed case study examines meteorological controls on landslide occurrence and the role of extreme weather is considered. A critical onset of landslide triggering rainfall intensity is determined to be between 80 mm and 100 mm in 24 hours and wind is determined to result in increased local precipitation. The role of rain-on-snow is also evaluated and determined to be crucial to landslide occurrence. Finally, a conceptual model of landslide-induced denudation for coastal mountain watersheds spanning 10,000 years of environmental change is presented. Recent human impacts are calculated for landslide frequencies over the 20th century. The impact of logging during the last 100 years is unambiguous; logging induced landslides almost doubles the effect frequency of the wettest millennia in the last 10,000 years. This suggests that the impact of logging outpaces that of climatic change. Debris slides and debris flows are estimated to have resulted in a landscape lowering of 0.7 m across the Vancouver Island during the last 10,000 years.

This thesis seeks to analyze the occurrence and behavior of rainfall-triggered landslides in coastal British Columbia. In particular, it focuses on the analysis of landslide temporal and spatial distributions occurrence and their magnitudes, and considers the major factors that influence regional landslide behavior. Implicit in the research is the understanding that the landscape of coastal BC is managed, and that landslides, in addition to occurring naturally may be caused by, and certainly impact, resources that are important to humankind. Underlying each chapter is the rationale that by better understanding the causes of, and controls on landslide occurrence and magnitude, we can reduce the impacts and lower the associated risk. Statistical magnitude-frequency relationships are examined in coastal BC. Observations suggest that landslides in coastal British Columbia tend to a larger size until about 10,000 m2 in total area. At this point larger landslides are limited by landscape controls according to a power law. Probabilistic regional hazard analysis is one logical outcome of magnitude-frequency analysis and a regional mass movement hazard map for Vancouver Island is presented. Physiographic controls on statistical magnitude-frequency distributions are examined using a cellular automata based model and results compare favorably to actual landslide behavior: modeled landslides bifurcate at local elevation highs, deposit mass preferentially where the local slopes decrease, find routes in confined valley or channel networks, and, when sufficiently large, overwhelm the local topography. The magnitude-frequency distribution of both the actual landslides and the cellular automata model follow a power law for magnitudes higher than 10,000 m2 - 20,000 m2 and show a flattening of the slope for smaller magnitudes. The results provide strong corroborative evidence for physiographic limitations related to slope, slope distance and the distribution of mass within landslides. The physiographic controls on landslide magnitude, debris flow mobility and runout behavior is examined using detailed field and air photograph analysis. The role of slope on deposition and scour is investigated and a practical method for estimating both entrainment and runout in the field, as well as in the GIS environment, is presented. Further controls on landslide mobility, including the role of gullies and stream channels, roads and benches and intact forests, are considered. The role of landslides in controlling landscape physiography is also examined. In particular, it is determined that moderate-sized landslides do the most work transporting material on hillslopes, defined by a work peak, and that magnitude varies based on local physiography and climate. Landslides that form the work peak are distinct from catastrophic landslides that are themselves formative and system resetting. The persistence time for debris slides/debris flows and rock slides/rock avalanches is calculated over six orders of magnitude and an event is considered catastrophic when it persists in the landscape ten times longer than the population of landslides that form the work peak. A detailed case study examines meteorological controls on landslide occurrence and the role of extreme weather is considered. A critical onset of landslide triggering rainfall intensity is determined to be between 80 mm and 100 mm in 24 hours and wind is determined to result in increased local precipitation. The role of rain-on-snow is also evaluated and determined to be crucial to landslide occurrence. Finally, a conceptual model of landslide-induced denudation for coastal mountain watersheds spanning 10,000 years of environmental change is presented. Recent human impacts are calculated for landslide frequencies over the 20th century. The impact of logging during the last 100 years is unambiguous; logging induced landslides almost doubles the effect frequency of the wettest millennia in the last 10,000 years. This suggests that the impact of logging outpaces that of climatic change. Debris slides and debris flows are estimated to have resulted in a landscape lowering of 0.7 m across the Vancouver Island during the last 10,000 years.

Mass movement can be activated by earthquakes, rapid snowmelt, or intense rainstorms in conjunction with gravity. Whereas mass movement plays a major role in the evolution of a hillslope by modifying slope morphology and transporting material from the slope to the valley, it is also a potential natural hazard. Determining the morphology of the mountain slopes and the relationships of frequency and magnitude of landslides are fundamental to understanding the role of landslides in the study of landscape evolution, and hazard assessment. Characteristics of the geomorphic zones in a periglacial landscape were evaluated by plotting local slopes and the drainage areas in Paonia-McClure Pass area of western Colorado. The study suggested that the steepness and concavity of mountain slopes and stream channels in the study area are related by an exponential equation. Seven hundred and thirty five shallow landslides (<160,000 m2) from the same study area were mapped to determine the frequency-magnitude relationships of shallow landslides and to develop an optimum model of mapping susceptibility to landslides. This study suggests that the frequency-magnitude of the landslides in Paonia-McClure Pass area are related by a double pareto equation with values α= 1.1, and β = 1.9 for the exponents. The total area of landslides is 4.8x10⁶ m² and the total volume of the landslides is 1.4x10⁷ m³. The areas (A) and the volumes (V) of landslides are related by V = 0.0254xA^1.45. The frequency-magnitude analysis shows that landslides with areas ranging in size from 1,600 m2 - 20,000 m2 are the most hazardous landslides in the study area. These landslides are the most frequent and also do a significant amount of geomorphic work. Three quantitative approaches: weight of evidence; fuzzy logic; and logistic regression; were employed to develop models of mapping landslides in western Colorado. The weight of evidence approach predicted 78 percent of the observed landslides, the fuzzy-logic approach also predicted 78 percent of the observed landslides, and the logistic regression approach predicted 86 percent of the observed landslides.