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Impacted by the global COVID-19 crisis and its sociopolitical shockwaves, pre-existing physical mobility patterns and traditional study-abroad experiences have been thoroughly disrupted and transformed. US higher education institutions have utilized the practices of transnational hybrid learning to sustain the quality and progress of international higher education. This article focuses on a study programme that integrates online and offline learning in Shanghai, China, coordinated by a non-profit international higher education exchange agency in partnership with eight US universities and one Chinese university from August 2020 to June 2021. Through semi-structured interviews with 32 Chinese students, this article finds that transnational hybrid learning offers students greater geographical and time flexibility, room for self-paced learning and controls on health risks while ensuring face-to-face interactions and physical activities. In addition, the localization of international education might motivate Chinese students to consider their career development that balances their interests and career prospects in response to political and economic uncertainties. However, the communication and learning gaps, weakened intercultural communication, sustained sociocultural alienation and contradictions of two sociocultural contexts render the overall programme experience less desirable. In sum, this article identifies the potential of virtual mobility beyond geographical and policy constraints in transforming and reimagining the practices of transnational higher education in a post-pandemic world.

Heavy metal contamination and its detrimental health effects are a growing concern globally. Several metal mitigation systems and regulatory approaches have been implemented to minimize the negative impacts on human health. However, none of these function at maximum efficiency, mainly due to the lack of accurate information about metal speciation. Therefore, there is a critical need to develop novel, cheap, efficient, and robust metal detecting sensors. In this study, we describe the application of a nanopipet based electrochemical sensor to detect aqueous Cd(ii) ions. The inner radius of our nanopipets is ∼300 nm, and the fundamental mechanism behind our sensor's response is ion transfer between two immiscible electrolyte solutions (ITIES). The absence of redox behavior makes ITIES an excellent, attractive electrochemical tool to study various ions in aqueous solutions. In this study, we used 1,10-phenanthroline as our ionophore in the organic phase (dichloroethane) to facilitate the transfer of Cd(ii) ions from the polar aqueous phase to the less polar organic phase. Unlike previous studies, we characterized our nanopipet in complicated matrices, including, but not limited to, tris buffer and artificial seawater. We performed quantitative assessments to determine our sensor's limit of detection, stability, sensitivity, and selectivity. We further show that our nanosensor can detect free Cd(ii) ions in the presence of strong complexing agents such as ethylenediaminetetraacetic acid, 2,3-dimercaptosuccinic acid

With climate change causing increased extreme weather events, megacities worldwide are experiencing unprecedentedly devastating floods and recurring flood damage. Investigating global megacities’ increased disposition to flooding will aid in developing sustainable flood-risk-management frameworks. Many studies have been conducted on the association between land-cover types and flood consequences, but few on investigating urban expansion patterns’ correlation with flood hazard and risk. This study examines the correlation between urban expansion patterns and increased flood hazards. Twelve megacities throughout the world were selected for this study. After exploring the possibility of the megacities having experienced flooding, we qualified their patterns of urban expansion and their potential to influence the elements of flood risk. Our results revealed that edge expansion and leapfrogging patterns had a strong positive correlation with statistical significance with flood hazard, while infilling had a weak positive correlation that showed no statistical significance with flood hazard. Further, we found that the megacities have all experienced devastating floods in the past two decades. Flood risk frameworks need to account for the impact of these patterns, and future urban planning designs and policies need to incorporate flood risk frameworks that account for patterns of urban expansion.

The Ocona River Valley, in the Arequipa Department in southern Peru, extends over 150 km from the Pacific coast to its headwaters in the Andes Mountains. While traditionally sparsely populated with farmers and crawfish fishermen, the valley has seen a large population growth in the last 20 years as small gold mines have developed. This change poses the opportunity to evaluate three research questions: How do geologic hazards and risks increase from mining activity? How does unplanned urban development affect risks? How do landforms restrict development and thereby increase risks? The combination of climate, topographic, and hydrologic conditions result in widespread hazards from debris flows, collapsible soils, erosion, rockfall, flooding, and liquefaction. We have developed maps of these hazards for three communities where mines have recently developed, Secocha, Alto Molino, and San Juan de Chorunga, and then we conducted a risk analysis for changing conditions, termed “Risk–Risk” analysis. Because of the lack of vegetation on mountain slopes, mining operations typically only affect rockfall hazards, mostly in the immediate vicinity of the mines and in the nearby runout zones. However, increased population and associated settlement infrastructure is constrained by steep slopes and regularly-flooded valleys, so residents live in fan and terrace areas with substantially increased risks from debris flows and collapsible soils and moderately increased risks from flooding and rockfall.

A scientific hazard zoning of debris flows can ensure that human activities are not performed therein, thereby reducing economic loss as much as possible. In this study, by considering the formation background conditions of mountain hazards and dynamic rainfall conditions, the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model (TRIGRS) and Flow path assessment of gravitational hazards at a Regional scale (Flow-R) are organically combined to establish a new coupled model for debris flow dynamic hazard assessment from the viewpoint of landslides providing the material source of debris flows. The coupled model was employed in Qingping township, Sichuan province of China, which was severely damaged by the “5·12” Wenchuan earthquake in 2008. Evaluation results show that the accuracy of the coupled model is 87.98%, which is significantly higher than that of the static Flow-R model (75.51%). This study not only considers the effect of the formation condition of mountain hazards and rainfall-induced shallow landslides on the source of debris flows, but also realises real-time hazard assessment and prediction of group-occurring debris flows. The coupled model used in this study provides a new perspective and is paramount for improving the accuracy and reliability of debris flow hazard assessment.

Postural orthostatic tachycardia syndrome (POTS) is an autonomic disorder that affects multiple organs, including the gastrointestinal system. These patients often have multiple GI complaints with a severe impact on their quality of life. GI dysmotility patterns in POTS remains poorly understood and difficult to manage. The aim of this study was to investigate the diagnostic yield of wireless motility capsule in patients with gastrointestinal symptoms and POTS, with use of a symptomatic control group without POTS as a reference. We retrospectively reviewed the charts of patients who had both autonomic testing and wireless motility capsule between 2016 and 2020. The two groups were divided into those with POTS and those without POTS (controls) as diagnosed through autonomic testing. We compared the regional transit times and motility patterns between the two groups using the data collected from wireless motility capsule. A total of 25% of POTS patients had delayed small bowel transit compared to 0% of non-POTS patients (p = 0.047). POTS patients exhibited hypo-contractility patterns within the small bowel, including decreased contractions/min (2.95 vs. 4.22, p = 0.011) and decreased motility index (101.36 vs. 182.11, p = 0.021). In multivariable linear regression analysis, migraine predicted faster small bowel transit (p = 0.007) and presence of POTS predicted slower small bowel transit (p = 0.044). Motility abnormalities among POTS patients seem to affect mostly the small bowel and exhibit a general hypo-contractility pattern. Wireless motility capsule can be a helpful tool in patients with POTS and GI symptoms as it can potentially help guide treatment.

Characterizing the zone of damaged and altered rock surrounding a fault surface is highly relevant to geotechnical and geo-environmental engineering works in the subsurface. Evaluating the uncertainty associated with 3D geologic modeling of these fault zones is made possible using the popular and flexible input-based uncertainty propagation approach to geologic model uncertainty assessment – termed probabilistic geomodeling. To satisfy the automation requirements of probabilistic geomodeling while still preserving the key geometry of fault zones in the subsurface, a clear and straightforward modeling approach is developed based on four geologic inputs used in implicit geologic modeling algorithms (surface trace, structural orientation, vertical termination depth and fault zone thickness). The rationale applied to identifying and characterizing the various sources of uncertainty affecting each input are explored and provided using open-source codes. In considering these sources of uncertainty, a novel model formulation is implemented using prior geologic knowledge (i.e., empirical and theoretical relationships) to parameterize modeling inputs which are typically subjectively interpreted by the modeler (e.g., vertical termination depth of fault zones). Additionally, the application of anisotropic spherical distributions to modeling disparate levels of information available regarding a fault zone's dip azimuth and dip angle is demonstrated, providing improved control over the structural orientation uncertainty envelope. The probabilistic geomodeling approach developed is applied to a simple fault zone geologic model built from historically available geologic mapping data, allowing for a visual comparison of the independent contributions of each modeling input on the combined model uncertainty, revealing that vertical termination depth and structural orientation uncertainty dominate model uncertainty at depth, while surface trace uncertainty dominates model uncertainty near the ground surface. The method is also successfully applied to a more complex fault network model containing intersecting major and minor fault zones. The impacts of the model parameterization choices, the fault zone modeling approach and the effects of fault zone interactions on the final geologic model uncertainty assessment are discussed.

Synthetic Aperture Radar (SAR) interferometry is a formidable technique to monitor surface deformation with a millimeter detection resolution. This study applies the Persistent Scatter-Interferometric Synthetic Aperture Radar (PSInSARTM) technique to measure ground subsidence related to a twin-tunnel excavation in downtown Los Angeles, USA. The PSInSARTM technique is suitable for urban settings because urban areas have strong reflectors. The twin tunnels in downtown Los Angeles were excavated beneath a densely urbanized area with variable overburden depths. In practice, tunneling-induced ground settlement is dominantly vertical. The vertical deformation rate in this study is derived by combining Line of Sight (LOS) deformation velocities obtained from SAR images from both ascending and descending satellite orbits. Local and uneven settlements up to approximately 12 mm/year along the tunnel alignment are observed within the allowable threshold. No severe damages to aboveground structures were reported. Furthermore, ground movements mapped one year before tunnel construction indicate that no concentrated ground settlements pre-existed. A Machine Learning (ML)-based permutation feature importance method is used for a parametric study to identify dominant factors associated with the twin-tunneling induced uneven ground subsidence. Six parameters are selected to conduct the parametric study, including overburden thickness, i.e., the thickness of artificial fill and alluvium soils above the tunnel springline, the distance between the two tunnel centerlines, the depth to the tunnel springline, building height, the distance to the tunnel, and groundwater level. Results of the parametric analysis indicate that overburden thickness, i.e., the thickness of artificial fill and alluvium soils above the tunnel springline, is the dominant contributing factor, followed by the distance between tunnel centerlines, depth to the tunnel springline, and building height. Two parameters, the distance to the tunnel, and the groundwater level, play lesser essential roles than others. In addition, the geological profile provides comprehension of unevenly distributed ground settlements, which are geologically sensitive and more concentrated in areas with thick artificial fill and alluvium soils, low tunnel depth, and high groundwater levels.

Landslide hazards occur throughout the world. There were 18,000 deaths worldwide due to landslides between 1998 and 2017 (World Health Origination, n.d.). Furthermore, landslides are often ...

Outburst sediments are widely distributed in the Upper Jinsha River in the Southeastern (SE) Tibetan Plateau. In order to understand the sedimentary characteristics of these sediments, gravel fabric, particle size distribution and quartz sand surface textures were used to analyze the mesotextures and microtextures of the Xuelongnang outburst sediments. It was determined that these sediments usually have a short transport distance, and are distributed over a distance of approximately 3.5 km. The gravel fabric and particle size distribution analysis represent the different mesotextures with different transport distances and suggest gradually changing hydrodynamic conditions. The statistical data of quartz surface textures exhibit the transformation process of quartz sands by outburst flood. The variation from abundant sub-angular shapes (> 75%); to common V-shaped percussion cracks, solution crevasse, medium relief, and chatter marks (50% to 75%); to rare meandering ridge, underwater polished surface, large conchoidal fracture (> 100 μm), directional etch pits, and crystalline overgrowths (< 5%), present the features in different combinations to other sedimentary environments. The microtexture characteristics of landslide-dam outburst deposits are also consistent with those of the mesotextures. As the distance from the residual dam increased, the quartz grain microtextures showed gradual or abrupt changes, such as increased frequencies of V-shaped percussion cracks, decreased frequencies of the adhering particles, and growth of the solution crevasses. These findings could potentially be used as a discriminant mark to distinguish outburst sediment from other types of sediments, e.g., subaqueous, eolian, glacial, etc.

Backward erosion piping (BEP) is a common hazard along artificial levees in the Lower Mississippi Valley (LMV). This study applies an empirical assessment of overbank deposit thickness, als...

Landslide-dammed lake outburst floods (LLOFs) may pose serious safety threats to nearby residents and their livelihoods, as well as cause major damages to the downstream areas in mountainous regions. This study presents the Diexi ancient landslide-dammed lake (DALL) in the Upper Minjiang River at the eastern margins of the Tibetan Plateau, which was known to an estimated previous maximal lake area of 1.1 × 107 m2 and an impounded volume of 2.9 × 109 m3. Then, at approximately 27 ka BP, the ancient landslide dam failed and catastrophic LLOFs occurred. It was determined that the peak discharge of the Diexi ancient LLOFs could be reconstructed using regression, parametric, and boulder competence approaches. The reconstructed maximum peak discharge might be 72,232.66 m3/s, with an average velocity of 17.23 m/s, indicating that the Diexi ancient LLOFs were the most gigantic outburst floods to occur in the Upper Minjiang River Valley since the Late Pleistocene Period. The differences in the widths and slopes within the former and the later reaches of the dam indicated that the geomorphic influences on the river channel resulting from the DALL and its LLOFs have existed for tens of thousands of years. These findings were of major significance in deepening the understanding of the existence and disappearances of important river-knickpoints on a time scale of tens of thousands of years.

Backward erosion piping (BEP) is a form of internal erosion and common failure mode along levees. Despite over a century of study, predicting where BEP will initiate is still a considerable challenge. This study proposes a new model for predicting BEP initiation focused on the widest range of applicability. A logit model is trained using data from 15 sites along the Lower Mississippi Valley. The included parameters are independent of geography or geological regime and exhibit recorded or suspected correlations to BEP. Three significant factors (95% confidence interval) are retained for the final model: cumulative clay thickness within the blanket (odds ratio (OR) 0.520), critical gradient (OR 0.001) and exit gradient (OR 63.15). Receiver operating characteristics analysis indicates an area under the curve of 0.823. The model demonstrates 71% classification accuracy, a dramatic 10% increase over previous logit model attempts. Model results are most applicable within 150 m of the levee toe to predict new incidents of BEP initiation. The final model is a useful tool for BEP assessment and mitigation efforts.

Postural orthostatic tachycardia syndrome (POTS) is an autonomic disorder that affects multiple organs, including the gastrointestinal system. These patients often have multiple GI complaints with a severe impact on their quality of life. GI dysmotility patterns in POTS remains poorly understood and difficult to manage.The aim of this study was to investigate the diagnostic yield of wireless motility capsule in patients with gastrointestinal symptoms and POTS, with use of a symptomatic control group without POTS as a reference.We retrospectively reviewed the charts of patients who had both autonomic testing and wireless motility capsule between 2016 and 2020. The two groups were divided into those with POTS and those without POTS (controls) as diagnosed through autonomic testing. We compared the regional transit times and motility patterns between the two groups using the data collected from wireless motility capsule.A total of 25% of POTS patients had delayed small bowel transit compared to 0% of non-POTS patients (p = 0.047). POTS patients exhibited hypo-contractility patterns within the small bowel, including decreased contractions/min (2.95 vs. 4.22, p = 0.011) and decreased motility index (101.36 vs. 182.11, p = 0.021). In multivariable linear regression analysis, migraine predicted faster small bowel transit (p = 0.007) and presence of POTS predicted slower small bowel transit (p = 0.044).Motility abnormalities among POTS patients seem to affect mostly the small bowel and exhibit a general hypo-contractility pattern. Wireless motility capsule can be a helpful tool in patients with POTS and GI symptoms as it can potentially help guide treatment.

The 2008 Wenchuan earthquake triggered tens of thousands of landslides, resulting in rich loose materials for the 8.13 debris flows. Longchi Town in southwest China’s Sichuan Province was o...

The accuracy of a debris-flow susceptibility assessment model can not be achieved to an acceptable level without rigorously selecting/processing model input parameters and reliably validating the results with ground truth. In this study, a modified logistic regression model was applied to examine the debris-flow susceptibility in the semi-arid mountainous areas of the southeast Tibetan Plateau, taking the case of the Benzilan-Changbo segment of the Jinsha River. The logistic regression model validation was supported by a field investigation and interpreting aerial photographs. The frequency ratio method was adapted for the sensitivity analysis of ten predisposing factors, including a factor of human activities that has never been considered in previous studies for the selected study area. The model with the highest prediction accuracy (83%) was obtained by comparing 55 possible combinations of the ten factors evaluated using a receiver operating characteristic curve technique. Composite analysis and random sample testing were also conducted to verify the reliability of the susceptibility assessment. The prediction results showed that the actual debris-flow area accounted for 92% of the total predicted debris-flow area. In summary, this study reveals that: (1) the highest susceptibility area was mainly distributed in the northeast and middle riparian zones, partially scattered in the southwest. Human activity was found to be closely related to the probability of debris flow occurrences; (2) under the two situations of independent and index combination participation evaluation, the performances of the same related factors showed largely different effects on the assessment results, which reflected the interrelation and interaction of the factors causing the debris flow; (3) the accuracy of the modified logistic regression model increased by 15%, when compared with the index entropy model in a previous study, and the reasons for this were discussed in the current study. The modified model, along with its enhanced validation process, could be easily extended to other regional mass movement susceptibility analyses.

A large number of the landslide dams located on the major rivers at the southeastern margin of the Tibetan Plateau have been previously identified through remote sensing analysis and field investigations. The Xuelongnang paleolake was one of the lakes formed by these landslide dams in the upper Jinsha River, where the association of a relict landslide dam, lacustrine sediment, and outburst sediment is well preserved. This preservation provides an opportunity to better understand the formation, evolution, and longevity of a large landslide-dammed lake in the upper Jinsha River. It was inferred that the Xuelongnang dammed lake may have been formed by an earthquake-induced paleoavalanche. The surface area of the lake at its peak was estimated at 7.0 × 106 m2, and the corresponding volume was approximately 3.1 × 108 m3. Two outburst flood events were determined to have occurred during the life span of the lake. Based on the 18 ages obtained from optically stimulated luminescence (OSL) and carbon-14 (14C) dating combined with stratigraphic sequences observed in the field, the paleolandslide-dammed lake was formed at approximately 2.1 ka and subsequently breached locally. The dammed lake was sustained for a period of some 900 years based on the chronological constraining. This study confirms that a major landslide-dammed lake can be sustained for at least hundreds of years and breached by several dam breaks in multiple periods, which contributed to the preservation of the knickpoints at millennial scale along the major rivers in the study area.

There is increasing recognition of the value from incorporating local and scientific hazard knowledge for disaster risk management, but practical integration remains limited. Much management activity remains underpinned by information deficit thinking, which inherently valorizes scientific knowledge and devalorizes local knowledge. To move away from deficit thinking, we develop the concept of “cross-validation” as a step toward integrating types of hazard knowledge. Rather than science validating local knowledge, cross-validation is multidirectional and focuses on identifying the strengths of each knowledge type and their areas of complementarity, to achieve a more complete hazard understanding. We applied the cross-validation approach to analyze geohazard knowledge in two case study sites in southern Peru. We identified substantial agreement around the most prominent local hazards, providing mutual reinforcement of each type of knowledge. We also identified complementary facets, where strengths in one knowledge type compensated for limitations in the other. The cross-validation approach shows promise as a first step toward incorporating knowledge, providing an opportunity to establish the foundation from which practical integration can build.

This study reveals that a distinct damming incident occurred during a prehistory period (approximately 30 ka BP) in the upper Minjiang River, at the southeastern margin of the Tibetan Plateau, which formed a giant dammed lake. It can be inferred that paleoseismic induced major landslides were the direct cause of the river damming. The dammed lake breached and caused a large outburst flood at about 27 ka BP. Between the section of the prehistoric ancient dam-body and its downstream areas (5 km), an abundance of diamicts consisting of a poor-sorted wide range of particle sizes, including gravel, sand, and minor silt and clay, have been observed. The outburst deposits in the Diexi area maybe divided into two periods: the thick outburst deposits represented the earlier and largest dammed-break event, and the deposit terrace was due to the subsequent and smaller dammed-break event. The sedimentary structures of the outburst deposits included imbrication, cavitation, matrix, and massive structures, as well as gravel support-stacked structures. Furthermore, a special sedimentary structure became evident, consisting of a rhythmite interbedded structure composed of a coarser gravel layer, and a finer sand and gravel layer, with no sand lens formed within the layers. This special structure can potentially provide an important original criterion for the outburst deposits in this area. The two types of facies associations have been recorded which indicate contrasting sediment transport regimes. The characteristics of boulder facies were most likely associated with hyperconcentrated flood flows. However, the finer-grained Gm/Gfm/GRm facies, which overlaid the Bcm facies, were determined to represent the waning stage of the flooding events. The delicate structures, as well as the absence of coarse components in the Sh facies, indicated an episode of accumulations, which was subsequent to the deposition of the underlying Bcm facies. The results of this study potentially provide important implications for the interpretation of the diamicts in the Diexi area. The grain-size frequency curves of the outburst deposits in the Diexi area were found to all be bimodal (a main peak and an inconspicuous sub-peak). These findings indicated a poorly sorted sedimentary structure. It was found that, from the upstream segment to the downstream segment, the gravel sediment became gradually lessened, while the fine-grained sediment increased. Additionally, the outburst flood hydrodynamic intensity was found to have gradually become weakened.

Introduction: Choledocholithiasis, the presence of gallstones in the common bile duct (CBD), commonly presents as abdominal pain, jaundice, and an elevated bilirubin and is further evaluated with abdominal ultrasound and consideration of MRCP or ERCP based on clinical predictors. Herein, we describe a novel approach to abdominal pain and hyperbilirubinemia due to SARS-CoV-2 (Covid 19) which led to additional imaging and an incidental malignancy diagnosis. Case Description/Methods: A 52-year old man with a history of chronic hepatitis B virus presented with one week of abdominal pain and jaundice. Admission labs were significant for a total bilirubin of 4.1mg/dL, and positive screening for Covid 19. Abdominal ultrasonography demonstrated a dilated CBD to 1.7cm. His presentation was highly suggestive of choledocolithiasis by ASGE criteria, but ERCP was deferred to abide by hospital-wide precautions at the time. As a result, the patient underwent confirmatory testing with MRCP, which showed no choledocholithiasis but demonstrated a 4.1cm enhancing lesion abutting the pancreatic body. Subsequent abdominal computed tomography found a 3.3cm soft tissue density encasing the celiac axis, suggesting lymphoma. Endoscopic ultrasound (EUS)-guided biopsy of the pancreatic lesion demonstrated an unreported 3.1cm liver mass, which was biopsied. On further review of imaging, the liver mass was not appreciated on ultrasound, CT or MRCP. It was suspected that the hyperbilirubinemia was likely due to this intrahepatic mass, described as poorly differentiated adenocarcinoma. Due to the early diagnosis he was able to be discharged and follow up with oncology to better guide his future directed therapy. Discussion: The Covid 19 pandemic forced all aspects of healthcare to adapt. Given gastroenterology's invasive nature this also encouraged gastroenterologists to consider alternative pathways of treatment aside from the published algorithms in place. This case demonstrates how deviating from the ASGE guidelines resulted in a cascade of diagnostics which led to an eventual malignancy diagnosis which may have been otherwise missed or delayed. Guidelines are established on large sets of data and patient prognostic indicators which to our knowledge have not considered infection status or isolation needs. Further research in this area may result in amending guidelines to address isolation status and reminds practitioners to consider the patient before them and their unique patient needs. (Figure Presented) .

The distribution of volcanogenic massive sulfide (VMS), porphyry-epithermal, Alaska-type ultramafic-mafic complexes, intrusion-related Au, and granitoid Sn-W ore deposits in southwest Alaska supports current metallogenic models linking the formation of these deposit types to the emplacement of different suites of igneous rocks during the evolution of this convergent plate margin. Regional-scale aeromagnetic data provide a continuous set of observations over the deposits and show contrasting patterns over the igneous rock suites hosting the various deposit types. Combined with surface geologic data and regional metallogenic constraints, aeromagnetic data—filtered to enhance the anomalous magnetic field and map magnetic domains—were used to produce a mineral potential map across this accreted island-arc setting. The reduced-to-pole, upward continuation, and total horizontal gradient transform maps show anomalies that could represent porphyry-epithermal deposits within the intraoceanic- and continental-arc terranes. The tilt derivative transform highlights lineaments within the back arc that may represent zones with potential for VMS deposits. The truncations of tilt derivative lineaments outline a major magnetic domain boundary between the back-arc and craton margin, which is prospective for granitoid Sn-W deposits. Annular tilt derivative highs outline granitoids that could be associated with intrusion-related Au deposits within the craton margin. Shallow, magnetite-rich Alaska-type ultramafic-mafic complexes are mapped by their short-wavelength, high-amplitude anomalies. Successful mineral potential mapping across southwestern Alaska as performed in the present study suggests that filtered aeromagnetic data can be effectively used in mineral exploration in convergent continental margin settings.

During high-water events, backward erosion piping poses a serious threat to the stability of artificial levee structures. Sand boils forming on the land-side of levees are presently the best indicator of active backward erosion piping, but surveying these features across extensive levee works during flood events is time and resource intensive. Using geographic information system (GIS) technology and a probabilistic statistical analysis, this study assimilates geologic, environmental, and spatial relationship data to generate models to predict the likelihood of sand boil development. Data such as unfavorable geologic orientation, normalized difference vegetation index (NDVI), and blanket thickness are assigned to over 100 km of levees along the Waal and IJssel rivers of the Netherlands. A binary logistic regression is then applied to identify factors with statistically significant relationships to historical sand boil locations, and generate a predictive model using the significant factors. The logit models generally support previous findings indicating unfavorable orientation of geologic deposits and NDVI have a significant relationship with the spatial occurrence of sand boils. Despite this statistical significance, the best predictive model yields an accuracy only 10.83% higher than a random prediction model. Given variance in factors between models, sand boil formation appears to be dependent on a combination of conditions experienced on a local scale. Furthermore, attempting to predict sand boils using a single logit model across multiple geologic environments reduces the influence of region-specific conditions, yielding a less effective model than evaluating the systems individually.

Incessant flooding is a major hazard in Lagos State, Nigeria, occurring concurrently with increased urbanization and urban expansion rate. Consequently, there is a need for an assessment of Land Use and Land Cover (LULC) changes over time in the context of flood hazard mapping to evaluate the possible causes of flood increment in the State. Four major land cover types (water, wetland, vegetation, and developed) were mapped and analyzed over 35 years in the study area. We introduced a map-matrix-based, post-classification LULC change detection method to estimate multi-year land cover changes between 1986 and 2000, 2000 and 2016, 2016 and 2020, and 1986 and 2020. Seven criteria were identified as potential causative factors responsible for the increasing flood hazards in the study area. Their weights were estimated using a combined (hybrid) Analytical Hierarchy Process (AHP) and Shannon Entropy weighting method. The resulting flood hazard categories were very high, high, moderate, low, and very low hazard levels. Analysis of the LULC change in the context of flood hazard suggests that most changes in LULC result in the conversion of wetland areas into developed areas and unplanned development in very high to moderate flood hazard zones. There was a 69% decrease in wetland and 94% increase in the developed area during the 35 years. While wetland was a primary land cover type in 1986, it became the least land cover type in 2020. These LULC changes could be responsible for the rise in flooding in the State.

The “East Muddy Creek Landslide Complex” in Gunnison County, Colorado, USA destroyed Colorado State Highway 133 from 1986 to 1987 and has been investigated over decades during different periods of reactivation. This paper presents a case study of novel landslide activity recognition related to the landslide complex using Advanced Land Observing Satellite-1 (ALOS-1) Interferometric Synthetic Aperture Radar (InSAR) analysis. We compare the result from ALOS-1 InSAR analysis to landslide recognition investigations from traditional field methods for ground motions at a watershed scale. Line of Sight (LOS) velocity mapping is used to characterize displacement zonation, failure modes, and hazard assessment activities. Mass wasting estimates using existing geological modeling are discussed in terms of potential of landslide element dynamics. ALOS-1 InSAR analysis reveals newly detected ground displacement at very slow to extremely slow velocities with a significantly increased spatial extent. The implications of expanded displacement activity in the context of landslide geomorphology, mountain denudation, exhumation, and future monitoring efforts for hazard and risk assessment are also examined and discussed.