Historical Aerial Photographs Research Articles

Historical Changes in the Vegetated Area of Salt Marshes

Salt marshes are valuable ecosystems, and there is concern that increases in the rate of sea level rise along with anthropogenic activities are leading to the loss of vegetated habitat. The area of vegetated marsh can change not only through advance and retreat of the open fetch edge, but also due to channel widening and contracting, formation and drainage of interior ponds, formation and revegetation of interior mud flats, and marsh migration onto upland areas, each of which is influenced by different processes. This study used historical aerial photographs to measure changes in the extent of vegetated marsh over approximately 70 years at study marshes located in three long-term ecological research (LTER) sites along the US East coast: Georgia Coastal Ecosystems (GCE), Virginia Coast Reserve (VCR), and Plum Island Ecosystems (PIE). Marsh features were categorized into vegetated marsh, ponds, interior mud flats, and channels for three time periods at each site. The three sites showed different patterns of change in vegetated marsh extent over time. At the GCE study site, losses in vegetated marsh, which were primarily due to channel widening, were largely offset by channel contraction in other areas, such that there was little to no net change over the study period. The study marsh at VCR experienced extensive vegetated marsh loss to interior mud flat expansion, which occurred largely in low-lying areas. However, this loss was counterbalanced by marsh gain due to migration onto the upland, resulting in a net increase in vegetated marsh area over time. Vegetated marsh at PIE decreased over time due to losses from ponding, channel widening, and erosion at the open fetch marsh edge. Digital elevation models revealed that the vegetated areas of the three marshes were positioned at differing elevations relative to the tidal frame, with PIE at the highest and VCR at the lowest elevation. Understanding the patterns of vegetation loss and gain at a given site provides insight into what factors are important in controlling marsh dynamics and serves as a guide to potential management actions for marsh protection.

Structure‐from‐motion photogrammetry analysis of historical aerial photography: Determining beach volumetric change over decadal scales

AbstractHistorical aerial photographs are an invaluable tool in shoreline mapping and change detection in coastal landscapes. We evaluate the extent to which structure‐from‐motion (SfM) photogrammetric methods can be applied to quantify volumetric changes along sandy beaches, using archival imagery. We demonstrate the application of SfM‐derived digital surface models (DSMs) at East Beach and Lady Bay in southwest Victoria, Australia, using photographic datasets taken in 1969, 1977 and 1986, and compare them to LiDAR‐derived DSMs acquired at both sites in 2007. The SfM approaches resulted in two entire and two partial suitable DSMs out of six datasets. Good‐quality DSMs were spatially continuous with a good spread of ground control points (GCPs) near the beach at Lady Bay, whereas unsuitable DSMs were mostly restricted by poor distribution and number of GCPs in spatially segmented areas of East Beach, due to limited overlapping of images, possible poor quality of GCPs and also the propagation of errors in the derived point clouds. A volume of approximately 223 000 ± 72 000 m3 was deposited at Lady Bay between 1969 and 2007, despite minimal erosion observed near the breakwater. The partially suitable dataset of East Beach indicated that beach erosion of at least 39 m3 m−1 occurred immediately to the east of the seawall after 1977. We also discuss the drawbacks and strengths of SfM approaches as a benchmark of historical erosion assessments along sandy beaches. © 2020 John Wiley & Sons, Ltd.

Seagrass cover expansion off Caja de Muertos Island, Puerto Rico, as determined by long-term analysis of historical aerial and satellite images (1950–2014)

Abstract Seagrass ecosystems affected by climate change and anthropogenic disturbances require baseline characterization of their cover, distribution, and dynamics for effective conservation strategies. Caja de Muertos Island (CMI) is an important nature reserve in Puerto Rico where long-term trends in seagrass cover are unknown but where availability of historical aerial photographs can provide elements for analyzing seagrass dynamics. The purpose of this study was to understand those dynamics in CMI, thereby providing a baseline for determining the severity of future disturbances and inform conservation strategies. We quantified changes in seagrass spatial extent using object-based image analysis in a 2014 WorldView-2 image and historical aerial photographs from 1950 to 2010. Contrasting with worldwide seagrass declining trends, seagrass extent in CMI showed a positive rate of expansion and increased 64%, which was mainly explained by the patchy seagrass cover category that was also the most persistent cover throughout the 64-year period analyzed. Findings suggest an increase in seagrass extent due to recolonization of seagrasses after impacts of tropical storm Baker in 1950, aided by other factors such as reduction in grazing pressure. Even though seagrass cover expanded, with other tropical storms and hurricanes, no negative effects were observed except between 1993 and 1999. The amount and frequency of changes in seagrass cover categories varied between zones and seemed to be linked to localized environmental conditions (e.g. wave exposure) and geomorphological characteristics. The present study represents a baseline of seagrass cover distribution and dynamics, offering valuable information for conservation strategies in Caja de Muertos Island Nature Reserve. In the absence of in situ long-term monitoring data, this study also shows how aerial photography and an object-based image analysis are effective for assessing trends and quantifying seagrass cover changes in clear oligotrophic waters.

Coastal Dune Morphology Evolution Combining Lidar and UAV Surveys, Truc Vert beach 2011-2019

Laporte-Fauret, Q.; Castelle, B.; Marieu, V.; Bujan, S.; Michalet, R., and Rosebery. D., 2020. Coastal dune morphology evolution combining Lidar and UAV surveys, Truc Vert beach 2011-2019. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 163–167. Coconut Creek (Florida), ISSN 0749-0208.In the context of climate change, coastal dunes, which provide significant ecosystem services, are one of the most vulnerable coastal environments. Moreover, the lack of high resolution and large spatial scale data limits our understanding of coastal dunes, which are subject to important morphological variations over a wide range of spatial and temporal scales. This study is focused on combining non-intrusive remote sensing methods including a series of historical aerial photographs, airborne Lidar and UAV surveys in order to better understand the coastal dune morphodynamic on a wide range of spatial and temporal scales. On the time scale of decades, aerial photos indicate a reasonably stable coastal dune position, with large anthropogenic reprofiling and vegetation planting resulting in a reasonably alongshore-uniform morphology. On shorter time scales, the combination of Lidar and UAV 4-km surveys between 2011 and 2019 shows a quasi-steady dune volume increase by approximately 64 m3/m, associated with a foredune crest growth and a landward migration reaching 1.1 m and 0.54 m in average, respectively. On the other hand, the dune foot shows a more complex dynamics, dominated by a large landward migration (shoreline erosion) of approximately 20 m during the outstanding winter of 2013/2014 followed by a slow seaward migration (recovery). This study provides new insight into coastal dune morphological changes driven by both Aeolian and marine processes from the time scale of storm to approximately a decade, highlighting the relevance of UAV surveys for such applications.

Leveraging historical aerial photographs and digital photogrammetry techniques for landslide investigation—a practical perspective

Aerial photography has been extensively used for civil engineering applications for more than a century. The availability of digital photogrammetry tools has allowed for aircraft, UAV, and ground-based digital photogrammetry to become a reliable and standard tool for landslide management. Digital photographs and digitized historic aerial photos can be used to develop digital surface elevation models. This technical note presents a recent example of the use of historical aerial photographs in combination with modern remote sensing techniques and digital photogrammetry tools. The note provides valuable insights into landslide kinematics and evolution of the Chin Coulee landslide in southern Alberta, Canada. Conventional aerial photo interpretation allowed for a qualitative understanding of landslide feature evolution as a response to external factors (road construction and reservoir infilling at the toe of the landslide). More importantly, topographic changes were quantified through change detection techniques between topographic surfaces derived from historical photographs and a ground-based laser scanner. The results from change detection allowed to confirm the kinematics of the Chin Coulee landslide as a compound slide, an assumption which was previously based on limited deformation measurements. Furthermore, the results helped define the boundary between the active wedge of the landslide moving downslope as it pushes the passive wedge into the reservoir. Although challenges remain regarding the aggregation of datasets with different resolutions, this note demonstrates the valid practical application of this approach for landslide assessment and management.

Evaluating Elevation Change Thresholds between Structure-from-Motion DEMs Derived from Historical Aerial Photos and 3DEP LiDAR Data

This study created digital terrain models (DTMs) from historical aerial images using Structure from Motion (SfM) for a variety of image dates, resolutions, and photo scales. Accuracy assessments were performed on the SfM DTMs, and they were compared to the United States Geological Survey’s three-dimensional digital elevation program (3DEP) light detection and ranging (LiDAR) DTMs to evaluate geomorphic change thresholds based on vertical accuracy assessments and elevation change methodologies. The results of this study document a relationship between historical aerial photo scales and predicted vertical accuracy of the resultant DTMs. The results may be used to assess geomorphic change thresholds over multi-decadal timescales depending on spatial scale, resolution, and accuracy requirements. This study shows that if elevation changes of approximately ±1 m are to be mapped, historical aerial photography collected at 1:20,000 scale or larger would be required for comparison to contemporary LiDAR derived DTMs.

Discovery of a significant cave entrance in stripe karst, Horsethief Creek Group, Wells Gray Provincial Park, British Columbia, Canada

In April 2018, a significant cave entrance was recognized during an aerial survey in Wells Gray Provincial Park, British Columbia. A September 2018 assessment of the site confirmed one of the largest known, and previously undocumented, cave entrances in Canada. The feature is a large vertically walled sink swallowing a small river, likely leading to a spring 2.16 km horizontally from, and 460 m below, the sink. The entrance shaft was partially descended, surveyed, and found to have a volume of over 450 000 m3. Formed in a carbonate unit of the upper Proterozoic Horsethief Creek Group, the cave entrance occurs in stripe karst extending well beyond the known cave drainage. The disappearing river drains an area of 6.3 km2 in a valley containing two small glaciers. The river has a low flow (September) rate estimated at 0.3–0.5 m3/s, comparable with some of the largest sinks in Canada. Historic aerial photographs of the area show the entrance was hidden by perennial snowfields until regional climatic warming caused the snow plug to collapse sometime within the past decade.

A Multi-Decadal Investigation of Tidal Creek Wetland Changes, Water Level Rise, and Ghost Forests

Coastal wetlands play a vital role in protecting coastlines, which makes the loss of forested and emergent wetlands devastating for vulnerable coastal communities. Tidal creeks are relatively small hydrologic areas that feed into larger estuaries, are on the front lines of the interface between saltwater and freshwater ecosystems, and are potentially the first areas to experience changes in sea level. The goal of this study was to investigate wetland changes through time at two tidal creeks (Smith Creek and Town Creek) of the Cape Fear River estuary in southeastern North Carolina, USA, to determine if there is a spatial relationship between habitat change, physical geography characteristics, and the rate of wetland migration upstream. Historic aerial photography and recent satellite imagery were used to map land cover and compute change through time and were compared with derived physical geography metrics (sinuosity, creek width, floodplain width, floodplain elevation, and creek slope). The primary results were: (1) there was a net gain in emergent wetlands even accounting for the area of wetlands that became water, (2) wetlands have migrated upstream at an increasing rate through time, (3) land cover change was significantly different between the two creeks (P = 0.01) where 14% (67.5 ha) of Smith Creek and 18% (272.3 ha) of Town Creek transitioned from forest to emergent wetland, and (4) the transition from emergent wetland to water was significantly related to average change in creek width, floodplain elevation, and average water level. In conclusion, this research correlated habitat change with rising water level and identified similarities and differences between neighboring tidal creeks. Future research could apply the methodologies developed here to other coastal locations to further explore the relationships between tides, sea level, land cover change, and physical geography characteristics.

The glacial landsystem of Fjallsjökull, Iceland: Spatial and temporal evolution of process-form regimes at an active temperate glacier

This study assesses the spatial and temporal evolution of the glacial landsystem signature at Fjallsjökull, southeast Iceland, using (a) mapping of the glacial geomorphology and surficial geology and (b) repeat uncrewed aerial vehicle (UAV) surveys. A small-scale (1: 15,000 scale) landsystem map has been compiled using LiDAR data (2011−2012) and historical aerial photographs (1945–1998), along with a large-scale (1: 2000 scale) map based on UAV imagery from May 2019. From our mapping and UAV surveys, we identify sediment-landform assemblages that are typical of active temperate glacial landsystems, including recessional push/squeeze moraines and intervening flutings, overridden moraine arcs, proglacial outwash (sandur) fans and linear/ribbon sandar. We recognize three landform zones that are defined by changes in moraine morphology and the nature of proglacial outwash deposition: (1) the outer foreland is characterized by proglacial outwash fans, overridden moraine arcs and broadly linear recessional moraines; (2) the middle foreland contains sawtooth moraines and linear sandar; and (3) the innermost zone comprises extremely sawtooth and hairpin moraines as well as associated crevasse-squeeze ridge limbs. This landform zonation reflects spatio-temporal changes in moraine-forming processes and outwash deposition as determined by changes in snout morphology and proglacial drainage characteristics. Within this general tripartite zonation, we also identify localized (azonal/intrazonal) sediment-landform assemblages that are not typically found at active temperate glaciers, including ice-cored/hummocky terrain and localized kame and kettle topography. Repeat UAV surveying in 2016–2019 has allowed us to capture and quantify recent intrazonal landsystem change at the southern glacier margin. We identify a switch from moraine formation to the development of ice-cored terrain and an ice-cored esker complex in association with the uncovering of a depositional overdeepening. Our study demonstrates the important role that variations in local boundary conditions (e.g. topography) can play in the process-form response of individual active temperate outlet glaciers, contributing to the expanding database on modern glacial landsystems.

Urban geomorphology of a historical city straddling the Tanaro River (Alessandria, NW Italy)

ABSTRACT The integration of field surveys, bibliographic research and multitemporal analysis of historical maps, aerial photographs and satellite images in a GIS environment, allowed the current and past geomorphological features of the old city of Alessandria and its surrounding areas, NW Italy, to be identified and mapped. Their analysis provided an overview of the geomorphological evolution of the city that is strictly related to the historical vicissitudes occurred since the Middle Ages. Nowadays, the most representative landforms and deposits characterizing the urban landscape result from human interventions and are associated with ancient military facilities and infrastructures, a historical man-made channel network no longer recognizable, the Tanaro riverbed channelization, and the urban sprawl occurred from the second half of the nineteenth century onwards. This study represents a useful tool for urban planning and management and for raising the citizens’ awareness of the urban-landscape geomorphological features and evolution, and therefore the geo-hydrological risk.

SfM 多視点ステレオ写真測量による過去の空中写真からの 三次元地形モデルの構築

SfM 多視点ステレオ写真測量による過去の空中写真からの 三次元地形モデルの構築

Relationship between Growth Faults, Subsidence, and Land Loss: An Example from Cameron Parish, Southwestern Louisiana, USA

O'Leary, M. and Gottardi, R., 2020. Relationship between growth faults, subsidence, and land loss: An example from Cameron Parish, Southwestern Louisiana, USA. Journal of Coastal Research, 36(4), 812–827. Coconut Creek (Florida), ISSN 0749-0208.This study investigates the relationship between faulting, subsidence, and land loss in coastal Louisiana. A methodology that integrates three-dimensional (3D) seismic data, well logs, high-resolution topographic mapping (LIDAR), and historical aerial photography is successfully developed to identify fault-related geomorphic changes in southwestern Louisiana's Chenier Plain. Analysis of a 3D seismic survey and well logs reveals the presence of 10 normal faults that form an east-west graben in the middle of the study area. Well logs were used to further constrain the geometry of the faults. Shallow water well logs were used to map the faults at shallow depth, below the resolution of the seismic survey. Fault traces were extrapolated to the surface by maintaining constant dip and projected on LIDAR data. Elevation profiles derived from the LIDAR were conducted across the different faults, and results show that a distinct difference between the upthrown and downthrown sides of the faults occurs. Historical aerial photographs were used to investigate any change in geomorphology from 1953 to 2017 within the study area. Results reveal the occurrence of water bodies on the immediate downthrown sides of suspected fault traces. These findings suggest that faulting influences and focuses areas where subsidence is happening and subsequent land loss may occur, and detailed understanding of active shallow faulting in coastal areas can be used to identify regions that are at risk of land loss.

Multi‐decadal stability of woody cover in a mesic eucalypt savanna in the Australian monsoon tropics

AbstractPrevious analyses of historical aerial photography and satellite imagery have shown thickening of woody cover in Australian tropical savannas, despite increasing fire frequency. The thickening has been attributed to increasing precipitation and atmospheric CO2 enrichment. These analyses involved labour‐intensive, manual classification of vegetation, and hence were limited in the extent of the areas and the number of measurement times used. Object‐based, semi‐automated classification of historical sequences of aerial photography and satellite imagery has enabled the spatio‐temporal analysis of woody cover over entire landscapes, thus facilitating measurement, monitoring and attribution of drivers of change. Using this approach, we investigated woody cover change in 4000 ha of intact mesic savanna in the Ranger uranium lease and surrounding Kakadu National Park, using imagery acquired on 10 occasions between 1950 and 2016. Unlike previous studies, we detected no overall trend in woody cover through time. Some variation in cover was related to rainfall in the previous 12 months, and there were weak effects of fire in the year of image acquisition and the antecedent 4 years. Our local‐scale study showed a mesic eucalypt savanna in northern Australia has been resilient to short‐term variation in rainfall and fire activity; however, changes in canopy cover could have occurred in other settings. When applying this semi‐automated approach to similar studies of savanna dynamics, we recommend maximising the time depth and number of measurement years, standardising the time of year for image acquisition and using many plots of 1 ha in area, rather than fewer, larger plots.

Forest restoration scenarios produce synergies for agricultural production in southern Ethiopia

Understanding the factors influencing agricultural productivity is vital to food security, especially for food insecure smallholder farmers. Within agricultural landscape mosaics, the arrangement of tree cover such as forests, trees, and hedgerows can positively or negatively impact agricultural productivity in fields. In such settings, forest restoration has the potential to impact food security goals in addition to the typical restoration goals of reversing land degradation and supporting carbon storage. Here, we compare and contrast forest restoration scenarios in order to explore whether there are ideal amounts and configurations of forests that optimize benefits for food production. To do so, we explored forest restoration scenarios in an agricultural-forest landscape in southern Ethiopia where previous research showed increased wheat productivity in sections of fields adjacent to forests. We used hypothetical historically-relevant and plausible future scenarios to examine the landscape-level implications of forest restoration on total wheat production. To accomplish this, we first characterized contemporary forest cover as well as long-term trends using remote sensing. Then, trends in forests and hedgerows were used to create a series of hypothetical yet realistic scenarios to explore trade-offs among total forest cover, its configuration, and total wheat production. From 1967–2013, analysis of historical aerial photography and Landsat imagery showed a general trend of reforestation (an 8% increase in forest cover). While the abundance of primary forests remained constant from 1986–2013, mixed vegetation expanded from 16 % to occupy 26 % of the landscape, generally in the form of small forest fragments with sparse tree cover. Our hypothetical reforestation and hedgerow planting scenarios found that field productivity increases near forest edges resulted in non-linear food production benefits with hedgerow expansion. Benefits to total landscape-level wheat production were almost twice as great when transitioning from low to medium tree cover than when transitioning from medium-high to high tree cover. Furthermore, the benefits of hedgerows on agricultural production were asymptotic; productivity gains eventually levelled off with increasing hedgerows. Our results highlight potential benefits of a landscape approach for enhancing smallholder agricultural productivity in southern Ethiopia and beyond. We argue that considering a landscape perspective can help support food security goals particularly within the context of climate change and should play a more prominent role in forest conservation and restoration.

Historical Aerial Surveys Map Long-Term Changes of Forest Cover and Structure in the Central Congo Basin

Given the impact of tropical forest disturbances on atmospheric carbon emissions, biodiversity, and ecosystem productivity, accurate long-term reporting of Land-Use and Land-Cover (LULC) change in the pre-satellite era (<1972) is an imperative. Here, we used a combination of historical (1958) aerial photography and contemporary remote sensing data to map long-term changes in the extent and structure of the tropical forest surrounding Yangambi (DR Congo) in the central Congo Basin. Our study leveraged structure-from-motion and a convolutional neural network-based LULC classifier, using synthetic landscape-based image augmentation to map historical forest cover across a large orthomosaic (~93,431 ha) geo-referenced to ~4.7 ± 4.3 m at submeter resolution. A comparison with contemporary LULC data showed a shift from previously highly regular industrial deforestation of large areas to discrete smallholder farming clearing, increasing landscape fragmentation and providing opportunties for substantial forest regrowth. We estimated aboveground carbon gains through reforestation to range from 811 to 1592 Gg C, partially offsetting historical deforestation (2416 Gg C), in our study area. Efforts to quantify long-term canopy texture changes and their link to aboveground carbon had limited to no success. Our analysis provides methods and insights into key spatial and temporal patterns of deforestation and reforestation at a multi-decadal scale, providing a historical context for past and ongoing forest research in the area.

Conflict Archaeology of Tactical Air Power: The Forêt Domaniale de la Londe-Rouvray and the Normandy Campaign of 1944

Over 1,600 extant WW2 impact craters in the Foret Domaniale de la Londe-Rouvray, Lower Seine valley, Normandy, France, have been mapped and analyzed using LiDAR, historic aerial photographs, archive documents, and field survey. Crater densities average 0.26/ha2 with values up to 31/ha2 in clusters around road and railway infrastructure. Some 576 craters can be dated using aerial photographs to intervals between May–August 1944 and are interpreted as bomb craters associated with Allied tactical air strikes on the Seine bridge at Orival (attacked during May in preparation for the D-Day landings) and German troop and vehicle concentrations towards the later stages of the Normandy Campaign.

Assessment of morphological changes of Taleghan river in upstream of Taleghan dam

River channels have been affected by climate changes and human interventions such as channelization, dam, gravel and sand mining and land use changes. Dam changes water and sediment transport in river systems. These changes are as one of the most important factors affecting upstream and downstream river morphology. The aim of this paper is to explain the effect of Taleghan dam (it was constructed from 2001-2006) on upstream of Taleghan River over the period 2000–2017. Taleghan River is very important river in the Central Alborz of Iran. For this reason, Taleghan River was divided 2 reaches as control reach and backwater reach. Channel morphology have been investigated using historical aerial photographs, remote sensing images and field observations. Also channel width, sinuosity index, and particle size distribution were calculated for two reaches pre and post-dam construction. Results showed that the channel width was increased in the post-dam period. Widening was dominated in the backwater and the control reaches but increasing in the channel width in the backwater reach is more than the control reach. the channel width has been increased due to the impact of the dam and flood events. Also the results of grain size distributions showed that dam affects the grain size distribution and leads to an increase in the fine particle size. Finally, the channel adjustment (aggradation and widening) in upstream of Taleghan River may cause floodplain inundation and damage to agriculture and residential area in floodplain.

Channel Changes and Controlling Factors over the Past 150 Years in the Basento River (Southern Italy)

Channel changes are receiving growing interest in relation to the relevant implications for river management and restoration. In this kind of analysis, purely qualitative approaches have been gradually replaced by quantitative approaches aimed at reconstructing the temporal variations in parameters (e.g., channel width and depth) to investigate not only the evolutionary trend of the river but also the possible cause-effect connections. This paper investigates the channel dynamics in the Basento River (Basilicata Region, Italy) over the past 150 years, when the river was heavily affected by human activities (e.g., hydraulic interventions and gravel mining) and climate changes. Channel adjustments were analysed with historical maps, aerial photos, and geomorphological surveys. The results show that the channel underwent a strong narrowing during the twentieth century, similar to many rivers in Italy, with the most intense phase from the 1950s to the 1990s (with the width varying from −30% to −80%). The morphology pattern remained almost completely unchanged, apart from a few reaches located in the hilly area that were affected by intense modifications before the 1940s. The causes of channel adjustments were identified as human disturbances (land use variations, channel interventions at the reach scale, sediment mining) from the end of the 1800s to present, as well as natural factors (changes in frequency, duration, and intensity of flood events), whose effects have intensified since the late 1990s.

Erosion of rocky shore platforms by block detachment from layered stratigraphy

AbstractThe majority of shore platforms form in rocks that are characterised by layered stratigraphy and pervasive jointing. Plucking of weathered, joint and bed bounded blocks is an important erosion process that existing models of platform development do not represent. Globally, measuring platform erosion rates have focused on microscale (< 1 mm) surface lowering rather than mesoscale (0.1‐1 m) block detachment, yet the latter appears to dominate the morphological development of discontinuity rich platforms. Given the sporadic nature of block detachment on platforms, observations of erosion from storm event to multi‐decadal timescales (and beyond) are required to quantify shore platform erosion rates. To this end, we collected aerial photography using an unmanned aerial vehicle to produce structure‐from‐motion‐derived digital elevation models and orthophotos. These were combined with historical aerial photographs to characterise and quantify the erosion of two actively eroding stratigraphic layers on a shore platform in Glamorgan, south Wales, UK, over 78‐years. We find that volumetric erosion rates vary over two orders of magnitude (0.1‐10 m3 yr‐1) and do not scale with the length of the record. Average rates over the full 78‐year record are 2‐5 m3 yr‐1. These rates are equivalent to 1.2‐5.3 mm yr‐1 surface lowering rates, an order of magnitude faster than previously published, both at our site and around the world in similar rock types. We show that meso‐scale platform erosion via block detachment processes is a dominant erosion process on shore platforms across seasonal to multi‐decadal timescales that have been hitherto under‐investigated. © 2019 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd

Assessment of seismic sources and capable faults through hierarchic tectonic criteria: implications for seismic hazard in the Levant

Abstract. We present a methodology for mapping faults that constitute a potential hazard to structures, with an emphasis on ground shake hazards and on surface rupture nearby critical facilities such as dams and nuclear power plants. The methodology categorises faults by hierarchic seismo-tectonic criteria, which are designed according to the degree of certainty for recent activity and the accessibility of the information within a given region. First, the instrumental seismicity is statistically processed to obtain the gridded seismicity of the earthquake density and the seismic moment density parameters. Their spatial distribution reveals the zones of the seismic sources, within the examined period. We combine these results with geodetic and pre-instrumental slip rates, historical earthquake data, geological maps and aerial photography to define and categorise faults that are likely to generate significant earthquakes (M≥6.0). Their mapping is fundamental for seismo-tectonic modelling and for probabilistic seismic hazard analyses (PSHAs). In addition, for surface rupture hazard, we create a database and a map of Quaternary capable faults by developing criteria according to the regional stratigraphy and the tectonic configuration. The relationship between seismicity, slip dynamics and fault activity through time is an intrinsic result of our analysis that allows revealing the dynamic of the deformation in the region. The presented methodology expands the ability to differentiate between subgroups for planning or maintenance of different constructions or for research aims, and it can be applied in other regions.