The southern - 100 km long Coachella section of the San Andreas fault is the only section of the fault in southern California that has not experienced a historical earthquake, and it may be the most overdue section of the fault. Numerical models of rupture propagation shows that a large earthquake with a nucleation one in the Durmid Hill field area would produce particularly destructive and deadly ground shaking in southern California. This is used as the model earthquake for the ShakeOut exercises in southern California because it is may represent the worst-case scenario for southern California but does not appear to be a very likely scenario following this research. Building on existing geologic mapping that shows major Pleistocene to Holocene contraction near the hypothesized nucleation, we use geologic mapping to develop and validate a competing geometric and kinematic model for the southern tip of the San Andreas Fault. A ladder-like-fault model explains the widespread contraction in the Durmid Hill study area as the result of contraction between the main strand of the San Andreas fault and East Shoreline strand. The East Shoreline strand of the San Andreas fault is the newly discovered fault and is dispersed across a zone between 0.5 to 1 km wide, and encompasses an area on the northeast shore of the Salton Sea. There is persistent and strong contraction across the entire - 1.5 to 3.5 km wide San Andreas fault zone because both dextral "side-rail" faults are counterclockwise, and in a contractional bend, relative to current plate motions. This contractional bend was previously documented for the main strand of San Andreas fault. A new digital geologic map and field studies document the stratigraphy and structures at a range of scales between Bombay Beach and Salt Creek. Numerous folds, narrow strike-slip and oblique-slip faults, and sheared damaged rocks in latest Miocene (?) to Holocene sediment lie within the wide and very complex damage zone of the main strand of the San Andreas fault zone. The East Shoreline strand of the San Andreas fault system buffers the main strand from major stress changes produced by deformation along the sinistral to sinistral-normal Extra fault array under the Salton Sea.

Global mean sea level rise (GMSLR) impacts the displacement of the world’s coasts and shorelinedifferently due to it being contingent on local topographic and geological conditions. The island of Gotlandis located in the Fennoscandian Shield which lies at the intersection between GMSLR and post-glacialrebound (PGR), at rates that vary latitudinally and, in some areas, are at equal levels. Therefore, the future for the shorelines on the Swedish island can be uncertain due to the shoreline displacement being non-uniform. In this thesis, Själsö, a village located on the north-eastern coast of the island with a higher GMSLR than PGR rate was studied to analyse the shoreline displacement and temporally project thepermanent inundation of the study area. Through a more a deductive analysis, the inundation of the studyarea is projected to take place in approx. 4000 yr. This result was compared with the results from anothermore inductive analysis based on finding displacement rates of the study area through satellite and aerialimagery presenting a wide-ranging results based on two particular set of data, early and late displacementrates. The former inductive results yielded a range between 177-211 yr. while the latter inductive resultsyielded a range between 500-588 yr. The inductive results suggest that the GMSLR is not the onlycontributing factor but also accounts for short-term SLR fluctuations, with the later displacementprojections being slightly more accurate than the early when comparing their results with the deductivelycalculated projection that only takes the GMSLR into consideration.

No description available.

<p> The nearshore morphology of sand beaches in the Great Lakes usually consists of a ridge and runnel unit in the shallow, inner portion of the nearshore zone and one or more longshore bar and trough units in the deeper, outer portion. These two sets of features are morphologically and genetically different and exhibit spatial and temporal variations indicating the relative importance of environmental factors in controlling the form of each. </p> <p> Ridges and runnels form and evolve in response to a combination of the controlling factors of wave and water level variations. Ridge formation occurs in response to a rapid decrease in wave energy and lowering of the water level during the subsiding period of a storm. Ridges, with heights of 0.04-0.40 m, take 5-10 days to migrate 10-30 m across an inner nearshore terrace toward the shore. Ridge migration produces laminations dipping at 20°-30° toward the shore. Ridge attachment to the shore produces an accretional berm composed of laminations dipping at about 5° toward the lake. </p> <p> An annual cycle of erosion and deposition occurs in the inner nearshore and foreshore zones and is due to seasonal wave energy and water level variations. Erosion occurs in spring and summer because of rising water levels while the deposition of planar laminations dipping at less than 5° toward the lake is caused by lower water levels and higher energy waves in autumn. </p> <p> Based on the analysis of over 100 echo sounder profiles of the outer nearshore zone of 7 beaches, longshore bar and trough morphologic properties (maximum depth of bar formation, number of bars, and bar amplitudes), are controlled by three main environmental factors (wave energy or surf base, nearshore slope, and sediment size). Bars are present at depths of 3.5 m and at distances of 500 m from the shore, the number of bars ranges up to 6, and bar amplitudes range up to 2 m. Surf base ranges from 3-6 m, slopes from 0.009-0.02, and mean sediment size from 1.85 Ø - 3.30 Ø. There is a good correlation between the slope and sediment size. Temporal variation in bar morphology during the summer period of study is small or insignificant. </p> <p> Individual longshore bars probably only approach, rather than attain, equilibrium forms because of the temporal flucuations in the environmental controls of wave energy and water level. The geometrical trend in all longshore bar systems for the bar amplitude and spacing between bars to increase with increasing depth and distance from the shoreline, suggests a wave energy dissipation process which is somewhat analogous to dampened oscillation. </p> / Thesis / Master of Science (MSc)

Coastal erosion can be described as the landward or seaward propagation of coastlines. Coastal processes occur over various space and time scales, limiting in-situ approaches of monitoring change. As such it is imperative to take advantage of multisensory, multi-scale and multi-temporal modern spatial technologies for multi-dimensional coastline change monitoring. The research presented here intends to showcase the synergy amongst remote sensing techniques by showcasing the use of coastal indicators towards shoreline assessment over the Kommetjie and Milnerton areas along the Cape Town coastline. There has been little progress in coastal studies in the Western Cape that encompass the diverse and dynamic aspects of coastal environments and in particular, sediment movement. Cape Town, in particular; is socioeconomically diverse and spatially segregated, with heavy dependence on its 240km of coastline. It faces sea level rise intensified by real-estate development close to the high-water mark and on reclaimed land. Spectral indices and classification techniques are explored to accommodate the complex bio-optical properties of coastal zones. This allows for the segmentation of land and ocean components to extract shorelines from multispectral Landsat imagery for a long term (1991-2021) shoreline assessment. The DSAS tool used these extracted shorelines to quantify shoreline change and was able to determine an overall averaged erosional rate of 2.56m/yr. for Kommetjie and 2.35m/yr. for Milnerton. Beach elevation modelling was also included to evaluate short term (2016-2021) sediment volumetric changes by applying Differential Interferometry to Sentinel-1 SLC data and the Waterline method through a combination of Sentinel -1 GRD and tide gauge data. The accuracy, validation and correction of these elevation models was conducted at the pixel level by comparison to an in-field RTK GPS survey used to capture the current state of the beaches. The results depict a sediment deficit in Kommetjie whilst accretion is prevalent along the Milnerton coastline. Shoreline propagation and coastal erosion quantification leads to a better understanding of geomorphology, hydrodynamic and land use influences on coastlines. This further informs climate adaptation strategies, urban planning and can support further development of interactive coastal information systems.

As the world continues to experience substantial rates of habitat loss, habitat restoration has become of prime interest to ecologists worldwide. Restoration has shown to be successful in recovering targeted components of certain ecosystems but it is important to achieve a holistic understanding of the resulting ecological impacts it has on communities. To address this, four oyster reefs and three living shorelines were restored during the summer of 2017. These sites, along with four dead oyster reefs, four living oyster reefs, and three undisturbed (control) living shorelines, were sampled before restoration and regularly post-restoration for one year using lift nets. Macroinvertebrates were collected and enumerated in the lab. Diversity indices, community composition, and similarity percentages were then calculated and compared across treatments, time, and treatment-by-time. Live reefs displayed significantly higher species richness and Shannon diversity than restored and dead reefs. Simpson diversity did not differ between live and restored oyster reefs but both were significantly higher than dead reefs. Though not statistically detectable, species richness and Shannon diversity on restored reefs were relatively similar to dead reefs before restoration but became increasingly similar to live reefs over the course of the study. Additionally, analyses revealed significantly different community compositions between live reefs and restored reefs, as well as between live and dead reefs. Living shorelines showed no significant differences in diversity indices but did experience similar seasonal fluctuations in diversity across treatments. Just as with oyster reefs, restored and control living shorelines harbored significantly different communities across time. The findings of this study emphasize the need for dedication to thorough monitoring and multi-metric evaluation of success in restoration efforts. This study and future research will equip resource managers with ways to quantify the effects of restoration that will consider several important ecosystem components.

No description available.

The purpose of the thesis is to explain the physical characteristics of Bosanquet township and to show their relationships to each other and to those who have occupied this part of the world for the last one hundred and thirty years. The "drowned lands" within Bosanquet are considered a paradise for the botanist, and Rock Glen is a veritable treasure chest of fossil finds for the exploring geologist. But it is the entire land area of the township that is so fascinating to the geographer because it is so complicated and diverse. There are no less than five different shorelines, including the present one of Lake Huron, eight different physiographic regions, and at least nineteen different soil types. It thus becomes a challenge to the geographer to see if man’s present use of the land reflects the history and natural phenomena of the area. To begin this difficult task the author carried out field work during the summer months and produced the Land Use map found inside the rear cover. During the autumn and winter months the work of many experts from various fields of learning was read and data concerning the area was compiled. The plan of the thesis is the presentation of the physical geography followed by the human geography of settlement. Then comes the writer’s views on the current land use, both agricultural and non-agricultural, and after a look at the urban geography of the study region, the writer comes to certain conclusions concerning the effect of man on this little segment of the earth’s surface. / Thesis / Bachelor of Arts (BA)

Living shorelines are designed to address coastal erosion and their use is encouraged over that of hard structures such as sea walls and bulkheads because they provide habitat, improve water quality and stabilize shorelines. Objectives of this study were to: (i) Compare soil Nitrogen [N], Phosphorus [P], Organic Carbon [OC], organic matter (SOM) and soil bulk density between living, hardened and natural shoreline to determine if soil present within living shorelines is comprised of higher SOM and lower bulk density, that encourage marsh growth, as compared to hardened shorelines. (ii) Use an experimental mesocosm to test the effect of shoreline substrate types (living vs hardened vs natural) and nitrogen loading (at four concentration 0, 12, 24, 36 ml) on the growth of Spartina alterniflora. No previous study has documented the growth of Spartina in response to inorganic N loading at various shoreline substrate types. My results show living shoreline has significantly lower soil bulk density [F 2, 138 = 10.79, p <0.01] and higher SOM content than hardened shoreline [F 2, 138 = 10.26, p <0.01]. Combinations of N addition decreased plant’s root-shoot ratio and resulted in increased dry shoot weight. These results indicate that living shoreline is capable of trapping sediments within the nearshore environment, contributing to vertical marsh accretion by accumulation of organic matter, in the face of sea level rise. Findings from this research provide insights to local government, planners, developers and consultants on the benefits of living shoreline structures for the purpose of best shoreline management practice.

Taking the establishment of Ice Age theory as its point of departure, the present dissertation examines aspects of geological, plant geographical and archaeological research on shoreline displacement conducted in Sweden during the period 1860-1930, and the significance of this research for the perception of "the Swedish landscape" and its post-glacial history. The research is analyzed on three levels under the rubrics "The Highest Shoreline and the Ancylus Lake", "The Question of Land Elevation", and "Charting Swedens Past", respectively. Taken together, these levels capture the varying perceptions and exchanges of opinion of the nature of shoreline displacement and the contexts in which they were applied. The present study is conducted via a theoretical and methodological approach where both the ideas and the practices of science are studied: activities in the field and at the various institutions (primarily the Swedish Geological Survey, its museum and the Geological Society of Stockholm); arguments and hypotheses presented in artides and handbooks, including visual images, diagrams and maps; social networks, career paths and controversies. Particular attention is paid to the relationship between science and nationalism, and comparisons are made with research conducted in an imperialist context. Ice Age theory helped initiate research whose purpose was to discover how the Swedish naturai and cultural landscape carne into being. The foremost task of geology became studying geographic evolution during the Quaternary epoch, how the land had "risen from ice and water". Plant geography studied how and whence plant life had migrated and how vegetation had evolved under the influence of biological, geological and climatological factors. In a similar manner, archaeologists studied the migration and dissemination of mankind during the StoneAge. When natural scientists primarily used "natural landmarks" as its source material, archaeologists relied on "archaeological finds", which were invested with scientific value but also became symbols of national collective memory. Through this survey, national identity was unifìed with the territory itself and its evolutionary history. Knowledge about shoreline displacement became significant for geology, plant geography and archaeology, which in turn encouraged interdisciplinary collaboration, but also locked the researchers into a similar way of thinking about the nature of shoreline displacement. According to this "thought style", the phenomenon was first and foremost the result of the vertical movement of the land rather than movement in the ocean surface. Up until the 1870s, the Ice Age was thought to have been followed by one single subsidence and elevation; during the 1880s, two such land oscillations; three during the 1910s and by the 1920s, five. Only toward the end of the 1920s did Swedish researchers begin to accept a multi-factor explanation, which succeeded in finally subverting the reigning thought style. According to this explanation, shoreline displacement was not solely the result of changes in the land or the sea, but of both. / digitalisering@umu