Abstract. We present a monitoring technique tailored to analysing change from near-continuously collected, high-resolution 3-D data. Our aim is to fully characterise geomorphological change typified by an event magnitude-frequency relationship that adheres to an inverse power law or similar. While recent advances in monitoring have enabled changes in volume across more than 7 orders of magnitude to be captured, event frequency is commonly assumed to be interchangeable with the time-averaged event numbers between successive surveys. Where events coincide, or coalesce, or where the mechanisms driving change are not spatially independent, apparent event frequency must be partially determined by survey interval.The data reported have been obtained from a permanently installed terrestrial laser scanner, which permits an increased frequency of surveys. Surveying from a single position raises challenges, given the single viewpoint onto a complex surface and the need for computational efficiency associated with handling a large time series of 3-D data. A workflow is presented that optimises the detection of change by filtering and aligning scans to improve repeatability. An adaptation of the M3C2 algorithm is used to detect 3-D change to overcome data inconsistencies between scans. Individual rockfall geometries are then extracted and the associated volumetric errors modelled. The utility of this approach is demonstrated using a dataset of ∼ 9 × 10 3 surveys acquired at ∼ 1 h intervals over 10 months. The magnitude-frequency distribution of rockfall volumes generated is shown to be sensitive to monitoring frequency. Using a 1 h interval between surveys, rather than 30 days, the volume contribution from small (< 0.1 m 3 ) rockfalls increases from 67 to 98 % of the total, and the number of individual rockfalls observed increases by over 3 orders of magnitude. High-frequency monitoring therefore holds considerable implications for magnitude-frequency derivatives, such as hazard return intervals and erosion rates. As such, while high-frequency monitoring has potential to describe short-term controls on geomorphological change and more realistic magnitude-frequency relationships, the assessment of longer-term erosion rates may be more suited to less-frequent data collection with lower accumulative errors.

. (2012) 'Modelling the eects of sediment compaction on salt marsh reconstructions of recent sea-level rise.', Earth and planetary science letters., 345-348 . pp. 180-193. Further information on publisher's website:http://dx.doi.org/10.1016/j.epsl.2012.06.045Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Earth and Planetary Science Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Earth and Planetary Science Letters, 345348, 2012Letters, 345348, , 10.1016Letters, 345348, /j.epsl.2012 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThis paper quantifies the potential influence of sediment compaction on the magnitude of nineteenth and twentieth century sea-level rise, as reconstructed from salt marsh sediments.We firstly develop a database of the physical and compression properties of low energy intertidal and salt marsh sediments. Key compression parameters are controlled by organic content (loss on ignition), though compressibility is modulated by local-scale processes, notably the potential for desiccation of sediments. Using this database and standard geotechnical theory, we use a numerical modelling approach to generate and subsequently 'decompact' a range of idealised intertidal stratigraphies. We find that compression can significantly contribute to reconstructed accelerations in recent sea level, notably in transgressive stratigraphies. The magnitude of this effect can be sufficient to add between 0.1 and 0.4 mm yr -1 of local sea-level rise, depending on the thickness of the stratigraphic column. In contrast, records from shallow (< 0.5 m) uniform-lithology stratigraphies, or shallow near-surface salt marsh deposits in regressive successions, experience negligible compaction. Spatial variations in compression could be interpreted as 'sea-level fingerprints'that might, in turn, be wrongly attributed to oceanic or cryospheric processes. However,

No abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.

Existing geotechnical approaches that describe volumetric changes in intertidal sediments in response to applied vertical effective stresses are limited by a lack of empirical research into their one-dimensional compression behaviour. In this paper we address this deficiency by presenting the results of an investigation into the compression behaviour of minerogenic low marsh and tidal flat sediments. We have tested samples of these sediment types obtained from Greatham Creek (Cowpen Marsh, Tees Estuary, UK). Analysis of physical properties and oedometer compression tests demonstrates that, contrary to the implicit assumptions of existing models, the surface sediments studied are overconsolidated. Structural variability between samples arises due to sedimentological factors, notably variations in organic content. We attribute overconsolidation to tidal exposure and falls in groundwater level that cause desiccation and capillary suction stresses. Greater rates of compression with respect to effective stress occur

. (2013) 'Coastline retreat via progressive failure of rocky coastal clis. ', Geology, 41 (8). pp. 939-942. Further information on publisher's website:http://dx.doi.org/10.1130/G34371.1Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Despite much research on the myriad processes that erode rocky coastal cliffs, accurately 7 predicting the nature, location and timing of coastline retreat remains challenging, confounded 8 by the apparently episodic nature of cliff failure. The dominant drivers of coastal erosion, marine 9 and sub-aerial forcing, are anticipated in future to increase, so understanding their present and 10 combined efficacy is fundamental to improving predictions of coastline retreat. We capture 11 change using repeat laser scanning across 2.7 x 10 4 m 2 of near-vertical rock cliffs on the UK 12 North Sea coast over 7 years to determine the controls on the rates, patterns and mechanisms of 13 erosion. For the first time we document that progressive upward propagation of failure dictates 14 the mode and defines the rate at which marine erosion of the toe can accrue retreat of coastline 15 above; notably a failure mechanism not conventionally considered in cliff stability models. 16Propagation of instability and failure operates at these sites at 10 1 year timescales and is 17 moderated by local rock mass strength and the time-dependence of rock fracture. We suggest 18 that once initiated, failure propagation can operate ostensibly independently to external 19 environmental forcing, and so may not be tightly coupled to prevailing subaerial and 20 oceanographic conditions. Our observations apply to coasts of both uniform and complex 21 lithology, where failure geometry is defined by rock mass strength and structure, and not intact 22 rock strength alone, and where retreat occurs via any mode other than full cliff collapse. 23

'Quantifying the contribution of sediment compaction to late Holocene salt-marsh sea-level reconstructions, North Carolina, USA.', Quaternary research., 83 (1). pp. 41-51. Further information on publisher's website:http://dx.doi.org/10.1016/j.yqres. 2014.08.003 Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Quaternary Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be re ected in this document. Changes may have been made to this work since it was submitted for publication. A de nitive version was subsequently published in Quaternary Research, 83/1, 2015Research, 83/1, , 10.1016Research, 83/1, /j.yqres.2014 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

Rockfalls commonly exhibit power law volume‐frequency distributions, where fewer large events are observed relative to more numerous small events. Within most inventories, the smallest rockfalls are the most difficult to detect and so may not be adequately represented. A primary challenge occurs when neighboring events within a single monitoring interval are recorded as one, producing ambiguity in event location, timing, volume, and frequency. Identifying measurement intervals that minimize these uncertainties is therefore essential. To address this, we use an hourly data set comprising 8,987 3‐D point clouds of a cliff that experiences frequent rockfalls. Multiple rockfall inventories are derived from this data set using change detections for the same 10‐month period, but over different monitoring intervals. The power law describing the probability distribution of rockfall volumes is highly sensitive to monitoring interval. The exponent, β, is stable for intervals >12 hr but increases nonlinearly over progressively short timescales. This change is manifested as an increase in observed rockfall numbers, from 1.4 × 103 (30 day intervals) to 1.4 × 104 (1 hr intervals), and a threefold reduction in mean rockfall volume. When the monitoring interval exceeds 4 hr, the geometry of detected rockfalls becomes increasingly similar to that of blocks defined by rock mass structure. This behavior change reveals a time‐dependent component to rockfall occurrence, where smaller rockfalls (identifiable from more frequent monitoring) are more sensitive to progressive deformation of the rock mass. Acquiring complete inventories and attributing discrete controls over rockfall occurrence may therefore only be achievable with high‐frequency monitoring, dependent upon local lithology.