Metre-scale cycles in ancient peritidal carbonate facies have long been thought to represent the product of shallow water carbonate accumulation under orbitally controlled sea-level oscillations. The theory remains somewhat controversial, however, and a contrasting view is that these cycles are the product of intrinsic, and perhaps random, processes. Owing to this debate, it is important to understand the conditions that do, or do not, favour the preservation of orbital forcing, and the precise stratigraphic expression of that forcing. In this work, a one-dimensional forward model of carbonate accumulation is used to test the ability of orbitally paced sea-level changes to reconstruct cyclicities and cycle stacking patterns observed in greenhouse peritidal carbonate successions. Importantly, the modelling specifically tests insolation-based sea-level curves that probably best reflect the pattern and amplitude of sea-level change in the absence of large-scale glacioeustasy. This study found that such sea-level histories can generate precession and eccentricity water depth/facies cycles in models, as well as eccentricity-modulated cycles in precession cycle thicknesses (bundles). Nevertheless, preservation of orbital forcing is highly sensitive to carbonate production rates and amplitudes of sea-level change, and the conditions best suited to preserving orbital cycles in facies/water depth are different to those best suited to preserving eccentricity-scale bundling. In addition, it can be demonstrated that the preservation of orbital forcing is commonly associated with both stratigraphic incompleteness (missing cycles) and complex cycle thickness distributions (for example, exponential), with corresponding implications for the use of peritidal carbonate successions to build accurate astronomical timescales.

[1] Fifteen years worth of Advanced Very High Resolution Radiometer (AVHRR) data is presented and used to quantitatively assess processes occurring at Bezymianny. This andesitic volcano is one of Kamchatka's most dangerous volcanoes with 16 eruptions in the last decade that have dispersed ash into North Pacific air routes. All known episodes of increased activity for which data were available were detected in band 3 (3.53-3.93 mm) AVHRR thermal data. Twenty-three peaks can be seen in the data; nineteen peaks correspond to known explosions, while the remaining three peaks correspond to known phases of dome growth that were not believed to have been accompanied by explosive activity. Start and end dates of extrusive phases defined by the thermal data are presented. Repose times between phases of extrusion vary from four months to just over two and half years with an average of just less than a year. Using rank-order statistics a 'maximum' time interval between consecutive explosions of 1288 ± 170 days is determined; this could serve as a cut-off time for declaring the current dome-growth activity over. The calculated cumulative erupted volume (0.28 km 3 ) and time-averaged extrusion rate (0.6 m 3 s (1) values that cluster around the mode of the data set prior to explosion, potentially due to endogenous dome growth, (2) upward trends that commence 15-20 days prior to explosion and reach sensor saturation levels are due to significant extrusion, and (3) a gradual upward trend that starts 5 days prior to explosion, probably due to ramping up of extrusion. This work shows that retrospectively analyzing and modeling of a volcano's thermal signal provides increased insight into its characteristic behavior. The methods used in this paper can be used at other dome-building volcanoes around the world. The insights presented here can be used to improve monitoring capabilities to aid in providing early warnings to large explosions at Bezymianny.

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This study takes a combined qualitative and quantitative approach to examining the chronic hazard posed by persistent degassing at Masaya volcano, Nicaragua. The gas is a highly salient threat in communities surrounding Masaya volcano, with the elevated salience level of his invisible hazard deriving from the highly perceptible impacts of the degassing; these include individual and material impacts such as increased prevalence of self-reported respiratory disease and decreased crop diversification and productivity. Qualitative results concur with findings from a quantitative assessment of ambient SO 2 exposure using diffusion tubes: the current level of SO 2 degassing far exceeds international guideline values, making it a likely cause of adverse health effects for the general population. Conversely contaminant levels of heavy and toxic metals in foodstuffs were found to be below international standards. A community-based integrated hazard mitigation approach identified by this research is the cultivation of crops, particularly pineapple (Ananas comosus) and pitaya (Hylocereus sp.), that are better able to withstand the local environmental conditions (e.g. increased atmospheric SO 2 and acid gas deposition). Despite this, little is known regarding disaster response and risk reduction at the community level and the gas hazard is largely overlooked. This shows large scope for increasing resilience in collaboration with the community, through for example the development of community-level risk management committees, improvement and implementation of (gas) mitigation strategies and disaster preparedness approaches. By reducing the impacts of the chronic hazard posed by persistent volcanic degassing, resilience to acute hazards is also likely to improve.

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