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We examined the radiocarbon (14C) reservoir effect in Lake Kutubu using tephrochronology and terrestrial plant material to deliver a precise age-depth profile and sedimentation rates for this lake. Based on the presence of two tephra horizons (Tibito and Olgaboli), we found a reservoir age offset in sediments of between 1490 and 228014C yr using the sediment ages derived from the lead-210 (210Pb) dating method. The live submerged biological samples collected exhibited a higher reservoir age offset than the sediment. This is most likely a result of delayed transport of “bomb”14C from the atmosphere to aquatic and sedimentary system. The14C reservoir effect increased with distance from the lake inlet and also decreased with depth. Dissolution of14C-depleted carbon from surrounding limestone and direct in-wash of old soil or vegetation remnants from the catchment are the most likely causes of the14C reservoir effect. Based on limestone areas mapped in Papua New Guinea, we indicate lakes which may be subject to a significant14C reservoir effect. The results of this study demonstrate the magnitude of the14C reservoir effect in lakes and provide insights to the correct interpretation of past environmental and archaeological events in PNG.

Tibito Tephra was first recorded in the central highlands of Papua New Guinea (PNG) in 1971. By the late 1970s, the tephra had been mapped across tens of thousands of square kilometres, traced to i...

Sediment cores were retrieved from Lake Kutubu, the largest upland lake in Papua New Guinea, to assess palaeoenvironmental baselines. Two prominent tephra layers were encountered within the cores. Using a combination of core stratigraphy, sediment properties and geochemical characterization (electron microprobe and laser ablation inductively coupled-plasma mass spectrometry techniques) we were able to correlate these tephras with Tibito and Olgaboli tephras, both previously described at adjacent distal localities. Glass shard compositional data of Tibito tephra from Lake Kutubu, Kuk swamp and from proximal volcaniclastic successions from Long Island are indistinguishable and this similarity strongly supports Long Island as the eruptive source. For Olgaboli tephra, the location of its eruptive source is less certain but the glass shard compositional data indicate a Karkar Island source. The occurrence of Tibito and Olgaboli tephras in Lake Kubutu sediments extends their known distributions further south-west into the southern Highlands region and affirms their importance as inter-regional stratigraphic markers, of late Holocene age, that have considerable potential for use in future palaeoenvironmental, archaeological and volcanic hazard and/or impact studies.

William Dampier, one of England’s greatest navigators, named, described, and drew a profile of Long Island, Papua New Guinea in 1700. As this island produced a very large volcanic eruption with a disputed seventeenth- or eighteenth-century date, his observations assist in determining whether the eruption occurred before or after his visit. This contribution uses Dampier’s recorded observations to elucidate where the Roebuck was when the Long Island profile was drawn so that an appropriate comparison can be made with a modern profile of the island. This comparison confirms that the most recent major eruption of Long Island occurred before Dampier’s observations were made.

Estimates of the age of the widespread Tibito Tephra and the VEI 6 eruption of Long Island, Papua New Guinea, have been based on genealogical records derived from oral histories of a ‘time of darkness’, the voyage of William Dampier who named Long Island in 1700 CE, radiocarbon, palaeomagnetic and 210Pb dating, and efforts from around the world to associate the eruption with a number of sulphur spikes in Greenland and Antarctic ice cores that were not linked to better-known eruptions. In total, there have been more than one hundred estimates of the timing of the eruption, with appraisals ranging from the late 16th century to the early 20th century. Some of these estimates have been based on solid science, some have ignored or been unaware of constraints on the possible eruption date imposed by the need to make an allowance for revegetation of the island before or after the observations of Dampier and other navigators, and some have tried to relate the eruption to the misdirected observation of sunsets over London in 1665. This account describes, more or less in chronological order, the narrowing of the supposed eruption date to the latter half of the 17th century, an early record suggesting a possible link to a 1667 acidity peak in the Crete, Greenland ice core, further constraints imposed by a renewed round of radiocarbon assays, and a final suggestion of a likely but not proven 1665–1668 eruption based on recent Antarctic and Greenland ice cores. We also elucidate missteps along the way introduced by the reliance on Royal Society of London records from the late 19th and 20th centuries and the role of the Victorian novelist William Harrison Ainsworth and Daniel Defoe's early-17th century accounts of bubonic plague in London in 1665 in leading us down dead-end pathways.

With increasing population densities and expanding urban boundaries, the potential for explosive volcanic eruptions to have adverse impacts upon urban areas is on the rise. This is particularly true for volcanoes along subduction zones, because they are almost exclusively explosive and often coincident with large populations. Explosive eruption hazards such as tephra fall have the potential to affect very large areas and numbers of people; populations in volcanic areas may therefore be exposed to tephra falls from more than one volcano. In this study we have simulated large numbers of plausible explosive eruptions of Volcanic Explosivity Index (VEI) 4 or greater for each of 141 volcanoes in the Asia-Pacific region. Tephra fall footprints are aggregated for 16 major cities, according to their probability of occurrence. This addresses an emerging need for international agencies and organizations to conduct regional-scale assessments, where at-risk areas can be compared on a like-for-like basis. Hazard in cities near subduction zones is two to three orders of magnitude greater than for those farther away. By combining our hazard estimates with indicators describing the exposure and vulnerability of people and infrastructure, tephra fall risk scores were calculated for each city. Risk is evaluated separately for human populations and potential economic impact, with the highest human risk scores calculated for Manila and the highest economic scores for Tokyo. The volcanoes with the greatest hazard contribution in the very populous cities of Manila, Tokyo, and Jakarta were identified as Taal (Manila), Fujisan (Tokyo), and six volcanoes equally (Jakarta). While this study provides a transparent and consistent method for assessing regional volcanic hazard and risk, there are challenges associated with the data-poor setting and we conclude by discussing what is required in order to improve regional tephra fall hazard and risk assessments. This study provides a regional-scale assessment that cannot replace hazard and risk information provided locally by official organizations. Published version

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Although probabilistic insurance loss models, particularly for ash fall, are currently being developed volcanic risk has been widely ignored by insurers and policy holders alike. Volcanic eruption cover is often grouped in insurance and reinsurance policies with earthquake and tsunami cover. Many volcanic eruptions include several perils occurring in different spaces around the volcano, with widely varying intensities and consequences, sometimes all at once, sometimes sequentially, and sometimes repeatedly. Given the possibly large differences in hazard characteristics, event durations and potential losses the policy alignment with earthquake and tsunami covers can be unfortunate. Does ‘volcanic activity’ have the same meaning as ‘volcanic eruption’? Do the terms ‘ash fall’ and ‘pyroclastic fall’ have identical meanings to an insurer—or to a volcanologist? Some policies cover all volcanic perils while others include only named volcanic perils such as pyroclastic flows, ash falls, and/or lava flows. Often the intent of the coverage is not clear—were some volcanic perils missing from a list excluded by accident or design? Does a policy that covers damage occasioned by a fall of volcanic ash also cover the cost of clean-up, removal, transport and appropriate storage of the ash—even if the fall of 5–10 mm of ash causes almost no property damage? Clear communication between the insurance sector and policy holders (and the media) is dependent upon informed understanding of the nature of volcanic perils and volcanic eruptions, insurance wordings, and the potential losses to property and business interruption covers. This chapter explores these issues using examples of policy wordings, evidence from past eruptions, insurance case law, and potential losses in future eruptions.

Volcanic ash falls are one of the most widespread and frequent volcanic hazards, and are produced by all explosive volcanic eruptions. Ash falls are arguably the most disruptive volcanic hazard because of their ability to affect large areas and to impact a wide range of assets, even at relatively small thicknesses. From an insurance perspective, the most valuable insured assets are buildings. Ash fall vulnerability curves or functions, which relate the magnitude of ash fall to likely damage, are the most developed for buildings, although there have been important recent advances for agriculture and infrastructure. In this paper, we focus on existing vulnerability functions developed for volcanic ash fall impact on buildings, and apply them to a hypothetical building portfolio impacted by a modern-day Tambora 1815 eruption scenario. We compare and contrast the different developed functions and discuss some of the issues surrounding estimation of potential building damage following a volcanic eruption. We found substantial variability in the different vulnerability estimates, which contribute to large uncertainties when estimating potential building damage and loss. Given the lack of detailed and published studies of building damage resulting from ash fall this is not surprising, although it also appears to be the case for other natural hazards for which there are far more empirical damage data. Notwithstanding the potential limitations of some empirical data in constraining vulnerability functions, efforts are required to improve our estimates of building damage under ash fall loading through the collection of damage data, experimental testing and perhaps theoretical failure analysis. For insurance purposes, the current building typologies provided for use with vulnerability functions are too detailed to map to the relatively limited information on building types that is typically available to insurers. Thus, efforts to provide vulnerability functions that can be used where only limited information is available regarding building types would also be valuable, both for insurers and for at-risk areas that have not been subject to detailed building vulnerability surveys. Published version

In a volcanic eruption crisis, robust, scientifically informed risk advice can assist individuals to adopt suitable policies for personal protection and societal decision makers in the implementation of rational mitigation strategies for communities. We outline a number of risk assessment procedures that inform volcanic risk management, recognising that it is difficult to construct a single uniform framework suitable for all situations and all economic circumstances. We list a number of post-1950 landmark eruptions that have prompted development of volcanic risk assessment techniques, and briefly consider the range of volcanic hazards involved, the assets at risk and associated vulnerabilities. Then, we focus on risk metrics, tolerable and intolerable risks, as low as reasonably practicable (ALARP) principles, and casualty scale aversion, using as examples some volcanic disasters embedded in an industrial health and safety framework. Risk matrices, and their limitations, and F-N curves, often used to express relative risk levels for communication, are described in some detail before exploring the role of cost–benefit analysis in characterizing societal and individual risks objectively. Attention is also paid to the enumeration of relative risks from a range of volcanic hazards and, for illustration, we outline a specific risk assessment approach that combines jointly measures of ash fall hazard, exposure, and vulnerability. Because we recognise that some of the inputs to volcanic risk management are subjective, there is a strong emphasis on the value of using structured expert elicitation to quantify volcanic hazard uncertainties as informatively as possible. We conclude with a commentary on public risk communication, and end by noting that information relating to “near-miss” and very rare events can be included in risk assessment through counterfactual analysis.