Towards real-time eruption forecasting in the Auckland Volcanic Field: application of BET_EF during the New Zealand National Disaster Exercise ‘Ruaumoko’

The Auckland Volcanic Field (AVF) is a young basaltic field that lies beneath the urban area of Auckland, New Zealand’s largest city. Over the past 250,000 years the AVF has produced at least 49 basaltic centers; the last eruption was only 600 years ago. In recognition of the high risk associated with a possible future eruption in Auckland, the New Zealand government ran Exercise Ruaumoko in March 2008, a test of New Zealand’s nation-wide preparedness for responding to a major disaster resulting from a volcanic eruption in Auckland City. The exercise scenario was developed in secret, and covered the period of precursory activity up until the eruption. During Exercise Ruaumoko we adapted a recently developed statistical code for eruption forecasting, namely BET_EF (Bayesian Event Tree for Eruption Forecasting), to independently track the unrest evolution and to forecast the most likely onset time, location and style of the initial phase of the simulated eruption. The code was set up before the start of the exercise by entering reliable information on the past history of the AVF as well as the monitoring signals expected in the event of magmatic unrest and an impending eruption. The average probabilities calculated by BET_EF during Exercise Ruaumoko corresponded well to the probabilities subjectively (and independently) estimated by the advising scientists (differences of few percentage units), and provided a sound forecast of the timing (before the event, the eruption probability reached 90%) and location of the eruption. This application of BET_EF to a volcanic field that has experienced no historical activity and for which otherwise limited prior information is available shows its versatility and potential usefulness as a tool to aid decision-making for a wide range of volcano types. Our near real-time application of BET_EF during Exercise Ruaumoko highlighted its potential to clarify and possibly optimize decision-making procedures in a future AVF eruption crisis, and as a rational starting point for discussions in a scientific advisory group. It also stimulated valuable scientific discussion around how a future AVF eruption might progress, and highlighted areas of future volcanological research that would reduce epistemic uncertainties through the development of better input models.     

A magnetic study of Etruscan bucchero pottery: An application of rock magnetism to archaeometry

We have applied techniques used in rock magnetism to the study of possible temporal changes in provenance and firing conditions of a collection of Etruscan bucchero pottery fragments representing the interval between 800 B.C. to 400 B.C. To our knowledge, this is the first time that such procedures have been applied to ancient ceramic wares. Our preliminary magnetic measurements demonstrate that this approach can provide useful archaeological information, as exemplified by the following results: (1) Bucchero ceramic styles sottile, spesso, and possibly pesante, contained magnetic particles of similar grain sizes, which suggested a common provenance and similar firing conditions for these pot typologies. (2) Ceramic styles buccheroid impasto and grey bucchero each had magnetic characteristics different from those in (1). However, too few samples of these were available for any definite conclusions. (3) The occurrence of magnetite, and not hematite, in all samples indicated that firing conditions were effectively reducing. (4) Variations in the amount of magnetite in different samples indicated that slight inhomogeneities must have existed in the iron oxide/hydroxide content of the local clay source. Most magnetic techniques are fast, easy, and generally nondestructive. Some magnetic properties, such as initial susceptibility, saturation remanent magnetization, and coercivity of remanence, can even be measured in the field. At the least, magnetic measurements can be used initially to discriminate among different groups of potsherds. Selected samples can then be analyzed with more elaborate methods of archaeometry.     

Distinctive C isotopic signature distinguishes a novel sea ice biomarker in Arctic sediments and sediment traps

A C₂₅ highly branched isoprenoid (HBI) monoene hydrocarbon, designated IP₂₅, has been proposed previously to originate from diatoms living in Arctic sea ice, while the presence of IP₂₅ in sediments has been suggested to be a proxy for the occurrence of former Arctic sea ice. Here, we show that the ¹³C isotopic composition of IP₂₅ in sea ice, in sediment trap material collected under sea ice, and in high latitude northern sediments, is distinctive (isotopically ‘heavy’) and distinguishable from that of organic matter of planktonic or terrigenous origin. Mean δ¹³C values for IP₂₅ were − 22.3 ± 0.4‰ (sea ice), − 19.6 ± 1.1‰ (sediment traps) and − 19.3 ± 2.3‰ (sediments). These measurements, therefore, support further the proposed use of IP₂₅ as an Arctic sea ice proxy.     

Distribution, condition, and growth of newly settled southern flounder (Paralichthys lethostigma) in the Galveston Bay Estuary, TX

Several flatfish species, including southern flounder (Paralichthys lethostigma) recruit to estuaries during early life. Therefore, evaluation of estuarine sites and habitats that serve as nurseries is critical to conservation and management. The present study used density data in conjunction with biochemical condition and growth measurements to evaluate settlement sites used by southern flounder in the Galveston Bay Estuary (GBE). In 2005, beam-trawl collections were made in three major sections of the GBE (East Bay, Galveston Bay, West Bay). Three sites were sampled in each bay. Within each sampling site, replicate collections were taken from three habitats: 1) marsh edge (< 1 m depth), 2) intermediate zone (10–20 m from marsh interface;  1 m depth), and 3) bay zone (typically > 100 m from marsh interface; depth > 1 m). Average size of southern flounder collected was 12–19 mm standard length, and peak densities occurred in January and February. Catch data indicated that densities of southern flounder were significantly greater in East Bay (2.75 per 100 m²) than in Galveston Bay (0.91 per 100 m²) or in West Bay (0.45 per 100 m²). Densities were statistically similar among habitats. Otolith-based estimates of age indicated that the majority of southern flounder collected were 35–45 days old and derived from early December to early January hatch-dates. Growth rates were similar among bays and among habitats, with the average growth rate being 0.40 mm day^− 1 (range: 0.21–0.76 mm day^− 1). RNA:DNA was above the established baseline value for nutritional stress, indicating that newly settled southern flounder in the GBE were in relatively high condition. Habitat-specific differences in RNA:DNA ratios were not observed; however, ratios were significantly lower in West Bay (average 8.0) than in East Bay (average 9.5) or in Galveston Bay (average 9.8), suggesting the condition of new recruits may vary spatially within the GBE. Findings from the current study suggest density and condition of newly settled southern flounder vary at the bay scale, suggesting that parts of GBE do not function equally as nurseries.     

Compounding impacts of hazard exposures on mental health in Houston,TX

Natural Hazards - Natural and anthropogenic hazards are increasingly becoming commonplace due to climate change and population pressures. The state of Texas is particularly vulnerable to these...     

Some challenges of monitoring a potentially active volcanic field in a large urban area: Auckland volcanic field,New Zealand

Natural Hazards - The city of Auckland (population 1.3&nbsp;million) is built on and around a potentially active basaltic intraplate volcanic system, the Auckland volcanic field. This...     

Geosite of a steep lava spatter cone of the 1256 AD, Al Madinah eruption, Kingdom of Saudi Arabia

UNESCO promotes geoconservation through various programs intended to establish an inventory of geologically and geomorphologically significant features worldwide that can serve as an important database to understand the Earth’s global geoheritage. An ultimate goal of such projects globally is to establish geoparks that represent an integrated network of knowledge transfer opportunities, based on a specific array of geological and geomorphological sites able to graphically demonstrate how the Earth works to the general public. In these complex geoconservation and geoeducational programs, the identification of significant geological and geomorphological features is very important. These are commonly referred to as ‘geosites’ or ‘geomorphosites’, depending on whether the feature or processes the site demonstrates is more geological or geomorphological, respectively. The Kingdom of Saudi Arabia is an extraordinary place due to its arid climate and therefore perfect exposures of rock formations. The Kingdom is also home to extensive volcanic fields, named “harrats” in Arabic, referring particularly to the black, basaltic lava fields that dominate the desert landscape. Current efforts to increase awareness of the importance of these volcanic fields in the geological landscape of Arabia culminated in the first proposal to incorporate the superbly exposed volcanic features into an integrated geoconservation and geoeducation program that will hopefully lead to the development of a geopark named, “The Harrat Al Madinah Volcanic Geopark” [1]. Here we describe one of the extraordinary features of the proposed Harrat Al Madinah Volcanic Geopark, namely a steep lava spatter cone formed during a historical eruption in 1256 AD.     

Does the Milky Way launch a large-scale wind?

The ROSAT All-Sky Survey revealed soft X-ray emission on kiloparsec scales towards the Galactic center. Separately, it has also been observed that the cosmic ray intensity (measured via γ-ray emission) rises only very slowly towards the center of the Galaxy, counter to expectations based on the greater number of cosmic ray sources there. A thermal and cosmic-ray driven wind could potentially explain both of these observations. We find that a cosmic-ray and thermally driven wind fits the X-ray observations well; in fact, a wind fits significantly better than an earlier-proposed static-polytrope gas model.