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Tephra fall from the August 1991 eruption of Volcán Hudson affected some 100,000 km 2 of Patagonia and was almost immediately reworked by strong winds, creating billowing clouds of remobilised ash, or 'ash storms'. The immediate impacts on agriculture and rural communities were severe, but were then greatly exacerbated by continuing ash storms. This paper describes the findings of a 3-week study tour of the diverse environments of southern Patagonia affected by ash storms, with an emphasis on determining the impacts of repeated ash storms on agriculture and local practices that were developed in an attempt to mitigate these impacts. Ash storms produce similar effects to initial tephra eruptions, prolonged for measures include deep cultivation of the ash into the soil and erecting windbreaks.

The paper analyzes the performance of a hospital system using a holistic and multidisciplinary approach. Data on impacts to the hospital system were collected using a standardized survey tool. A fault-tree analysis method is adopted to assess the functionality of critical hospital services based on three main contributing factors: staff, structure, and stuff. Damage to utility networks and to nonstructural components was found to have the most significant effect on hospital functionality. The functional curve is integrated over time to estimate the resilience of the regional acute-care hospital with and without the redistribution of its major services. The ability of the hospital network to offer redundancies in services after the earthquake increased the resilience of the Christchurch Hospital by 12%. The resilience method can be used to assess future performance of hospitals, and to quantify the effectiveness of seismic retrofits, hospital safety legislation, and new seismic preparedness strategies.

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. A recent consideration in aircraft design is the use of folding wing-tips with the aim of enabling higher aspect ratio aircraft with less induced drag, but also meeting airport gate limitations. This study investigates the effect of exploiting folding wing-tips in-flight, as device to reduce both static and dynamic loads. A representative civil jet aircraft aeroelastic model was used to explore the effect of introducing a wing-tip device, connected to the wings with an elastic hinge, on the loads behavior. For the dynamic cases, vertical discrete gusts and continuous turbulence were considered. The effect of hinge orientation, stiffness, damping and wing-tip weight on the static and dynamic response was investigated. It was found that significant reductions in both the static and dynamic loads were possible. For the case considered, a 25% increase in span using folding wing-tips resulted in almost no increase in loads.

Tephra: Fragments of rock, regardless of size, that become airborne during a volcanic eruption. Lapilli: Fragments of rock, between 2 and 64 mm in diameter, produced explosively during a volcanic eruption. Volcanic ash: Tephra less than 2 mm in diameter, produced explosively during a volcanic eruption. Ash (tephra) fall: Volcanic ash and lapilli dispersed by winds away from the volcano, falling out of suspension to form a deposit. Tephra falls are commonly referred to colloquially as ash falls. Hazard: Potential threat arising from the physical phenomenon. Hazard intensity: A parameter describing the severity of a hazard at a location, e.g. ash fall thickness. Exposure: Societal assets (e.g. people, property, infrastructure networks) present in hazard zones that are thereby subject to potential losses. Vulnerability: The degree to which characteristics and the circumstances of an individual, community, system, network or asset, and any interdependencies, makes it susceptible to the damaging effects of a hazard. Impact: Function of the hazard and vulnerability on the exposed asset. Risk: Function of both the characteristics of the hazardous event and the consequences for the exposed assets. Resilience: The ability of a system, community or society exposed to hazards to resist, absorb, accommodate to and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic structures and functions.

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