2,081 research outputs found
Tsunami threat in the Indian Ocean from a future megathrust earthquake west of Sumatra
No full textAbstract not availableJohn McCloskey, Andrea Antonioli, Alessio Piatanesi, Kerry Sieh, Sandy Steacy, Suleyman Nalbant, Massimo Cocco, Carlo Giunchi, JianDong Huang, Paul Dunlo
A tale of two disasters: biases in risk communication
No full textTheme for 2016: Recognizing and representing eventsRisk communication, where scientists inform policy-makers
or the populace of the probability and magnitude of possible
disasters, is essential to disaster management – enabling
people to make better decisions regarding preventative steps,
evacuations, etc. Psychological research, however, has
identified multiple biases that can affect people’s
interpretation of probabilities and thus risk. For example,
availability (Tversky & Kahneman, 1973) is known to
confound probability estimates while the descriptionexperience
gap (D-E Gap) (Hertwig & Erev, 2009) shows low
probability events being over-weighted when described and
under-weighted when learnt from laboratory tasks. This paper
examines how probability descriptions interact with real
world experience of events. Responses from 294 participants
across 8 conditions showed that people’s responses, given the
same described probabilities and consequences, were altered
by their familiarity with the disaster (bushfire vs earthquake)
and its salience to them personally. The implications of this
for risk communication are discussed.Matthew B. Welsh, Sandy Steacy, Steve H. Begg, Daniel J. Navarr
Interseismic coupling, stress evolution, and earthquake slip on the Sunda megathrust
No full textThe extent to which interseismic coupling controls the slip distribution of large megathrust earthquakes is unclear, with some authors proposing that it is the primary control and others suggesting that stress changes from previous earthquakes are of first-order importance. Here, we develop a detailed stress history of the Sunda megathrust, modified by coupling, and compare the correlation between slip and stress with that of slip versus coupling. We find that the slip distributions of recent earthquakes are more consistent with the stress field than with the coupling distributions but observe that in places, the stress pattern is strongly dependent on poorly constrained values of slip in historical earthquakes. We also find that of the 13 earthquakes in our study for which we have hypocentral locations, only two appear to have nucleated in areas of negative stress, and these locations correspond to large uncertainties in the slip distribution of pre-instrumental events.Suleyman Nalbant, John McCloskey, Sandy Steacy, Mairead NicBhloscaidh, and Shane Murph
Non-discursive knowledge and the construction of identity. Potters, potting and performance at the bronze age tell of Százhalombatta, Hungary
No full textThis article explores the relationship between the making of things and the making of people at the Bronze Age tell at Százhalombatta, Hungary. Focusing on potters and potting, we explore how the performance of non-discursive knowledge was critical to the construction of social categories. Potters literally came into being as potters through repeated bodily enactment of potting skills. Potters also gained their identity in the social sphere through the connection between their potting performance and their audience. We trace degrees of skill in the ceramic record to reveal the material articulation of non-discursive knowledge and consider the ramifications of the differential acquisition of non-discursive knowledge for the expression of different kinds of potter's identities. The creation of potters as a social category was essential to the ongoing creation of specific forms of material culture. We examine the implications of altered potters' performances and the role of non-discursive knowledge in the construction of social models of the Bronze Ag
Structural analysis and parametric study ballasted track in sandy regions
No full textThe sand intrusion in railway tracks in sandy regions can significantly change the mechanical behaviour of tracks and thus threaten the safety of train operation. This paper presents substantial field tests on both sandy and clean railway tracks to study the effect of sand intrusion on the longitudinal resistance of ballast bed and the vibration behaviour of track structures. After that, a 3D multi-scale the discrete element model is developed to study the micro-contact between ballast particles and the vibration behaviour of sandy tracks during train passing in detail. Also, the effect of train speeds and axle loads on the mechanical behaviour of sandy tracks is discussed. The results show that the sand intrusion increases the vibration acceleration amplitude of rail and sleeper by 11.3% and 50.3%, while ballast bed decreases by 44.9%. Besides, the sand intrusion significantly changes the energy distribution in the track, wherein the frequencies of the highest energy of rail and sleeper are increased while that of the ballast bed is decreased. The parametric study shows the high train speed can cause the increase in overall acceleration of the ballast bed and high axle load can cause an increase in the micro-contact forces between ballast particles, diffusion angle of the contact force chain, displacements of ballast particles, acceleration of ballast particles, and sleeper displacements.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Mechanics and Physics of Structure
Crushed rock and clay amelioration of a nutrient decifient, sandy soil of Maputaland
No full textBibliography: leaves 57-62.Various studies have suggested the possibility that food derived through subsistence agriculture in the Mseleni region of Maputaland contributes to malnutrition within the local community, particularfy within the high proportion of the population which suffers from a severe, disabling form of osteoarthritis. This study was conducted to determine if the application of local crushed rock or black clay to these nutrient deficient, sandy soils would increase available nutrient concentrations and improve the growth of plants in the ameliorated soil
Sandy coastlines under threat of erosion
No full textSandy beaches occupy more than one-third of the global coastline1 and have high socioeconomic value related to recreation, tourism and ecosystem services2. Beaches are the interface between land and ocean, providing coastal protection from marine storms and cyclones3. However the presence of sandy beaches cannot be taken for granted, as they are under constant change, driven by meteorological4,5, geological6 and anthropogenic factors1,7. A substantial proportion of the world’s sandy coastline is already eroding1,7, a situation that could be exacerbated by climate change8,9. Here, we show that ambient trends in shoreline dynamics, combined with coastal recession driven by sea level rise, could result in the near extinction of almost half of the world’s sandy beaches by the end of the century. Moderate GHG emission mitigation could prevent 40% of shoreline retreat. Projected shoreline dynamics are dominated by sea level rise for the majority of sandy beaches, but in certain regions the erosive trend is counteracted by accretive ambient shoreline changes; for example, in the Amazon, East and Southeast Asia and the north tropical Pacific. A substantial proportion of the threatened sandy shorelines are in densely populated areas, underlining the need for the design and implementation of effective adaptive measures.Accepted Author ManuscriptCoastal Engineerin
Tidal stress triggering of earthquakes in Southern California
No full textWe analyse the influence of the solid Earth tides and ocean loading on the occurrence time of Southern California earthquakes. For each earthquake, we calculate tidal Coulomb failure stress and stress rate on a fault plane that is assumed to be controlled by the orientation of the adjacent fault. To reduce bias when selecting data for testing the tide-earthquake relationship, we create four earthquake catalogues containing events within 1, 1.5, 2.5 and 5 km of nearest faults. We investigate the difference in seismicity rates at times of positive and negative tidal stresses/stress rates given three different cases. We consider seismicity rates during times of positive versus negative stress and stress rate, as well as 2 and 3 hr surrounding the local tidal stress extremes. We find that tidal influence on earthquake occurrence is found to be statistically non-random only in close proximity to tidal extremes meaning that magnitude of tidal stress plays an important role in tidal triggering. A non-random tidal signal is observed for the reverse events. Along with a significant increase in earthquake rates around tidal Coulomb stress maxima, the strength of tidal correlation is found to be closely related to the amplitude of the peak tidal Coulomb stress (τp). The most effective tidal triggering is found for τp ≥ 1 kPa, which is much smaller than thresholds suggested for static and dynamic triggering of aftershocks.Magda Bucholc and Sandy Steac
Column on author Sandy Phippen, who was born in White Plains, NY, but moved to M
No full textColumn on author Sandy Phippen, who was born in White Plains, NY, but moved to Maine when he was two months old, and a review of his new book, Kitchen Boy
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