125 research outputs found

    Earthquake propensity and the politics of mortality prevention

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    Governments can significantly reduce earthquake mortality by implementing and enforcing quake-proof construction regulation. The authors examine why many governments do not. Contrary to intuition, controlling for the strength and location of actual earthquakes, mortality is lower in countries with higher earthquake propensity, where the payoffs to mortality prevention are higher. Importantly, however, the government response to earthquake propensity depends on country income and the political incentives of governments to provide public goods to citizens. The opportunity costs of earthquake mortality prevention are higher in poorer countries; rich countries invest more in mortality prevention than poor countries in response to a higher earthquake propensity. Similarly, governments that have fewer incentives to provide public goods, such as younger democracies, autocracies with less institutionalized ruling parties and countries with corrupt regimes, respond less to an elevated quake propensity. They therefore have higher mortality at any level of quake propensity compared to older democracies, autocracies with highly institutionalized parties and non-corrupt regimes, respectively. The authors find robust evidence for these predictions in our analysis of earthquake mortality over the period 1960 to 2005.Population Policies,Natural Disasters,Hazard Risk Management,Labor Policies,Disaster Management

    Tobler’s law and wavefront patterns in the spatial spread of COVID-19 across Europe during the Delta and Omicron waves

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    Aims Epidemic wave front models predict well the spread of medieval pandemics like the plague. Our aim is to explore whether they still contribute to understanding the spread of COVID-19, the first truly global pandemic of the modern age with fast and frequent international travel links. Methods We analyse the spatial spread of reaching a threshold of very high incidence of new daily infections of the virus across European countries in the autumn of 2021 in which the Delta variant was dominant as well as an even higher threshold of incidence in the subsequent spread of infections across the same set of countries during the winter of 2021/22 when the Omicron variant of the virus became dominant. Results We find patterns that are consistent with wave front models for both periods of the pandemic in Europe. Conclusions Modern means of transportation strongly accelerate the spread of the virus and typically generate diffusion patterns along bi-directional constrained mobility networks in addition to stochastic diffusion processes. However, since the majority of mobility, including mobility across international borders, remains of the short-distance kind, wavefront patterns in the spread of a pandemic are still to be expected

    Subseismic to Seismic Slip in Smectite Clay Nanofoliation

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    Smectite clays are the main constituent of slipping zones found in subduction zone faults at shallow depth (e.g., <1-km depth in the Japan Trench) and in the decollements of large landslides (e.g., 1963 landslide, Vajont, Italy). Therefore, deformation processes in smectite clays may control the mechanical behavior from slow creep to fast accelerations and slip during earthquakes and landslides. Here, we use (1) laboratory experiments to investigate the mechanical behavior of partly water-saturated smectite-rich gouges sheared from subseismic to seismic slip rates V and (2) nanoscale microscopy to study the gouge fabric. At all slip rates, deformation localizes in volumes of the gouge layer that contain a \u201cnanofoliation\u201d consisting of anastomosing smectite crystals. \u201cSeismic\u201d nanofoliations produced at V = 0.01, 0.1, and 1.3 m/s are similar to \u201csubseismic\u201d nanofoliations obtained at V = 10 125 m/s. This similarity suggests that frictional slip along water-lubricated smectite grain boundaries and basal planes may occur from subseismic to seismic slip rates in natural smectite-rich faults. Thus, if water is available along smectite grain boundaries and basal planes, nanofoliations can develop from slow to fast slip rates. Still, when nanofoliations are found highly localized in a volume, they can be diagnostic of slip that occurred at rates equal or larger than 0.01 m/s. In such a case, they could be markers of past seismic events when found in natural fault rocks

    Dynamic evolution of porosity in lower-crustal faults during the earthquake cycle

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    Earthquake-induced fracturing of the dry and strong lower crust can transiently increase permeability for fluids to flow and trigger metamorphic and rheological transformations. However, little is known about the porosity that facilitates these transformations. We analyzed microstructures that have recorded the mechanisms generating porosity in the lower crust from a pristine pseudotachylyte (solidified earthquake-derived frictional melt) and a mylonitized pseudotachylyte from Lofoten, Norway to understand the evolution of fluid pathways from the coseismic to the post- and interseismic stages of the earthquake cycle. Porosity is dispersed and poorly interconnected within the pseudotachylyte vein (0.14 vol%), with a noticeably increased amount along garnet grain boundaries (0.25–0.41 vol%). This porosity formed due to a net negative volume change at the grain boundary when garnet overgrows the pseudotachylyte matrix. Efficient healing of the damage zone by fluid-assisted growth of feldspar neoblasts resulted in the preservation of only a few but relatively large interconnected pores along coseismic fractures (0.03 vol% porosity). In contrast, porosity in the mylonitized pseudotachylyte is dramatically reduced (0.02 vol% overall), because of the efficient precipitation of phases (amphibole, biotite and feldspars) into transient pores during grain-size sensitive creep. Porosity reduction on the order of &gt;85% may be a contributing factor in shear zone hardening, potentially leading to the development of new pseudotachylytes overprinting the mylonites. Our results show that earthquake-induced rheological weakening of the lower crust is intermittent and occurs when a fluid can infiltrate a transiently permeable shear zone, thereby facilitating diffusive mass transfer and creep

    Neutron/Proton Structure Function Ratio at Large x

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    We re-examine the large-x neutron/proton structure function ratio extracted from the latest deuteron data, taking into account the most recent developments in the treatment of Fermi motion, binding and nucleon off-shell effects in the deuteron. Our findings suggest that as x->1 the ratio of the neutron to proton structure functions (F_2^n/F_2^p) is consistent with the perturbative QCD expectation of 3/7, but larger than the value of 1/4 obtained in earlier analyses.Comment: 18 pages RevTeX, 4 postscript figures, accepted for publication in Phys. Lett.

    Higher education and unemployment in Europe : an analysis of the academic subject and national effects

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    This paper examines the impact of an academic degree and field of study on short and long-term unemployment across Europe (EU15). Labour Force Survey (LFS) data on over half a million individuals are utilised for that purpose. The harmonized LFS classification of level of education and field of study overcomes past problems of comparability across Europe. The study analyses (i) the effect of an academic degree at a European level, (ii) the specific effect of 14 academic subjects and (iii) country specific effects. The results indicate that an academic degree is more effective on reducing the likelihood of short-term than long-term unemployment. This general pattern even though it is observed for most of the academic subjects its levels show significant variation across disciplines and countries

    An experimental study of the carbonation of serpentinite and partially serpentinised peridotites

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    In situ sequestration of CO2 in mantle peridotites has been proposed as a method to alleviate the amount of anthropogenic CO2 in the atmosphere. This study presents the results of 8-month long laboratory fluid-rock experiments on representative mantle rocks from the Oman-United Arab Emirates ophiolite to investigate this process. Small core samples (3 cm long) were reacted in wet supercritical CO2 and CO2-saturated brine at 100 bar and 70◩C. The extent of carbonate formation, and hence the degree of carbon sequestration, varied greatly depending on rock type, with serpentinite (lizardite-dominated) exhibiting the highest capacity, manifested by the precipitation of magnesite MgCO3 and ferroan magnesite (Mg,Fe)CO3. The carbonate precipitation occurred predominantly on the surface of the core and subordinately within cross-cutting fractures. The extent of the CO2 reactions appeared to be principally controlled by the chemical and mineralogical composition of the rock, as well as the rock texture, with all these factors influencing the extent and rate of mineral dissolution and release of Mg and Fe for subsequent reaction with the CO2. It was calculated that ≈0.7 g of CO2 was captured by reacting ≈23 g of serpentinite, determined by the mass of magnesite formed. This equates to ≈30 kg CO2 per ton of host rock, equivalent to ≈3% carbonation in half a year. However, recycling of carbonate present in veins within the original rock sample could mean that the overall amount is around 2%. The increased reactivity of serpentinite was associated with preferential dissolution of more reactive types of serpentine minerals and brucite that were mainly present in the cross-cutting veins. The bulk of the serpentinite rock was little affected. This study, using relatively short term experiments, suggests that serpentinite might be a good host rock for CO2 sequestration, although long term experiments might prove that dunite and harzburgite could be as effective in an engineered system of CCSM. Wet scCO2 proved to be chemically more aggressive than CO2-saturated brine and its ingress along fractures and grain boundaries resulted in greater host rock dissolution and subsequent carbonate precipitation

    DEEP INELASTIC SCATTERING FROM POLARIZED DEUTERONS

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    The spin-dependent structure function of the deuteron, g_1D, is calculated within a covariant framework. The off-shell structure of the bound nucleon gives corrections to the convolution model at a level of half a percent for x below 0.7, increasing to more than five percent at larger x. Overall, the dominant source of error comes from the lack of knowledge associated with the deuteron D-state, which may introduce an uncertainty in the neutron spin structure function, g_1n, extracted from deuterium data of up to ten percent for x around 0.2.Comment: 11 pages, LaTeX, 4 uuencoded figure

    The tourism and economic growth enigma: Examining an ambiguous relationship through multiple prisms

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    This paper revisits the ambiguous relationship between tourism and economic growth, providing a comprehensive study of destinations across the globe which takes into account the key dynamics that influence tourism and economic performance. We focus on 113 countries over the period 1995-2014, clustered, for the first time, around six criteria that reflect their economic, political and tourism dimensions. A Panel Vector Autoregressive model is employed which, in contrast to previous studies, allows the data to reveal any tourism-economy interdependencies across these clusters, without imposing a priori the direction of causality. Overall, the economic-driven tourism growth hypothesis seems to prevail in countries which are developing, non-democratic, highly bureaucratic and have low tourism specialization. Conversely, bidirectional relationships are established for economies which are stronger, democratic and with higher levels of government effectiveness. Thus, depending on the economic, political and tourism status of a destination, different policy implications apply
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