Modeling the integrated roles of insurance and retrofit in managing natural disaster risk: a multi-stakeholder perspective

This paper introduces a new modeling framework to understand and improve regional natural disaster risk management in the USA, including the interactions among key stakeholders and between the two important risk management mechanisms of insurance and retrofit. The framework includes a stochastic programming optimization to represent insurer decisions, which interacts with a utility-based model of individual homeowners’ decisions to insure and/or retrofit. Reinsurer and government roles are represented as inputs, and the decision models are integrated with a detailed regional catastrophe loss estimation model. This modeling framework is applied to a full-scale, realistic case study for hurricane risk to residential buildings in Eastern North Carolina. Several alternative system configurations are considered that affect the incentives for adoption of alternative risk management methods. They include providing a government subsidy for insured homeowners to encourage retrofit, providing both a government subsidy and insurance rebate to reduce retrofit costs, and mandating insurance purchase with a cap on insurance premiums. For each configuration, outcomes are presented from the perspectives of all key stakeholders—primary insurer, homeowners (insured and uninsured, in high- and low-risk areas), reinsurers, and the government. Results suggest that it is possible to design policies in which all stakeholders can be better off simultaneously. Retrofit incentives for insured homeowners can be effective in linking and strengthening the benefits of retrofit and insurance. Mandatory insurance coupled with capped profit loading factors and possibly retrofit rebates from the insurer to the homeowner can also reduce overall system risk.     

Fragmentation as a Strategy for Caulerpa Species: Fates of Fragments and Implications for Management of an Invasive Weed

Abstract. The successful growth of fragments to full size macroalgal clones is well known for many taxa in mariculture. From an ecological context, however, few studies relate success by invasive species to the ability to fragment readily, disperse widely or re-attach rapidly - obvious hallmarks of weedy species. This study compares morphologically and ecologically distinct species of the green alga Caulerpa : in the Mediterranean, Caulerpa taxifolia is well known as an invasive weed; Caulerpa prolifera grows around or inside seagrass beds and is not apparently invasive; Caulerpa verticillata is among the most diminutive species, with potentially the most restricted reef distribution. We tested three hypotheses: (i) fragment success is independent of size, (ii) fragment success is independent of position within the plant and (iii) fragments from all species will be equally successful in establishing rhizoids, the first step to re-attachment. The success of small fragments (5–40 mm lengths) cut from distinct locations within replicate plants was scored for survival and establishment of rhizoids in bioassays. Additionally, for C. taxifolia , estimates were made of the force needed to puncture upright and prostrate axes, thereby estimating forces required to generate fragments from these two sources. Among the three species, only upright axes of C. taxifolia readily recovered from fragmentation stress for fragment sizes > 10 mm. The forces required to fragment upright axes were substantially less than for comparable rhizome portions. Fragments of C. prolifera were viable only for rhizome portions; fragments of C. verticillata were not viable at any size examined in this study. Estimates of viable fragment size, origin and force required to fragment axes for C. taxifolia support existing field data suggesting that fragmentation is the effective propagation mechanism underlying the spread of this invasive weed.     

The estimation of spectra from time‐frequency transforms for use in attenuation studies

We introduce the signal dependent time–frequency distribution, which is a time–frequency distribution that allows the user to optimize the tradeoff between joint time–frequency resolution and suppression of transform artefacts. The signal‐dependent time–frequency distribution, as well as the short‐time Fourier transform, Stockwell transform, and the Fourier transform are analysed for their ability to estimate the spectrum of a known wavelet used in a tuning wedge model. Next, the signal‐dependent time–frequency distribution, and fixed‐ and variable‐window transforms are used to estimate spectra from a zero‐offset synthetic seismogram. Attenuation is estimated from the associated spectral ratio curves, and the accuracy of the results is compared. The synthetic consisted of six pairs of strong reflections, based on real well‐log data, with a modeled intrinsic attenuation value of 1000/Q = 20. The signal‐dependent time–frequency distribution was the only time–frequency transform found to produce spectra that estimated consistent attenuation values, with an average of 1000/Q = 26±2; results from the fixed‐ and variable‐window transforms were 24±17 and 39±10, respectively. Finally, all three time–frequency transforms were used in a pre‐stack attenuation estimation method (the pre‐stack Q inversion algorithm) applied to a gather from a North Sea seismic dataset, to estimate attenuation between nine different strong reflections. In this case, the signal‐dependent time‐frequency distribution produced spectra more consistent with the constant‐Q model of attenuation assumed in the pre‐stack attenuation estimation algorithm: the average L1 residuals of the spectral ratio surfaces from the theoretical constant‐Q expectation for the signal‐dependent time‐frequency distribution, short‐time Fourier transform, and Stockwell transform were 0.12, 0.21, and 0.33, respectively. Based on the results shown, the signal‐dependent time‐frequency distribution is a time–frequency distribution that can provide more accurate and precise estimations of the amplitude spectrum of a reflection, due to a higher attainable time–frequency resolution.     

Dynamical mass estimates of young massive clusters in NGC1140 and M83

We present virial mass estimates of young massive clusters (YMCs) in the starburst galaxies NGC1140 and M83, determined from high spectral resolution VLT echelle spectroscopy and high spatial resolution Hubble Space Telescope imaging. The survivability of such clusters is important in testing the scenario that YMCs are potentially proto-globular clusters. As young clusters, they lie in the domain in which dynamical masses appear to overestimate true cluster masses, most likely due to the clusters not being virialised. We find that the dynamical mass of NGC1140-1 is approximately ten times greater than its photometric mass. We propose that the most likely explanation for this disparity is the crowded environment of NGC1140-1, rather than this being solely due to a lack of virial equilibrium.     

Experimental and petrological constraints on lunar differentiation from the Apollo 15 green picritic glasses

Abstract— Phase equilibrium experiments on the most magnesian Apollo 15C green picritic glass composition indicate a multiple saturation point with olivine and orthopyroxene at 1520°C and 1.3 GPa (about 260 km depth in the moon). This composition has the highest Mg# of any lunar picritic glass and the shallowest multiple saturation point. Experiments on an Apollo 15A composition indicate a multiple saturation point with olivine and orthopyroxene at 1520°C and 2.2 GPa (about 440 km depth in the moon). The importance of the distinctive compositional trends of the Apollo 15 groups A, B, and C picritic glasses merits the reanalysis of NASA slide 15426,72 with modern electron microprobe techniques. We confirm the compositional trends reported by Delano (1979, 1986) in the major element oxides SiO₂, TiO₂, Al₂O₃, Cr₂O₃, FeO, MnO, MgO, and CaO, and we also obtained data for the trace elements P₂O₅, K₂O, Na₂O, NiO, S, Cu, Cl, Zn, and F. Petrogenetic modeling demonstrates that the Apollo 15 A‐B‐C glass trends could not have been formed by fractional crystallization or any continuous assimilation/fractional crystallization (AFC) process. The B and C glass compositional trends could not have been formed by batch or incremental melting of an olivine + orthopyroxene source or any other homogeneous source, though the A glasses may have been formed by congruent melting over a small pressure range at depth. The B compositional trend is well modeled by starting with an intermediate A composition and assimilating a shallower, melted cumulate, and the C compositional trend is well modeled by a second assimilation event. The assimilation process envisioned is one in which heat and mass transfer were separated in space and time. In an initial intrusive event, a picritic magma crystallized and provided heat to melt magma ocean cumulates. In a later replenishment event, the picritic magma incrementally mixed with the melted cumulate (creating the compositional trends in the green glass data set), ascended to the lunar surface, and erupted as a fire fountain. A barometer created from multiple saturation points provides a depth estimate of other glasses in the A‐B‐C trend and of the depths of assimilation. This barometer demonstrates that the Apollo 15 A‐B‐C trend originated over a depth range of ?460 km to ?260 km within the moon.     

Cassini thermal observations of Saturn's main rings: Implications for particle rotation and vertical mixing

In late 2004 and 2005 the Cassini composite infrared spectrometer (CIRS) obtained spatially resolved thermal infrared radial scans of Saturn's main rings (A, B and C, and Cassini Division) that show ring temperatures decreasing with increasing solar phase angle, α, on both the lit and unlit faces of the ring plane. These temperature differences suggest that Saturn's main rings include a population of ring particles that spin slowly, with a spin period greater than 3.6 h, given their low thermal inertia. The A ring shows the smallest temperature variation with α, and this variation decreases with distance from the planet. This suggests an increasing number of smaller, and/or more rapidly rotating ring particles with more uniform temperatures, resulting perhaps from stirring by the density waves in the outer A ring and/or self-gravity wakes.The temperatures of the A and B rings are correlated with their optical depth, τ, when viewed from the lit face, and anti-correlated when viewed from the unlit face. On the unlit face of the B ring, not only do the lowest temperatures correlate with the largest τ, these temperatures are also the same at both low and high α, suggesting that little sunlight is penetrating these regions.The temperature differential from the lit to the unlit side of the rings is a strong, nearly linear, function of optical depth. This is consistent with the expectation that little sunlight penetrates to the dark side of the densest rings, but also suggests that little vertical mixing of ring particles is taking place in the A and B rings.     

The dynamics of the ring nebula surrounding the LBV candidate He 3-519

High spatial and spectral resolution observations of the ring nebula surrounding the LBV candidate He 3-519 are presented. The data were obtained at the AAT with the UCL echelle spectrograph and cover the H and [N II] emission lines for two slit positions. The nebular motions are clearly resolved and have a total velocity spread of -40 to +100 km s^–1. The shell shows some deviations from spherical symmetry but overall is expanding at 61 km s^–1 and has an ionized mass of 2 M. The nebular parameters are found to be similar to those of the AG Car nebula, suggesting that it resulted from a bulk ejection of material 2 × 10⁴ yr ago.     

Fall,classification, and exposure history of the Mifflin L5 chondrite

The Mifflin meteorite fell on the night of April 14, 2010, in southwestern Wisconsin. A bright fireball was observed throughout a wide area of the midwestern United States. The petrography, mineral compositions, and oxygen isotope ratios indicate that the meteorite is a L5 chondrite fragmental breccia with light/dark structure. The meteorite shows a low shock stage of S2, although some shock‐melted veins are present. The U,Th‐He age is 0.7 Ga, and the K‐Ar age is 1.8 Ga, indicating that Mifflin might have been heated at the time of the 470 Ma L‐chondrite parent body breakup and that U, Th‐He, and K‐Ar ages were partially reset. The cosmogenic radionuclide data indicate that Mifflin was exposed to cosmic rays while its radius was 30–65 cm. Assuming this exposure geometry, a cosmic‐ray exposure age of 25 ± 3 Ma is calculated from cosmogenic noble gas concentrations. The low ²²Ne/²¹Ne ratio may, however, indicate a two‐stage exposure with a longer first‐stage exposure at high shielding. Mifflin is unusual in having a low radiogenic gas content combined with a low shock stage and no evidence of late stage annealing; this inconsistency remains unexplained.     

Progressive deformation of feldspar recording low‐barometry impact processes,Tenoumer impact structure,Mauritania

The Tenoumer impact structure is a small, well‐preserved crater within Archean to Paleoproterozoic amphibolite, gneiss, and granite of the Reguibat Shield, north‐central Mauritania. The structure is surrounded by a thin ejecta blanket of crystalline blocks (granitic gneiss, granite, and amphibolite) and impact‐melt rocks. Evidence of shock metamorphism of quartz, most notably planar deformation features (PDFs), occurs exclusively in granitic clasts entrained within small bodies of polymict, glass‐rich breccia. Impact‐related deformation features in oligoclase and microcline grains, on the other hand, occur both within clasts in melt‐breccia deposits, where they co‐occur with quartz PDFs, and also within melt‐free crystalline ejecta, in the absence of co‐occurring quartz PDFs. Feldspar deformation features include multiple orientations of PDFs, enhanced optical relief of grain components, selective disordering of alternate twins, inclined lamellae within alternate twins, and combinations of these individual textures. The distribution of shock features in quartz and feldspar suggests that deformation textures within feldspar can record a wide range of average pressures, starting below that required for shock deformation of quartz. We suggest that experimental analysis of feldspar behavior, combined with detailed mapping of shock metamorphism of feldspar in natural systems, may provide critical data to constrain energy dissipation within impact regimes that experienced low average shock pressures.