Storm surge disaster risk management: the Xynthia case study in France

In recent years, a series of catastrophic storm surges have occurred in Europe. The large number of fatalities and high material damage are mainly due to an increase in vulnerability and exposure to coastal flooding of hit regions. It is, therefore, necessary to intensify research activities in order to better understand this kind of disasters, to reduce their impacts and to reinforce risk management. This study describes the consequences of Xynthia windstorm that hit France in 2010: strong wind gusts, associated to high-coefficient tides and very low pressure, caused a phenomenon of storm surge in the Atlantic coastal area of France. Sea walls, lacking maintenance and originally built to defend agricultural land, were not able to protect houses. Fourty-seven people were killed, most of them from drowning, and direct losses amounted to more than 2.5?billion Euros. Around 10,000 people were forced to evacuate after the inundation of their properties. Uncontrolled urbanization was involved in the increase of stakes, as demonstrated by the fact that all the 29 victims in the city of la Faute-sur-Mer were living in houses built after 1980. The paper describes the event considering the aspect of increased vulnerability in the affected area, the lack of preparedness that exacerbated the final damage, the emergency response phases and the adaptation strategies adopted by the French Government after the disaster. We conclude that an attentive governance should include a balanced approach to risk protection, to reduce vulnerability and exposure.     

On a class of law invariant convex risk measures

We consider the class of law invariant convex risk measures with robust representation r_h,p(X)=sup_fò₀¹ [AV@R_s(X)f(s)-f^p(s)h(s)] ds\rho_{h,p}(X)=\sup_{f}\int_{0}^{1} [AV@R_{s}(X)f(s)-f^{p}(s)h(s)]\,ds, where 1≤p<∞ and h is a positive and strictly decreasing function. The supremum is taken over the set of all Radon–Nikodym derivatives corresponding to the set of all probability measures on (0,1] which are absolutely continuous with respect to Lebesgue measure. We provide necessary and sufficient conditions for the position X such that ρ _h,p (X) is real-valued and the supremum is attained. Using variational methods, an explicit formula for the maximizer is given. We exhibit two examples of such risk measures and compare them to the average value at risk.     

Mean square error for the Leland–Lott hedging strategy: convex pay-offs

Leland’s approach to the hedging of derivatives under proportional transaction costs is based on an approximate replication of the European-type contingent claim V _T using the classical Black–Scholes formula with a suitably enlarged volatility. The formal mathematical framework is a scheme of series, i.e., a sequence of models with transaction cost coefficients k _n =k ₀ n ^−α , where α∈[0,1/2] and n is the number of portfolio revision dates. The enlarged volatility [^(s)]_n\widehat{\sigma}_{n} in general depends on n except for the case which was investigated in detail by Lott, to whom belongs the first rigorous result on convergence of the approximating portfolio value Vⁿ_TV^{n}_{T} to the pay-off V _T . In this paper, we consider only the Lott case α=1/2. We prove first, for an arbitrary pay-off V _T =G(S _T ) where G is a convex piecewise smooth function, that the mean square approximation error converges to zero with rate n ^−1/2 in L ² and find the first order term of the asymptotics. We are working in a setting with non-uniform revision intervals and establish the asymptotic expansion when the revision dates are t_iⁿ=g(i/n)t_{i}^{n}=g(i/n), where the strictly increasing scale function g:[0,1]→[0,1] and its inverse f are continuous with their first and second derivatives on the whole interval, or g(t)=1−(1−t) ^β , β≥1. We show that the sequence n^1/2(V_Tⁿ-V_T)n^{1/2}(V_{T}^{n}-V_{T}) converges in law to a random variable which is the terminal value of a component of a two-dimensional Markov diffusion process and calculate the limit. Our central result is a functional limit theorem for the discrepancy process.     

Nonparametric estimation for a stochastic volatility model

Consider discrete-time observations (X _{? δ} )_1≤?≤n+1 of the process X satisfying $dX_{t}=\sqrt{V_{t}}dB_{t}Consider discrete-time observations (X _{ℓ δ} )_{1≤ℓ≤n+1} of the process X satisfying dX_t=?{V_t}dB_tdX_{t}=\sqrt{V_{t}}dB_{t} , with V a one-dimensional positive diffusion process independent of the Brownian motion B. For both the drift and the diffusion coefficient of the unobserved diffusion V, we propose nonparametric least square estimators, and provide bounds for their risk. Estimators are chosen among a collection of functions belonging to a finite-dimensional space whose dimension is selected by a data driven procedure. Implementation on simulated data illustrates how the method works.     

Preparing for the unknown… unknowns: ‘doomsday’ prepping and disaster risk anxiety in the United States

This article examines the collapse-based thinking energising ‘doomsday’ prepping: a growing American phenomenon centred on storing food, water and weapons for the purpose of surviving disasters. Existing understandings of prepping indicate that its practitioners are driven to prepare by peculiar and delusional certainty that apocalyptic collapse will occur in the near future. This view, however, has not yet been tested by empirical research. This article draws on ethnography with 39 preppers in 18 American states to present a new understanding of this phenomenon, as it shows prepping consistently being practiced in the absence of both apocalyptic predictions and certainty regarding the future occurrence of disaster. Demonstrating that preppers’ activities are undergirded by precautionary projections around numerous non-apocalyptic ‘threats’, the article argues that prepping principally responds to uncertain anxieties around disaster risks. Moreover, it establishes that these imprecise anxieties are regularly influenced by preppers’ consumption of disaster-based speculation in mainstream news media – showing that their concerns tend to emerge in response to numerous disaster risks that are widely reported and recognised in wider American culture, rather than marginal conceptions of ‘threats’. The article, therefore, contends that, rather than being a marginal apocalyptic practice, prepping is a phenomenon with clear, previously unacknowledged links to broader risk communications and concerns in the twenty-first century United States – one that must be understood as a reflection of the broader resonance of disaster-based speculation and uncertainty in this cultural context.     

Cointegration and forward and spot exchange rate regressions

We investigate the relationship between cointegration models of the current spot exchange rate, s_t, and the current forward rate, f_t, and cointegration models of the future spot rate, s_t+1, and f_t and the implications of this relationship for tests of the forward rate unbiasedness hypothesis (FRUH). We show that simple models of cointegration between s_t and f_t imply complicated models of cointegration between s_t+1 and f_t. Consequently, standard methods are often inappropriate for modeling the cointegrated behavior of (s_t+1, f_t)′ and we show that the use of such methods can lead to erroneous inferences regarding the FRUH.     

Delayed Expected Loss Recognition and the Risk Profile of Banks

This paper investigates the extent to which delayed expected loan loss recognition (DELR) is associated with greater vulnerability of banks to three distinct dimensions of risk: (1) stock market liquidity risk, (2) downside tail risk of individual banks, and (3) codependence of downside tail risk among banks. We hypothesize that DELR increases vulnerability to downside risk by creating expected loss overhangs that threaten future capital adequacy and by degrading bank transparency, which increases financing frictions and opportunities for risk‐shifting. We find that DELR is associated with higher correlations between bank‐level illiquidity and both aggregate banking sector illiquidity and market returns (i.e., higher liquidity risks) during recessions, suggesting that high DELR banks as a group may simultaneously face elevated financing frictions and enhanced opportunities for risk‐shifting behavior in crisis periods. With respect to downside risk, we find that during recessions DELR is associated with significantly higher risk of individual banks suffering severe drops in their equity values, where this association is magnified for banks with low capital levels. Consistent with increased systemic risk, we find that DELR is associated with significantly higher codependence between downside risk of individual banks and downside risk of the banking sector. We theorize that downside risk vulnerability at the individual bank level can translate into systemic risk by virtue of DELR creating a common source of risk vulnerability across high DELR banks simultaneously, which leads to risk codependence among banks and systemic effects from banks acting as part of a herd.     

旱灾风险的特征及其防范研究——由西南旱灾和冬麦区大旱引发的思考

旱灾不是所有自然灾害中发生频率最高、等级最重,却是受灾人数最多、影响范围最广的一种自然灾害.旱灾的缓发性、后延性、复杂性特征,容易引发饥荒、贫困、政治冲突甚至社会动荡等风险,故旱灾的风险管理日益成为一个国家自然灾害管理或社会管理的重要内容.传统的"危机管理"模式对旱灾等自然灾害管理的作用有限,"综合风险防范"模式具有很...     

The effect of interventions on realignment probabilities

The expected future change of the exchange rate within its currency band and the expected realignment rate are estimated using the Regime–Switching Model. There exists an unobserved variable s_t, which characterises the equilibrium state of the expected future change of the exchange rate within its currency band at any time t with certain probabilities. Different values of s_t correspond to states with high and low risk of realignment, respectively. The probabilities of switching between one regime and another depend on central bank intervention in the foreign exchange market. Daily data on intervention by Norges Bank are used. The data contain relatively few actual realignments, and the sample distribution of realignments may not be representative enough to capture the discrete changes in the exchange rate caused by a non-zero subjective probability of realignment (even when no realignment has in fact taken place). This causes the very well known peso problem in the estimation.     

The Property Tax as a Tax on Value: Deadweight Loss

Consider an atomistic developer who decides when and at what density to develop his land, under a property value tax system characterized by three time-invariant tax rates: τ_V, the tax rate on pre-development land value; τ_S, the tax rate on post-development residual site value; and τ_K, the tax rate on structure value. Arnott (2005) identified the subset of property value tax systems that are neutral. This paper investigates the relative efficiency of four idealized, non-neutral property value tax systems [(i) “Canadian' property tax system: τ_V = 0, τ _S = τ_K; (ii) simple property tax system: τ_V = τ _S = τ_K; (iii) residual site value tax system: τ_K = 0,τ _V = τ_S; (iv) two-rate property tax system: τ_V = τ _S > τ_K > 0] under the assumption of a constant rental growth rate. JEL Code: H2     

Numerical evaluation of the compound Poisson distribution: Recursion or Fast Fourier Transform?

1. The problem

The finite vector p=(p ₁,p ₂, ...,p_s ) defines a probability distribution on the integers 1,2, ...,s.     

Look who is warning: individual differences in motivation activation influence behaviors during disasters

Abstract

This study investigated individual differences in responses to disasters based on participants’ motivational reactivity and ethical ideology. Motivational reactivity was measured using the motivational activation measure (MAM), which assesses individual differences in appetitive and defensive system activations. Participants (N?=?240) answered survey questions about how they would respond to natural disasters or emergency situations. Results showed that (1) participants with higher defensive activation scores were more likely to report they would share warnings during a disaster situation, (2) high appetitive system activation is associated with high ethical relativism, (3) high defensive system activation is associated with high ethical idealism, and (4) individuals’ personal moral philosophy moderates the effects of MAM score on intention to warn others. Theoretical and practical implications are also discussed.     

The Prestige disaster: risk or danger?

The sinking of the Prestige off the coast of Galicia in north-west Spain in November 2002 was an enormous environmental disaster and it had an immense media impact both nationally and internationally, lasting weeks as a social and political phenomenon. Five days before the ship sank, the captain had reported to the maritime authorities that the old tanker was damaged and in trouble. During these five days leading up to the shipwreck, a crucial decision had to be made: what should be done with this dangerous oil tanker? Temporality is a property of the hazardous events which, after being noticed, are evaluated as imminent or deferred. This temporality makes a clear difference between a risk and a danger. Whereas the risk has time to anticipate the events, danger has just a very short time or even has no time. At this point, the Prestige disaster turns to be paradigmatic. To tow away this damaged oil tanker was a risk decision which estimated that there was still a time to prevent its running aground what meant to follow the story repeatedly told by the narrative context of risk. However, the Prestige had been spilling out oil all the time and the damage was not a probability but a fait accompli. This accident has not a risk temporality; in fact, it had not temporality at all because it demanded an immediate intervention. My conclusion here is that this crisis was managed in terms of risk when it should have been treated as a danger situation.     

An Approach to Fair Valuation of Insurance Liabilities Using the Firm’s Cost of Capital

Abstract

There are two competing and seemingly different methodologies for calculating fair values—the direct and indirect methods. The direct approach has the advantage of providing a more reliable assessment of the risk of financial leverage. The indirect method can be structured to adjust for financial leverage, however, the methodology becomes excessively complex. The advantage of the indirect method is that it can be more easily related to exit prices. Intuitively, an exit price should reflect both the creditworthiness of the firm and the cost of capital of the firm. How are these two concepts related? This paper attempts to advance the fair valuation methodology by addressing these questions and presenting a methodology for deriving the firm or own credit risk assumption (to be used with the direct method) that is consistent with the cost of capital assumption used with the indirect method.     

Community social capital and individual disaster preparedness in immigrants and Canadian-born individuals: an ecological perspective

Abstract

Psychological research on the predictors of disaster preparedness has mainly focused on individual-level factors, although the social environment plays an important role. Our goal is to provide a systemic perspective to help improve risk communication and risk management for natural disaster risks. We examined how community-level social capital related to individual-level disaster preparedness in immigrants compared with Canadian-born individuals. We characterised participants’ communities’ social capital by conceptually linking two national surveys using postal codes. We performed sequential linear multiple regression analysis to examine the relationship between community social capital and individual disaster preparedness. Results revealed three components of social capital: societal trust, interaction with friends, and neighbourhood contact. Societal trust positively predicted the extent to which immigrants and Canadian-born individuals knew someone who would search for them post-disaster. Interestingly, results revealed that Canadian-born individuals were more likely to uptake emergency planning when living in a community with strong societal trust, while the reverse was true for immigrants. Results suggest that some components of social capital may have an effect on certain preparedness behaviours. Societal trust could have both positive and negative effects on emergency planning depending on individuals’ immigrant status. Risk communication and risk management should consider social capital as part of the framework for effective disaster preparedness.     

Fire Sales in a Model of Complexity

We present a model of financial crises that stem from endogenous complexity. We conceptualize complexity as banks' uncertainty about the financial network of cross exposures. As conditions deteriorate, cross exposures generate the possibility of a domino effect of bankruptcies. As this happens, banks face an increasingly complex environment since they need to understand a greater fraction of the financial network to assess their own financial health. Complexity dramatically amplifies banks' perceived counterparty risk, and makes relatively healthy banks reluctant to buy risky assets. The model also features a novel complexity externality.     

Periodic threshold-type dividend strategy in the compound Poisson risk model

In this paper, the compound Poisson risk model is considered. Inspired by Albrecher, Cheung, & Thonhauser. [(2011b). Randomized observation periods for the compound Poisson risk model: dividend. ASTIN Bulletin 41(2), 645–672], it is assumed that the insurer observes its surplus level periodically to decide on dividend payments at the arrival times of an Erlang(n) renewal process. If the observed surplus is larger than the maximum of a threshold b and the last observed (post-dividend) level, then a fraction of the excess is paid as a lump sum dividend. Ruin is declared when the observed surplus is negative. In this proposed periodic threshold-type dividend strategy, the insurer can have a ruin probability of less than one (as opposed to the periodic barrier strategy). The expected discounted dividends before ruin (denoted by V) will be analyzed. For arbitrary claim distribution, the general solution of V is derived. More explicit result for V is presented when claims have rational Laplace transform. Numerical examples are provided to illustrate the effect of randomized observations on V and the optimization of V with respect to b. When claims are exponential, convergence to the traditional threshold strategy is shown as the inter-observation times tend to zero.     

A characterization of the exponential distribution and of the geometric distribution

Abstract

Cook (1978) has proved that n positive random variables X ₁ ..., X _n are independent and follow the same exponential distribution iff the random vectors (X ₁ ..., X _s ) and (X _s+1, ..., X _n ) are independent for some s ∈ {1, ..., n-l} and E(Π} _j=1 ⁿ max {X _j -a _j , 0}) is a function of Σ _j=1 ⁿ a _j for a ₁, ..., a _n ∈ dR ⁺. In this paper a generalization of this characterization of the exponential distribution and an analogous characterization of the geometric distribution are given.     

The rise of defensive engineering: how personal liability considerations impact decision-making

Abstract

Based on a survey of Australian engineers (n = 275) this paper examines the impact of personal liability considerations on engineering decision-making. Almost all respondents who make high-stakes decisions saw questions of liability as having both positive (90%) and negative (87%) impacts. Our analysis shows that awareness of personal liability acts to focus the attention of many engineers on the moral dimension of their work. However, it also encourages more expensive decision-making, inhibition of innovation and professional paralysis. We argue that while personal legal liability is a legitimate way to focus engineers’ attention on the potential impact of their work, a problem arises when decision-makers are held responsible for disasters over which they had little control. The focus then shifts to ‘defensive engineering’ practices that are aimed at limiting individual liability rather than disaster prevention. Legal processes that are seen to unfairly allocate blame do not encourage practices that support future disaster prevention.