Earthquake Size Distribution: Power-Law with Exponent Beta = 1/2?

We propose that the widely observed and universal Gutenberg-Richter relation is a mathematical consequence of the critical branching nature of earthquake process in a brittle fracture environment. These arguments, though preliminary, are confirmed by recent investigations of the seismic moment distribution in global earthquake catalogs and by the results on the distribution in crystals of dislocation avalanche sizes. We consider possible systematic and random errors in determining earthquake size, especially its seismic moment. These effects increase the estimate of the parameter beta of the power-law distribution of earthquake sizes. In particular, we find that estimated beta-values may be inflated by 1-3% because relative moment uncertainties decrease with increasing earthquake size. Moreover, earthquake clustering greatly influences the beta-parameter. If clusters (aftershock sequences) are taken as the entity to be studied, then the exponent value for their size distribution would decrease by 5-10%. The complexity of any earthquake source also inflates the estimated beta-value by at least 3-7%. The centroid depth distribution also should influence the beta-value, an approximate calculation suggests that the exponent value may be increased by 2-6%. Taking all these effects into account, we propose that the recently obtained beta-value of 0.63 could be reduced to about 0.52--0.56: near the universal constant value (1/2) predicted by theoretical arguments. We also consider possible consequences of the universal beta-value and its relevance for theoretical and practical understanding of earthquake occurrence in various tectonic and Earth structure environments. Using comparative crystal deformation results may help us understand the generation of seismic tremors and slow earthquakes and illuminate the transition from brittle fracture to plastic flow.Comment: 46 pages, 2 tables, 11 figures 53 pages, 2 tables, 12 figure

Socio-legal status and experiences of forced labour among asylum seekers and refugees in the UK

Socio-legal status determines the differential rights to residence, work and social welfare that accrue to migrants depending on their particular immigration status. This paper presents analysis of original empirical data generated in qualitative interviews with migrants who had both made a claim for asylum and experienced conditions of forced labour in the UK. Following an outline of the divergent socio-legal statuses assigned to individual migrants within the asylum system, early discussions in the paper offer a summary of key aspects and indicators of forced labour. Subsequent sections highlight the significance of socio-legal status in constructing such migrants as inherently vulnerable to severe exploitation. It is concluded that immigration policy and, more particularly, the differential socio-legal statuses that it structures at various stages of the asylum process, helps to create the conditions in which severe exploitation and forced labour are likely to flourish among asylum seekers and refugees in the UK

"The End of Immortality!" Eternal Life and the Makropulos Debate

Responding to a well-known essay by Bernard Williams, philosophers (and a few theologians) have engaged in what I call “the Makropulos debate,” a debate over whether immortality—“living forever”—would be desirable for beings like us. Lacking a firm conceptual grounding in the religious contexts from which terms such as “immortality” and “eternal life” gain much of their sense, the debate has consisted chiefly in a battle of speculative fantasies. Having presented my four main reasons for this assessment, I examine an alternative and neglected conception, the idea of eternal life as a present possession, derived in large part from Johannine Christianity. Without claiming to argue for the truth of this conception, I present its investigation as exemplifying a conceptually fruitful direction of inquiry into immortality or eternal life, one which takes seriously the religious and ethical surroundings of these concepts

Introduction to Plato's Phaedo: arguments for the existence of the soul: part 2 [Death]

Educação Superior::Ciências Humanas::FilosofiaPresents a class with the Philosophy professor at Yale, Shelly Kagan about death. In this lecture the professor discusses with the students the existence of the soul through Plato's Phaedo and presents an argument that dualists use against the physicalists ideas: the free wil

Deontological Desert

Although the nature of moral desert has sometimes been examined in axiological terms—focusing on the thought that it is a good thing if people get what they deserve—deontologists typically think desert is more appropriately treated in terms of duties and obligations. They may, for example, prefer to talk in terms of there being a moral duty to give people what they deserve. This essay distinguishes a number of forms such a duty might take, and examines four of them more closely. (In particular, it looks at positive and negative duties with regard to both comparative and noncomparative desert). Questions about the contents of each of these duties are raised, making clearer just how much work would be involved in spelling out the relevant duties more completely. The essay concludes with a brief discussion of the possible implications of such desert-based duties for population ethics