Human-triggered earthquakes and their impacts on human security

A comprehensive understanding of earthquake risks in urbanized regions requires an accurate assessment of both urban vulnerabilities and earthquake hazards. Socioeconomic risks associated with human-triggered earthquakes are often misconstrued and receive little scientific, legal, and public attention. However, more than 200 damaging earthquakes, associated with industrialization and urbanization, were documented since the 20th century. This type of geohazard has impacts on human security on a regional and national level. For example, the 1989 Newcastle earthquake caused 13 deaths and US$3.5 billion damage (in 1989). The monetary loss was equivalent to 3.4 percent of Australia’s national income (GDI) or 80 percent of Australia’s GDI per capita growth of the same year. This article provides an overview of global statistics of human-triggered earthquakes. It describes how geomechanical pollution due to large-scale geoengineering activities can advance the clock of earthquakes or trigger new seismic events. Lastly, defense-oriented strategies and tactics are described, including risk mitigation measures such as urban planning adaptations and seismic hazard mapping

The Network of Ecological Compensation Areas in Switzerland

Since 1993, the Swiss law and Ordinance on Direct Payments for Agriculture (ODP) enables farmers to be compensated for ecological measures. A catalogue lists different possible measures which can be implemented at farm level both to create space for nature and biodiversity and to generate an alternative income for farmers. Measures include the maintenance of e. g. semi-natural structures in the landscape such as high-stem trees, hedges, pastures and meadows which are not intensively used (detailed catalogue: ART 2009). Succeeding a fast increase in the number of these areas, stagnation has been observed (BIODIVERSITYMONITORING 2009). Additionally, it has become evident, that many compensation areas are in unfavourable conditions for biodiversity and their quality, especially species richness, is low. This motivated the extension of the ODP with an additional ordinance which tackles two main points: Ordinance on Regional Promotion of Quality and Networking of Ecological Compensation Areas in Agriculture (OEQ 2001)

On stable rationality of some conic bundles and moduli spaces of Prym curves

We prove that a very general hypersurface of bidegree (2, n) in P^2 x P^2 for n bigger than or equal to 2 is not stably rational, using Voisin's method of integral Chow-theoretic decompositions of the diagonal and their preservation under mild degenerations. At the same time, we also analyse possible ways to degenerate Prym curves, and the way how various loci inside the moduli space of stable Prym curves are nested. No deformation theory of stacks or sheaves of Azumaya algebras like in recent work of Hasset-Kresch-Tschinkel is used, rather we employ a more elementary and explicit approach via Koszul complexes, which is enough to treat this special case.Comment: 23 pages; Macaulay 2 code used for verification of parts of the paper available at http://www.math.uni-hamburg.de/home/bothmer/m2.html and at the end of the TeX file; v2: in section 4, we now included a proof of the main theorem that works for all n (unconditional on the parity) that was communicated to us by Zhi Jiang, Zhiyu Tian, and Letao Zhang. Several other minor expository improvement

Degenerations of Gushel-Mukai fourfolds, with a view towards irrationality proofs

We study a certain class of degenerations of Gushel-Mukai fourfolds as conic bundles, which we call tame degenerations and which are natural if one wants to prove that very general Gushel-Mukai fourfolds are irrational using the degeneration method due to Voisin, Colliot-Th\'{e}l\`{e}ne-Pirutka, Totaro et al. However, we prove that no such tame degenerations do exist.Comment: 25 page

Maximal mixing by incompressible fluid flows

We consider a model for mixing binary viscous fluids under an incompressible flow. We proof the impossibility of perfect mixing in finite time for flows with finite viscous dissipation. As measures of mixedness we consider a Monge--Kantorovich--Rubinstein transportation distance and, more classically, the $H^{-1}$ norm. We derive rigorous a priori lower bounds on these mixing norms which show that mixing cannot proceed faster than exponentially in time. The rate of the exponential decay is uniform in the initial data