Properties of Dynamic Earthquake Ruptures With Heterogeneous Stress Drop

Earthquake rupture is a notoriously complex process, at all observable scales. We introduce a simplified semi-dynamic crack model to investigate the connection between the statistical properties of stress and those of macroscopic source parameters such as rupture size, seismic moment, apparent stress drop and radiated energy. Rupture initiation is treated consistently with nucleation on a linear slip-weakening fault, whereas rupture propagation and arrest are treated according to the Griffith criterion. The available stress drop is prescribed as a spatially correlated random field and is shown to potentially sustain a broad range of magnitudes. By decreasing the amplitude of the stress heterogeneities or increasing their correlation length the distribution of earthquake sizes presents a transition from Gutenberg- Richter to characteristic earthquake behavior. This transition is studied through a mean-field analysis. The bifurcation to characteristic earthquake behavior is sharp, reminiscent of a first-order phase transition. A lower roll-off magnitude observed in the Gutenberg-Richter regime is shown to depend on the correlation length of the available stress drop, rather than being a direct signature of the nucleation process. More generally, we highlight the possible role of the stress correlation length scale on deviations from earthquake source self-similarity. The present reduced model is a building block towards understanding the effect of structural and dynamic fault heterogeneities on the scaling of source parameters and on basic properties of seismicity

The rhythms of life

A report on the symposium 'Clocks and Rhythms', Cold Spring Harbor, USA, 30 May-4 June 2007

In the wake of Terra Nullius?

Terra nullius is the principle of a violence that inheres in every origin. And, in its wake, there is no law, no text, no culture, free ofthat violence. The origin is no accident. Terra nullius is not an historical error. Our conceptual legacy is the unsettled and unsettling history of this violence. It demands critical... thinking. Or else... we are condemned to repeat this origin again and again

Ground motion and macroseismic intensities of a seismic event related to geothermal reservoir stimulation below the city of Basel—observations and modelling

To stimulate a geothermal reservoir below the city of Basel, Switzerland, fluid was injected in December 2006 at high pressure into a 5 km deep borehole. This stimulation led to an increase in local seismicity with the largest seismic event (ML = 3.4) occurring on 2006 December 8. The event was widely felt by the local population, slight non-structural damage to buildings was reported and ultimately this event was the cause to put the geothermal project on hold. In this study, we present recorded ground motion and determinations of macroseismic intensity of the ML 3.4 event as well as simulations of seismic wave propagation and a model to predict macroseismic intensities. As the two models are based on different simplifying assumptions and different underlying physical processes, the predicted intensity distributions exhibit differences in their details. However, the first-order characteristics of the observed macroseismic intensity distribution are well matched. Based on this result, we compute intensities also for hypothetical scenarios of earthquakes with larger magnitude

The mammalian circadian timing system: from gene expression to physiology

Many physiological processes in organisms from bacteria to man are rhythmic, and some of these are controlled by self-sustained oscillators that persist in the absence of external time cues. Circadian clocks are perhaps the best characterized biological oscillators and they exist in virtually all light-sensitive organisms. In mammals, they influence nearly all aspects of physiology and behavior, including sleep-wake cycles, cardiovascular activity, endocrinology, body temperature, renal activity, physiology of the gastro-intestinal tract, and hepatic metabolism. The master pacemaker is located in the suprachiasmatic nuclei, two small groups of neurons in the ventral part of the hypothalamus. However, most peripheral body cells contain self-sustained circadian oscillators with a molecular makeup similar to that of SCN (suprachiasmatic nucleus) neurons. This organization implies that the SCN must synchronize countless subsidiary oscillators in peripheral tissues, in order to coordinate cyclic physiology. In this review, we will discuss some recent studies on the structure and putative functions of the mammalian circadian timing system, but we will also point out some apparent inconsistencies in the currently publicized model for rhythm generatio

Problemer av den norske velferdsøkonomien og noen konsekvenser av en bærekraftig reproduksjon

Als Ausgangspunkt für die Bearbeitung und Untersuchung des Themas wird die Auseinandersetzung mit einigen theoretischen Auffassungen von Nachhaltigkeit in seiner Dreidimensionalität von Ökologie-Ökonomie-Sozialem im Allgemeinen als auch aus norwegischem Blickwinkel im Besonderen gestellt. Aufgrund der Komplexität der hierbei zu untersuchenden Problemstellungen und Strukturen sowie der mehrschichtigen Interaktionen der beteiligten Handlungsakteure konnte mittels eines transdisziplinären Forschungsansatzes dem Anliegen dieser Aufgabenstellung am ehesten entsprochen werden. Unter Zugrundelegung der theoretischen Grundlagen des Wohlfahrtsstaates wird im Kapitel II unter Einbeziehung der drei Nachhaltigkeitsdimensionen Ökologie-Ökonomie-Soziales der Bezug zum norwegischen Wohlfahrtsstaat hergestellt. Notwendigerweise wird hierbei insbesondere auch die Abhängigkeit vom Erdöl und deren gewaltigen Einnahmen dargestellt. In diesem Zusammenhang erfolgt eine Auseinandersetzung mit unterschiedlichen Auffassungen hinsichtlich der Verwendung der enormen Erdöleinnahmen und deren Anlage in Fonds auseinander. Konsequenterweise werden am Ende dieses Kapitels die Defizite des norwegischen Wohlfahrtsmodells und Möglichkeiten seiner Weiterentwicklung aufgezeigt. Die in Kapitel III durchgeführte Analyse der norwegischen Wohlfahrtsökonomie und der Industriepolitik untersucht und diskutiert besonders die norwegische Industriepolitik und Erdölwirtschaft, die Wertschöpfungslücke und Symptome der Holländischen Krankheit, die von wesentlicher Bedeutung für das Gesamtverständnis des untersuchten Gegenstandes sind. Wie bereits im einführenden Kapitel angesprochen, setzt eine nachhaltige Reproduktion der norwegischen Wohlfahrtsökonomie v. a. eine Transformation des gegenwärtigen industriellen Systems der Produktion in eine nachhaltige Art und Weise des Wirtschaftens voraus. Folgerichtig werden im Kapitel IV, ausgehend von verschiedenen Nachhaltigkeitsauffassungen – hier starke und schwache Nachhaltigkeit –, die drei Zieldimensionen von Nachhaltigkeit im sogenannten Drei-Säulen-Modell betrachtet und versucht, diese Sichtweise bei der Operationalisierung von Nachhaltigkeit durch Integration des im nationalen Handlungsplans enthaltenen Indikatorensatzes in das integrierte Nachhaltigkeitsdreieck (IND) auf die norwegischen Wohlfahrtsökonomie anzuwenden. Bei der Operationalisierung unter Anwendung des IND wurde der Umfang der Unzulänglichkeiten der im nationalen Nachhaltigkeitskonzept verwendeten Indikatoren deutlich. Gleichzeitig wurde versucht, einen Ausblick für die weitere Arbeit in Richtung der Entwicklung einer nachhaltigen Entwicklung der norwegischen Gesellschaft in Form eines nationalen Masterplanes zu geben. Im Ergebnis dessen wurde in Kapitel V zusammenfassend herausgearbeitet, dass in Abhängigkeit von der jeweiligen Entscheidung für welche Art von Nachhaltigkeit sich die politischen Entscheidungsträger in Norwegen entscheiden, vorrangig eine Umgestaltung der gegenwärtigen industriellen Struktur in eine nachhaltige Art und Weise des Wirtschaftens, bei der diese in die Ökologie und die sozialen Prozesse der norwegischen Gesellschaft zu inkludieren sind, erforderlich ist. Wie in der Einleitung angemerkt, war die Frage einer Optimierung der Portfoliostruktur der in Fonds angelegten Einnahmen aus der Erdöl- und Erdgasförderung nicht Gegenstand der durchgeführten Untersuchung. Daher konnten auch keine begründeten Aussagen getroffen werden, ob aus den Fondserträgen das gegenwärtige Wohlfahrtsniveau auch für zukünftige Generationen nachhaltig zu finanzieren sein wird.Sustainability has an economic, an ecological, and a social dimension. These three dimensions are combined with peculiarities of the Norwegian case. This multidimensional approach relating to the Norwegian case has been pursued in a trans-disciplinary manner. Starting from the theoretical bases of welfare economics, a three-dimensional approach to sustainability is related to the Norwegian case in chapter 1. Obviously, for Norway, the dependence on crude oil and the enormous revenues this generates are in the focus of this analysis. Different approaches as to how to invest these revenues in different investment funds are discussed. Some shortcomings of the current approach are identified and remedies are looked for. The analysis of the Norwegian welfare state in chapter 3 and the industrial policy it pursues require some considerations, whose character is philosophy of science. The so-called Dutch disease (stemming from an utter dependence on revenues from natural gas extraction) are related to Norwegian industrial policy, notably as far as the oil-based industrial sector is concerned. A sustainable industrial policy requires a deep transformation of the current industrial sector. Different concepts of sustainability are translated into policy options for Norway in chapter 4. Deficiencies of the current approach to Norwegian industrial policy are made apparent from the three-dimensional sustainability point of view. Consequently, suggestions for a sustainable approach to Norwegian economic policy are followed. In chapter 5 it is shown in conclusion how a systematic reorientation of Norwegian industrial policy should be accomplished with a view to sustainability. Optimizing the revenues from funds in which the Norwegian oil revenues have been invested is not the purpose of this dissertation. For this reason, the sustainability of revenues from these funds and their benefits to future generations is not part of the analysis.Problemer av den norske velferdsøkonomien og noen konsekvenser av en bærekraftig reproduksjon Som et utgangspunkt for behandlingen og undersøkelse av emnet tas noen av de teoretiske begrepene av bærekraft generelt, samt fra det norske synspunktet særdeles. Pga. kompleksiteten i saken skal undersøkes problemer og strukturer samt lagdelte interaksjoner av impliserte handlingsaktører kunne oppfylles best ved hjelp av en trans-disiplinær forskningsansats for denne oppgaven. Basert på det teoretiske grunnlaget for velferdsstaten lykkes i kapittel II å lage, gjennom involvering av de tre bærekraftige dimensjonene økologi- økonomi-sosial hensynet til den norske sosiale velferdsstaten. Nødvendigvis fremstilles hermed avhengigheten av enorme oljeinntektene. I denne sammenheng, drøfter forfatteren med ulike meninger om bruk av svære oljeinntekter og sine investeringer i fonder. Følgelig identifiseres på slutten av dette kapittelet manglene ved den norske velferdsmodellen og sine utviklingsmuligheter. Analysen av den norske velferdsstaten økonomi og næringspolitikk gjennomføres i kapittel III. Her er de spesielle avsnittene som utforsker den norske petroleumsindustrien, politikk og økonomi, hull i verdikjeden og symptomene på nederlandsk sykdom og som er viktig for den totale forståelsen av forskningsgjenstanden. Som omtalt i innledningskapitlet, er en bærekraftig reproduksjon av den norske velferdsøkonomien primært en transformasjon av dagens industrielle system som må erstattes gjennom et bærekraftig produksjonssystem. Logisk, er betraktet i kapittel IV på grunnlag av ulike bærekraft ideer – her kalles sterk og svak - tre siktemål-dimensjoner i den såkalte tre-søyle modell og prøvet denne sikten under operasjonaliseringen av bærekraft gjennom integrering av den i den nasjonale handlingsplanen innholdene sett av indikatorer i den integrerte bærekraft trekanten å anvende det på den norske velferdsøkonomien. Med operasjonaliseringen av den integrerte bærekraft trekant ble gjort omfanget av manglene av de nasjonale indikatorene som er brukt i bærekraftighets-konseptet åpenlyst. Samtidig ble forsøkt å gi et utsyn for videre arbeid mot utviklingen av en bærekraftig utvikling av det norske samfunnet i form av en nasjonal hovedplan. Som et resultat, ble utarbeidet og oppsummert i kapittel V at, avhengig av bestemte valg av hva slags bærekraft, beslutningstakere bestemmer seg for i Norge, er først og fremst en omlegging av dagens industrielle strukturen i en bærekraftig. Som nevnt i innledningen, var spørsmålet om en operasjonalisering av den porteføljestrukturen av inntektene fra olje-og gas investert i fond ikke gjenstand av den gjennomførte undersøkelsen. Derfor kunne heller ikke underbygget begrunnende uttalelser, om fra fondavkastningene kan finansieres dagens velferdsnivå for tilkommende generasjoner også.Die URN ist in der pdf-Datei fälschlicherweise mit "urn:nbn:de:gbv:547-2013300069" angegeben

Earthquake source characteristics from dynamic rupture with constrained stochastic fault stress

One of the challenging tasks in predicting near-source ground motion for future earthquakes is to anticipate the spatiotemporal evolution of the rupture process. The final size of an event but also its temporal properties (propagation velocity, slip velocity) depend on the distribution of shear stress on the fault plane. Though these incipient stresses are not known for future earthquakes, they might be sufficiently well characterized in a stochastic sense. We examine the evolution of dynamic rupture in numerical models of a fault subjected to heterogeneous stress fields with varying statistical properties. By exploring the parameter space of the stochastic stress characterization for a large number of random realizations we relate generalized properties of the resulting events to the stochastic stress parameters. The nucleation zone of the simulated earthquake ruptures in general has a complex shape, but its average size is found to be independent of the stress field parameterization and is determined only by the material parameters and the friction law. Furthermore, we observe a sharp transition in event size from small to system-wide events, governed mainly by the standard deviation of the stress field. A simplified model based on fracture mechanics is able to explain this transition. Finally, we find that the macroscopic rupture parameters ( e. g., moment, moment rate, seismic energy) of our catalog of model quakes are generally consistent with observational data

Normalisation against circadian and age-related disturbances enables robust detection of gene expression changes in liver of aged mice

The expression of some genes is affected by age. To detect such age-related changes, their expression levels are related to constant marker genes. However, transcriptional noise increasing with advancing age renders difficult the identification of real age-related changes because it may affect the marker genes as well. Here, we report a selection procedure for genes appropriate to normalise the mouse liver transcriptome under various conditions including age. These genes were chosen from an initial set of 16 candidate genes defined based on a RNA-sequencing experiment and published literature. A subset of genes was selected based on rigorous statistical assessment of their variability using both RNA-sequencing and Nanostring hybridization experiments. The robustness of these marker genes was then verified by the analysis of 130 publicly available data sets using the mouse liver transcriptome. Altogether, a set of three genes, Atp5h, Gsk3β, and Sirt2 fulfilled our strict selection criteria in all assessments, while four more genes, Nono, Tprkb, Tspo, and Ttr passed all but one assessment and were included into the final set of marker genes to enhance robustness of normalisation against outliers. Using the geometric mean of expression of the genes to normalise Nanostring hybridization experiments we reliably identified age-related increases in the expression of Casein kinase 1δ and 1ϵ, and Sfpq, while the expression of the glucose transporter Glut2 decreased. The age- related changes were verified by real-time PCR and Western blot analysis. As conclusion, proper normalisation enhances the robustness of quantitative methods addressing age-related changes of a transcriptome