A reappraisal of explosive–effusive silicic eruption dynamics: syn-eruptive assembly of lava from the products of cryptic fragmentation

Silicic volcanic eruptions range in style from gently effusive to highly explosive, and may switch style unpredictably during a single eruption. Direct observations of subaerial rhyolitic eruptions (Chaiten 2008, Cordón Caulle 2011–2012, Chile) challenged long-standing paradigms of explosive and effusive eruptive styles and led to the formulation of new models of hybrid activity. However, the processes that govern such hybrid explosive–effusive activity remain poorly understood. Here, we bring together observations of the well-studied 2011–2012 Cordón Caulle eruption with new textural and petrologic data on erupted products, and video and still imagery of the eruption. We infer that all of the activity – explosive, effusive, and hybrid – was fed by explosive fragmentation at depth, and that effusive behaviour arose from sticking and sintering, in the shallow vent region, of the clastic products of deeper, cryptic fragmentation. We use a scaling approach to determine that there is sufficient time available, during emplacement, for diffusive pyroclast degassing and sintering to produce a degassed plug that occludes the shallow conduit, feeding clastogenic, apparently effusive, lava-like deposits. Based on evidence from Cordón Caulle, and from other similar eruptions, we further argue that hybrid explosive–effusive activity is driven by episodic gas-fracking of the occluding lava plug, fed by the underlying pressurized ash- and pyroclast-laden region. The presence of a pressurized pocket of ash-laden gas within the conduit provides a mechanism for generation of harmonic tremor, and for syn-eruptive laccolith intrusion, both of which were features of the Cordón Caulle eruption. We conclude that the cryptic fragmentation models is more consistent with available evidence than the prevailing model for effusion of silicic lava that assume coherent non-fragmental rise of magma from depth to the surface without wholesale explosive fragmentation

Wie professionell und reformfähig ist die Lehrerinnen- und Lehrerbildung an deutschen Hochschulen?

Die Lehrerinnen- und Lehrerbildung in Deutschland steht seit einiger Zeit zum wiederholten Male im Zentrum der Kritik. Eine von vielen Reformbemühungen, die den häufig angeführten Missständen Abhilfe schaffen sollen – die sogenannten Zentren für Lehrerbildung und die Schools of Education –, und ihre bisherigen Auswirkungen auf die Lehrerinnen- und Lehrerbildung stehen im Mittelpunkt der Auseinandersetzung dieses Beitrags. Zusätzlich werden die Lehrenden an den Universitäten in ihrer Funktion als Lehrerbildnerinnen und Lehrerbildner betrachtet und wir fragen nach ihrer Rolle im Kontext der Organisation Hochschule.In recent times, teacher education in Germany has once more been in the focus of criticism. The implementation of «Centres for Teacher Education» or «Schools of Education» at universities is expected to be one major reform instrument for overcoming the frequently described deficits of teacher education. These organizations and their effects on teacher education are discussed in the following article. In addition, we look at the functions and roles of the academic staff at the Schools or Centres and relate them to the organizational structure of universities

AgriSens DEMMIN 4.0

Die Digitalisierung der Landwirtschaft schreitet seit einigen Jahren immer weiter voran, wird aber in Deutschland noch nicht im großen Maßstab in landwirtschaftlichen Betrieben umgesetzt. Im Bereich der Geodatennutzung liegen die Herausforderungen vor allem bei der unzureichenden Definition von Schnittstellen sowie in einem mangelnden Daten- und Wissenstransfer zwischen Wissenschaft und Praxis. Hier setzt das Projekt AgriSens DEMMIN 4.0 an, das vom Bundesministerium für Ernährung und Landwirtschaft (BMEL) im Rahmen der digitalen Experimentierfelder gefördert wird. Methoden zur Nutzung von Geodaten, insbesondere Fernerkundungsdaten, im Pflanzenbau werden analysiert und neu entwickelt und in konkreten Anwendungsfällen wie Ertragsabschätzung oder teilschlagspezifische Bewässerung dem Landwirt nutzbar gemacht

Pathways to using remote sensing in crop cultivation and management - the German digital test field AgriSens DEMMIN 4.0.

In Germany, the agriculture produces by far the largest share of basic food and animal feed. In addition, raw materials such as construction and insulation materials and fuels are increasingly being produced for industrial use by the agricultural sector.Arable production systems thus represent an indispensable part of food security. At the same time, agriculture is facing growing challenges from advancing climate change and the increasingly urgent need to preserve biodiversity. Furthermore, land is still being lost continuously due to the requirements of settlement and traffic construction. Nevertheless, in order to meet the ever-increasing demand for agricultural products, technologies that promote resource efficiency and sustainability as well as productivity in agriculture must be used while arable land remains unchanged or even shrinks. Remote sensing technologies such as the Sentinel satellites of the European Copernicus program can make an important contribution in this regard. The poster addresses the use of Copernicus data for sustainable, climate-smart agriculture. These data should help to increase the quality and quantity of crop production and reduce stocks while reducing the impact on natural resources. Based on concrete applications in practical crop production in the AgriSens DEMMIN4.0 trial field (funded by the German Federal Ministry of Food and Agriculture - BMEL), the poster will highlight and discuss potentials, current challenges and perspectives