ALBERT

Description: In der Geoelektromagnetik werden oft großflächige Quellen, beispielsweise Leiterschleifen, näherungsweise als Punktquellen aufgefasst. Diese Annahme ist jedoch nur für hinreichend große Entfernungen zwischen Quelle und Messpunkt zulässig. Da die Messung mit relativ kleinen Spulen durchgeführt werden, die Sendespulen aber bis zu 10 000m2 Spulenfläche aufweisen, liegt es nahe, das Reziprozitätsprinzip auszunutzen, um Sender und Empfänger zu vertauschen. So wird das Feld eines Sendedipols am Ort des eigentlichen Empfängers genutzt, um über die Lösung dieses Dipols am Ort des eigentlichen Senders zu integrieren. Die Integrationsfläche entspricht dabei der Fläche der eigentlichen Sendeschleife. Dabei kann die Lösung des Dipols entweder analytisch über homogenen oder geschichteten Leitfähigkeitsmodellen oder numerisch über beliebigen Leitfähigkeitsverteilungen berechnet werden. Um den Einfluss der Spulengeometrie abzuschätzen, gen¨ugt meist die Auswertung der analytischen L¨osung. Die numerische Integration geschieht dabei durch eine zweidimensionale Gaußquadratur. Eine Konvergenzstudie zeigt die Abhängigkeit der Genauigkeit dieses Ansatzes von der Knotenzahl der Gaußquadratur in Verbindung mit ausgew¨ahlten Entfernungen zwischen Senderzentrum und Messpunkt.

Description: Vorliegender Datensatz gibt auf Basis einer Analyse im Dezember 2015 im re3data.org - Registry of Research Data Repositories1 einen Überblick über Forschungsdaten-Repositorien die unter Beteiligung deutscher Institutionen betrieben werden.

Description: Vortrag beim Workshop „Der Kerndatensatz Forschung - und nun? - Nutzen, Grenzen und Umsetzungsstrategien des Kerndatensatz Forschung und von Forschungsinformationssystemen“

Description: Die vorliegende Ausgabe des GFZ-Journals „System Erde“ soll einen Einblick in die am GFZ betriebene Forschung zur Seismologie geben.

Description: Gashydrate sind natürlich vorkommende feste Verbindungen aus Wasser und Gas, deren Erschließung als zukünftige Energiequelle von Interesse ist. Für die bohrtechnische Erschließung mariner Gashydratlagerstätten ist eine leistungsfähige Bohrspülung notwendig. Das vom Bohrmeißel gelockerte Sediment und darin enthaltenes Gashydrat werden durch die Bohrspülung nach übertage transportiert. Die Gashydratpartikel verlassen beim Aufsteigen im Ringraum in ca. 300 m Wassertiefe ihren Stabilitätsbereich und dissoziieren in Wasser und Gas. Um eine Verdünnung und eine Dichteerniedrigung der Bohrspülung zu verhindern, soll das Gashydratbohrklein stabilisiert werden. Gleichzeitig darf sich in der Bohrspülung bei Anwesenheit von freiem Gas in der Lagerstätte kein neues Gashydrat bilden. Die Arbeit beschäftigt sich mit der Suche nach Additiven, welche die Gashydratneubildung und -dissoziation gleichzeitig hemmen. Es wurde ein Schüttelautoklav genutzt, um die Dissoziationstemperatur von Methanhydrat bei ca. 85 bar zu ermitteln und die Verzögerung des Hydratzerfalls bei Anwesenheit verschiedener Additive zu vergleichen. Es konnte ein Additiv gefunden werden, das diese Anforderungen erfüllt. Des Weiteren wurden neue rheologische Untersuchungsprogramme für verschiedene Spülungstypen erarbeitet, die eine detaillierte Charakterisierung der Fließfähigkeit, Thixotropie und Geleigenschaften von Bohrspülungen erlauben.

Description: Mit ihren katastrophalen Auswirkungen, die den ganzen Globus betreffen, stellen Supereruptionen alle geschichtlich dokumentierten Eruptionen in den Schatten.

Description: Supereruptions represent enormous natural disasters which potentially impact the whole planet. They are unlike any other known and documented eruption.

Description: Die Weltklimakonferenz ist in Bonn zu Ende gegangen. Es wird klar, dass die Vertragsstaaten des Pariser Abkommens ohne die USA auskommen müssen.

Description: Bei phreatischen Eruptionen fehlen häufig warnende Vorzeichen. Der plötzliche Ausbruch des japanischen Vulkans Ontake im Herbst 2014 traf viele unvorbereitet.

Description: Phreatic eruptions often occur without any forewarning. Many were unprepared for the sudden eruption of Ontake volcano, Japan in autumn 2014.

Description: Menschliche Eingriffe ins Flusssystem oder natürliche Faktoren: Welche Einflüsse wiegen wie stark? Forscher des GFZ modellierten dies quantitativ.

Description: Human encroachment on the river system or natural factors: what are the influences and how heavily do they factor in? Researchers at the GFZ quantitatively modelled the impact.

Description: Angesichts der anhaltend dynamischen Veränderungen, welche die Digitalisierung für alle Wissenschaftsbereiche mit sich bringt, erscheint der Bedarf an einer Vernetzungs-, Abstimmungs- und Handlungsstruktur wie der Allianz-Initiative ungebrochen hoch. Die erfolgreiche Zusammenarbeit der deutschen Wissenschaftsorganisationen in der Allianz-Initiative wird daher für die Jahre 2018 bis 2022 fortgesetzt. Die Grundlagen der Zusammenarbeit werden im vorliegenden Leitbild Den digitalen Wandel in der Wissenschaft gestalten. Die Schwerpunktinitiative „Digitale Information“ der Allianz der deutschen Wissenschaftsorganisationen 2018 – 2022 dargelegt. Das Leitbild beschreibt Grundsätze und Anspruch der Allianz-Initiative (Kapitel 1), umreißt die Ausgangslage und das thematische Umfeld, in das sich die Initiative in ihrer dritten Periode der Zusammenarbeit einfügt (Kapitel 2) und benennt die Handlungsfelder des digitalen Wandels in der Wissenschaft sowie die sich daraus ergebenden potentiellen Arbeitsschwerpunkte für die Allianz-Initiative „Digitale Information“ (Kapitel 3).

Description: Subduction earthquakes are the most powerful naturally occurring terrestrial processes often resulting in catastrophic fatality counts and decimation of human infrastructure. Over the past decades, great efforts have been undertaken to improve the understanding of the subduction earthquake physics. The Integrated Plate Boundary Observatory in Chile (IPOC) is a multi-instrument network installed in 2007 in the Northern Chile Seismic Gap, where a large magnitude earthquake was expected soon. On April 1st 2014, a portion of the IPOC-monitored region broke, producing the Mw 8.1 Iquique earthquake. In the year leading up to this event, IPOC’s instruments captured some unusual transient seismic and geodetic signals, resulting in a unique dataset recording the preparatory phase of a large earthquake. We combined IPOC data with satellite radar interferometry (InSAR) data to analyze not only the earthquake itself but also the interseismic phase and a detailed foreshock series before the main event. We found that the earthquake ruptured a zone on the plate interface that was highly locked before the earthquake. Additionally, we were able to characterize the aseismic (silent) slip that occurred in the two weeks leading up to the event by combining seismic and geodetic data. Application of these analyses in real-time might enable geoscientists to identify runaway processes that can precede large subduction earthquakes.

Description: Rupture processes show strong similarities on broad spatial scales suggesting that in parts the governing physics for microcrack formation in the laboratory or a large earthquake along a tectonic plate boundary are the same. We discuss examples ranging from rock deformation experiments in the laboratory under controlled boundary conditions, induced seismicity in mines and geological reservoirs to natural earthquakes posing tremendous seismic hazard to population centers. We describe fundamental relations for the entire bandwidth of rupture processes involving fractures, faults and shear zones and their seismic characteristics such as b-value or seismic source properties. Laboratory tests on small-scale rock samples allow studying aspects of processes that control earthquake nucleation and rupture propagation. However, up-scaling of laboratory results to the field scale requires that dominant deformation processes remain the same on vastly different scales, and that potential effects of changing kinematic boundary conditions may successfully be accounted for by appropriate constitutive equations. Our approach shows that constitutive models capturing fundamental physical processes on the laboratory scale may be successfully applied to improve process understanding of deformation on the field scale with the potential to improve seismic hazard estimation.

Description: The element carbon forms the basic building block of all organic biomass on Earth. It consists of two stable isotopes with a mass of 12u (atomic mass unit) and 13u. Biological formation, degradation and alteration processes fractionate the carbon isotopes. Biological systems typically prefer the incorporation of 12C into their biomass and discriminate with regard to 13C. Thus, the compound-specific carbon isotope analysis on characteristic biomolecules for specific precursor organisms allows to assess biological sources and processes being involved in the biological cycling of carbon and to conclude on environmental and climatic conditions affecting these processes. Here two examples from the ongoing work at GFZ are presented showing the influence of geogenic processes on biological systems. This Geo-Bio-coupling is revealed by analyzing the carbon isotope composition of specific key components in the respective biological carbon system. Carbon sources and biological processes were discovered and the obtained results provide deep insights into the feedback of biological ecosystems to increased levels of greenhouse gas concentration in natural systems.

Description: Detailed geological mapping in the Barberton Mountains of north-eastern South Africa has identified units once deposited on a river flood plain. Investigations using an optical microscope have found structures that strongly suggested they developed within a soil profile, and these units had been previously dated to an age of 3.22 billion years. Within these soil horizons we found pyrite grains (FeS2) which contained rounded cores, and these most likely resulted from abrasion during river transport. These cores are commonly overgrown by pyrite rims that have well expressed morphologies. Furthermore, trace element data indicate these rims crystallized on the grain cores at or near the time of soil formation. Using a Secondary Ion Mass Spectrometer, a highly advanced analytical technology, we found that the sulphur isotopic composition of the pyrite cores is consistent with a magmatic origin. In contrast, the rim forming pyrite has a 34S/32S isotope ratio which is some 20 ‰ lower, indicative of a biological processing of sulphur. Our results demonstrate that biological processes were already taking place outside of the marine environment at 3.22 billion years ago, which is 400 million years earlier than previously documented.

Description: Seismology is often associated with the investigation of earthquake processes and indeed this is a very important target of the science. However, seismology is also the primary means by which we can obtain images of the internal structure of the Earth on all scales, ranging from the deep interior, i.e. the Earth’s core and lower mantle over the mantle lithosphere and crust, the scale at which plate tectonics ‘happens’ all the way to the unconsolidated material in the near-surface. Seismology uses earthquakes and artificial sources as signal generators but also the ambient background wavefield, previously considered to be merely noise. Methodological and instrumental innovations have allowed ever more detailed investigations of the earthquake process and the seismic structure, and opened up new targets such as as the monitoring of geomorphological events and investigations of the time-dependency of seismic structure. Finally seismology is not restricted to waveform analysis and the instrumental period but draws on historical data and, in the field of paleoseismology, geological markers to constrain seismic activity in the pre-instrumental past. Direct societal benefits from seismology accrue for example from improved seismic hazard estimates and early-warning technologies in the area of natural hazards, from improved recovery and usage of natural resources, including geothermal energy as a sustainable energy source and much more, e.g. the possibility to monitor and thus enforce compliance with the nuclear test ban treaty.

Description: In the Earth’s subduction zones, some material from the down-going plate is transferred into the overlying mantle wedge and partly into subduction-related volcanic rocks. Lithium (Li) and boron (B) of subducted rocks, in particular of altered oceanic crust and siliciclastic sedimentary rocks, show a large and characteristic variation in their isotopic compositions. During progressive metamorphism and partial melting of the subducting material, Li and B are largely lost from the subducted rocks by fluid-mediated processes. The rising fluids eventually produce a geochemically and isotopically heterogeneous mantle wedge just above the subducting plate. The loss of Li and B from the down-going rocks is controlled by mineral stability in the subducting slab. Small-volume melts from this mantle wedge inherit the isotopic and chemical signature of the subducted material, i. e., of the altered oceanic crust and/or of siliciclastic sedimentary rocks. Thus, small-volume melts derived from the mantle wedge may reveal the nature of old sutures in orogenic belts.

Description: From 15 years of time-variable gravity fields of the GRACE mission, the mass-induced part of the global mean sea-level rise is estimated to be 1.5 mm/a, superimposed with large seasonal and also interannual variations as a consequence of climate change and anthropogenic use of continental water resources. Circulation-induced bottom pressure anomalies additionally observed by GRACE are found to be in line with predictions from ocean general circulation models and are related to large-scale variations in ocean transport in response to shifts in the surface wind regimes.

Description: Petroleum hydrocarbons in reservoirs are subjected to different degrees of abiotic and biotic alteration processes, which often have strong economic consequences since they lead to a decrease in oil quality and reduce the total volume of petroleum in place. Moreover, producibility of the respective fluids strongly depends on physical properties and hence composition. To evaluate these microbial processes in more detail, different approaches can be followed. Here, the changes in stable carbon isotopic signatures of petroleum hydrocarbons are evaluated in detail as biodegradation processes are known to result in an enrichment of the heavier isotopes in the residual hydrocarbons. The change in the isotopic composition can be used to quantify biodegradation by applying the Rayleigh-equation. The Rayleigh-equation correlates the decrease in concentration and the enrichment in the isotopic composition by a fractionation factor (a). This factor depends on the degradation mechanism and the substrate molecule and can be derived from degradation experiments. Thus, the use of carbon isotope ratios has become a sensitive tool in identification and quantification of biodegradation processes in petroleum reservoirs. This quantification is demonstrated using a set of slightly to moderately biodegraded crude oils from the Gullfaks oil field which was analysed for δ13C of the light hydrocarbons.

Description: Mit dem Journal „System Erde“ berichtet das Deutsche GeoForschungsZentrum GFZ über die unterschiedlichen Facetten seiner Forschungsarbeiten. Die Reihe richtet sich vor allem an Entscheidungsträger in Wissenschaft, Gesellschaft und Politik, an interessierte Wissenschaftlerinnen und Wissenschaftler sowie an die fachinteressierte Öffentlichkeit.

Description: Since the early days of Deep Biosphere research almost 100 years ago, this research field has gained momentum over the last 30 years. Much new information could be gained, some of it challenged our concepts about the limits of life and the mechanisms of global biogeochemical cycles. Besides the scientifically motivated questions, there are many applied aspects that play a major role in this research area. Industrial utilization of the deep subsurface is rapidly increasing, and decisions about utilization concepts require a profound knowledge about the processes that control these environments. Much of this process understanding is still lacking. Additional to research on processes, GFZ cultivates previously unknown microbes from deep biosphere environments. These organisms allow studying the adaptations to the peculiar environmental conditions and isolation of novel biomolecules with potential biotechnological applications.

Description: A glance at the stars and, based on their location in the night sky, the calculation of your individual position on Earth was one of the three approaches used 125 years ago by the Royal Prussian Geodetic Institute on the Telegrafenberg. When “Sputnik 1”, the Earth’s first artificial escort (lat. Satellite), took up duty in 1957 the night shift for an astronomical geodesist changed dramatically. From that moment on not only objects from the catalog on stars were taken into account but satellites were now also tracked. Since then, the role of satellites in all geoscientific research has been steadily increasing. For a long time, satellites have not only provided details on position, but this modern positioning also provides exciting insights into the Earth‘s atmosphere. Furthermore, for years, satellites themselves have also provided images of the Earth‘s surface so that geo-researchers can, thus, analyze ongoing processes on the surface of our planet. This paper presents a loose outline of the development of satellite application on the Telegrafenberg and puts the reader in the mood for the following articles on geoscientific applications of satellites at the GFZ.

Description: The water cycle is of paramount importance to human society: shortage of water and intensive droughts have been linked to the downfall of ancient civilizations. At the same time water is an important agent of change on the Earth’s surface, removing and transporting vast amounts of sediments from their source to marine sinks. As such, water is the basis of life as well as a pacemaker of the biogeochemical cycles, such as the carbon cycle. Short-term, abrupt changes (101 to 103 years) in the water cycle have the potential to threaten human societies directly, while long-term changes can affect the global biogeochemical cycles, in particular the carbon cycle. In the Organic Surface Geochemistry Lab (Section Geomorphology) of GFZ we are using biomarker based molecular methods a) to understand the drivers of change in the short-term water cycle during past, abrupt climatic changes; and b) to investigate processes that determine the erosion, transport and burial of organic carbon into long-term geological sinks – processes which are responsible for the relatively stable climatic conditions which have allowed the sustainment of life on Earth. By combining paleoclimatic, geomorphological and organic-geochemical approaches we gain new insights into the stabilizing and destabilizing factors, that control the water and the carbon cycles over various geological timescales.

Description: Deep seismic sounding provides important information on the seismic structure of the crust. Seismic experiments make use of controlled sources (explosions, Vibroseis) or natural sources (earthquakes, ambient noise), or combinations of both types. Seismic velocities are derived from modelling or tomographic inversion of diving waves and refractions. Particularly the combined interpretation of compressional and shear velocities allows for insight into the lithological structure of the crust. Seismic reflectivity is derived from imaging of waves reflected at geological boundaries. Typical patterns of crustal reflectivity are observed for specific tectonic settings. Case studies are shown from two studies at plate boundary systems. (1) The old plate boundary at the Namibian margin was formed by Cretaceous continental rifting and its interplay with the activities of the Tristan da Cunha mantle plume. Traces of intensive magmatic overprinting of the crust at the landfall region of Walvis Ridge can be seen in the derived velocity model and also in the reflectivity image. (2) The Dead Sea transform marks the active boundary between the African and Arabian plates. The Dead Sea basin was formed by pull-apart in response to step-over of the fault system. Results from tomography reveal a deep asymmetric basin structure. An anomalous body was found under the basin, between 13 and 18 km depth, which is interpreted as pre-basin sediments. Our results are supported by the distribution of earthquakes. The results provide new constraints for the modeling of plate boundary processes.

Description: Für erfolgreich betriebene Wissenschaft ist es unerlässlich, als Forschender auf seinem Fachgebiet die neuesten Entwicklungen zu verfolgen. Dafür bietet Current Awareness (CA) Wissenschaftlern eine Reihe von kommerziellen Services und Dienstleistungen an, aber auch Alternativen wie das Suchportal ALBERT. Mit dieser Arbeit wird die Funktion von ALBERT als CA-Service hinsichtlich Aktualität und Informationsbedarf von Wissenschaftlern untersucht. Der erste Teil der Arbeit vergleicht die Erfassungsgeschwindigkeit von Metadaten von Artikeln in ALBERT mit den etablierten Datenbanken Web of Science, Scopus und PubMed. Im zweiten Teil der Arbeit werden auf Grundlage von Experteninterviews Aspekte ausgewertet und diskutiert, die in Zusammenhang mit dem Stellenwert von CA in der aktuellen Forschung und einer bibliothekarischen Dienstleistung dazu stehen. Komplettiert wird die Arbeit mit einer Auseinandersetzung der technischen Dimension un der Metadatenqualität eines CA-Services.

Description: The Earth and its surface are tightly linked to the global climate system by turbulent exchange fluxes of energy and matter, for example greenhouse gases. This is true both for “deep Earth” geologically generated heat or gases reaching the surface and those of biogenic origin in the near-surface environment. For a better understanding of Earth-atmosphere interactions and in particular their feedbacks, the Helmholtz Young Investigators Group TEAM at GFZ studies the surface-atmosphere exchange of heat, water vapor, carbon dioxide (CO2) and methane (CH4) on a range of temporal and spatial scales – from hours to years and from 〈 1m² to more than 10 000 km². A regional focus is on degraded peatlands. While natural peatlands play a central role in the climate system as major carbon sink storing twice the amount of carbon that is contained in the Earth’s forests, a large fraction of the world’s peatlands has been drained for agriculture and subsequently lost that carbon storage capacity. Drained and degraded peatlands are significant and longterm carbon dioxide sources and thus contribute to further climate warming. In NE Germany, up to 20 % of the overall carbon dioxide emissions are from drained peat and a tool in reducing national greenhouse gas emission is therefore the re-wetting of peatlands to restore their natural carbon sink capacity. TEAM monitors the long-term greenhouse gas dynamics in such re-wetted sites and investigates the underlying processes and spatiotemporal drivers of the dynamics.

Description: The Rb-Sr decay system forms the basis for one of the oldest and most established isotopic dating techniques in geology. Its versatility arises from the fact that Rb and Sr are present in most rock-forming minerals, which provides the means to date geologic processes in a wide variety of rocks and geologic environments. In recent years, one of the main innovations of the Rb-Sr method was the direct age dating of deformation processes in the Earth’s crust. Since deformation is a key factor in shaping the Earth’s surface and the internal architecture of the crust, age data for deformation processes are essential to constrain the time scales of crustal evolution. Time constraints on deformation facilitate the calculation of rates of movements of crustal units, the understanding of orogenic processes and ultimately of the dynamics of the Earth’s crust. Deformation processes occur over the entire range of depths and temperatures in the crust, from migration of melts at depth, through ductile deformation in the middle crust, to brittle fragmentation of rocks in earthquake-related near-surface shear zones. This contribution provides an overview of the potential of Rb-Sr geochronology of rock deformation.

Description: Mit dem Journal „System Erde“ berichtet das Deutsche GeoForschungsZentrum GFZ über die unterschiedlichen Facetten seiner Forschungsarbeiten. Die Reihe richtet sich vor allem an Entscheidungsträger in Wissenschaft, Gesellschaft und Politik, an interessierte Wissenschaftlerinnen und Wissenschaftler sowie an die fachinteressierte Öffentlichkeit.

Description: The nucleation of earthquakes and their seismic waves cannot be predicted in a deterministic sense. However probabilistic hazard and risk estimations can be conducted which help to increase the preparedness and reduce the vulnerability of societies. Those estimations are based on the rapidly growing number of empirical earthquake data recorded by seismic networks or known from historical or geological studies, which show that earthquakes are not randomly occurring. They typically occur clustered in space and time with specific characteristics such as the Gutenberg-Richter law for the frequency-magnitude distribution. Seismicity models have to account for earthquake interactions to avoid erroneous estimations of the activity level and spatial distribution of future activity. Additionally, the vulnerability of societies is changing with with time, because of the dynamic reconstruction and growth of cities in earthquake-prone regions. Thus new sophisticated models, strategies, and methods have to be developed and tested for all components of the earthquake risk chain to improve our probabilistic hazard and risk estimations.

Description: Diese Ausgabe des GFZ-Journals „System Erde“ wurde im Dezember 2016 produziert und erscheint im Januar 2017. Das ist der Monat, in dem das Deutsche GeoForschungsZentrum seinen 25. Geburtstag feiert. Der Schwerpunkt Südamerika ist dabei durchaus passend, denn die Forscherinnen und Forscher des GFZ arbeiten dort seit der Gründung des Zentrums. Die Südpazifikküste mit den großen Subduktionsbeben, die Anden mit ihren Vulkanen und all die geologischen Prozesse, die in der Region sichtbar werden, sind wie die Seiten eines Lehrbuchs der Geologie – wenn man sie denn zu entziffern weiß. Selbst die so genannten passiven Kontinentalränder an den Küsten des Südatlantiks bieten uns tiefe Einblicke in die Erdgeschichte; sie sind Geoarchive erster Ordnung. Hinzu kommt, dass sie Lagerstätten für Rohstoffe bergen.

Description: To satisfy the increasing demand for food, water, raw materials, and energy resources, we need to understand the fundamental interactions between the solid earth and its surface. These interactions shape landscapes and provide the basis for sustaining ecosystems. The research field of metal stable isotope geochemistry that emerged over the past two decades has substantial potential to contribute towards this understanding. Advances in mass spectrometry facilitated precise measurements of stable isotope ratios of metal and metalloid elements (e g., Li, B, Mg, Si, Ca, Cr, Fe, Cu, Zn, Sr, Mo, etc). As novel biogeochemical process tracers they now begin to complement the traditional stable isotope systems (H, C, O, N, S). Here, we present a brief introduction in the Earth surface weathering reactor and show how stable isotopes trace the dissolution of rocks by interaction with fluids and subsequent soil formation. Also, the uptake of nutrients into plants produces a characteristic isotope fingerprint. We illustrate the isotopic legacy of processes initiated at the nanometer scale and propagated to the global scale. Combining isotope studies of modern ecosystems with studies of the Earth’s past surfaces as disclosed from geological archives will enable new discoveries on the evolution of our planet millions of years back and into its future. Exploiting this ‘new periodic table’ promises new insights into the nature of a multitude of reactions, thereby bridging several disciplines such as geochemistry, geology, biology, hydrology and life sciences.

Description: Seismic interferometry is a methodology to recover the signals of waves propagating between seismic stations from records of random wavefields such as the ambient seismic noise or the coda of an earthquake. Teleseismic body waves excited by a very deep earthquake close to Kamchatka are investigated to unveil the composition of the teleseismic wavefield at long propagation times which is key to understand how teleseismic waves can be reconstructed by seismic interferometry. Waves at high frequencies around 1s period are shown to be scattered strongly in the Earth crust where they are quickly attenuated. At low periods, seismic waves circle the Earth for many hours as surface waves with clear arrivals of the different orders. At intermediate periods around 40s waves still propagate for several hours but individual arrivals cannot be identified in the data any more – indicating a randomization process. It is shown here that to a large extent this randomization is due to the interaction with the Earth’s 1D structure that does not alter the azimuthal distribution of the wavefield. Even after 8 h the seismic energy propagates dominantly along the great circle and the mean free time of the azimuthal randomization is estimated to 10 h. This means that the recovery of the teleseismic wavefield by seismic interferometry is strongly dependent on the distribution of ambient sources. For a successful application of seismic interferometry sources need to be present at suitable distances on the great circle connecting the stations.

Description: Länge: 15 Min.

Description: Der Schwerpunkt des Gutachtens soll darauf liegen, wie ORCID an wissenschaftlichen Einrichtungen in Deutschland implementiert wird. Dabei werden die institutionellen Regularien sowie die deutschen und europäischen Normen, denen wissenschaftliche Einrichtungen in Deutschland unterliegen, die ORCID implementieren, betrachtet. Dabei soll auch der Tatsache Rechnung getragen werden, dass dabei Datenflüsse in die USA entstehen. Zentrale Anforderung ist, dass das Gutachten möglichst allgemein verständlich und allgemeingültig formuliert wird und somit einen Orientierungsrahmen für die rechtliche Prüfung vor Ort, also etwa an Hochschulen und außeruniversitäre Forschungseinrichtungen bietet. Anliegen des Gutachtens ist es, wissenschaftliche Einrichtungen bei der rechtskonformen Umsetzung der Autorenidentifikation mit ORCID zu unterstützen. Der Erstellung des Gutachtens ging ein Prozess voraus, der die Zusammenarbeit mit dem DFG-Projekt ORCID DE gewährleisten sollte. So wurden im November 2016 im Rahmen eines Workshops nach Darstellung grundsätzlicher Datenschutzprinzipien spezifische Fragestellungen erarbeitet (Annex I14); im Rahmen eines weiteren „Community Inputs“ (Annex II15), der über das Projekt ORCID DE gesammelt wurde, wurden weitere Aspekte adressiert. Eingeflossen in das Gutachten ist ebenfalls eine Korrespondenz mit den Betreibern von ORCID, in der zu einzelnen Fragen, die im Rahmen der Bearbeitung aufgetaucht sind, Stellung genommen wurde.

Description: The warm water geothermal reservoir below the village of Waiwera in New Zealand has been known by the native Maori for centuries. Development by the European immigrants began in 1863. Until the year 1969, the warm water flowing from all drilled wells was artesian. Due to overproduction, water up to 50 °C now needs to be pumped to surface. Further, between 1975 and 1976, all warm water seeps on the beach of Waiwera ran dry. Within the context of sustainable water management, hydrogeological models must be developed as part of a management plan. Approaches of varying complexity have been set-up and applied since the 1980s. However, none of the models directly provide all results required for optimal water management. Answers are given simply to parts of the questions, nonetheless improving resource management of the geothermal reservoir.

Description: Das geothermische Warmwasserreservoir unterhalb der Kleinstadt Waiwera in Neuseeland ist seit vielen Jahrhunderten bei den Ureinwohnern, den Maori, bekannt. Die Nutzung durch die europäischen Einwanderer begann 1863. Bis in das Jahr 1969 waren die bis dahin abgeteuften Förderbohrungen für das warme Wasser artesisch. Ausgelöst durch eine Überproduktion muss das bis zu 50 °C heiße Wasser heute mit Pumpen gefördert werden. In den Jahren 1975 und 1976 kam es zusätzlich zum Versiegen der Warmwasserquellen am Strand von Waiwera. Im Rahmen einer nachhaltigen Wasserbewirtschaftung ist es notwendig, hydrogeologische Modelle einzusetzen. Unterschiedlich komplexe Ansätze wurden seit den 1980er- Jahren umgesetzt. Keines der Modelle liefert allerdings direkt alle für dasWassermanagement benötigten Ergebnisse. Es werden jeweils Antworten auf Teilaspekte gegeben, die das Ressourcenmanagement des geothermischen Reservoirs verbessern.

Description: One of the major goals of the Geosciences is to identify and comprehend material cycling in our planet in order to understand mantle geodynamic processes. These processes are fundamental to the formation of the continental crust and the atmosphere, mantle-crustatmosphere interactions, and planetary formation as a whole. With our systematic, integrated studies of He, Ne, Sr, Nd and Pb isotopes of globally distributed mid-ocean ridge basalts and ocean island basalts we have contributed significantly to refining existing models on the behaviour of He and Ne during melt formation and evolution as well as models of the geochemical structure of the entire mantle. We have e.g. shown that He and Ne are more compatible during melt formation than their mother isotopes 235U, 238U and 232Th. Therefore, it is no longer necessary to postulate the existence of a virtually non-degassed, isolated lower mantle reservoir. We have also shown that the upper mantle is chemically heterogeneous at different spatial and temporal scales, indicating that the mixing efficiency of the upper mantle is not as good as previously thought. In addition, based on He, Ne and Ar isotope and trace-element data from the Foundation hotspot we have shown that the associated near ridge seamounts erupt lavas with a trace-element signature characteristic of oceanic gabbro, which indicates the existence of recycled, virtually unchanged oceanic lithosphere in the plume source.

Description: The relationship between gas hydrates, microorganisms and the surrounding sediment is extremely complex. Microorganisms can either act as producer or consumer of organic compounds. By converting organic matter microorganisms produce methane and therefore provide the prerequisite for gas hydrate formation. In natural environment clay minerals immobilize the substrates feeding the methane producing microorganisms. As a result of microbial activity gas hydrates are surrounded by a great variety of organic compounds which are not incorporated into the hydrate structure but influence the formation process. Through anaerobic metabolic activity special bacteria produce biosurfactants which were found to enhance the hydrate formation process significantly and act as nucleation centres. Another source of organic compounds is sediment organic matter (SOM) originating from plant material or animal remains which may also enhance hydrate growth. On the other hand methane is an energy source for special microbial methanotroph communities growing either aerobically or anaerobically. In sediments containing oxygen this methane will be oxidized into carbon dioxide. In the lower parts of the sediment methane originating from gas hydrates is oxidized anaerobically into bicarbonate by methanogenic archaea and sulphur reducing bacteria. In presence of dissolved calcium bicarbonate precipitates as calcium carbonate und forms carbonate crusts within the upper sediment layers of the sea floor.

Description: Energiewende ist Daseinsvorsorge. Eine erfolgreiche Energiewende benötigt eine Wärmewende! Innovationen, Demonstration und gesellschaftliche Akzeptanz spielen dabei eine Schlüsselrolle. Das „Zwanzig20- Forum Wärmewende“ entwickelt Strategien für den zukünftigen Einsatz von innovativen Technologien zur Realisierung der Wärmewende. Wir sind davon überzeugt, dass eine effiziente Wärmeversorgung urbaner Räume aus heimischen, regenerativen Energiequellen nicht nur möglich, sondern auch umsetzbar ist. Die Wärmewende kan gelingen, wenn die Energieeffizienz und der Anteil erneuerbarer Wärme gesteigert werden und der Sektor Strom geschickt in die Wärmeerzeugng eingebunden wird. Effizienzmaßnahmen haben Vorrang, stoßen aber an Grenzen. Erneuerbare Energien besitzen im Wärmesektor ein hohes Entwicklungspotential. Es gibt kein Patentrezept, die Wärmewende muss technologieoffen gestaltet werden. Im Transformationsprozess spielen Akzeptanz, Demografie und strukturierte Stadtentwicklung eine Schlüsselrolle. Deshalb sind die technologischen Lösungsansätze in eine holistische Sichtweise zu integrieren. Für eine Wärmewende sollten Lösungen ab der Dimension „Quartier“ vorrangig umgesetzt werden. Städte sind stark verdichtete Lebensräume des Menschen. Wärme-, Kälte- und Gasnetze bringen erneuerbare Energien in diese Lebensräume. Daher werden diese Netze in Städten erhalten und ausgebaut. In Großstädten gibt es auch künftig einen substanziellen Bedarf für eine zentrale Fernwärmeversorgung. Hierfür ist zukünftig die Nutzung von Erdwärme unverzichtbar. Die Netze sind die Energieversorgungsinfrastrukturen, die eine Integration der Innovationen von morgen ermöglichen, also von Lösungen, die wir heute noch nicht kennen. Bei vielen technologischen Prozessen fällt Abwärme an, die ungenutzt an die Umwelt abgegeben wird. Die Stadt der Zukunft heizt und kühlt mit dieser Abwärme. Dafür sind Speicher notwendig, auch saisonale Großspeicher. Demonstration ist wichtig für den Erfolg der Wärmewende. Demonstration adressiert die vorhandenen Zielkonflikte, hilft den Veränderungsprozess lösungsorientiert zu gestalten und fördert die Akzeptanz. Benötigt werden mehr Demonstrationsprojekte. Ausgehend von technologischen Lösungen bauen sichtbare und erfolgreiche Demonstrationsprojekte Vorbehalte und Unsicherheiten ab und schaffen Blaupausen für erfolgreiches Handeln und Wirtschaften. Dabei vernetzten sie an einem konkreten Standort die relevanten Akteure und verhelfen Innovationen zum Markteinstieg. Der Entwicklung von regenerativen Demonstrationsvorhaben stehen deutliche Hemmnisse gegenüber, daher ist sie für alle Beteiligten zeit- und ressourcenintensiv. Eine regenerative Wärmeversorgung erfordert zusätzliche Investitionen und muss sich als neuer Teilnehmer in einem etablierten und gedeckten Wärmemarkt behaupten. Kostendruck und Konkurrenzstellung liefern dabei wenig Anreize für Versorger und Verbraucher, regenerative Technologien zu implementieren. Die Anwendung innovativer Technologien stellt vielfach die etablierten Rollen zwischen Erzeuger und Verbraucher sowie dem Produkt der Wertschöpfung in Frage. Neue Geschäftsmodelle haben es schwer sich durchzusetzen, da die etablierten Modelle gut funktionieren. Demonstrationsvorhaben müssen daher durch staatliche Förderprogramme stimuliert werden. Integrierte Verbundprojekte zwischen der Wärmewirtschaft und öffentlichen Forschungsinstitutionen liefern gute Voraussetzungen für eine Förderfähigkeit.

Description: Mit dem Internet und der Digitalisierung haben sich fur die Wissenschaft neue M ¨ ¨oglichkeiten der Verbreitung und des Austausches von Wissen und Information er¨offnet. Unter dem Stichwort Open Science wird neben Open Access auch die Zug¨anglichkeit und Nachnutzung von digitalen Forschungsdaten diskutiert. Peter Schirmbacher hat sich in Forschung und Lehre mit der Relevanz, der Gestaltung und der Nutzung von Informationsinfrastrukturangeboten fur digitale Forschungsdaten befasst und damit wegweisende Beitr ¨ ¨age zur Weiterentwicklung dieser Services fur die digital arbeitende Wissenschaft geleistet. Vorliegender ¨ Beitrag gibt einen Uberblick ¨ uber den Entwicklungsstand der Informationsinfrastrukturan- ¨ gebote fur digitale Forschungsdaten und ordnet sie in die wissenschaftspolitische Diskussio- ¨ nen um Open Science ein.

Description: In recent years a widely disseminated microbial deep biosphere was discovered in the subsurface of the Earth. This finding opens the view to a fascinating new world under our feet and forms a new topic in modern microbiology and geoscience research. With its recognition the curiosity arises how these deeply buried microorganisms are able to survive in the deep subsurface. Important questions concerning theses survivalists are: what are the carbon and energy resources of these microbial ecosystems, what are the biotic and abiotic processes of substrate provision and what is the role of the deep biosphere in the organic matter transformation in the geological subsurface carbon cycle? The topic concerning the feedstock for deep microbial life forms the core of the deep biosphere research in Section Organic Geochemistry at GFZ German Research Centre for Geosciences.

Description: The Atacama Fault System (AFS) is an active trench-parallel fault system, located in the forearc of N-Chile directly above the subduction zone interface. Due to its well-exposed position in the hyper arid forearc of N-Chile it is the perfect target to investigate the interaction between the deformation cycle in the overriding forearc and the subduction zone seismic cycle of the underlying megathrust. Although the AFS and large parts of the upper crust are devoid of any noteworthy seismicity or historically documented earthquakes, at least three M=7 earthquakes in the past 10 ky have been documented in the paleoseismological record, demonstrating the potential of large events in the future. We apply a two-fold approach to explore fault activation and reactivation patterns through time and to investigate the triggering potential of upper crustal faults. 1) A new methodology using high-resolution topographic data allows us to investigate the number of past earthquakes for any given segment of the fault system as well as the amount of vertical displacement of the last increment. This provides us with a detailed dataset of past earthquake rupture of upper plate faults which is potentially linked to large subduction zone earthquakes. 2) The IPOC Creepmeter array provides us with high-resolution time series of fault displacement accumulation for eleven stations along the four most active branches of the AFS.

Description: Der Film dokumentiert den Kurs für Grundschulkinder „Geochemische Schatzsuche“. Ziel des Kurses ist es, Grundschulkinder für Naturwissenschaften zu begeistern. Länge: 6:37 min

Description: Als erstes Arbeitsergebnis legt die Ad-hoc-AG Open-Access-Gold dieses Positionspapier vor. Es richtet sich an wissenschaftliche Einrichtungen, die sich aktiv mit Aspekten des Open-Access-Publizierens befassen und bündelt und bewertet die Anforderungen an Verträge nach dem Publikationskostenmodell. Darüber hinaus greift es die Verknüpfung von Subskription und Open Access auf und gibt den adressierten Institutionen Anregungen zur Gestaltung ihrer Open-Access-Strategien. Das Ziel ist es, im Bereich des wissenschaftlichen Publizierens Transparenz und Nachhaltigkeit im Sinne der Wissenschaft herzustellen und die Perpetuierung früherer Fehlentwicklungen zu vermeiden.

Description: Film 7: "Die Stilllegung eines CO2-Speichers – Pilotstandort Ketzin" (Länge 10:39) Produktionsjahr: 2015

Description: In news reports we are accustomed to see earthquakes symbolised with a dot or star on a map and associated with a magnitude, the bigger the scarier. For at least moderately sized earthquakes seismologists additionally have been routinely determining the type of rupture just from observing the pattern of radiated seismic energy. In reality earthquakes do not occur as a point but rupture a fault plane. For small earthquakes this distinction can be neglected but for the largest earthquakes the rupture plane can extend for hundreds of kilometres, and the actual rupture propagation begins to have a strong influence on the hazard that the earthquake presents – whether the rupture proceeds to the north or the south and how deep and shallow it reaches determines which cities will be hit the hardest, whether shaking is moderate or intense, and whether a sizeable tsunami is triggered. The explosion of the availability of ground-, ocean- and space-based observation technologies in the last decade has allowed seismologists to map the rupture process in unprecedented detail even for challenging subduction zone earthquakes. The same technology can be used to observe potential precursory processes and the postseismic relaxation by which the earth regains its equilibrium following the disturbance that a great earthquake represents. Focussing on the Mw 8.1 Iquique earthquake in northern Chile on April 1, 2014, we will discuss the state-of-the-art in monitoring great earthquakes and their aftermath.

Description: The Earth’s surface is constantly changing. Sometimes these changes are very fast. When glaciers shrink or when natural disasters such as landslides or volcanic eruptions occur, their impact on landscapes can directly be observed. Other changes are too slow to be observed by the human eye. Such slow changes still form lofty mountain ranges like the Himalaya, because tectonic forcing has uplifted them persistently by a few millimeters each year over many millions of years. Such mountain ranges affect wind and rain patterns and thus the water cycle, and, by the process of erosion, they deliver sediment to valleys and floodplains where fertile soils form. Rare radioactive or stable cosmogenic nuclides have become the state-of-the-art clocks to time these rates of change in all kinds of landscapes. Produced by cosmic ray bombardment in the atmosphere or in minerals at the Earth’s surface, they are used to date landforms and to measure the erosion rate of landscapes. For example, we apply them to constrain the ages of glacial surfaces over hundreds to thousands of years. In river sediments they tell us how fast a mountain range is eroding and how much sediment is exported from a catchment. When buried in the sedimentary record, they inform us on erosion rates in the geologic past. Because of their power to infer landscape-forming forces, cosmogenic nuclides allow to predict the impact of changes of the human habitat induced by man.

Description: Since March 2002 the GFZ German Research Centre for Geosciences, together with NASA’s Jet Propulsion Laboratory (JPL) and the German Space Agency (DLR), operates the twin satellite mission GRACE (Gravity Recovery and Climate Experiment) and is part of the joint US-German Science Data System. Over GRACE‘s 15+ years of operation, researchers from GFZ and other national/ international institutions have developed innovative techniques to use the GRACE mass transport data set and to combine it with other observations and models for new insights into the Earth system. Highlights are the monitoring of changes in the hydrological cycle such as ground water depletion and related droughts, prognosis of floods in large river systems, the melting of Greenland’s and Antarctica’s ice sheets and large glacier systems, changes in the ocean dynamics and related sea level rise or observation of postseismic relaxation after large earthquakes. Currently, GFZ implements with JPL/NASA the successor mission GRACE-FO (Follow-on) which is due for launch in early 2018. The primary objective of GRACE-FO is to continue mass transport monitoring as only by long time series reliable conclusions on climate change can be drawn. The secondary objectives are to continue GRACE’s radio occultation measurements for provision to Numerical Weather Services and to demonstrate the improvement of the measurement of the inter-satellite separation by an innovative laser ranging interferometer. This is a necessary prerequisite to improve the spatial and temporal resolution by Next Generation Gravity Missions.

Description: In our meeting Dynamic Earth – from Alfred Wegener to today and beyond we will review how Wegener‘s findings evolved into to modern Earth system science including its impact on climate and the Earth surface, and how this system affects our daily life: where humans live, what risks we are exposed to, where we find our resources. In the meeting we will hold sessions that cover the entire geoscience spectrum (from mineral physics over solid earth geodynamics to the climate sciences) and that explore the consequences of Wegeners findings on how humans use our planet today (from energy and mineral resources over georisks to utilisation of the subsurface and materials for modern society). We have invited keynote speakers that are eminent international scientists in these fields. In events open to the general public we will get an account of Wegeners final trip to Greenland on the history of science of his hypothesis.

Description: This assessment focuses on how ORCID will be implemented in scientific institutions in Germany. In doing so, the institutional rules and German and European standards to which the scientific institutions in Germany which implement ORCID are subject, will be considered. In the process, account should be taken of the fact that personal data being collected in the European Union will be transferred into the USA. The key requirement of this assessment is that the assessment be formulated such that it is as generally understandable and universally applicable as possible, thus offering a guiding framework for legal evaluation onsite, for example in colleges and non-university research institutions. The concern of the assessment is to support scientific institutions in the legally compliant implementation of author identification using ORCID. The preparation of the assessment was preceded by a process which ought to ensure cooperation with the DFG Project ORCID DE. Specific questions were compiled in this manner (Annex I)14 during a workshop in 2016 after a presentation of fundamental data protection principles; further issues were addressed within the scope of an additional “Community Input” (Annex II), which was gathered by the project ORCID DE. Also, part of the assessment was a correspondence with the operators of ORCID. The corresponding questions of this exchange are also addressed in this assessment.

Description: The possibility of seismic risk mitigation in high hazard region like Central Asia requires the availability of strong motion recordings.When available also in real time, they can be precious for enabling early warning systems and efficient rapid response procedure. TheACROSS project is implementing the installation of the first real time strong motion network for Central Asia. It offers the opportunityfor developing, testing and implementing new methodologies for strong motion data analysis in real time, improving the transfer ofknowledge from research to application.

Description: Der Report des Helmholtz Open Science Workshops „Zugang zu und Nachnutzung von wissenschaftlicher Software“ #hgfos16 behandelt die Themen Standards und Qualitätssicherung; Reproduzierbarkeit; Lizenzierung und weitere rechtliche Aspekte; Zitation und Anerkennung; Sichtbarkeit und Modularität; Geschäftsmodelle; Personal, Ausbildung, Karrierewege. Diese Themen sind eng miteinander verzahnt. Für jeden Themenbereich werden jeweils die Relevanz, Fragestellungen, Herausforderungen, mögliche Lösungsansätze und Handlungsempfehlungen betrachtet.

Description: The geomagnetic field originates in the Earth’s outer core and reaches into space for several Earth radii. It thereby tells us about variations in the deep Earth, controls the shape and strength of electric currents and particle drift in the ionosphere and magnetosphere, and protects Earth’s life from solar and cosmic radiation. It is therefore important to understand the geophysical processes that lead to geomagnetic variations, and how the solar-terrestrial system is affected by space weather events. Research on geomagnetism, upper atmosphere research and magnetospheric as well as radiation belt physics profit enormously from dedicated satellite missions in low Earth orbit. GFZ’s scientific achievements in these research areas significantly benefit from ESA’s Swarm constellation mission, launched in 2013. GFZ contributed largely to its design and product definition by leveraging experiences from the successful CHAMP mission operated by GFZ during the last decade. Parameters including the geomagnetic and electric field, air density and wind, electron content and temperature are measured with high precision and global coverage. Also, particle flux measurements on the Lomonosov satellite will help us better understand the loss of particles from the Van Allen radiation belts into the atmosphere. The data from these missions are currently also utilized within the GFZ-coordinated Priority Programme 1788 “Dynamic Earth” funded by the German Research Foundation.

Description: Significant scientific findings are often directly related to innovations in measurement technology. For investigating the Earth’s interior the invention of the seismography played the most important role. Starting with the first seismograph suitable for scientific investigations by Ewing, Gray and Milne in the 1870s and its improvement by Wiechert around 1900, seismic instrumentation was available in the beginning of the last century to reveal the layered structure of our planet. Since then, instruments were steadily improved, and controlled source experiments and seismic networks significantly contribute today to our understanding of the Earth’s structure and the ongoing dynamic processes as well as to the exploration of resources as oil, gas, water and minerals. At the GFZ German Research Centre for Geosciences we work on technical innovations and apply them in experiments around the world and at a variety of scales. We develop highly portable, low-cost, high-performance seismic data recording systems, which are designed to be used in “large-N” array configurations (〉1000 receivers) and on the sea floor (shallow water). Distributed accoustic sensors (DAS) based on fibre-optic cables allow extremely dense sampling of the seismic wavefields. Seismic sources and receivers integrated in borehole tools illuminate in high-resolution the subsurface during drilling operations (Seismic prediction while drilling, SPWD).

Description: Das Wissen um die lokale Struktur von Seltenen Erden Elementen (SEE) in silikatischen und aluminosilikatischen Schmelzen ist von fundamentalem Interesse für die Geochemie der magmatischen Prozesse, speziell wenn es um ein umfassendes Verständnis der Verteilungsprozesse von SEE in magmatischen Systemen geht. Es ist allgemein akzeptiert, dass die SEE-Verteilungsprozesse von Temperatur, Druck, Sauerstofffugazität (im Fall von polyvalenten Kationen) und der Kristallchemie kontrolliert werden. Allerdings ist wenig über den Einfluss der Schmelzzusammensetzung selbst bekannt. Ziel dieser Arbeit ist, eine Beziehung zwischen der Variation der SEE-Verteilung mit der Schmelzzusammensetzung und der Koordinationschemie dieser SEE in der Schmelze zu schaffen.

Description: Knowledge of the local structure around rare earth elements (REE) in silicate and aluminosilicate melts is of fundamental interest for the geochemistry of magmatic processes, particularly for comprehensive understanding of the partitioning processes of REE in magmatic systems. It is generally accepted that mineral-melt partitioning of REE’s is controlled by temperature, pressure, oxygen fugacity (in case of polyvalent cations) and crystal chemistry but less is known about the influence of the melt composition. The aim of this thesis is to establish a relationship between the variation of the REE distribution with the melt composition and the coordination chemistry of this REE in the melt.

Description: Stable isotopes of the light elements Hydrogen (H), Carbon (C), Nitrogen (N), and Oxygen (O) are being measured in section 5.2 Climate Dynamics and Landscape Evolution at the GFZ in different terrestrial climate archives such as lake sediments, speleothems and tree rings. The stable isotope ratios of these elements reflect environmental conditions like precipitation, temperature, productivity and vegetation type. To translate isotope parameters into high-quality proxies of past climate and environmental variability, monitoring devices have been deployed which detect seasonal variations, pathways and distortions of stable isotope signals. Oxygen stable isotopes play a major role in paleoclimatology because of their broad variation and fractionation of 16O and 18O in water, carbonate and biological systems. In general, the isotopic ratios of oxygen isotopes reflect changes in atmospheric circulation systems which are important drivers for climate variability. Back through time, the variations of oxygen isotope ratios (18O/16O) in precipitation and their corresponding climate fingerprint are conserved in lake sediments, speleothems and tree rings. Oxygen isotope records from networks of these geoarchives allow local to regional assessments of past climate variability.

Description: Satellite remote sensing offers the possibility to continuously, globally collect information about Earth’s surface properties, and thus possesses an enormous scientific and economic potential. The spatio-temporal recording of information opens up a wide range of possibilities for large-scale monitoring of changes and influencing factors, e.g. in atmospheric research, agriculture and forestry, geology, urban areas and the analysis of natural hazards. The European Union‘s Copernicus programme marks the beginning of a new era in satellite-based Earth observation by designing and launching the Sentinel series, an operational fleet of high-continuity, multi-combinable observation systems. This enables completely new objects of investigation, but also requires a new level of automated data processing in order to make the huge amounts of data available for analysis. This article provides an insight into current remote sensing research at the GFZ. First, it presents the activities related to the creation of preprocessing standards and interfaces for data evaluation, geo-data management and visualization. In the following, examples for multi-sensor analysis of land use potentials and natural hazards are shown, in order to finally discuss the role of the GFZ in the development of hyperspectral satellite missions and related data analysis.

Description: Volcanic activity involves different processes on different scales at depth and at the surface. Many of them generate seismic signals, ranging from tiny, earthquake-like signals to increased continuous vibrations to significant ground motion events before and during volcanic eruptions. A range of modern tools of volcano seismology is nowadays used to monitor changes in the volcanic activity and volcanic unrest. Additionally, advanced seismology is able to image the deep volcanic structures at high resolution and to map the depth and size of magmatic reservoirs beneath volcanoes. Although seismology is a key technology for volcano research and the assessment of volcanic hazard, novel concepts of volcano monitoring combine seismology with different types of multi-parameter sensors to characterize the processes accompanying volcanic unrest. GFZ is developing advanced approaches for volcano monitoring and volcano modeling involving a broad scale of instruments and disciplines. The article focuses mainly on two examples from volcanoes in South America and Iceland showing how large magmatic reservoirs are slowly filled over periods of decades and abruptly depleted over periods of months during volcanic eruptions.

Description: Sedimentary basins represent geological archives. Accordingly, 3D basin models that integrate geological and geophysical observations can be used to reproduce not only their present-day structural configuration and distribution of physical properties, but also their evolution including the subsidence history. For example, the thickness of deposited sediments reflects the amount of subsidence caused by the sediment load. The corresponding load-dependent vertical movements (called isostatic subsidence) can be sequentially subtracted from the total subsidence in order to reconstruct past depth configurations. Another aspect of basin subsidence is caused by thermal processes that can also be approximated by studying the present-day basin configuration. If the basin formation is related to lithospheric stretching and thinning, it initially involves a thermal disturbance due to which the geothermal gradient is increased by an amount depending on the observed strain. After stretching has ceased, the lithosphere starts cooling down and approaches a thermal equilibrium. This cooling process is accompanied by an increase in rock density and related thermal subsidence, which can also be assessed. By calculating the two subsidence components for certain stratigraphic intervals, the corresponding temporal changes in water depths (paleobathymetries) can be reconstructed for our understanding of subsidence dynamics. This research methodology was applied to the conjugate passive continental margins of Africa and Argentina in order to analyse and compare the evolution of sedimentary basins after the formation of the South Atlantic. This study mainly focussed on the Argentinian Colorado Basin because of its complex evolution and economic resource potential.

Description: Very long baseline interferometry (VLBI) is one of the fundamental space geodetic techniques. Important goals for the next generation of VLBI technology are continuous operations as well as automated data processing. For this reason, it is necessary to introduce real time capable parameter estimation algorithms, such as Kalman filters, to VLBI data analysis. In this study, such a filter was implemented in the VLBI software VieVS@GFZ, and several aspects related to VLBI data processing were investigated. Within the corresponding module VIE_KAL it is possible, for example, to estimate all parameters important in VLBI analysis, adapt their stochastic models, flexibly define the datum, integrate external data, as well as extract datum free normal equations. The foci of the investigations were on the effects of the troposphere, the most important error source in VLBI analysis, and on the determination of station positions, which are of great importance in geodesy. For the stochastic model of the tropospheric delays, station- and timedependent differences were considered. In comparisons with tropospheric parameters from GNSS, water vapor radiometers and numerical weather models, the Kalman filter solution yielded 5 to 15% smaller differences than a least squares solution based on the same models and VLBI data. Also in the case of estimated station coordinates, the Kalman filter solution exhibited better baseline length and station coordinate repeatabilities. The application of station-based process noise led to additional improvements. Furthermore, the Kalman filter was used to estimate subdaily station coordinate variations caused by tidal and loading effects. Finally, the findings were used to determine Kalman-filter-based global terrestrial reference frames (TRFs). For the stochastic model of the coordinate variations of particular stations, loading deformation time series were utilized. The non-deterministic approach of the Kalman filter allowed the consideration of non-linear station movement, for example, due to irregular seasonal effects or post-seismic deformations. In comparisons with a VLBI TRF solution from a classical adjustment and ITRF2008, a good agreement in terms of transformation parameters and station velocities was achieved. The findings from testing different options related to the parameterization and to the stochastic model will help to improve future reference frames.

Description: Seismic hazard assessments can only be as good as the historical past is known. Therefore, reliable seismicity records have to be extended back into history as far as possible. Hence, historical seismological investigation is of utmost importance in order to achieve long-term earthquake catalogue data of high quality. This basic research has been performed at the GFZ German Research Centre for Geosciences as a multidisciplinary approach of seismologists and historians for many years. Seismic activity before the installation of the first seismographs in the beginning of the 20th century can only be reconstructed based on written sources For Central Europe, these documents date back up to the middle of the 8th century. The historical information for each earthquake has to be source-critically analyzed and transferred into parameterized information, which is then catalogued. During the long tradition of collecting past seismic information starting more than a century ago, many mistakes were made, like duplications of events, misinterpreted strength, location and wrong dating of earthquakes, which could be identified by our investigation. We show exemplarily how these uncertainties can be mitigated. Historical passing on of information is transferred to modern seismicity parameters by applying historic-critical methods. Thus, we are able to acquire better and more reliable long-term data for historical earthquake catalogues and for trustworthy long-term seismic hazard assessments.

Description: To this date, the question of why and how a plateau-type orogen formed with massive crustal thickening at the leading edge of western South America remains one of the hotly debated issues in geodynamics. During the Cenozoic, the Altiplano and Puna plateau of the Central Andes developed during continuous subduction of the oceanic Nazca plate in a convergent continental margin setting – a situation that is unique along the 60 000 km of convergent margins around the globe. The key challenge is to understand why a first-order mechanical instability of the later plateau extent developed along the central portion of the leading edge of South America only, as well as why and how this feature developed only during the Cenozoic, although the cycle of Andean subduction had been ongoing since at least the Jurassic. Although the widespread presence of partial melts or metamorphic fluids at mid-crustal level has been suggested to indicate upper plate weakening from heating and partial melting, it is recently found that upper plate strain weakening at lithospheric scale plays a significantly larger role. This first order control is tuned by factors affecting the strength balance between the upper plate lithosphere and the plate interface of the Nazca and South American plates such as variations in trenchward sediment flux affecting plate interface coupling and slab rollback or the role of inherited structures. Late initiation of orogeny in the Eocene, however, and its sustained action over tens of million years is now found to be related to the penetration of the slab into the lower mantle around 50 Ma ago, producing a slowdown of the lateral slab migration (‚slab anchoring’), and dragging the upper plate against the subduction zone by large-scale return flow. The combination of these parameters was highly uncommon during the Phanerozoic leading to very few plateau style orogens at convergent margins like the Cenozoic Central Andes in South America or the Laramide North American Cordillera.

Description: Along with cell phones and the internet, satellite navigation is an integral part of everyday life. However, satellite navigation signals provide much more than precise information on user locations. Even before the GPS was declared fully operational in 1995, the potential for these globally and continuously available navigation signals for Earth observation and geoscientific applications was recognized. Such applications include the precise monitoring of continental plate movements with sub-mm/year accuracy (now used in real-time as part of early earthquake warning systems), regional and global atmospheric and ionospheric sounding to improve weather forecasts and climate change predictions, and for monitoring of water, ice, and land surfaces. The Earth observation prospects and related spectrum of applications are continuously growing, mainly stimulated by the transition from a single constellation (GPS) to Multi-GNSS (Global Navigation Satellite System) with the Russian GLONASS, Chinese BeiDou and European Galileo satellites and by the increasing number of GNSS receivers available both on the ground and aboard Low Earth Orbiting satellites.

Description: In der Arbeit wird ein kombiniertes hochaufgelöstes globales Schwerefeldmodell bis Grad und Ordnung 720 mit zugehöriger voller Varianz-Kovarianz Matrix berechnet. Als Datenbasis dienen Messungen der Schwerefeldsatellitenmissionen GRACE und GOCE, sowie terrestrische und altimetrische Schwereanomalien. Die Schätzung erfolgt durch kleinsten-Quadrate Ausgleichung, im Rahmen derer eine optimale relative Gewichtung der Einzeldatensätze und der einzelnen Beobachtungen erzielt wird. Die rechentechnische Umsetzung erfolgt mit Hilfe von Hochleistungsrechensystemen.

Description: Die Allianz der deutschen Wissenschaftsorganisationen empfiehlt wissenschaftlichen Einrichtungen, Informationen zu gezahlten Open-Access-Publikationsgebühren offenzulegen, damit die Kostenstrukturen des Open-Access-Publikationsmarkts klar erkennbar werden.

Description: This article provides first insights into some of the fascinating aspects of astrobiology. The central focus of this research theme is directed towards questions which have interested humans for millennia: How has life developed? Where do we come from? Are we alone in the Universe? In order to approach these questions, astrobiology brings together a variety of disciplines such as astronomy, astrophysics, biology, biochemistry, chemistry, geology, mineralogy, and cosmology. In particular, scientists are more and more interested into the biological aspects and the interactions of (micro)-organisms with their geological environment. This interest is further fueled by numerous NASA and ESA missions to Mars that have spawned new insights into Mars as a potential habitat for life. Earth analog environments, which are characterized by conditions that occur in other parts of our solar system in even more extreme forms play an important role for astrobiological research. Examples include habitats that are characterized by extreme dryness and/or coldness such as the Atacama Desert in Chile, liquid asphalt lakes in Trinidad or the permafrost areas in Siberia. Extremophilic microorganisms such as cyanobacteria and methanogenic archaea or higher organisms such as lichens and bryophytes are used as model organisms to study the limits of life under simulated extreme conditions. In recent years, an active research network has been established in the Berlin-Brandenburg region that carried out joint astrobiology and habitability studies and which among other projects is currently conducting an ESA experiment onboard the International Space Station ISS.