ALBERT

Beschreibung: The Central Andes of southern Peru, Bolivia, Argentina and Chile (between 12°S and 42°S) comprise the largest orogenic plateau in the world associated with abundant arc volcanism, the Central Andean Plateau, as well as multiple segments of flat-slab subduction making this part of the Earth a unique place to study various aspects of active plate tectonics. The goal of this continental-scale ambient noise tomography study is to incorporate broad-band seismic data from 20 seismic networks deployed incrementally in the Central Andes from 1994 May to 2012 August, to image the vertically polarized shear wave velocity (Vsv) structure of the South American Cordillera. Using dispersion measurements calculated from the cross-correlation of 330 broad-band seismic stations, we construct Rayleigh wave phase velocity maps in the period range of 8–40 s and invert these for the shear wave velocity (Vsv) structure of the Andean crust. We provide a dispersion misfit map as well as uncertainty envelopes for our Vsv model and observe striking first-order correlations with our shallow results (∼5 km) and the morphotectonic provinces as well as subtler geological features indicating our results are robust. Our results reveal for the first time the full extent of the mid-crustal Andean low-velocity zone that we tentatively interpret as the signature of a very large volume Neogene batholith. This study demonstrates the efficacy of integrating seismic data from numerous regional broad-band seismic networks to approximate the high-resolution coverage previously only available though larger networks such as the EarthScope USArray Transportable Array in the United States.

Beschreibung: Am 20. Januar hieß es auf unserem Berg ein weiteres Mal: „Drei Minuten Zeit, ein Quadratmeter Platz. Nicht mehr. Kein PowerPoint. Nur das, was man am Körper tragen kann. Und damit das eigene Forschungsgebiet kurz, knapp, verständlich und mitreißend vorstellen.“ Das GFZ veranstaltete nach dem Erfolg im Jahr 2011 erneut den regionalen Vorentscheid Brandenburg-Berlin des FameLab Germany 2012.

Beschreibung: The International Geomagnetic Reference Field (IGRF) is a very frequently used model of the Earth’s main magnetic field by both the science community and the industry. This model is updated every five years. We present here the second generation of the GRIMM magnetic field model that was derived to contribute to the IGRF-11. The model has been developed from a newly, reprocessed CHAMP satellite data set covering nearly 10 years. It has a temporal and spatial resolution significantly improved compared to previous models.

Beschreibung: Borehole measurements or downhole logging is a powerful method to in-situ gain quasi-continuous profiles of physical, chemical and structural rock parameters with high depth accuracy. It is widely used in both academic research and commercial exploration for oil and gas, mining industry, geothermal and water engineering. The GFZ section Scientific Drilling facilitates logging in two ways, first through service and applying a set of downhole instruments and second through developing novel methods and tools. Logging support is provided to scientific projects and covers assistance with planning and logistics of downhole logging programs, logging service through operating a versatile set of own downhole sondes, including geophysical and structural logging tools, a seismic chain and a fluid sampler. In order to expand the possibilities of in-situ borehole information new tools are developed jointly with academic and industrial partners. The most advanced sonde development strives to image geological structures by using high-resolution borehole seismics to explore hydrocarbons or geothermal resources by detecting thin layers and faults. The SPWD (Seismic Prediction While Drilling) borehole prototype sonde combines seismic sources and receivers in one device to improve the resolution. Two downhole test sites, the KTB-Deep Crustal Lab in Windischeschenbach and the GFZ Underground Lab in the mine “Reiche Zeche” in Freiberg offer unique in-situ conditions for experiments and tests of the borehole equipment.

Beschreibung: The ability of any satellite gravity mission concept to monitor mass transport processes in the Earth system is typically tested well ahead of its implementation by means of various simulation studies. Those studies often extend from the simulation of realistic orbits and instrumental data all the way down to the retrieval of global gravity field solution time-series. Basic requirement for all these simulations are realistic representations of the spatio-temporal mass variability in the different sub-systems of the Earth, as a source model for the orbit computations. For such simulations, a suitable source model is required to represent (i) high-frequency (i.e., subdaily to weekly) mass variability in the atmosphere and oceans, in order to realistically include the effects of temporal aliasing due to non-tidal high-frequency mass variability into the retrieved gravity fields. In parallel, (ii) low-frequency (i.e., monthly to interannual) variability needs to be modelled with realistic amplitudes, particularly at small spatial scales, in order to assess to what extent a new mission concept might provide further insight into physical processes currently not observable. The new source model documented here attempts to fulfil both requirements: Based on ECMWF’s recent atmospheric reanalysis ERA-Interim and corresponding simulations from numerical models of the other Earth system components, it offers spherical harmonic coefficients of the time-variable global gravity field due to mass variability in atmosphere, oceans, the terrestrial hydrosphere including the ice-sheets and glaciers, as well as the solid Earth. Simulated features range from sub-daily to multiyear periods with a spatial resolution of spherical harmonics degree and order 180 over a period of 12 years. In addition to the source model, a de-aliasing model for atmospheric and oceanic high-frequency variability with augmented systematic and random noise is required for a realistic simulation of the gravity field retrieval process, whose necessary error characteristics are discussed. The documentation of the updated ESA Earth System Model (updated ESM) for gravity mission simulation studies is organized as follows: The characteristics of the updated ESM along with some basic validation is presented in Volume 1. A detailed comparison to the original ESA ESM (Gruber et al., 2011) is provided in Volume 2, while Volume 3 contains the description of a strategy to derive realistic errors for the de-aliasing model of high-frequency mass variability in atmosphere and ocean.