ALBERT

Description: 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.

Description: 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.

Description: On 2012 May 20 and 29, two damaging earthquakes with magnitudes Mw 6.1 and 5.9, respectively, struck the Emilia-Romagna region in the sedimentary Po Plain, Northern Italy, causing 26 fatalities, significant damage to historical buildings and substantial impact to the economy of the region. The earthquake sequence included four more aftershocks with Mw ≥ 5.0, all at shallow depths (about 7–9 km), with similar WNW–ESE striking reverse mechanism. The timeline of the sequence suggests significant static stress interaction between the largest events. We perform here a detailed source inversion, first adopting a point source approximation and considering pure double couple and full moment tensor source models. We compare different extended source inversion approaches for the two largest events, and find that the rupture occurred in both cases along a subhorizontal plane, dipping towards SSW. Directivity is well detected for the May 20 main shock, indicating that the rupture propagated unilaterally towards SE. Based on the focal mechanism solution, we further estimate the co-seismic static stress change induced by the May 20 event. By using the rate-and-state model and a Poissonian earthquake occurrence, we infer that the second largest event of May 29 was induced with a probability in the range 0.2–0.4. This suggests that the segment of fault was already prone to rupture. Finally, we estimate peak ground accelerations for the two main events as occurred separately or simultaneously. For the scenario involving hypothetical rupture areas of both main events, we estimate Mw = 6.3 and an increase of ground acceleration by 50 per cent. The approach we propose may help to quantify rapidly which regions are invested by a significant increase of the hazard, bearing the potential for large aftershocks or even a second main shock.

Description: This paper presents the application of two different active contour models for the segmentation of high-resolution TerraSAR-X data. Both methods facilitate the detection of land-water-boundaries in semi-automated procedures and can be used to delineate flood extent and to map open water surfaces in general. For the extraction of smooth water bodies amplitude thresholding approaches are quite common and often applied. For rough water bodies however the application of amplitude thresholding methods is not successful. This paper demonstrates the poten-tials and limitations of active contour models for mapping both smooth and rough water bodies in high-resolution SAR data. Examples of both different segmentation methods are presented.

Description: The addition of clay to growing media aims at constant supply of potassium, phosphorus and micro nutrients, pH-buffering, improvement of rewettability, and cohesion of growing media. The identification of suitable clays and their classification is a prerequisite for product and cultivation safety. A range of different clays highly variable in their mineral parameters were selected for experiments on nutrient buffering (P) and Mn toxicity, their ability to improve the rewettability and binding capacity of growing media. From batch experiments and growth trials it was derived that a threshold value for the sum of exchangeable and easy reducible Mn in clays for growing media is not justified, as even very high Mn contents in clay were not phytotoxic. The P binding capacity of clays was strongly correlated with the oxalate extractable Fe and Al content. A newly developed capillary rise method (WOK) was used to characterize the rewettability of growing media. The speed of rewetting mainly depends on the fineness of the amended clay. Surface free energy (SFE) data of the growing media indicate that those with a good rewettability show also high values for SFE. Compared to the kaolinitic and illitic clay amendments, bentonites show no significant increase in the SFE. Surfaces of clay minerals exhibiting originally polar and hydrophilic surfaces, can render hydrophobic when coated with weakly or non-polar organic matter moieties. Dissolved organic carbon (DOC) sorption was found to be positively correlated with the specific surface area (SSA), cation exchange capacity (CEC) and amount of dithionite extractable Al and Fe. Clays containing expandable clay minerals with high CEC and SSA (e.g. smectites) and those rich in Al- and Fe-oxides seem to be less effective for improving rewettability, whereas an addition of non-expandable clays with lower SSA, CEC (e. g. kaolinitic and illitic clays) and amorphous oxide content appears more promising. New insights on the adsorption of DOM on clay mineral`s surfaces will be obtained in the third year by chemical analysis of the surface with X- ray photoelectron spectroscopy (XPS), surface topography analysis and contact angle measurements. A new method for the determination of the binding capacity of clays in blocking media is currently being tested and will be studied together with determinations on K-dynamics.

Description: The Sumatra-Andaman earthquake with a magnitude of 9.3, and the subsequent destructive tsunami which caused more than 225 000 fatalities in the region of the Indian Ocean, happened on 26 December 2004. Less than one month later, the United Nations (UN) World Conference on Disaster Reduction took place in Kobe, Japan to commemorate the 1995 Kobe earthquake. The importance of preparedness and awareness on regional, national and community levels with respect to natural disasters was discussed during this meeting, and resulted in the approval of the Hyogo Declaration on Disaster Reduction. Based on this declaration the UN mandated the Intergovernmental Oceanographic Commission (IOC) of UNESCO (United Nations Education, Science and Cultural Organization), taking note of its over 40 years of successful coordination of the Pacific Tsunami Warning System (PTWC), to take on the international coordination of national early-warning efforts for the Indian Ocean and to guide the process of setting up a Regional Tsunami Early Warning System for the Indian Ocean.

Description: A unique and very interesting earthquake of magnitude Mw 7.2 occurred in the Van region of Turkey on October 23, 2011 that caused a heavy loss of human lives and properties. The earthquake occurred on a blind oblique thrust fault oriented towards the NE–SW direction and dipping towards NW as evidenced by focal mechanism solution and aftershock distribution. In this study, we analyzed the seismogenesis and earthquake triggering during this sequence with the help of estimated seismological parameters (b-value of frequency–magnitude relation, p-value of aftershocks temporal decay and D-value of fractal dimension), 2D mapping of b- and p-values, 3D mapping of b-value and coseismic Coulomb stress modeling. The estimated seismic b-value equal to 0.89 reveals that the mainshock occurred in a highly stressed region and sequence comprised larger magnitude aftershocks due to the presence of large size asperities within the rupture zone. The normal estimate of p-value (0.98) suggests a tectonic genesis of the aftershocks sequence. The estimated D-value equal to 1.80 reveals that rupture propagated in a two-dimensional plane filled up by fractures. The spatial 2D and 3D mapping of seismic b-value suggests that the Van earthquake originated in a highly heterogeneous fractured rock matrix with fluid intrusions into it at deeper depth beneath the mainshock hypocenter region. The estimated coseismic Coulomb stress using the variable slip model for depth range 0–30 km exhibits a ‘butterfly’ pattern and most of the aftershocks fall (90%) in the region of enhanced Coulomb stress. This suggests that most of the aftershock activities have been triggered by transfer of positive Coulomb stress due to coseismic slip of the mainshock. The results estimated in the present study have potential useful implications in future seismic hazard assessment and risk mitigation in Van and the surrounding regions.

Description: We present an attenuation model for midperiod Rayleigh waves in Central Asia and surrounding regions. This model is defined by maps of attenuation coefficient across the region of study in the period band 14–24 s. The model is constructed to characterize the regional variations in attenuation of seismic waves in the crust, which are related to the tectonic history of the studied territory, to calibrate the regional surface-wave magnitude scale, and to extend the teleseismic 'surface-wave magnitude – body wave magnitude' (Ms-mb) discriminant to regional distances. The construction of the model proceeds in three stages. The first stage in model construction is the measurement of Rayleigh wave spectral amplitudes. We collected and processed waveform data for 200 earthquakes occurring from 2003 to 2006 inside and around Eurasia, and used records of about 135 broadband permanent and temporary stations. This data set provided a sufficient number of spectral amplitude measurements between 14 and 24 s periods for the construction of two–dimensional tomographic maps of attenuation coefficients. At the second stage of the work, the integral of attenuation coefficients along given paths is estimated using both inter-station measurements and single-station measurements corrected for source and receiver terms. The third stage includes the refining of source parameters, recalculation of attenuation coefficient integrals after this refinement, grooming of resulting coefficients, and multistage tomographic inversion of the data. Tomographic maps for the set of periods from 14 to 24 s, which exhibit clear correlation with geology and tectonics of the territory under study, were obtained. Validation of these maps using the inter-station measurements confirms their accuracy in predicting the observations.

Description: An ascorbic acid extraction at pH 7.5 has been examined to assess the influence of reaction conditions (pH, ascorbic acid concentration) on the dissolution of Fe from synthetic 2-line ferrihydrite and from other Fe-bearing minerals. The method was highly selective for Fe in ferrihydrite with only small amounts of Fe extracted from other (oxyhydr)oxides or clays. The labile Fe extracted from the synthetic 2-line ferrihydrite stored as a slurry decreased with time, and high resolution microscopy showed that the older materials formed networked aggregates that slow down the dissolution. The apparent rate constant for the dissolution of fresh 2-line ferrihydrite (similar to 10(-3) s(-1)) was an order of magnitude larger than that for aged suspensions (similar to 10(-4) s(-1)). Fresh 2-line ferrihydrite that was filtered, freeze-dried, frozen and freeze-dried, and stored in the dry was even less readily dissolved (apparent rate constants similar to 10(-6) s(-1)). These ferrihydrites also contained networked aggregates and, additionally, appear to occur as granular aggregates (visible to the naked eye) during the early stages of dissolution. Storage of filtered, freeze-dried, and frozen and freeze-dried ferrihydrites, whether in water or air, produced similar dissolution behaviour because aggregation caused by de-watering decreases the labile Fe content and is not reversed by re-hydration. The determination of labile Fe in ferrihydrite requires that natural samples should be collected, stored and extracted wet. The most aged samples dissolved by parabolic dissolution kinetics indicate that the rates of dissolution were controlled by the diffusion of reactant into the internal porosity of aggregates. (C) 2010 Elsevier B.V. All rights reserved.

Description: The high elevation of the southern Puna plateau, the widespread melting of its crust, the gap in intermediate depth seismicity and the recent eruptions of ignimbrite complexes can be explained by delamination of the lithospheric mantle beneath it. To test this hypothesis, an array consisting of 73 broad band and short period seismic stations was deployed in the region for a period of 2 years starting in 2007. We inverted the data using the two plane wave approach and obtained 1-D and 3-D Rayleigh wave phase velocities. Our dispersion curve shows that at short periods (〈70 s) the phase velocities are slightly higher than those of the Tibetan plateau and lower than those of the Anatolian plateau. At periods of 100–140 s we observe a low velocity zone that might be remnant hot asthenosphere below a flat slab (7–10 Ma). We estimate the average continental lithosphere thickness for the region to be between 100 and 130 km. Our three-dimensional Rayleigh wave phase velocities show a high velocity anomaly at low frequencies (0.007, 0.008, and 0.009 Hz) slightly to the north of Cerro Galan. This would be consistent with the hypothesis of delamination in which a piece of lithosphere has detached and caused upwelling of hot asthenosphere, which in turn caused widespread alkaline-collision related volcanism. This interpretation is also corroborated by our shear wave velocity model, where a high velocity anomaly beneath the northern edge of Cerro Galan at 130 km depth is interpreted as the delaminated block on top of the subducting Nazca slab.

Description: The seismicity data file used for this study is represented by the earthquake catalogue CENEC for Europe north of 44°N (Grünthal et al. 2009a). This paper describes in detail how this homogeneous data file in terms of moment magnitudes Mw (with Mw greater than 3.5) has been derived. The degree of harmonization achieved in CENEC is quantitatively analysed in Grünthal et al. (2009b).

Description: A mobile volcano fast response system (VFRS) that can be used for volcano monitoring in case of volcanic unrest anywhere in the world is currently under development in Germany. The main goal of the project called Exupéry is to provide the communication technology for stations in the field and an expert system that collects all data from various sources, assembles them in a database, and allows users to assess the data through one common web GIS interface. The system also includes an integrated automatic alert level including the alert level estimation in order to characterize the activity state of the volcano. The web GIS interface serves as a decision support system to assist scientists and local authorities in deciding how to react in the case of volcanic unrest.

Description: The Laramide orogeny (80-50 Ma) resulted in thick-skinned deformation of the western United States, more than 700 km inboard of the plate boundary where the Farallon Plate was subducting below North America. Most studies conclude that this event was the result of low-angle or flat subduction of the Farallon plate, whereby horizontal compressive stress from the shallow slab produced inboard crustal compression and shortening. However, it is still not clear what factors caused the Farallon plate to shallow prior to Laramide time or how stress was transferred from the flat slab to the continental interior. Three hypotheses have been proposed for triggering flat subduction: (1) an increase in the westward velocity of the North American plate; (2) subduction of an buoyant oceanic plateau with abnormally thick crust and possibly a low density harzburgite mantle lithosphere layer; and (3) slab suction produced by subduction-induced mantle wedge flow and enhanced by the presence of thick Colorado Plateau lithosphere in the backarc. In this study, we use numerical models to study the development of low-angle subduction below a continental plate with a structure similar to that of the western US. The two-dimensional, plain strain models use the SOPALE code, in which Arbitrary Lagrangian-Eulerian finite element techniques are used to compute the coupled thermal-mechanical evolution of the lithosphere-upper mantle system. We first assess what factors are needed to dynamically develop low-angle subduction. We find that the main control is the continental velocity, with enhanced slab shallowing as the continental velocity increases. In order to create a section of horizontal (i.e., flat) subduction, a further requirement is the presence of an oceanic plateau with a low-density harzburgite layer. The slab suction force seems to be less capable of creating a flat slab than the other two factors. This may be due to the low viscosity in the mantle wedge in our models (10^19~10^20Pa s), which cannot produce a sufficiently large hydrodynamic force to flatten the oceanic plate. Future work will examine variations in the strength of both the continental plate and the interface between the continent and low-angle oceanic plate, in order to explore the relationship between flat subduction and Rocky Mountain foreland deformation during Laramide time.

Description: Frequency-domain helicopter-borne electromagnetic (HEM) data sets are commonly interpreted using one-dimensional (1-D) modelling and inversion tools. In many cases this approach is valid (e.g., horizontally layered targets and groundwater applications) but there are areas of higher dimension that are not recovered correctly applying 1-D methods. In recent years multi-dimensional forward modelling codes became available. As there is no analytic solution to verify (or falsify) the obtained numerical solutions, comparison with 1-D values as well as amongst various two-dimensional (2-D) and three-dimensional (3-D) codes is essential. Values obtained over the background structure and at the centre of a large (a few hundred metres edge length) structure should match 1-D values. At the edges of the structure – i.e., at higher dimensional parts – only a comparison of different codes is possible. The more codes – especially if based on different methods and/or written by different programmers – agree the more reliable is the obtained synthetic data set.

Description: The seismic signature of the Moho from which geologic and tectonic evolution hypotheses are derived is to a large degree a result of the seismic methodology which has been used to obtain the image. Seismic data of different types, passive source (earthquake) broad-band recordings, and controlled source seismic refraction, densely recorded wide-angle deep seismic reflection, and normal incidence reflection (using VibroseisTM, explosives, or airguns), have contributed to the description of the Moho as a relatively complex transition zone. Of critical importance for the quality and resolution of the seismic image are the acquisition parameters, used in the imaging experiments. A variety of signatures have been obtained for the Moho at different scales generally dependent upon bandwidth of the seismic source. This variety prevents the development of a single universally applicable interpretation. In this way source frequency content, and source and sensor spacing determine the vertical and lateral resolution of the images, respectively. In most cases the different seismic probes provide complementary data that gives a fuller picture of the physical structure of the Moho, and its relationship to a petrologic crust–mantle transition. In regional seismic studies carried out using passive source recordings the Moho is a relatively well defined structure with marked lateral continuity. The characteristics of this boundary change depending on the geology and tectonic evolution of the targeted area. Refraction and wide-angle studies suggest the Moho to be often a relatively sharp velocity contrast, whereas the Moho in coincident high quality seismic reflection images is often seen as the abrupt downward decrease in seismic reflectivity. The origin of the Moho and its relation to the crust–mantle boundary is probably better constrained by careful analysis of its internal details, which can be complex and geographically varied. Unlike the oceanic Moho which is formed in a relatively simple, well understood process, the continental Moho can be subject to an extensive variety of tectonic processes, making overarching conclusions about the continental Moho difficult. Speaking very broadly: 1) In orogenic belts still undergoing compression and active continental volcanic arcs, the Moho evolves with the mountain belt, 2) In collapsed Phanerozoic orogenic belts the Moho under the collapse structure was formed during the collapse, often by a combination of processes. 3) In regions having experienced widespread basaltic volcanism, the Moho can result from underplated basalt and basaltic residuum. In Precambrian terranes the Moho may be as ancient as the formation of the crust, in others Precambrian tectonic and magmatic processes have reset it. We note that seismic reflection data in Phanerosoic orogens as well as from Precambrian cratonic terranes often show thrust type structures extending as deep as the Moho, and suggest that even where crust and mantle xenoliths provide similar age of formation dates, the crust may be semi-allochothonous

Description: Analysis of seismic anisotropy in the crust and the uppermost mantle gives lots of information about the ambient mantle flow, stress state, and the dynamic processes inside the Earth. Thus, seismic anisotropy and its main distinctive features beneath the southeastern Mediterranean region are studied through the analysis of teleseismic shear-wave splitting observed at six broadband seismic stations belonging to the GEOFON and the MedNet. Although the number of the recording stations is small; a total of 495 splitting parameters are obtained, which revealed significant variations in the observed fast polarization directions beneath the study area. The stations in northern Egypt and Cyprus show fast velocity directions oriented roughly N–S to NNE–SSW, coincident with many previous results. A slightly different splitting pattern comprising NE–SW fast polarization directions is observed in the stations located along the Dead Sea fault in the southeastern Mediterranean; which are consistent with the current strike-slip motion between Africa and Arabia. In addition, NW–SE fast polarization directions are recognized in the latter group. The observed delay times vary greatly but their averages lie between 0.35 and 1 s. Although large-scale mechanisms, such as the absolute plate motion of Africa and Arabia towards Eurasia and the differential motion between Arabia and Africa can be invoked to predominantly explain the origin of anisotropic features, we suggest that density-driven flow in the asthenosphere is a possible additional cause of the wide range of the splitting pattern observed beneath some stations.

Description: In eastern Turkey, the ongoing convergence of the Arabian and African plates with Eurasia has resulted in the westward extrusion of the Anatolian Plate. To better understand the current state and the tectonic history of this region, we image crust and uppermost mantle structure with ambient noise tomography. Our study area extends from longitudes of 32° to 44°E. We use continuous data from two temporary seismic deployments, our 2006–2008 North Anatolian Fault Passive Seismic Experiment and the 1999–2001 Eastern Turkey Seismic Experiment, as well as from additional seismographs in the region. We compute daily cross-correlations of noise records between all station pairs and stack them over the entire time period for which they are available, as well as in seasonal subsets, to obtain interstation empirical Green's functions. After selecting interstation cross-correlations with high signal-to-noise ratios and measuring interstation phase velocities, we compute phase velocity maps at periods ranging from 8 to 40 s. At all periods, the phase velocity maps are similar for winter and summer subsets of the data, indicating that seasonal variations in noise sources do not bias our results. Across the study area, we invert the phase velocity estimates for shear velocity as a function of depth. The shear velocity model, which extends to 50 km depth, highlights tectonic features apparent at the surface: the Eastern Anatolian Plateau is a prominent low-velocity anomaly whereas the Kırşehir Massif has relatively fast velocities. There is a large velocity jump across the Inner Tauride Suture/Central Anataolian Fault Zone throughout the crust whereas the North Anatolian Fault does not have a consistent signature. In addition, in the southeastern part of our study area, we image a high velocity region below 20 km depth which may be the northern tip of the underthrusting Arabian Plate.

Description: Fifteen earthquakes (Mw 4.1–6.4) occurring at ten major segments of the Sumatran Fault Zone (SFZ) were analyzed to identify their respective fault planes. The events were relocated in order to assess hypocenter uncertainty. Earthquake source parameters were determined from three-component local waveforms recorded by IRIS-DMC and GEOFON broadband lA networks. Epicentral distances of all stations were less than 10°. Moment tensor solutions of the events were calculated, along with simultaneous determination of centroid position. Joint analysis of hypocenter position, centroid position, and nodal planes produced clear outlines of the Sumatran fault planes. The preferable seismotectonic interpretation is that the events activated the SFZ at a depth of approximately 14–210 km, corresponding to the interplate Sumatran fault boundary. The identification of this seismic fault zone is significant to the investigation of seismic hazards in the region.

Description: This study attempts to constrain the lithospheric strength in Central Tibet by studying the rebound of the lithosphere and uppermost mantle subjected to loading or unloading due to lake Siling Co water level fluctuations.This lake is a large endhoreic lake at 4500~m elevation located North of the strike-slip right lateral Gyaring Co fault, and South of the Bangong Nujiang suture zone, on which numerous left-lateral strike slip faults are branching. The Siling Co lake water level has strongly changed in the past, as testified by numerous traces of palaeo-shorelines, clearly marked until 60 m above present-day level. Altimetric measures show that during the period 2003-2008 the Siling Co water level increased by about 0.7~m/yr, a remarkably fast rate given the large lake surface (1600~km2). To extent the lake level observation duration, we extract the lake contour from all cloud-free LANDSAT images available on the USGS GLOVIS server. The lake surface, used as a proxy for lake elevation, shows that the water level in the Siling Co lake in Tibet was more or less stagnant from 1973 to 1999 and increased between 2000 and 2010 at an average rate of 0.8 m/yr. A clear seasonal signal is superimposed on the interannual trend. The ground motion associated to the water level increase is studied by InSAR using all ERS and Envisat data on tracks 491 and 219 in the period 1992-2010, obtained through the Dragon ESA-MOST cooperation program. A redundant network of small baseline interferograms is computed with perpendicular baseline smaller than 500~m. The coherence is quickly lost with time (over one year), particularly to the North of the lake because of freeze-thaw cycles. The interferograms covering the period 1992-1999 show no detectable deformation, whereas the ones covering the period 2000-2010 present bowl shape pattern centered on the lake that extend from the shore to about ~100 km from the lake center. The amplitude is about 5 mm/yr close to the lake shores. The interferograms are also affected by decorrelation noise, residual orbital ramp and atmospheric delays. To increase the signal to noise ratio, they are first analysed in time assuming a constant deformation shape. We then obtain the temporal evolution of the deformation amplitude : the amplitude remains constant for the period 1992-1999, and increased from 2000 until 2010. This curve follows closely the lake level temporal evolution. An average velocity map for the period 2000-2010 is also produced to better assess the shape of the ground displacement. Both the amplitude temporal evolution and the average velocity map are used to explore possible rheological models : the elastic model could explain the amplitude evolution if static moduli are set about twice lower than the dynamic moduli derived from the lithosphere seismic velocity profiles. A visco-elastic model with a low viscosity lower crust can also adjust the data. We will discuss to what extent the models can be constrained considering the available data and its noise.

Description: In order to increase our knowledge on the lithosphere rheological structure under the Tibetan plateau, we study the loading response due to lake Siling Co water level changes. The challenge here is to measure the deformation with an accuracy good enough to obtain a correct sensivity to model parameters. InSAR method in theory allow to observe the spatio-temporal pattern of deformation, however its exploitation is limited by unwrapping difficulties linked with temporal decorrelation and DEM errors in sloppy and partially incoherent areas. This lake is a large endhoreic lake at 4500~m elevation located North of the strike-slip right lateral Gyaring Co fault, and just to the south of the Bangong Nujiang suture zone, on which numerous left-lateral strike slip are branching. The Siling Co lake water level has strongly changed in the past, as testified by numerous traces of palaeo-shorelines, clearly marked until 60 m above present-day level. In the last years, the water level in this lake increased by about 1~m/yr, a remarkably fast rate given the large lake surface (1600~km2). The present-day ground subsidence associated to the water level increase is studied by InSAR using all ERS and Envisat archived data on track 219, obtained through the Dragon cooperation program. We chose to compute 750~km long differential interferograms centered on the lake to provide a good constraint on the reference. A redundant network of small baseline interferograms is computed with perpendicular baseline smaller than 500~m. The coherence is quickly lost with time (over one year), particularly to the North of the lake because of freeze-thaw cycles. Unwrapping thus becomes hazardous in this configuration, and fails on phase jumps created by DEM contrasts. The first work is to improve the simulated elevation field in radar geometry from the Digital Elevation Model (here SRTM) in order to exploit the interferometric phase in layover areas. Then, to estimate DEM error, we mix the Permanent Scattered and Small Baseline methods. The aim is to improve spatial and temporal coherence. We use as a reference strong and stable amplitude points or spatially coherent areas, scattered within the SAR scene. We calculate the relative elevation error of every point in the neighbourhood of reference points. A global inversion allows to perform spatial integration of local errors at the radar image scale. Finally, we evaluate how the DEM correct ion of wrapped interferograms improves the unwrapping step. Furthermore, to help unwrapping we also compute and then remove from the wrapped interferograms the residual orbital trend and the phase-elevation relationship due variations in atmospheric stratification. Stack of unwrapped small baseline interferograms show clearly the average subsidence rate around the lake of about 4 mm/yr associated to the present-day water level increase. To compare the observed deformation to the water level elevation changes, we extract from satellite images in the period 1972 to 2009 the water level changes. The deformation signal is discussed in terms of end-members visco-elastic models of the lithosphere and uppermost mantle.

Description: The Van (Eastern Anatolia, Turkey) earthquake occurred on Sunday, October 23, 2011 with a moment magnitude of 7.2. The tectonics of this region is characterized by strike–slip faulting on the Bitlis Suture Zone, and thrusting in the Zagros fold and thrust belt. Using high-rate (1 second) GPS data from permanent GNSS stations from the CORS-TR network, co-seismic displacements of eleven stations were determined using precise point positioning during this earthquake. We used the time series of coordinate changes for fourteen CORS-TR stations, and calculated the crust movements before and after the earthquake. According to the PPP solutions computed using high frequency GPS data to determine the co-seismic motions of stations, we conclude for the Van earthquake an occurrence time of 10:41:22 (UTC). No pre-seismic horizontal movement of stations at the level more than 5 mm before the earthquake could be observed. That means that no kinematic warning or prediction before the earthquake exists. Along an east–west horizontal line north of the Van Sea with a length of about 100 km, the northern part of this line experienced extension of 0.2–1 ppm in a NW–SE direction. The southern part experienced N–S shortening of 0.5–1.5 ppm. The N–S shortening we estimated geodetically matches well with the N–S shortening and thrust focal mechanism derived independently using seismic data by the USGS. Co-seismic surface displacements derived from the GPS data are consistent with the teleseismic source model given by the USGS. The geodetic source model derived from the GPS data reproduces the same moment magnitude and centroid as the teleseismic model, but shows a higher spatial resolution of the slip distribution. We also analyzed the post-seismic surface displacements derived from the GPS data within the first two weeks after the mainshock. No reasonable slip distribution on the co-seismic fault plane could be found, indicating that the sources for the early post-seismic deformation might come from the widely scattered aftershocks.

Description: The mechanism of green rust sulfate (GR-SO(4)) formation was determined using a novel in situ approach combining time-resolved synchrotron-based wide-angle X-ray scattering (WAXS) with highly controlled chemical synthesis and electrochemical (i.e., Eh and pH) monitoring of the reaction. Using this approach,GR-SO(4) was synthesized under strictly anaerobic conditions by coprecipitation from solutions with known Fe(II)/Fe(III) ratios (i.e., 1.28 and 2) via the controlled increase or pH. The reaction in both systems proceeded via a three-stage precipitation and transformation reaction. During the first stage,schwertmannite (Fe(8)O(5)(OH)(4.5)(SO(4))(1.75)) precipitated directly from solution at pH 2.8-4.5. With increasing pH ( 〉5), Fe(2+) ions adsorb to the surface of schwertmannite and catalyze its transformation to goethite (alpha-FeOOH) during the second stage of the reaction. In the third stage, the hydrolysis of the adsorbed Fe(2+) ions on goethite initiates its transformation to GR-SO(4) at pH 〉7, The GR-SO(4) then continues to crystallize up to pH similar to 8.5. These results suggest that with an Fe(II)/Fe(III) ratio of 〈= 2 in the initial solution the structural Fe(II)/Fe(III) of the GR-SO(4) will be close to that of the starting composition.

Description: The German geoscience satellite CHAMP (CHAllenging Minisatellite Payload) has collected the currently longest available time series of GPS radio occultation (RO) data comprising nearly eight years. Around 570,000 occultation measurements were performed between Feb. 2001 and Oct. 2008. This time series is continued by the U.S./German GRACE (Gravity Recovery And Climate Experiment) mission. To generate a homogeneous and high quality long-term set of GPS-RO data for climatological applications and trend analyses, a consistent reprocessing is needed. Major objectives of the GEOTECHNOLOGIEN research project ATMO-CHAMP/GRACE therefore are: a) improve ment of the scientific GPS RO processing software, b) consistent reprocessing of the CHAMP/GRACE GPS-RO long-term data set applying this improved software and c) the demonstration of climatological applications for the long-term data set. In this paper the status of the CHAMP/GRACE processing is overviewed and climatological applications regarding global temperature and tropopause trends and irregularities of the ionospheric E-region are demonstrated.

Description: Deep-Earth convection can be understood by studying hotspot volcanoes that form where mantle plumes rise up and intersect the lithosphere, the Earth’s rigid outer layer. Hotspots characteristically leave age-progressive trails of volcanoes and seamounts on top of oceanic lithosphere, which in turn allow us to decipher the motion of these plates relative to “fixed” deep-mantle plumes, and their (isotope) geochemistry provides insights into the long-term evolution of mantle source regions. However, it is strongly suggested that the Hawaiian mantle plume moved ~15° south between 80 and 50 million years ago. This raises a fundamental ques- tion about other hotspot systems in the Pacific, whether or not their mantle plumes experienced a similar amount and direction of motion. Integrated Ocean Drilling Program (IODP) Expedition 330 to the Louisville Seamounts showed that the Louisville hotspot in the South Pacific behaved in a different manner, as its mantle plume remained more or less fixed around 48°S latitude during that same time period. Our findings demonstrate that the Pacific hotspots move independently and that their trajectories may be controlled by differ- ences in subduction zone geometry. Additionally, shipboard geochemistry data shows that, in contrast to Hawaiian volcanoes, the construction of the Louisville Seamounts doesn’t involve a shield-building phase dominated by tholeiitic lavas, and trace elements confirm the rather homoge- nous nature of the Louisville mantle source. Both observations set Louisville apart from the Hawaiian-Emperor seamount trail, whereby the latter has been erupting abundant tholeiites (char- acteristically up to 95% in volume) and which ex- hibit a large variability in (isotope) geochemistry and their mantle source components.

Description: The Open Geospatial Consortium (OGC) addresses the requirement of integrating sensor information into spatial information infrastructures by developing service interfaces, protocols and data types in the Sensor Web Enablement (SWE) specification series. Using web-based services as tools for interdisciplinary data exchange, as well as for the extensive usage of heterogeneous data resources is an important step towards addressing today’s larger scale environmental problems (Bacharach, 2008). By making measurements and results discoverable and accessible over the internet, data producers can reduce data redundancy and existing data sets can be used to their full capacity. Even though SWE services are designed to be a foundation for »plug&play« access to sensors and sensor networks, questions about how to apply standards for information providers still have to be answered. Compared to the »state of the art« of specialised mass-market ready sensor and communication technology, SWE standards appear bloated, impractical and hard to implement. The project SLEWS (Sensor-based Landslide Early Warning System) uses existing commercial sensor products, implementing SWE technologies on top as a middleware layer to provide the data in an open and interoperable manner as a proof-of-concept. Results of the project’s work outline approaches to improve the process of providing sensor data in a SWE-enabled format using today’s commonly used internet technologies. The components considered are based on the Open Source Spatial Data Infrastructure framework deegree. It is outlined which components comprise the system, how spatial information can be accessed by users and which technologies are relevant. Based on the concept of grid-computing, a proposal for ensuring fail-safe operation is laid out.

Description: Rapid improvements in telemetry technology and the general decrease in communication costs have raised a growing interest in low-cost wireless sensing units. This is especially the case for structural monitoring purposes, where they are becoming a more valuable alternative to conventional wired monitoring system. The main advantages associated with the use of wireless sensing unit include a considerable decrease in installation costs, decentralization of data analysis, and the possibility of broadening the functional capabilities by exploiting the use, at the same time and place, of different sensors. In this work, the design of a low-cost wireless sensing unit able both to collect, analyze, store, and communicate data and estimated parameters is presented. The suitability of a network of these low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of strategic civil infrastructures is validated during a ambient vibration recording field test on the Fatih Sultan Mehmet Bridge in Istanbul, Turkey.

Description: We use local earthquake data observed by the amphibious, temporary seismic MERAMEX array to derive spatial variations of seismic attenuation (Qp) in the crust and upper mantle beneath Central Java. The path-averaged attenuation values (t∗) of a high quality subset of 84 local earthquakes were calculated by a spectral inversion technique. These 1929 t∗-values inverted by a least-squares tomographic inversion yield the 3D distribution of the specific attenuation (Qp). Analysis of the model resolution matrix and synthetic recovery tests were used to investigate the confidence of the Qp-model. We notice a prominent zone of increased attenuation beneath and north of the modern volcanic arc at depths down to 15 km. Most of this anomaly seems to be related to the Eocene–Miocene Kendeng Basin (mainly in the eastern part of the study area). Enhanced attenuation is also found in the upper crust in the direct vicinity of recent volcanoes pointing towards zones of partial melts, presence of fluids and increased temperatures in the middle to upper crust. The middle and lower crust seems not to be associated with strong heating and the presence of melts throughout the arc. Enhanced attenuation above the subducting slab beneath the marine forearc seems to be due to the presence of fluids.

Description: For a long time the root mean square (RMS) error has been used in the EM community: - to characterize data fit for a particular model; - as a criterion to compare several models obtained from inversion. The RMS error appears to be a natural choice since we usually tackle inverse problems in a least-squares sense. Over the years, RMS became a customary criterion and gained ultimate significance. However, on the hunt for low RMS values, one often needs to introduce subjectivity by arbitrarily adjusting error floors or masking “bad” data without referring to the assumptions behind RMS. In this contribution, we revisit basic assumptions behind RMS, demonstrate its deficiency and propose alternative ways, which may provide more insight into our data and allow a more comprehensive assessment of the quality of the modelling result/resistivity model.

Description: We determined a high-resolution 3-D S-wave velocity model for a 26 km × 12 km area in the northern part of the basin of Santiago de Chile. To reach this goal, we used microtremor recordings at 125 sites for deriving the horizontal-to-vertical (H/V) spectral ratios that we inverted to retrieve local S-wave velocity profiles. In the inversion procedure, we used additional geological and geophysical constraints and values of the thickness of the sedimentary cover already determined by gravimetric measurements, which were found to vary substantially over short distances in the investigated area. The resulting model was derived by interpolation with a kriging technique between the single S-wave velocity profiles and shows locally good agreement with the few existing velocity profile data, but allows the entire area, as well as deeper parts of the basin, to be represented in greater detail. The wealth of available data allowed us to check if any correlation between the S-wave velocity in the uppermost 30 m (v30S) and the slope of topography, a new technique recently proposed by Wald and Allen, exists on a local scale. We observed that while one lithology might provide a greater scatter in the velocity values for the investigated area, almost no correlation between topographic gradient and calculated v30S exists, whereas a better link is found between v30S and the local geology. Finally, we compared the v30S distribution with the MSK intensities for the 1985 Valparaiso event, pointing out that high intensities are found where the expected v30S values are low and over a thick sedimentary cover. Although this evidence cannot be generalized for all possible earthquakes, it indicates the influence of site effects modifying the ground motion when earthquakes occur well outside of the Santiago basin.

Description: In the frame of the R&D-programme GEOTECHNOLOGIEN thirteen joint interdisciplinary projects have been launched in April 2008. The object of research is the better understanding of the multiple physical and chemical reactions at mineral surfaces. The abstract volume summarizes the scientific results presented during the status seminar at the Johannes Gutenberg University in Mainz, Germany in October 2010.

Description: The geometry, kinematics, and mode of back‐arc extension along the Andaman Sea plate boundary are refined using a new set of significantly improved hypocenters, global centroid moment tensor (CMT) solutions, and high‐resolution bathymetry. By applying cross‐correlation and double‐difference (DD) algorithms to regional and teleseismic waveforms and arrival times from International Seismological Centre and National Earthquake Information Center bulletins (1964–2009), we resolve the fine‐scale structure and spatiotemporal behavior of active faults in the Andaman Sea. The new data reveal that back‐arc extension is primarily accommodated at the Andaman Back‐Arc Spreading Center (ABSC) at ~10°, which hosted three major earthquake swarms in 1984, 2006, and 2009. Short‐term spreading rates estimated from extensional moment tensors account for less than 10% of the long‐term 3.0–3.8 cm/yr spreading rate, indicating that spreading by intrusion and the formation of new crust make up for the difference. A spatiotemporal analysis of the swarms and Coulomb‐stress modeling show that dike intrusions are the primary driver for brittle failure in the ABSC. While spreading direction is close to ridge normal, it is oblique to the adjacent transforms. The resulting component of E‐W extension across the transforms is expressed by deep basins on either side of the rift and a change to extensional faulting along the West Andaman fault system after the Mw = 9.2 Sumatra‐Andaman earthquake of 2004. A possible skew in slip vectors of earthquakes in the eastern part of the ABSC indicates an en‐echelon arrangement of extensional structures, suggesting that the present segment geometry is not in equilibrium with current plate‐motion demands, and thus the ridge experiences ongoing re‐adjustment.

Description: The lithosphere–asthenosphere boundary (LAB) remains a controversial subject in Earth sciences, and beneath cratonic regions appears to be a particularly difficult boundary to consistently image. Seismic methods give different indicators on the velocity structure of the upper mantle: tomographic models provide estimates of the velocity variations at a variety of lateral scales, but have limited vertical resolution; receiver function techniques provide good indication of the depth to seismic discontinuities, but less information on the absolute velocities. This study assesses whether the different methods give consistent estimates for the depth of the LAB in southern Africa. Using a surface wave dataset with nearly 12,000 paths in the African region, new tomographic models of central and southern Africa are calculated. To show the non-unique nature of tomography, results are presented for two different parameterisations. The models indicate varying velocity structure beneath the cratonic regions of central and southern Africa, which yield estimates of the LAB depth from around 150 km depth in Tanzania, to approximately 200 km depth beneath the Kalahari Craton, down to depths of 225–250 km beneath parts of the Congo. At a broad-scale these depth estimates are compatible with geothermometry from kimberlite xenoliths. In regions such as Tanzania, the kimberlite magmatism is observed to occur along strong horizontal gradients in upper mantle seismic velocity structure — potentially edge features in lithospheric structure. In contrast, a detailed comparison beneath the Kalahari Craton indicates that in this region, and given the present resolution of the tomography, there is no clear link between the kimberlites and velocity gradients. However, in general the kimberlites do not sample the regions of fastest seismic velocities. The relationship between LAB depth estimates from the tomographic modelling and those estimates from receiver functions is not clear. Results from receiver function techniques beneath southern Africa tend to place discontinuities at either shallower (100–150 km), or deeper (300–350 km), depths than the thermally defined LAB estimates. As such, particular care should be taken in automatically associating a discontinuity from fast to slow seismic velocities as the same location as a thermally defined lithosphere–asthenosphere boundary.

Description: Overall goal of this GEOTECHNOLOGIEN project called »The impact of mineral and rock surface topography on colloid retention« is a systematic approach to determine, characterize, and quantify the interaction between rough mineral surfaces and colloidal particles. A previous systematic study using pitted calcite single crystal surfaces yielded results about the general correlation between surface roughness parameters and the efficiency of colloidal retention under electrostically unfavorable conditions (Darbha et al. 2010). Here we present results about (i) the controlled variation of colloidal retention at well-defined, artificial surface structures, (ii) the characterization and quantification of sources and sinks of natural particles in a quasi-closed system that is used as a test site for field experiments, and (iii) the quantitative experimental results about the retention of particles on natural rock surfaces that allows for a predictive approach to natural systems. In detail, the following results are discussed in this report: (i) As an analog to rough mineral surfaces with halfpores in the submicron size, the deposition behavior of latex colloids was studied on a regular pit pattern (pit diameter = 400 nm, pit spacing = 400 nm, pit depth = 100 nm). Effects of hydrodynamics and colloidal interactions in transport and deposition dynamics of a colloidal suspension were investigated in a parallel plate flow chamber. The experiments were conducted at pH ~6.6 under both favorable and unfavorable conditions (in terms of electrostatic forces) using carboxylate functionalized colloids to study the impact of surface topography on particle retention. The influence of particle diameter variation (0.3-2 μm) on retention of monodisperse as well as polydisperse suspensions as a function of flow velocity over a wide range was studied. The impact of surface topography deviations was found to be more significant for smaller colloids (0.3 and 0.43 μm). Larger colloids (1 and 2 μm) beyond a critical velocity of 7 x 10-5 and 3 x 10-6 m/s tend to detach from the surface irrespective of the impact of roughness since drag forces exceed adhesion forces. For polydisperse suspensions, an increase in both polydi- spersity and fluid flow velocity resulted in the decrease of colloid deposition efficiency due to enhanced double layer repulsions. Hematite colloids of quasi-spherical shape with diameters of about 950 nm showed a higher deposition flux compared to spherical latex colloids of equivalent size. These experimental results provide quantitative constraints for the prediction of particle retention as a function of fluid-flow velocity, polydispersity, and particle shape and size. (ii) The investigation of the source (iron sulfidebearing rocks), the processes of particle generation (oxidative weathering, acidic mine water conditions, mine water mixing), the particle transport, and the deposition of particles at water-rock interfaces within the well-defined system of an abandoned alum slate mine enables a first-order approach for balancing of particle retention at rough surfaces in nature. The quantification of particle concentration in the mine outflow as well as the quantification of the deposited material enables an estimation of the kinetics of particles retention within such a system. For comparison, experiments were conducted to get laboratory results about the kinetics of particle retention using substrates with similar ranges of topography variations. (iii) Colloid adsorption experiments at natural rock samples were performed using black slate and micrite limestone as substrates. Micrite samples were etched to obtain variances in surface roughness and topography. Generally, surface steps at grain boundaries are the major cause for the overall roughness variations. A positive correlation between surface roughness of micrite surfaces and the surface-normalized density of adsorbed particles was found. For surface sections 〈 20 μm, a remarkable dispersion of the surface-normalized particle density was found. We conclude that the variance in surface reactivity responsible for the recognized variance in particle deposition is caused by the density of grain boundaries of the rock material. An analog experiment using a grid pattern with varying grid line density confirmed this conclusion: A strong correlation between line density and adsorbed particle density was found. The results presented here show the quantitative impact of surface topography variations on colloid retention under electrostically unfavorable conditions. An important application of these results is their utilization as an input parameter for predictive approaches to the fate of colloids in the environment.

Description: Magnetotellurics (MT) relies on natural electromagnetic field variations to investigate the electrical conductivity structure of the subsurface. Modern MT data are often multivariate due to simultaneous recordings of multiple-channel time series of two (horizontal) electric and three magnetic field components at multiple stations. Single site and remote reference processing only use a small portion of data to estimate the impedance tensor. The multiple-station approach, initially presented by Egbert (1997), uses all data information to improve the signal-to-noise ratios, which results in better estimations of the transfer functions. This is particularly import in industrialized regions, where the influence of man-made noise signals often exceeds the natural EM fields and hampers the estimation of MT impedance tensors. We have included the multiple-station data approach in our processing scheme EMERALD and tested it with different data sets. A non-robust calculation of the impedance tensor based on the multiple-station approach shows already slightly improved results compared to robust single site or even remote reference estimators. However, in case of high level man-made noise advances of the multiple-station algorithm are not observed. Tests with existing robust routines within EM, which are based on bivariate assumptions, do not reveal a significant improvement.

Description: Cratons with their thick lithospheric roots can influence the thermal structure, and thus the convective flow, in the surrounding mantle. As mantle temperatures are hard to measure directly, depth variations in the mantle transition zone (MTZ) discontinuities are often employed as a proxy. Here, we use a large new data set of P-receiver functions to map the 410 km and 660 km discontinuities beneath the western edge of the East European Craton and adjacent Phanerozoic Europe across the most fundamental lithospheric boundary in Europe, the Trans-European Suture Zone (TESZ). We observe significantly shorter travel times for conversions from both MTZ discontinuities within the craton, caused by the high velocities of the cratonic root. By contrast, the differential travel time across the MTZ is normal to only slightly raised. This implies that any insulating effect of the cratonic keel does not reach the MTZ. In contrast to earlier observations in Siberia, we do not find any trace of a discontinuity at 520 km depth, which indicates a rather dry MTZ beneath the western edge of the craton. Within most of covered Phanerozoic Europe, the MTZ differential travel time is remarkably uniform and in agreement with standard Earth models. No widespread thermal effects of the various episodes of Caledonian and Variscan subduction that took place during the amalgamation of the continent remain. Only more recent tectonic events, related to Alpine subduction and Quarternary volcanism in the Eifel area, can be traced. While the East European craton shows no distinct imprint into the MTZ, we discover the signature of the TESZ in the MTZ in the form of a linear region of about 350 km width with a 1.5 s increase in differential travel time, which could either be caused by high water content or decreased temperature. Taking into account results of recent S-wave tomographies, raised water content in the MTZ cannot be the main cause for this observation. Accordingly, we explain the increase, equivalent to a 15 km thicker MTZ, by a temperature decrease of about 80 K. We discuss two alternative models for this temperature reduction, either a remnant of subduction or an indication of downwelling due to small-scale, edge-driven convection caused by the contrast in lithospheric thickness across the TESZ. Any subducted lithosphere found in the MTZ at this location is unlikely to be related to Variscan subduction along the TESZ, though, as Eurasia has moved significantly northward since the Variscan orogeny.

Description: An array of broadband seismometers transecting the Talamanca Range in southern Costa Rica was operated from 2005 until 2007. In combination with data from a short-period network near Quepos in central Costa Rica, this data is analyzed by the receiver function method to image the crustal structure in south-central Costa Rica. Two strong positive signals are seen in the migrated images, interpreted as the Moho (at around 35 km depth) and an intra-crustal discontinuity (15 km depth). A relatively flat crustal and Moho interface underneath the north-east flank of the Talamanca Range can be followed for a lateral distance of about 50 km parallel to the trench, with only slight changes in the overall geometry. Closer to the coast, the topography of the discontinuities shows several features, most notably a deeper Moho underneath the Talamanca Mountain Range and volcanic arc. Under the highest part of the mountain ranges, the Moho reaches a depth of about 50 km, which indicates that the mountain ranges are approximately isostatically compensated. Local deviations from the crustal thickness expected for isostatic equilibrium occur under the active volcanic arc and in south Costa Rica. In the transition region between the active volcanic arc and the Talamanca Range, both the Moho and intracrustal discontinuity appear distorted, possibly related to the southern edge of the active volcanic zone and deformation within the southern part of the Central Costa Rica Deformed Belt. Near the volcanoes Irazu and Turrialba, a shallow converter occurs, correlating with a low-velocity, low-density body seen in tomography and gravimetry. Applying a grid search for the crustal interface depth and vp/vs ratio cannot constrain vp/vs values well, but points to generally low values (〈1.7) in the upper crust. This is consistent with quartz-rich rocks forming the mountain range.

Description: Powdered calcium carbonates from natural sources are being widely used as fillers in adhesive systems to improve processing and in service performance characteristics. The converting of limestone and marble to adhesive filler materials typically includes grinding and in some cases precipitation and coating to adjust particle size, processability and chemical reaction with the adhesive. It has been frequently observed that calcium carbonate powder batches with apparently similar particle-specific characteristics (e. g. density, chemical composition and particle size distribution) may exhibit significantly varying processing properties in terms of their effect on rheology, curing and adhesive performance of the adhesives formulation. This indicates that different calcium carbonates as raw materials for fillers obviously feature intrinsic characteristics which have not yet been identified and examined sufficiently and whose effect on the processing and product characteristics of highly filled reactive adhesive systems is essential to achieve a sufficient level of process stability, batch-to-batch reproducibility and last not least uniform product quality. The aim of this research project therefore is to reveal the structure-property- relationship between the manifold calcium carbonate particle characteristics on one hand and the physicochemical and technical properties of the resulting adhesives formulation on the other hand.

Description: Integrated Ocean Drilling Program (IODP) Expedition 340T returned to the 1.4-km-deep Hole U1309D at Atlantis Massif to carry out borehole logging including vertical seismic profiling (VSP). Seismic, resistivity, and temperature logs were obtained throughout the geologic section in the footwall of this oceanic core complex. Reliable downhole temperature measurements throughout and the first seismic coverage of the 800–1400 meters below seafloor (mbsf) portion of the section were obtained. Distinct changes in velocity, resistivity, and magnetic susceptibility characterize the boundaries of altered, olivine-rich troctolite intervals within the otherwise dominantly gabbroic se-quence. Some narrow fault zones also are associated with downhole resistivity or velocity excursions. Small deviations in temperature were measured in borehole fluid adjacent to known faults at 750 mbsf and 1100 mbsf. This suggests that flow of seawater remains active along these zones of faulting and rock alteration. Vertical seismic profile station coverage at zero offset now extends the full length of the hole, including the uppermost 150 mbsf, where detachment processes are expected to have left their strongest imprint. Analysis of wallrock properties, together with alteration and structural characteristics of the cores from Site U1309, highlights the likely interplay between lithology, structure, lithospheric hydration, and core complex evolution.

Description: A series of linked marine and land studies have recently targeted the Sumatra subduction zone, focusing on the 2004 and 2005 plate boundary earthquake ruptures in Indonesia. A collaborative research effort by scientists from the United Kingdom (UK Sumatra Consortium), Indonesia, United States, France, and Germany is focusing on imaging the crustal structure of the margin to examine controls on along-strike and updip earthquake rupture propagation. The fundamental science objective is to examine how margin architecture and properties control earthquake rupture location and propagation.

Description: We study the distribution of the aftershocks of Tocopilla Mw 7.7 earthquake of 2007 November 14 in northern Chile in detail. This earthquake broke the lower part of the seismogenic zone at the southern end of the Northern Chile gap, a region that had its last megathrust earthquake in 1877. The aftershocks of Tocopilla occurred in several steps: the first day they were located along the coast inside the co-seismic rupture zone. After the second day they extended ocean-wards near the Mejillones peninsula. Finally in December they concentrated in the South near the future rupture zone of the Michilla intermediate depth earthquake of 2007 December 16. The aftershock sequence was recorded by the permanent IPOC (Integrated Plate Boundary Observatory in Chile) network and the temporary task force network installed 2 weeks after the main event. A total of 1238 events were identified and the seismic arrival times were directly read from seismograms. Initially we located these events using a single event procedure and then we relocated them using the double-difference method and a cross-correlation technique to measure time differences for clusters of aftershocks. We tested a 1-D velocity model and a 2-D one that takes into account the presence of the subducted Nazca Plate. Relocation significantly reduced the width of the aftershock distribution: in the inland area, the plate interface imaged by the aftershocks is thinner than 2 km. The two velocity models give similar results for earthquakes under the coast and a larger difference for events closer to the trench. The surface imaged by the aftershocks had a length of 160 km. It extends from 30 to 50 km depth in the northern part of the rupture zone; and between 5 and 55 km depth near the Mejillones peninsula. We observed a change in the dip angle of the subduction interface from 18° to 24° at a depth of 30 km. We propose that this change in dip is closely associated with the upper limit of the rupture zone of the main event. We also studied the focal mechanisms of the aftershocks, most of them were thrust events like the mainshock. As the aftershock activity was significantly reduced, on 2007 December 13, an ML 6.1 event occurred offshore of the Mejillones peninsula reactivating the seismicity. Three days later the Michilla intraslab earthquake of Mw 6.8 ruptured an almost vertical fault with slab-push mechanism. The aftershocks locations of this event define a planar zone about 11 km in depth, situated right bellow the subduction interface.

Description: In the past two decades, the behavior of lithium (Li) isotopes has been studied in various marine systems, including mid-ocean ridge and sediment-hosted hydrothermal systems, subduction zone settings and normal coastal and deep-sea sediments recovered by the Ocean Drilling Program (ODP). Major processes identified to cause deviations from the seawater isotopic composition are adsorption/desorption reactions, formation and transformation of silicate minerals, and leaching of Li from sediments or underlying crust at high temperature. As a result of the accomplished work, Li isotopes are considered a promising tracer for the diagenetic evolution and provenance of pore fluids in overpressured sedimentary environments. Here, we present Li concentration and isotope data of 18 cold seep locations and reference fluids from shallow marine sediments, a sediment-hosted hydrothermal system and two Mediterranean brine basins. The new reference data and literature data of hydrothermal fluids and pore fluids from the ODP follow an empirical relationship reflecting increasing Li release and decreasing isotope fractionation during clay mineral authigenesis with increasing temperature. Lithium concentration and isotope data of cold seep fluids are mostly in agreement with this empirical relationship. Ubiquitous diagenetic signals of clay dehydration in all cold seep fluids indicate that authigenic smectite-illite is an important sink for light pore water Li in deeply buried continental margin sediments. Deviations from the general relationship are attributed to the varying proportion of weatherable (e.g. volcanogenic) components and to transport-related fractionation trends. A simple transport-reaction model was applied to simulate Li isotope fractionation during upwelling of pore fluids to the seafloor. It is demonstrated that slow pore water advection (order of mm a-1) suffices to convey much of the deep-seated diagenetic Li signal into shallow sediments. If carefully applied, Li isotope systematics may, thus, provide a valuable record of fluid/mineral interaction that has been inherited several hundreds or thousands of meters below the seafloor.

Description: Microbial biofilms are an extremely successful way of life. Bacteria and fungi benefit in this symbiotic life form of metabolic exchange, protection and genetic flexibility. They produce a matrix of organic molecules in which they are embedded and which offers new habitats to other organisms, such as other bacteria or fungi. Biofilms cannot be avoided to colonize surfaces in unsterile habitats. So, they can be found everywhere in nature and in technical systems, but they play an ambivalent role. On the one hand biofilms are essential to degrade and transform water contaminations, but on the other hand they can diminish product qualities and damage capital equipment. Biofilms can cover medical equipment such as catheters and pathogenic bacteria, which may be living in the biofilms, are a continuous source of infection of the patients. In addition, the metabolism of the biofilm microorganisms may change the composition of the fluids or contaminate them with their products. As biofilms are all-round, the understanding of the biofilm formation and its manipulation are of prime importance in microbiology and material sciences. The choice of a material and the corresponding surface properties like mechanical properties, structure, polarity, and chemistry influence the binding of various molecules and cells. The surface properties affect the biocompatibility of a material and consequently also bacterial adhesion, and biofilm growth. In this project hydrophobins are used as a novel modification of surfaces to change surface properties like hydrophobicity and thus might have an effect on biofilm formation. Hydrophobins are fungal proteins, which selfassemble on hydrophobic as well as hydrophilic surfaces into extremely stable monolayers. Recombinant hydrophobins provide the opportunity to use these highly surface-active proteins for large-scale surface coatings. Hydrophobins are non-toxic and can be used for surface modification and functionalization (with e.g. enzymes) of industrial relevant materials like steel, plastics, and ceramics. In this project hydrophobin coated surfaces and their properties are studied with respect to bacterial cell adhesion, cell differentiation, and cellular growth with the aim to influence biofilm formation. In the first part of the project recombinant hydrophobins were produced and purified. Different surfaces were coated with hydrophobins and characterized, since the coating efficiency is the basis for subsequent biofilm formation studies. Biofilms were grown on natural as well as hydrophobin coated surfaces and different methods were established to analyse biofilm formation. Since the hydrophobin coated surfaces did not reduce microbial growth, we designed modified fusion hydrophobins and attached cationic antimicrobial peptides (AMPs) to the hydrophobins.

Description: This study represents the first investigating potential kinematic boundary conditions for subduction erosion in a systematic manner. For the subduction erosional process, the aperture at the box's rear, which allowed rearward material loss, was shown to have the largest influence on obtained results. If the amount of material leaving the system was larger than the amount of material subducted at the wedge's toe, the margin evolved as erosional. We found the surface slope to be the second important parameter, which strongly controls the amount of basally eroded material.

Description: A sequence of large strike‐slip earthquakes occurred west of Sunda Trench beneath the Wharton Basin. First reports indicate that the main shock was extremely complex, involving three to four subevents (Mw 〉 8) with a maze of aftershocks. We investigate slip models of the two largest earthquakes by joint inversion of regional and teleseismic waveform data. Using the Mw7.2 foreshock, we developed hybrid Green's Functions for the regional stations to approximate the mixture of oceanic and continental paths. The main shock fault geometry is defined based on the back projection results, point‐source mechanisms, aftershock distribution, and fine tune of grid searches. The fault system contains three faults, labeled F1 (89°/289° for dip/strike), F2 (74°/20°), and F3 (60°/310°). The inversion indicates that the main rupture consisted of a cascade of high‐stress drop asperities (up to 30 MPa), extending as deep as 50 km. The rupture propagated smoothly from one fault to the next (F1, F2, and F3 in sequence) with rupture velocities of 2.0–2.5 km/s. The whole process lasted about 200 s, and the major moment release (〉70%) took place on the N‐S oriented F2. The Mw8.2 aftershock happened about 2 h later on a N‐S oriented fault with a relatively short duration (~60 s) and also ruptured as deep as 50 km. The slip distributions suggest that the earthquake sequence was part of a broad left‐lateral shear zone between the Australian and Indian plates and ruptured the whole lithosphere. These earthquakes apparently reactivated existing fracture zones and were probably triggered by unclamping of the great Sumatran earthquake of 2004.

Description: We present and discuss a set of 77 moment tensor solutions for earthquakes in the Iberia–Maghreb region from mid 2005 to the end of 2008, with moment magnitudes ranging from 3.2 to 6.0. Inversion is based upon full, three-component, intermediate period waveforms recorded at regional seismic broadband stations. Following the recent densification of permanent broadband networks and large scale temporary deployments, at present more than 150 stations are recording in Spain, Portugal and Morocco. This unprecedented station density allows analysis of small events from available short-distance recordings, and in general leads to more reliable source estimates due to data redundancies that permit elimination of waveforms affected by noise or complicated propagation effects. The solutions for 2005–2008 constitute an important upgrade of the Iberia–Maghreb moment tensor inventory to 225 solutions to date, enhancing the image of seismotectonics at the compressive N-Algerian margin, in the Betic–Alboran shear zone and at the transpressive SW-Iberian margin, as well as providing valuable constraints on seismic deformation in the western Betics and the Iberian foreland where little information has been previously available. New solutions for the foreland and three recent seismic series in the western Betics show strike-slip and reverse faulting style, contrasting with the dominance of normal faulting in the adjacent areas towards east. In these areas, as well as at the SW-Iberian margin, faulting orientations are heterogeneous, including solutions with opposite kinematics. This indicates control by local stress conditions, and points to fault interaction. Along the N-Algerian margin, a counterclockwise rotation of slip vectors of thrust events from east to west becomes apparent. Several solutions for the area offshore Cape St. Vincent are located at sub-Moho depths between 40 and 60 km, supporting a large brittle layer thickness in the oceanic lithosphere.

Description: The transformation of ferrihydrite (5Fe(2)O(3)center dot 9H(2)O) to hematite (alpha-Fe2O3) under alkaline condition in the presence and absence of lead was for the first time investigated using in situ, time-resolved synchrotron-based energy dispersive X-ray diffraction combined with off-line chemical characterization and imaging. The results showed that the crystallization of hematite occurred via a two-stage process with goethite (alpha-FeOOH) as an intermediate phase. The presence of lead enhanced the formation of hematite and reduced the induction times (similar to 20-30%) but had little effect on the mechanism of the transformation reactions. The reaction rates for the two systems (with and without lead) ranged from 12 to 259 x 10(-4) s(-1) and 19 to 461 x 10(-5) s(-1) for the first and second stage, respectively. The activation energies of nucleation of the two systems were 16(+/- 3) and 9(+/- 2) kJ/mol, while the activation energies for crystallization ranged from 41(+/- 7) to 77(+/- 14) kJ/mol. During the hematite crystallization, the majority of the lead in the system was rapidly and irreversibly incorporated into the final hematite, while only minor amounts of lead were released back into solution.

Description: Ambient noise tomography is applied to the significant data resources now available across Tibet and surrounding regions to produce Rayleigh wave phase speed maps at periods between 6 and 50 s. Data resources include the permanent Federation of Digital Seismographic Networks, five temporary U.S. Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL) experiments in and around Tibet, and Chinese provincial networks surrounding Tibet from 2003 to 2009, totaling ∼600 stations and ∼150,000 interstation paths. With such a heterogeneous data set, data quality control is of utmost importance. We apply conservative data quality control criteria to accept between ∼5000 and ∼45,000 measurements as a function of period, which produce a lateral resolution between 100 and 200 km across most of the Tibetan Plateau and adjacent regions to the east. Misfits to the accepted measurements among PASSCAL stations and among Chinese stations are similar, with a standard deviation of ∼1.7 s, which indicates that the final dispersion measurements from Chinese and PASSCAL stations are of similar quality. Phase velocities across the Tibetan Plateau are lower, on average, than those in the surrounding nonbasin regions. Phase velocities in northern Tibet are lower than those in southern Tibet, perhaps implying different spatial and temporal variations in the way the high elevations of the plateau are created and maintained. At short periods (〈20 s), very low phase velocities are imaged in the major basins, including the Tarim, Qaidam, Junggar, and Sichuan basins, and in the Ordos Block. At intermediate and long periods (〉20 s), very high velocities are imaged in the Tarim Basin, the Ordos Block, and the Sichuan Basin. These phase velocity dispersion maps provide information needed to construct a 3-D shear velocity model of the crust across the Tibetan Plateau and surrounding regions.

Description: This volume contains 23 short papers which summarise the main subjects of talks and posters presented at the eighth TRACE (Tree Rings in Archaeology, Climatology and Ecology) conference organized by Jožica Gričar, Tom Levanič, Špela Jagodic, Robert Krajnc and Polona Hafner and held in Otočec, Slovenia on April 16th - 19th, 2009.

Description: A long, complex aftershock sequence has followed an Mw 6.1 mainshock in February 2008, in Storfjorden, Svalbard. Relatively located aftershock epicenters and focal mechanisms from moment tensor inversion suggest that the series took place along a NE–SW trending and steeply SSE dipping oblique-normal fault, with the total aftershock extent exceeding the mainshock rupture. The magnitude of the mainshock and the duration of the aftershock activity render the Storfjorden sequence important in terms of earthquake hazard assessment in the Svalbard region. We have evaluated all involved uncertainties and combined seismological information with background knowledge for the area, in order to achieve as sound a seismotectonic interpretation as possible. Our results clearly indicate that the activity in Storfjorden should be attributed to a previously unknown tectonic structure. In addition, there are indications of activation of secondary structures and possibly of stress triggering. These new findings affect our understanding of the region's earthquake potential.

Description: Amplitude ratio of 30 short-period conspicuous P5KP and PKPab phases from five intermediate depth or deep events in Fiji-Tonga recorded at European stations around 150° distance shows a mean value two to three times the ratio of the synthetic amplitudes obtained by the normal-mode theory (and ak135 model) or by full-wave theory (and PREM). There is a large variance in the results, also observed in five amplitude ratios from one event in Argentina observed at temporary stations in China around 156°. Global recordings of three major deep earthquakes in Fiji, Bonin, and Western Brazil observed at ASAR, WRA, and ZRNK arrays, at 59 North America stations and at six South Pole stations displayed conspicuous P4KP and PcP (or ScP) phases. The amplitude ratio values of P4KP vs P(S)cP are sometimes almost one order of magnitude larger than the corresponding values of the synthetics. In both cases, arrival times and slowness values (corrected for ellipticity and station elevation) at the distances up to 23° beyond the A cutoff point predicted by ray theory match both the synthetics, suggesting the observations are the AB branch of PmKP (m = 4, 5) around 1 Hz. In disagreement to ray theory, no reliable BC branch is observed neither on the recordings nor on the normal-mode synthetics. The high amplitude ratio values cannot be explained by realistic perturbations of the velocity or attenuation values of the global models in the proximity of the core-to-mantle boundary (CMB). We speculate that the focusing effects and/or strong scattering most likely associated to some anomalous velocity areas of the lowermost mantle are responsible for that. The results suggest limitations of the previous evaluations of the short-period attenuation in the outer core from PmKP amplitudes (m ≥ 3), irrespective of the fact that they are obtained by using ray theory, normal-mode or full-wave synthetics. Attempts to use PmKP arrival times in order to refine velocity structure in the proximity of CMB should be also regarded with care if the propagation times have been computed with ray theory.

Description: This document serves as a record of the processing standards, models & parameters adopted for the generation of monthly and weekly (aligned to GPS weeks) Level-2 gravity field data products by the GRACE Science Data System component at the GFZ German Research Centre for Geosciences.

Description: The territory of Lithuania and adjacent areas of the East European Craton have always been considered a region of low seismicity. Two recent earthquakes with magnitudes of more than 5 in the Kaliningrad District (Russian Federation) on 21 September 2004 motivated re-evaluation of the seismic hazard in Lithuania and adjacent territories. A new opportunity to study seismicity in the region is provided by the PASSEQ (Pasive Seismic Experiment) project that aimed to study the lithosphere–asthenosphere structure around the Trans-European Suture Zone. Twenty-six seismic stations of the PASSEQ temporary seismic array were installed in the territory of Lithuania. The stations recorded a number of local and regional seismic events originating from Lithuania and adjacent areas. This data can be used to answer the question of whether there exist seismically active tectonic zones in Lithuania that could be potentially hazardous for critical industrial facilities. Therefore, the aim of this paper is to find any natural tectonic seismic events in Lithuania and to obtain more general view of seismicity in the region. In order to do this, we make a manual review of the continuous data recorded by the PASSEQ seismic stations in Lithuania. From the good quality data, we select and relocate 45 local seismic events using the well-known LocSAT and VELEST location algortithms. In order to discriminate between possible natural events, underwater explosions and on-shore blasts, we analyse spatial distribution of epicenters and temporal distribution of origin times and perform both visual analysis of waveforms and spectral analysis of recordings. We show that the relocated seismic events can be grouped into five clusters (groups) according to their epicenter coordinates and origin and that several seismic events might be of tectonic origin. We also show that several events from the off-shore region in the Baltic Sea (at the coasts of the Kaliningrad District of the Russian Federation) are non-volcanic tremors, although the origin of these tremor-type events is not clear.