ALBERT

Description: We report on earthquake and temperature-related velocity changes in high-frequency autocorrelations of ambient noise data from seismic stations of the Integrated Plate Boundary Observatory Chile project in northern Chile. Daily autocorrelation functions are analyzed over a period of 5 years with passive image interferometry. A short-term velocity drop recovering after several days to weeks is observed for the Mw 7.7 Tocopilla earthquake at most stations. At the two stations PB05 and PATCX, we observe a long-term velocity decrease recovering over the course of around 2 years. While station PB05 is located in the rupture area of the Tocopilla earthquake, this is not the case for station PATCX. Station PATCX is situated in an area influenced by salt sediment in the vicinity of Salar Grande and presents a superior sensitivity to ground acceleration and periodic surface-induced changes. Due to this high sensitivity, we observe a velocity response of several regional earthquakes at PATCX, and we can show for the first time a linear relationship between the amplitude of velocity drops and peak ground acceleration for data from a single station. This relationship does not hold true when comparing different stations due to the different sensitivity of the station environments. Furthermore, we observe periodic annual velocity changes at PATCX. Analyzing data at a temporal resolution below 1 day, we are able to identify changes with a period of 24 h, too. The characteristics of the seismic velocity with annual and daily periods indicate an atmospheric origin of the velocity changes that we confirm with a model based on thermally induced stress. This comprehensive model explains the lag time dependence of the temperature-related seismic velocity changes involving the distribution of temperature fluctuations, the relationship between temperature, stress and velocity change, plus autocorrelation sensitivity kernels.

Description: This thesis analyzes temporal variations of crustal properties in northern Chile. The seismic broadband stations of the Integrated Plate Boundary Observatory Chile which started operating in 2006 deliver the data for this work. In the neighborhood of the seismic stations a MW 7.7 earthquake occurred near Tocopilla on 14 November 2007 at 52 km depth. Velocity changes following large earthquakes have been observed by different authors in ambient noise data. There are indications that also receiver functions could be used for that purpose. Though the origin of crustal velocity changes is still debated, they certainly provide insights into physical processes in the Earth’s crust. In this work I employ two complementary methods to study the velocity variations. In the first part of the work, the feasibility to use receiver functions for monitoring purposes in northern Chile is investigated and an appropriate method is developed. The receiver function technique could permit to locate possible velocity variations in depth. To avoid varying travel paths of different events the arrival of converted phases is compared for events located in a small source region. Although temporal variations are found in this study, the conclusion on a spatially persistent velocity change is not possible because statistical variations are still too high. In the second part of the thesis the temporal variability of Green’s functions constructed from the cross- and auto-correlation of ambient noise is studied with the help of a technique called passive image interferometry. Daily cross-correlation and autocorrelation functions are calculated over a period of 5 years for low (under 0.5 Hz) and high (above 1 Hz) frequencies. Earthquake and temperature related velocity changes in the correlation functions are observed only for high frequencies. The necessary stacking over 10 days hides potential velocity changes on a shorter time scale for low frequencies. Short-term velocity drops recovering after several days to weeks are observed for the Tocopilla earthquake at most stations. At the two stations PB05 and PATCX a velocity decrease is observed, which recovers over the course of around two years. While station PB05 is located in the rupture area of the Tocopilla earthquake this is not the case for station PATCX. Station PATCX is situated in an area with particular geological conditions and presents superior sensitivity to ground acceleration and periodic surface induced changes. Due to this high sensitivity a velocity response of several regional earthquakes at PATCX is observed. It can be shown that a linear relationship between the amplitude of velocity drops and peak ground acceleration exists for data from a single station. This relationship does not hold true when comparing different stations due to the different sensitivities of the station environments. Besides, periodic annual velocity changes measured at PATCX are presented. By analyzing data at a temporal resolution below one day it is possible to identify velocity changes with a period of 24 hours. The results indicate an atmospheric origin of the velocity changes that can be confirmed with a model based on thermally induced stress. This comprehensive model explains the frequency and lag time dependence of the temperature-related seismic velocity changes involving the distribution of temperature fluctuations, the relationship between temperature, stress and velocity change plus autocorrelation sensitivity kernels.

Description: Constraints on the potential size and recurrence time of strong subduction-zone earthquakes come from the degree of locking between the down-going and overriding plates, in the period between large earthquakes. In many cases, this interseismic locking degree correlates with slip during large earthquakes1, 2, 3, 4 or is attributed to variations in fluid content at the plate interface5. Here we use geodetic and seismological data to explore the links between pore-fluid pressure and locking patterns at the subduction interface ruptured during the magnitude 8.8 Chile earthquake in 2010. High-resolution three-dimensional seismic tomography reveals variations in the ratio of seismic P- to S-wave velocities (Vp/Vs) along the length of the subduction-zone interface. High Vp/Vs domains, interpreted as zones of elevated pore-fluid pressure, correlate spatially with parts of the plate interface that are poorly locked and slip aseismically. In contrast, low Vp/Vs domains, interpreted as zones of lower pore-fluid pressure, correlate with locked parts of the plate interface, where unstable slip and earthquakes occur. Variations in pore-fluid pressure are caused by the subduction and dehydration of a hydrothermally altered oceanic fracture zone. We conclude that variations in pore-fluid pressure at the plate interface control the degree of interseismic locking and therefore the slip distribution of large earthquake ruptures.

Description: The Tyrrhenian Sea in the Mediterranean formed as the result of roll-back of the Adriatic and Ionian subducting plates. It is mostly underlain by strongly thinned continental lithosphere, but contains two small oceanic basins in the southern Tyrrhenian, the youngest one located just behind the active magmatic arc. Its regional setting with dense station coverage provides a unique opportunity to derive a high-resolution, 3-D shear-velocity model of this back-arc basin and surrounding onshore areas using interstation Rayleigh-wave dispersion measurements. Our tomographic model, extending to a depth of approximately 160 km, displays a pronounced, nearly ring-shaped low shear-velocity zone between 70 and 110 km depth which surrounds the older oceanic Vavilov Basin. The sharp velocity decrease at 70 km depth can be explained by the transition from a relatively dry lithospheric mantle to more hydrous asthenospheric mantle material. The tectonic evolution of the region and the correlation of the low-velocity anomaly with subduction-related volcanism indicate that the low-velocity anomaly reflects hydrous mantle material in (present or former) mantle wedge regions. We suggest that the absence of the low-velocity zone beneath the Vavilov Basin is due to mantle dehydration caused by the creation of MORB crust. Whereas temperature effects may dominate the asthenospheric shear-velocity differences between various back-arc basins, we find that the variations in shear-velocity structure within the Tyrrhenian area are best explained by variations in mantle water content.

Description: The Maule earthquake (2010 February 27, Mw 8.8, Chile) broke the subduction megathrust along a previously locked segment. Based on an international aftershock deployment, catalogues of precisely located aftershocks have become available. Using 23 well-located aftershocks, we calibrate the classic teleseismic backprojection procedure to map the highfrequency seismic radiation emitted during the earthquake. The calibration corrects traveltimes in a standard earth model both with a static term specific to each station, and a ‘dynamic’ term specific to each combination of grid point and station. The second term has been interpolated over the whole slipping area by kriging, and is about an order of magnitude smaller than the static term. This procedure ensures that the teleseismic images of rupture development are properly located with respect to aftershocks recorded with local networks and does not depend on accurate hypocentre location of the main shock. We track a bilateral rupture propagation lasting ∼160 s, with its dominant branch rupturing northeastwards at about 3 kms−1. The area of maximum energy emission is offset from the maximum coseismic slip but matches the zone where most plate interface aftershocks occur. Along dip, energy is preferentially released from two disconnected interface belts, and a distinct jump from the shallower belt to the deeper one is visible after about 20 s from the onset. However, both belts keep on being active until the end of the rupture. These belts approximately match the position of the interface aftershocks, which are split into two clusters of events at different depths, thus suggesting the existence of a repeated transition from stick-slip to creeping frictional regime.

Description: An understanding of the formation of large magmatic reservoirs is a key issue for the evaluation of possible strong volcanic eruptions in the future. We estimated the size and level of maturity of one of the largest volcanic reservoirs, based on radial seismic anisotropy. We used ambient-noise seismic tomography below the Toba caldera (in northern Sumatra) to observe the anisotropy that we interpret as the expression of a fine-scale layering caused by the presence of many partially molten sills in the crust below 7 kilometers. This result demonstrates that the magmatic reservoirs of present (non-eroded) supervolcanoes can be formed as large sill complexes and supports the concept of the long-term incremental evolution of magma bodies that lead to the largest volcanic eruptions.

Description: Within the framework of the international DESIRE (DEad Sea Integrated REsearch) project, a dense temporary local seismological network was operated in the southern Dead Sea area. During 18 recording months, 648 events were detected. Based on an already published tomography study clustering, focal mechanisms, statistics and the distribution of the microseismicity in relation to the velocity models from the tomography are analysed. The determined b value of 0.74 leads to a relatively high risk of large earthquakes compared to the moderate microseismic activity. The distribution of the seismicity indicates an asymmetric basin with a vertical strike-slip fault forming the eastern boundary of the basin, and an inclined western boundary, made up of strike-slip and normal faults. Furthermore, significant differences between the area north and south of the Bokek fault were observed. South of the Bokek fault, the western boundary is inactive while the entire seismicity occurs on the eastern boundary and below the basin-fill sediments. The largest events occurred here, and their focal mechanisms represent the northwards transform motion of the Arabian plate along the Dead Sea Transform. The vertical extension of the spatial and temporal cluster from February 2007 is interpreted as being related to the locking of the region around the Bokek fault. North of the Bokek fault similar seismic activity occurs on both boundaries most notably within the basin-fill sediments, displaying mainly small events with strike-slip mechanism and normal faulting in EW direction. Therefore, we suggest that the Bokek fault forms the border between the single transform fault and the pull-apart basin with two active border faults.

Description: Shear wave splitting of SK(K)S phases is often used to examine upper mantle anisotropy. In specific cases, however, splitting of these phases may reflect anisotropy in the lowermost mantle. Here we present SKS and SKKS splitting measurements for 233 event‐station pairs at 34 seismic stations that sample D″ beneath Africa. Of these, 36 pairs show significantly different splitting between the two phases, which likely reflects a contribution from lowermost mantle anisotropy. The vast majority of discrepant pairs sample the boundary of the African large low shear velocity province (LLSVP), which dominates the lower mantle structure beneath this region. In general, we observe little or no splitting of phases that have passed through the LLSVP itself and significant splitting for phases that have sampled the boundary of the LLSVP. We infer that the D″ region just outside the LLSVP boundary is strongly deformed, while its interior remains undeformed (or weakly deformed).

Description: A day and a half after the earthquake (mb =5.3, MS =5.6, MW =5.6) in the Bárðarbunga central volcano on Sept. 29th 1996, a volcanic eruption broke out under the Vatnajökull glacier. The eruption was located approximately 20 km SSE of the earthquake epicenter, midway between the Bárðarbunga and Grímsvötn central volcanoes. Course of events suggests a connection between earthquake and eruption and therefore a connection with a sequence of earthquakes of the same characteristics in Bárðarbunga during the years 1973–1996. The earthquakes in question are of an unusually low frequency character (corner frequency), explained by exceptionally low dynamic stress drop (〈 10 bars) at shallow depth (≤5.0 km). The sequence which lasted for 22 years is characterised by ∼annual main events of magnitudes in the range of 4.5–5.7 (mb). It intensified in the 1990s, with some of the largest earthquakes of the whole episode occurring at that time. Moment tensor solutions of teleseismic signals and locally recorded waveforms reveal that the main events are thrust faulting earthquakes with a significant non-double couple component. Arguments are presented that the faulting occurred on a steeply inward dipping caldera fault, with reactivated motion on a weak fault. As a consequence of this hypothesis magma inflation in Bárðarbunga is the most probable cause of the 1973–1996 events. However, the loading force (the magma) may or may not have resided at a similar shallow depth as the earthquakes. Cast in the frame of the inflation model, the Bárðarbunga 1973–1996 sequence implies a resurgent caldera of at least 0.2–0.7 km 3 for approximately a quarter of a century, exceeding its magma storage capacity in 1996. However, these calculations are model dependent. Bárðarbunga and neighbouring area were relatively calm during the period mid-1997 to 2004. There was a renewed activity of small earthquakes during the years 2005–2009. From the beginning of continuous seismic recording in Iceland in 1925, all eruptions in Vatnajökull on record have been accompanied with earthquake(s) of magnitude ≥4.0, within two months of the initial eruption.

Description: This paper presents an investigation to the estimation of the surface movements over the region of Yakutsk using TerraSAR-X data acquired during two months. The interferometric phase generated from the data stack presents a deterministic behavior over the most of the image, due to short temporal baseline and frozen surface context, and reveals fringes due to surface deformation over different geo-morphologic objects as alluvial deposits, alasses and other thermokarstic depressions, but also on the Lena river.

Description: The results of seismic monitoring in the area of the Franz Victoria and Orla trenches in 2011–2013 are discussed in the paper. A seismic catalog of recorded earthquakes with calculated source parameters is given, and the spatial distribution of these earthquakes is characterized. The results of monitoring are compared with the data on historical earthquakes. A cumulative graph of recurrence has been constructed.

Description: Recently, the 2014 MW=8.1 Pisagua earthquake ruptured a substantial part of the Northern Chile seismic gap north of 21°S. We present data from a temporary local seismic network that was in operation in this region between 2005 and 2012, in the phase of late interseismic locking. We localized over 5,300 seismic events (ML ∼0.5–4) with high precision using hand-picked seismic arrival times. Seismicity is pervasive within the entire crust of the South American continental plate. In the subducting slab the seismicity exhibits three distinct bands of activity. The highest concentration is found in a sharp band at the contact zone between the continental and the oceanic lithosphere. Here it constraints the transitionally locked zone between 30 and 50 km depth. A second band is visible near the oceanic Moho and a third one in the lithospheric mantle of the subducting plate, 30km below the plate contact. Seismicity tightly correlates with the reflectivity image acquired in the ANCORP '96 experiment. We complement our observations with the determination of local seismic P- to S-wave velocity ratios (Vp/Vs) that we determined in full independence of the localization procedure following the approach of Lin and Shearer (2007). Along the plate contact we observe a clear down-dip decrease of Vp/Vs from high values (〉1.80) in the shallow part (~30km depth) to moderate values (~1.70) in the deeper part of the system (~90km). Locally very high or very low Vp/Vs occur (〉1.90 or ~1.60, respectively). The continental crust exhibits rather typical Vp/Vs (~1.75). Towards the trench we find a continuation of high Vp/Vs from the subducting slab into the lower continental crust. Arc-ward of the down-dip end of interplate seismicity, below the continental Moho as constrained by receiver functions, we find very low Vp/Vs (~1.60). In the oceanic mantle we observe high Vp/Vs (~1.90) at a depth between 50 and 60km. Fluids and serpentine are prominent candidates to explain anomalously high Vp/Vs. Values as found at the plate contact between 30 and 40km depth may therefore witness the presence of free fluids there. A migration of these fluids into the overriding continental plate would be consistent with our data. In case of the oceanic mantle, the degree of serpentinization of peridotite may be estimated, constraining the water budget of the down-going plate.

Description: The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. The moment magnitude (Mw) 8.1 Iquique earthquake of 1 April 2014 broke a highly coupled portion of this gap. To understand the seismicity preceding this event, we studied the location and mechanisms of the foreshocks and computed Global Positioning System (GPS) time series at stations located on shore. Seismicity off the coast of Iquique started to increase in January 2014. After 16 March, several Mw 〉 6 events occurred near the low-coupled zone. These events migrated northward for ~50 kilometers until the 1 April earthquake occurred. On 16 March, on-shore continuous GPS stations detected a westward motion that we model as a slow slip event situated in the same area where the mainshock occurred.

Description: High-frequency seismic waves are generated by abrupt changes of rupture velocity and slip-rate during an earthquake. Therefore, analysis of high-frequency waves is crucial to understanding the dynamic rupture process. Here, we developed a hybrid back-projection method that considers variations in focal mechanisms by introducing a non-planar fault model that reflects the subducting slab geometry. We applied it to teleseismic P-waveforms of the Mw 8.8 2010 Chile earthquake to estimate the spatiotemporal distribution of high-frequency (0.5–2.0 Hz) radiation. By comparing the result with the coseismic slip distribution obtained by waveform inversion, we found that strong high-frequency radiation can precede and may trigger a large asperity rupture. Moreover, in between the large slip events, high-frequency radiation of intermediate strength was concentrated along the rupture front. This distribution suggests that by bridging the two large slips, this intermediate-strength high-frequency radiation might play a key role in the interaction of the large slip events.

Description: In this paper we describe a stable automatic method to estimate in real time the seismic moment, moment magnitude and corner frequency of events recorded by a network comprising broad-band and accelerometer sensors. The procedure produces reliable results even for small-magnitude events MW≈3. The real-time data arise from both the Transfrontier network at the Alps-Dinarides junction and from the Italian National Accelerometric Network (RAN). The data is pre-processed and the S-wave train identified through the application of an automatic method, which estimates the arrival times based on the hypocenter location, recording site and regional velocity model. The transverse component of motion is used to minimize conversion effects. The source spectrum is obtained by correcting the signals for geometrical spreading and intrinsic attenuation. Source spectra for both velocity and displacement are computed and, following Andrews (1986), the seismic moment and the first estimate of the corner frequency, f0, derived. The procedure is validated using the recordings of some recent moderate earthquakes (Carnia 2002; Bovec 2004; Parma 2008; Aquila 2009; Macerata 2009; Emilia 2012) and the recordings of some minor events in the SE Alps area for which independent seismic moment and moment magnitude estimates are available. The results obtained with a dataset of 843 events recorded by the Transfrontier and RAN networks show that the procedure is reliable and robust for events with MW≥3. The estimates of f0 are less reliable. The results show a scatter, principally for small events with MW≤3, probably due to site effects and inaccurate locations.

Description: Isostatic and dynamic models of Earth's surface topography can provide important insights into the driving processes of tectonic deformation. We analyze these two estimates for the tectonically-active western United States using refined structural models derived from EarthScope USArray. For the crust, use of recent Moho depth measurements and crustal density anomalies inferred from passive source seismology improve isostatic models. However, seismically determined lithospheric thickness variations from “lithosphere–asthenosphere boundary” (LAB) maps, and lithospheric and mantle density anomalies derived from heat flow or uppermost mantle tomography, do not improve isostatic models substantially. Perhaps this is a consequence of compositional heterogeneity, a mismatch between thermal and seismological LAB, and structural complexity caused by smaller-scale dynamics. The remaining, non-isostatic (“dynamic”) component of topography is large. Topography anomalies include negative residuals likely due to active subduction of the Juan de Fuca plate, and perhaps remnants of formerly active convergence further south along the margin. Our finding of broad-scale, positive residual topography in the Basin and Range substantiates previous results, implying the presence of anomalous buoyancy there which we cannot fully explain. The Colorado Plateau does not appear dynamically anomalous at present, except at its edges. Many of the residual topography features are consistent with predictions from mantle flow computations. This suggests a convective origin, and important interactions between vigorous upper mantle convection and intraplate deformation.

Description: Obduction is an odd geodynamic process characterized by the emplacement of dense oceanic “ophiolites” atop light continental plates in convergent settings. We herein present analog models specifically designed to explore the conditions (i.e., sharp increase of plate velocities — herein coined as ‘acceleration’, slab interaction with the 660 km discontinuity, ridge subduction) under which obduction may develop as a result of subduction initiation. The experimental setup comprises an upper mantle modeled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and high-viscosity silicone plates. Convergence is simulated by pushing a piston with plate tectonics like velocities (1–10 cm/yr) onto a model comprising a continental margin, a weakness zone with variable resistance and dip (W), an oceanic plate (with or without a spreading ridge), a preexisting subduction zone (S) dipping away from the piston and an upper active continental margin, below which the oceanic plate is being subducted at the start of the model (as for the Neotethyan natural example). Several configurations were tested over thirty-five parametric models, with special emphasis on comparing different types of weakness zone and the degree of mechanical coupling across them. Measurements of displacements and internal deformation allow for a precise and reproducible tracking of deformation. Models consistently demonstrate that once conditions to initiate subduction are reached, obduction may develop further depending on the effective strength of W. Results (1) constrain the range of physical conditions required for obduction to develop/nucleate and (2) underline the key role of such perturbations for triggering obduction, particularly plate ‘acceleration’. They provide an explanation to the short-lived Peri-Arabic obduction, which took place along thousands of km almost synchronously (within ∼50–10 Myr), from Turkey to Oman, while the subduction zone beneath Eurasia became temporarily jammed. They also demonstrate that the emplacement of dense, oceanic material on continental lithosphere is not a mysterious process requiring extraordinary boundary conditions but results from large-scale, normal (oceanic then continental) subduction processes.

Description: The formation and evolution of a backarc basin are linked to the dynamics of the subduction system. The opening of the central Mediterranean basins is a well-documented example of backarc extension characterized by short-lived episodes of spreading. The underlying reasons for this episodicity are obscured by the complexity of this subduction system, in which multiple continental blocks enter the subduction zone. We present results from three-dimensional numerical models of laterally varying subduction to explain the mechanism of backarc basin opening and the episodic style of spreading. Our results show that efficient backarc extension can be obtained with an along-trench variation in slab buoyancy that produces localized deformation within the overriding plate. We observe peaks in the trench retreating velocity corresponding first to the opening of the backarc basin, and later to the formation of slab windows. We suggest that the observed episodic trench retreat behavior in the central Mediterranean is caused by the formation of slab windows.

Description: It is expected that climate change will have significant impacts on ecosystems. Most model projections agree that the ocean will experience stronger stratification and less nutrient supply from deep waters. These changes will likely affect marine phytoplankton communities and will thus impact on the higher trophic levels of the oceanic food web. The potential consequences of future climate change on marine microbial communities can be investigated and predicted only with the help of mathematical models. Here we present the application of a model that describes aggregate properties of marine phytoplankton communities and captures the effects of a changing environment on their composition and adaptive capacity. Specifically, the model describes the phytoplankton community in terms of total biomass, mean cell size, and functional diversity. The model is applied to two contrasting regions of the Atlantic Ocean (tropical and temperate) and is tested under two emission scenarios: SRES A2 or “business as usual” and SRES B1 or “local utopia.” We find that all three macroecological properties will decline during the next century in both regions, although this effect will be more pronounced in the temperate region. Being consistent with previous model predictions, our results show that a simple trait-based modeling framework represents a valuable tool for investigating how phytoplankton communities may reorganize under a changing climate.

Description: In tectonically active areas, the landscape response to tectonic forcing is described and possibly quantified by regional topographic and hydrographic features as well as by spatial variation in rates of surface processes. We investigated the recent landscape evolution of the Iberian Chain (NE Spain), an intraplate thrust-belt formed in Cenozoic times and characterized by a dome-shaped topography. In its central sector the landscape is dominated by low relief surfaces, Late Neogene (?) in age, presently standing at an average altitude of 1300 m. A recent regional uplift controlled the organization of the present fluvial network and dissection of the landscape. In this framework we investigated the geomorphic responses to tectonic forcing by the calculation of morphometric parameters, focusing on topography (map of local relief, swath profiles) and hydrography (basin hypsometric curve and integral, basin asymmetry factor, river longitudinal profiles and relative indices), and using SRTM DEM. The results of morphometric analysis have been coupled with radiometric uranium-series dating of calcareous tufas lying on fluvial strath terraces. The obtained ages allow the estimation of incision rate along the High Tajo and Martín rivers. Our results indicate that uplift and rock-type erodibility are the main factors influencing landscape evolution of the study area. The incision rates are very similar throughout the central sector of the range, indicating that, despite subtle local variation, the rivers are responding to a main tectonic input: the regional uplift. In conclusion, the Iberian Chain landscape is in a transient state in response to a recent dome-like uplift. Indeed, the fluvial processes that weakly incised this landscape at a rate of ~ 0.6 mm/yr are approaching a radial pattern. On the basis of geological and geomorphic constraints, we hypothesize that the uplift started around or after 3 Ma.

Description: The elevation of an orogenic belt is commonly related to crustal/lithosphere thickening. Here, we discuss the Apennines as an example to show that topography at a plate margin may be controlled not only by isostatic adjustment but also by dynamic, mantle-driven processes. Using recent structural constraints for the crust and mantle we find that the expected crustal isostatic component explains only a fraction of the topography of the belt, indicating positive residual topography in the central Apennines and negative residual topography in the northern Apennines and Calabria. The trend of the residual topography matches the mantle flow induced dynamic topography estimated from regional tomography models. We infer that a large fraction of the Apennines topography is related to mantle dynamics, producing relative upwellings in the central Apennines and downwellings in the northern Apennines and Calabria where subduction is still ongoing. Comparison between geodetic and geological data on vertical motions indicates that this dynamic process started in the early Pleistocene and the resulting uplift appears related to the formation and enlargement of a slab window below the central Apennines. The case of the Apennines shows that at convergent margins the elevation of a mountain belt may be significantly different from that predicted solely by crustal isostasy and that a large fraction of the elevation and its rate of change are dynamically controlled by mantle convection.

Description: We report the paleomagnetic and magnetic fabric results of 58 sites from Cretaceous-Miocene marine and continental strata from the Eastern Cordillera (EC) and the Cucuta zone, at the junction between the Santander Massif and the Merida Andes of Colombia. The EC is an intracontinental doubly vergent range inverting a Triassic to Early Cretaceous rift zone. Twenty-three sites reveal nonsystematic tectonic rotations, including unrotated areas of the EC range with respect to stable South America. Our data show that the EC inverted a NNE oriented rift zone and that the orientation of the Mesozoic rift and the mountain chain roughly correspond. Interestingly, magnetic lineations from anisotropy of magnetic susceptibility analysis do not trend parallel to the chain but rather are oblique to the main orogenic trend. By also considering GPS evidence of a ~1 cm/yr ENE displacement of central western Colombia accommodated by the EC, we suggest that the Miocene-Recent deformation event of this belt arises from ENE oblique convergence reactivating a NNE oriented rift zone. Oblique shortening was likely partitioned into pure dip-slip shear characterizing thick-skinned frontal thrust sheets (well known along both chain fronts) and by range-parallel right-lateral strike-slip faults, which have not been identified yet, but likely exist in the axial part of the EC. Finally, the 35° ± 9° clockwise rotation observed in four post-Miocene magnetically overprinted sites from the Cucuta zone reflects late Cenozoic and ongoing right-lateral strike-slip displacement occurring along faults parallel to the Boconó fault system, possibly connected with the right-lateral faults inferred to exist along the axial part of the EC.

Description: In this paper we investigate the influence of atmospheric turbulence on the performance of the uplink of a planetary transceiver laser ranging system using a single photon detector. We numerically combine the influence of turbulence in the mean intensity profile variations, scintillation, beam-wander induced pointing errors and stochastic time-of-flight variations, using the Hufnagel-Valley turbulence profile to model the ground turbulence behavior. We map the intensity variations due to turbulence to variations in the probability distribution of the arrival time of the 1st photon in a laser pulse, which influences the range measurement error probability distribution. The turbulence models are applied to assess the influence on single-pass range accuracy and precision statistics, as well as the parameter estimation quality of a Phobos Laser Ranging (PLR) mission. The difference in range measurement error between weak and strong turbulence is 3-4 mm in a PLR concept. This indicates that turbulence is a potentially important contributor to the error budget of interplanetary laser ranging missions, which aim at mm-level accuracy and precision. The single-shot precision is weakly influenced by turbulence, but strong turbulence is found to cause a strong decrease in detected pulse fraction, reducing normal point precision. We show that a trade-off between range accuracy and precision must be made when selecting laser system parameters, considerations for which are influenced by atmospheric turbulence effects. By consistently operating at the single-photon signal strength level, accuracy variations can be largely removed, at the expense of normal point precision, due to the reduced detection probability. We perform parameter estimation of Phobos initial state and observation biases using simulated measurements with and without turbulence, using a daily periodic turbulence strength model. We show that the parameter estimation quality is degraded significantly below that of the turbulence-free case only in the presence of strong turbulence. This shows the existence of a limit of ground turbulence strength below which its influence on parameter estimation becomes negligible.

Description: The granitic rocks around the Utla area (Gadoon), north western, Pakistan are studied in terms of their petrographic features and geochemical characteristics. Although predominantly mega-porphyritic, some of the Utla granites are massive and display fine-grained equi-granular texture. Some of the mega-porphyritic varieties exhibit foliation and seem to be restricted to shear zones. In addition to being distributed largely as phenocrysts, all the essential minerals (plagioclase, perthitic alkali feldspar and quartz) also constitute the groundmass. The studied samples also contain minor to accessory amounts of tourmaline, muscovite and biotite and accessory to trace amounts of apatite, andalusite, garnet, zircon, monazite, epidote and sphene. A detailed geochemical investigation reveals a calc-alkaline and peraluminous character of the Utla granites. The peraluminous character and total lack of hornblende designate their S-type character while a volcanic arc or syn-collisional tectonic setting for their emplacement is indicated by discrimination diagrams. Further examination shows that the melt parental to the Utla granite was derived from a plagioclase-poor, clay-rich rock, i.e., pelite. The petrogenetically significant petrographic and geochemical features of the Utla granite show greater similarity with the Mansehra than the Ambela granites. These include (i) the predominantly megaporphyritic texture, (ii) the presence of andalusite and tourmaline, (iii) the calc-alkaline geochemical signature and (iv) an indication of similar melt source rock character.

Description: We have investigated the seismic anisotropy beneath the Central Andean southern Puna plateau by applying shear wave splitting analysis and shear wave splitting tomography to local S waves and teleseismic SKS, SKKS and PKS phases. Overall, a very complex pattern of fast directions throughout the southern Puna plateau region and a circular pattern of fast directions around the region of the giant Cerro Galan ignimbrite complex are observed. In general, teleseismic lag times are much greater than those for local events which are interpreted to reflect a significant amount of sub and inner slab anisotropy. The complex pattern observed from shear wave splitting analysis alone is the result of a complex 3-D anisotropic structure under the southern Puna plateau. Our application of shear wave splitting tomography provides a 3-D model of anisotropy in the southern Puna plateau that shows different patterns depending on the driving mechanism of upper-mantle flow and seismic anisotropy. The trench parallel a-axes in the continental lithosphere above the slab east of 68W may be related to deformation of the overriding continental lithosphere since it is under compressive stresses which are orthogonal to the trench. The more complex pattern below the Cerro Galan ignimbrite complex and above the slab is interpreted to reflect delamination of continental lithosphere and upwelling of hot asthenosphere. The a-axes beneath the Cerro Galan, Cerro Blanco and Carachi Pampa volcanic centres at 100 km depth show some weak evidence for vertically orientated fast directions, which could be due to vertical asthenospheric flow around a delaminated block. Additionally, our splitting tomographic model shows that there is a significant amount of seismic anisotropy beneath the slab. The subslab mantle west of 68W shows roughly trench parallel horizontal a-axes that are probably driven by slab roll back and the relatively small coupling between the Nazca slab and the underlying mantle. In contrast, the subslab region (i.e. depths greater than 200 km) east of 68W shows a circular pattern of a-axes centred on a region with small strength of anisotropy (Cerro Galan and its eastern edge) which suggest the dominant mechanism is a combination of slab roll back and flow driven by an overlying abnormally heated slab or possibly a slab gap. There seems to be some evidence for vertical flow below the slab at depths of 200–400 km driven by the abnormally heated slab or slab gap. This cannot be resolved by the tomographic inversion due to the lack of ray crossings in the subslab mantle.

Description: Pakistan and the western Himalaya is a region of high seismic activity located at the triple junction between the Arabian, Eurasian and Indian plates. Four devastating earthquakes have resulted in significant numbers of fatalities in Pakistan and the surrounding region in the past century (Quetta, 1935; Makran, 1945; Pattan, 1974 and the recent 2005 Kashmir earthquake). It is therefore necessary to develop an understanding of the spatial distribution of seismicity and the potential seismogenic sources across the region. This forms an important basis for the calculation of seismic hazard; a crucial input in seismic design codes needed to begin to effectively mitigate the high earthquake risk in Pakistan. The development of seismogenic source zones for seismic hazard analysis is driven by both geological and seismotectonic inputs. Despite the many developments in seismic hazard in recent decades, the manner in which seismotectonic information feeds the definition of the seismic source can, in many parts of the world including Pakistan and the surrounding regions, remain a subjective process driven primarily by expert judgment. Whilst much research is ongoing to map and characterise active faults in Pakistan, knowledge of the seismogenic properties of the active faults is still incomplete in much of the region. Consequently, seismicity, both historical and instrumental, remains a primary guide to the seismogenic sources of Pakistan. This study utilises a cluster analysis approach for the purposes of identifying spatial differences in seismicity, which can be utilised to form a basis for delineating seismogenic source regions. An effort is made to examine seismicity partitioning for Pakistan with respect to earthquake database, seismic cluster analysis and seismic partitions in a seismic hazard context. A magnitude homogenous earthquake catalogue has been compiled using various available earthquake data. The earthquake catalogue covers a time span from 1930 to 2007 and an area from 23.00° to 39.00°N and 59.00° to 80.00°E. A threshold magnitude of 5.2 is considered for K-means cluster analysis. The current study uses the traditional metrics of cluster quality, in addition to a seismic hazard contextual metric to attempt to constrain the preferred number of clusters found in the data. The spatial distribution of earthquakes from the catalogue was used to define the seismic clusters for Pakistan, which can be used further in the process of defining seismogenic sources and corresponding earthquake recurrence models for estimates of seismic hazard and risk in Pakistan. Consideration of the different approaches to cluster validation in a seismic hazard context suggests that Pakistan may be divided into K = 19 seismic clusters, including some portions of the neighbouring countries of Afghanistan, Tajikistan and India.

Description: In any probabilistic seismic-hazard model, the earthquake activity that cannot be associated with well-characterized fault structures is taken into account as seismicity distributed over a geographical region. Ground-motion prediction equations (GMPEs) are generally based on predictor variables describing the spatial extension of a rupture. The approach taken to model rupture finiteness can therefore bias the estimation of seismic hazard. We study the effect of rupture finiteness in modeling distributed seismicity using the OpenQuake (OQ) engine, the open-source software for seismic hazard and risk assessment promoted by the Global Earthquake Model initiative. For a simple test case we show how the inclusion of rupture finiteness, with respect to the point-rupture approximation, leads to a significant increase in the probabilities of exceedance for a given level of motion. We then compare the OQ engine with the calculation software developed by the U.S. Geological Survey-National Seismic Hazard Mapping Project. By considering a gridded seismicity model for California, we show how different approaches for modeling finite ruptures affect seismic-hazard estimates. We show how sensitivity to rupture finiteness depends not only on the spatial distribution of activity rates but also on the GMPE model. Considering two sites in Los Angeles and San Francisco, we show that for a return period of 475 years, the percent difference in the associated ground-motion levels when using point and finite ruptures ranges from 19% to 46%; for a return period of 2475 years the difference ranges from 29% to 58%.

Description: Global warming, the overall extraction of minerals and the expansion of cultivated land for biomass harvest are growing globally. These "Big Three" represent key environmental pressures which may lead to a continuous degradation of the living environment, if not controlled at levels with acceptable low risk. The situation is complex, because countries and regions consume products which require resources such as minerals and land in various parts of the world. Nevertheless, it is possible to measure the global resource use which is associated with the domestic consumption. In order to inform policies at the national and supranational level whether it may be necessary to adjust the incentive framework for industry and households, reference data are needed to compare the status quo of their countries with what may be deemed acceptable at a global level. This chapter outlines a rationale for the derivation of possible long-term targets for total material consumption of abiotic materials (TMCabiot) and global land use for crops (GLUcropland). The indicated targets are expressed in tentative per capita values which may serve as a first orientation and basis for further debate and research.

Description: EXIOPOL (A New Environmental Accounting Framework Using Externality Data and Input–Output Tools for Policy Analysis) was a European Union (EU)-funded project creating a detailed, global, multiregional environmentally extended Supply and Use table (MR EE SUT) of 43 countries, 129 sectors, 80 resources, and 40 emissions. We sourced primary SUT and input–output tables from Eurostat and non-EU statistical offices. We harmonized and detailed them using auxiliary national accounts data and co-efficient matrices. Imports were allocated to countries of exports using United Nations Commodity Trade Statistics Database trade shares. Optimization procedures removed imbalances in these detailing and trade linking steps. Environmental extensions were added from various sources. We calculated the EU footprint of final consumption with resulting MR EE SUT. EU policies focus mainly on energy and carbon footprints. We show that the EU land, water, and material footprint abroad is much more relevant, and should be prioritized in the EU's environmental product and trade policies.

Description: The European Waste Framework Directive has defined waste prevention as top of the waste hierarchy meaning nothing less than a fundamental change of the sociotechnical system of waste infrastructures with all its economic, legal, social and cultural elements. Based on an empirical analysis of more than 300 waste prevention measures this paper assesses which prevention effects can realistically be achieved by applying the measures described in the German waste prevention programme or in those of other EU member states. Taking into account waste streams like packaging, food waste, bulky waste and production waste the results show that waste generation is not an unavoidable evil but can be significantly reduced at current level of technology.

Description: In this article, the author discusses efforts to establish financial transparency as a norm for the extractive sector. The paper resulted from a fellowship at the American Institute for Contemporary German Studies (AICGS) at Johns Hopkins University, Washington, DC, in May and June 2013.

Description: Global transportation energy use is steeply rising, mainly as a result of increasing population and economic activity. Petroleum fuels remain the dominant energy source, reflecting advantages such as high energy density, low cost, and market availability. The movement of people and freight makes a major contribution to economic development and social well-being, but it also negatively impacts climate change, air quality, health, social cohesion, and safety. Following a review published 20 years ago in the Annual Review of Environment and Resources (then named the Annual Review of Energy and the Environment) by Lee Schipper, we examine current trends and potential futures, revising several major global transport/energy reports. There are significant opportunities to slow travel growth and improve efficiency. Alternatives to petroleum exist but have different characteristics in terms of availability, cost, distribution, infrastructure, storage, and public acceptability. The transition to low-carbon equitable and sustainable transport will take time but can be fostered by numerous short- and medium-term strategies that would benefit energy security, health, productivity, and sustainability.

Description: The concept Material Input per Service Unit (MIPS) was developed 20 years ago as a measure for the overall natural resource use of products and services. The material intensity analysis is used to calculate the material footprint of any economic activities in production and consumption. Environmental assessment has developed extensive databases for life cycle inventories, which can additionally be adopted for material intensity analysis. Based on practical experience in measuring material footprints on the micro level, this paper presents the current state of research and methodology development: it shows the international discussions on the importance of accounting methodologies to measure progress in resource efficiency. The MIPS approach is presented and its micro level application for assessing value chains, supporting business management, and operationalizing sustainability strategies is discussed. Linkages to output-oriented Life Cycle Assessment as well as to Material Flow Analysis (MFA) at the macro level are pointed out. Finally we come to the conclusion that the MIPS approach provides relevant knowledge on resource and energy input at the micro level for fact-based decision-making in science, policy, business, and consumption.

Description: It is widely accepted that environmental awareness is essential, yet does not inevitably lead to responsible use of resources. Additional factors on the individual level include the meaning constructed by the term "resources" and the individual and social norms that influence the relevant behavior. Current didactic concepts do not take into account such aspects. Therefore, this article uses a didactic-psychological approach for designing an educational concept for raising awareness for a responsible use of natural resources. Combining insights of environmental psychology and of constructivist didactics, a general principal of "norm-oriented interpretation learning" is outlined to enrich the didactic debate on responsible and efficient resource use. Based on the presentation of a qualifying module for resource efficiency consultants as a practical example of resource education, a new didactical approach, namely "open-didactic exploration" (short form: ODE) is introduced. The article discusses the theory-based elements of ODE and illustrates a step by step process for designing educational materials. This adds to the theoretical debate about a didactic design for resource oriented education. Furthermore, this method can be directly used by practitioners developing education and training material (e.g., teachers, trainers in vocational education). The Wuppertal Institute developed and applied this method in numerous projects. The conclusion and outlook discusses future expectations and scope of the introduced ODE method as a contribution to foster "norm-oriented interpretation learning", suggesting perspectives for further development.

Description: The year 2015 has special importance for the transformation towards sustainable development. New Sustainable Development Goals (SDGs) are then supposed to replace the Millennium Development Goals (MDGs). The aim is to offer a new orientation for political action in the coming decades. The WBGU recommends orienting the new catalogue of goals towards the key message of the 1992 Earth Summit: that development and environmental protection must be considered together and do not contradict each other. The SDGs should not be reduced to poverty eradication, but must address all dimensions of sustainable development. In particular, global environmental change must be incorporated, otherwise even poverty eradication will become impossible. Up to now, too little attention has been paid to this link in the ongoing discourse on SDGs. Although many reports mention the concept of planetary guard rails or planetary boundaries, they do not back this up with specific targets. The WBGU presents recommendations on how guard rails for global environmental problems should be incorporated in the SDG catalogue and operationalized by means of corresponding targets.

Description: Access to sustainable and affordable energy services is a crucial factor in reducing poverty in developing countries. In particular, small-scale and community-based renewable energy projects are recognized as important forms of development assistance for reaching the energy poor. However, to date only a few empirical evaluations exist which analyze and compare the impact of these projects on local living conditions and their sustainability ex-post implementation. To better understand the impacts and the conditions that influence sustainability of these projects, the research presented in this paper evaluated 23 local development projects post implementation. By applying an standardized evaluation design to a cross-sectional sample in terms of renewable energy sources (solar, wind, biomass, hydro), user needs (electricity, food preparation, lighting, productive uses), community management models, finance mechanisms and geographical locations, the review results provide valuable insights on the underlying conditions that influence the success or failure of these small-scale local energy interventions. The empirical evidence suggests that the sustainability of small-scale energy implementations (≤100 kW) in developing countries is determined by the same factors, independent of the socio-cultural, political and ecological context. These findings allow to better predict the long-term success of small sustainable energy projects in developing countries, this can help to improve project designs and increase the certainty for future investment decisions.

Description: The paper examines policies and measures that promote the usage of pedelecs and that contribute to climate friendly passenger transportation thereby. As pedelecs allow the rider to pedal at lower efforts, pedelecs provide the potential to increase the share of bicycle trips in metropolitan regions with hilly landscapes and with a significant share of medium commuting distances. The paper develops attitude-based mobility types and defines their specific pedelec affinity based upon differentiated reasons to use a pedelec. Thereafter policies and measures are examined that foster purchase and usage of pedelecs, and factors influencing the modal behaviour of (potential) attitude-based target groups are defined. Quantification of climate protection effects is conducted based on two scenarios for the German city of Wuppertal, a city known for its steep slopes. The first scenario assumes business as usual, and the second scenario is based on the introduction of ambitious policies and measures to encourage purchase and usage of pedelecs. Following a mixed-method approach, qualitative scenario assumptions are calculated by a quantitative model, which incorporates the analyses on attitude-based mobility types respective pedelec affinities.The results indicate that ambitious promotion of pedelecs significantly contributes to climate change mitigation. Compared to business as usual, ambitious policies and measures to purchase and use pedelecs reduce CO2-emissions of passenger transport in Wuppertal by 11 per cent in 2050. A spatially inclusive and comprehensive 30 kph speed limit proves to be particularly effective. In the scenario of ambitious promotion of pedelecs, interventions solely fostering the purchase of pedelecs significantly increase the modal share of pedelecs, whereas in a business as usual case such efforts remain ineffective. The traditional bicycle profits from the promotion of pedelecs, but its increased usage does not bring about similar climate protection effects.

Description: A desirable future critically depends on our ability to ensure the supply of key resources while simultaneously respecting planetary boundaries. This paper looks at the potential implications of living within the "safe operating space" for people, business and the economy. It develops a positive vision of the future based on three pillars: a safe and fair use of global resources, a sustainable society, and a transformed economy. We review and build on recent sustainability visions to develop a holistic reflection on what life in 2050 could look like, and explore the key changes in the economy needed to get there. In particular we show that resource efficiency requires a systemic shift in values, innovation, governance and management regimes. We present a bold vision for Europe underlined by indicators and targets, explore transition challenges to getting there and conclude with a list of key policies needed for overcoming challenges and reaching the vision.

Description: While strategic studies on natural resources usually focus on the criticality of certain single materials, our paper starts from the inter-linkages between and among resources (called "the resource nexus"). It examines the impact any food and water stress may have on extraction activities in fragile states and regions. According to our approach, conflicts are likely to increase and may escalate in a number of countries, many of which are of relevance for the global supply of strategic materials. Future criticality for European and other industries, thus, is more likely to result from particular regions surpassing their adaptive capacities, and not mainly from limited availability or bottlenecks in the supply chain. The paper first develops a heuristic model of drivers for stress in resource-rich regions. Applying this approach, our paper then develops a global three-layered map along the dimensions of (i) future regional food and water stress, (ii) fragility of countries, and (iii) resource-rich countries with relevant reserves of strategic materials. As a result our paper tentatively identifies 15 countries at high risk and some 30 other countries being at relevant risk of causing resource supply disruptions. The conclusions underline the need to analyse those global inter-linkages and institutional mechanisms for strategic futures studies at a regional scale. As this may go beyond the capacities of actors on commodity markets, our paper also draws conclusions towards the establishment of an international data hub on the global resource nexus and for futures research. The paper points to some of the long-term implications of these issues.

Description: In contrast to the original investigation by William Stanley Jevons, compensations of energy savings due to improved energy efficiency are mostly analyzed by providing energy consumption or greenhouse gas emissions. In support of a sustainable resource management, this paper analyzes so-called rebound effects based on resource use. Material flows and associated expenditures by households allow for calculating resource intensities and marginal propensities to consume. Marginal propensities to consume are estimated from data of the German Socio-Economic Panel (SOEP) in order to account for indirect rebound effects for food, housing and mobility. Resource intensities are estimated in terms of total material requirements per household final consumption expenditures along the Classification of Individual Consumption according to Purpose (COICOP). Eventually, rebound effects are indicated on the basis of published saving scenarios in resource and energy demand for Germany. In sum, compensations due to rebound effects are lowest for food while the highest compensations are induced for mobility. This is foremost the result of a relatively high resource intensity of food and a relatively low resource intensity in mobility. Findings are provided by giving various propensity scenarios in order to cope with income differences in Germany. The author concludes that policies on resource conservation need to reconsider rebound effects under the aspect of social heterogeneity.

Description: Increasing concerns regarding the world's natural resources and sustainability continue to be a major issue for global development. As a result several political initiatives and strategies for green or resource-efficient growth both on national and international levels have been proposed. A core element of these initiatives is the promotion of an increase of resource or material productivity. This dissertation examines material productivity developments in the OECD and BRICS countries between 1980 and 2008. By applying the concept of convergence stemming from economic growth theory to material productivity the analysis provides insights into both aspects: material productivity developments in general as well as potentials for accelerated improvements in material productivity which consequently may allow a reduction of material use globally.The results of the convergence analysis underline the importance of policy-making with regard to technology and innovation policy enabling the production of resource-efficient products and services as well as technology transfer and diffusion.​

Description: Sufficient lifestyles can be considered both necessary and desirable on a personal level, but supporting framework conditions need to be created politically. This includes overall economic policy and its goals as well as specific sectors like mobility, education or health policy.

Description: Living Labs for Sustainable Development aim to integrate users and actors for the successful generation of low-resource innovations in production-consumption systems. This paper investigates potentials of and measures towards the realization of a German Living Lab infrastructure to support actor-integrated sustainability research and innovations in Germany. Information was primarily derived from extensive dialog with experts from the fields of innovation, sustainable development and the Living Lab community (operators, users, etc.), which was facilitated through interviews and workshops. A status quo analysis revealed that, generally, the sustainability and Living Lab communities are hardly intertwined. Twelve Living Labs that explicitly consider sustainability aspects were identified. The application fields "Living and Working", "Town, Region and Mobility", and “Retail and Gastronomy" were identified as particularly suitable for investigation in Living Labs and highly relevant in terms of resource efficiency. Based on the analyses of drivers and barriers and SWOT, keystones for the development of a research infrastructure for user integrated development of sustainable products and services were formulated. Suggested strategies and measures include targeted funding programs for actor-integrated, socio-technical research based on a Living Lab network, a communication campaign, and programs to foster networking and the inclusion of SMEs.