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In this article, the authors investigate the attitude of the population of the Republic of Moldova towards the main events of 2020, which was a difcult one for both humanity and Moldovan society. Wanting to identify the problems faced by citizens and to establish the main events of 2020, we conducted a sociological study dedicated to researching social factors impacting the electoral behavior of citizens and the interdependence of economic, political and social processes in the country. The research established the most important socio-political events of the year, as well as a set of conclusions and recommendations.

Alcohol, opioid, and stimulant withdrawal syndromes are serious clinical presentations, some of which can be life-threatening if untreated. Patients presenting with withdrawal syndromes offer an important opportunity for healthcare providers to ally in deciding the most appropriate treatment setting, safely treating withdrawal symptoms, preventing potentially severe medical complications, and facilitating a transition to longer-term low-barrier substance use care including, where available, psychosocial interventions, evidence-based pharmacotherapies, and referrals for other community-based or specialist-led services. Given that substance use disorders are chronic biopsychosocial disorders commonly characterized by periods of relapse and remission, patients presenting in substance withdrawal deserve a long term and holistic approach to management that cannot be simply achieved in short-term withdrawal management siloed and separate from a continuum of care. This narrative review of withdrawal management literature describes recent advances in clinical care for patients in withdrawal from alcohol, opioids, and stimulants.

The geographic coincidence of the Chile Ridge slab window and the Patagonia ice fields offers a unique opportunity for assessing the effects of slab window rheology on glacial isostatic adjustment (GIA). Mass loss of these ice fields since the Little Ice Age causes rapid but variable crustal uplift, 12–24 mm/yr around the North Patagonia ice field, increasing to a maximum of 41 mm/yr around the South Patagonia ice field, as determined from newly collected or processed geodetic data. We used these observational constraints in a three-dimensional Maxwell viscoelastic finite element model of GIA response above both the subducting slab and slab window in which the upper-mantle viscosity was parameterized to be uniform with depth. We found that the viscosity of the northern part of the slab window, ~2 × 1018 Pa·s, is lower than that of the southern part by approximately an order of magnitude. We propose that this along-strike viscosity contrast is due to late Cenozoic ridge subduction beneath the northern part of the slab window, which increases asthenospheric temperature and reduces viscosity.

The successful interpretation of open-hole well logging data relies on jointly using all available petrophysical and geological information. This paper presents relevant case studies related to the integration of well logs with core measurements for exploration wells drilled in the Romanian continental shelf area of the Western Black Sea basin. The analyzed wells targeted gas-bearing sands and silts complexes of Early Pliocene (Dacian) age, developed in a deltaic to shallow marine sedimentary environment in two distinct fields. The wireline logging programs included conventional formation evaluation logs, pressure surveys, nuclear magnetic resonance, and borehole electrical imaging logs. The core dataset comprised routine and special measurements (porosity, grain density, permeability, water saturation, and Archie parameters) carried out at quasi-reservoir confining pressure. The wireline logging suites were interpreted via a deterministic workflow, including core-derived interpretation parameters. Other core-derived parameters were used for constraining and validating the log interpretations. The results show that a problem related to the ambiguity of formation water resistivity can be overcome through resistivity–porosity dependencies constructed to include potential aquifer zones in the proximity of the Dacian gas-bearing reservoirs. This study also revealed and quantified uncertainties regarding the estimation of gas–water contacts from formation pressure surveys, which can be mitigated by the confirmation or correction of pressure-derived fluid contacts via the well log interpretation results. Lastly, we identified a probable resistivity logs suppression effect related both to high contents of capillary-bound water and also to the limited resolution of electrical logging tools in the presence of sand-shale thin bedding or laminations.

Modeling method, Table S1 (newly obtained uplift rates for the ten continuous GNSS sites shown in Figure1A),Table S2 (slab window viscosity values and RMS data), supplemental figures, and the weekly solutions for GNSS data used in the study.

Geothermal energy is known as a renewable source that has little effect on environment, since no burning process is involved in the producing of thermal and electric energy. Geothermal water is considered an environmentally friendly energy source which is valuable especially in polluted areas. Our study area, the Baia Mare region, is located in the northwestern part of Romania, a region known as one of the most polluted environment in Romania due to its long-lasting local mining and metallurgical activities. Additional quantities of CO2 emissions resulted from the use of various, relatively cheap, heating sources by the local population. The main goals of our study are to evaluate the subsurface geothermal potential of the Baia Mare area and to identify promising geothermal exploitation sites. Heat flow values in this area are among the highest in Romania. We therefore plan to combine geological, geophysical, geochemical and hydrogeological data (geo-data) in order to provide a geoscientific solution for increasing the geothermal energy production in this part of Romania. Our research program contains surface geological mapping, geophysical surveys (active and passive seismic, magnetic, magnetotelluric and geothermal), geochemical analysis, hydrogeological surveys, modeling of geo-data and joint interpretation of geo-data. An initial 3D geothermal model will be built using existent geo-data. This model will help us to identify subsurface structures which show high potential for geothermal exploration. Interpretation of existent active seismic data collected during previous hydrocarbon exploration will provide information about the subsurface structural geology. The results of the new interpretation will be compared and correlated with the existent geological maps and sections for the study area. The magnetic data available in the public domain will be used to identify subsurface igneous bodies. The temperature data available from previous measurements will be used to build temperature-versus-depth distributions. These results will be analysed within a larger geodynamic framework. A pilot site will be selected after the analysis of the initial 3D geothermal model on which we plan to collect and record new geo-data. Data processing, inversion and modeling will be performed in order to create the final geothermal model with locations of promising exploitation wells.

Netrins are secreted proteins that direct cell migration and axon extension in the developing CNS and are essential for normal neural development. In the mature CNS, netrin-1 is expressed by neurons and oligodendrocytes and implicated in the stability of axo-oligodendroglial paranodal junctions. Here we report that the netrin receptor UNC5B is highly expressed by mature oligodendrocytes and enriched at paranodes. We demonstrate that paranodes become disorganized following conditional deletion of UNC5B in oligodendrocytes, with disruption of the interface between glial loops and detachment of glial loops from the axon. Examining axoglial domain segregation, Caspr1 and Kv1.1 disperse along the axon, internodes shorten, and the periodicity of compact myelin is reduced, indicating significant breakdown of myelin organization in UNC5B cKOs. Paranodal disruption and axoglial domain disorganization progressively worsen with age and a delay in motor learning develops specifically in aged animals that lack oligodendroglial UNC5B. We detect reduced amounts of oligodendroglial Claudin-11 and JAM-C proteins in UNC5B knockouts, suggesting that disruption of the specialized autotypic junctions between glial loops may underlie paranodal disorganization. Our findings reveal an essential contribution of oligodendroglial UNC5B at axoglial junctions that is required for the stability of mature myelin.

RomUkrSeis is a controlled source wide-angle reflection and refraction (WARR) profile acquired in August 2014. It is 675 km long, running roughly SW-NE from the Apuseni Mountains in Romania and the Transylvanian Basin, crossing the arc of the Eastern Carpathian orogen and terminating in the East European Craton (EEC) in SW Ukraine. Well-constrained 2-D ray-tracing P- and partly S-wave velocity models have been constructed along the profile from 348 single-component seismic recorders and eleven shot points. The Eastern Carpathian arc formed in the Cenozoic and have obscured the pre-existing Teisseyre-Tornquist Zone (TTZ), which is a transition zone between the Precambrian EEC and continental terranes accreted to it from the southwest in the Palaeozoic. The TTZ is characterised by low-velocity through its entire crust (6.0–6.3 km/s) and a considerable width (~140 km). It is interpreted as EEC crust stretched during rifting and continental margin formation in the Neoproterozoic and early Palaeozoic. The crust of the TTZ has a “trough in trough” structure wherein an upper body of ~40 km width comprising Outer Carpathian (Vp 4.9 km/s) and Late Palaeozoic-Mesozoic (Vp 5.4 km/s) units to 15 km depth lies above a wider, deeper one of inferred Neoproterozoic-early Palaeozoic strata. The crust of the Transylvanian Basin and Apuseni Mountains is relatively thin (~32 km). A high-velocity body at 4–12 km depth in this area is interpreted as a rootless fragment of an ophiolite complex exposed at the surface in this area. The lower crust beneath the Transylvanian Basin displays higher velocities than adjacent segments. Moho topography is strongly differentiated along the profile, varying from 32 to 50 km. The Moho shape, especially in the area between the Inner and Outer Carpathians, suggests a NE dip and, hence, thrusting of the Tisza-Dacia lowermost crustal and upper mantle units under the TTZ domain which, in turn, could be thrust under the cratonic (EEC) block.

The Romanian segment of the Eastern Pannonian Basin and the Moesian Platform are known for their geothermal and hydrocarbon-bearing structures. We used seismic, gravity, and geothermal data to analyze the geothermal behavior in the Oradea and Timisoara areas, from the Romanian segment of Eastern Pannonian Basin, and the Craiova–Bals–Optasi area, from the Moesian Platform. We processed 22 seismic reflection data sets recorded in the Oradea and Timisoara areas to obtain P-wave velocity distributions and time seismic sections. The P-wave velocity distributions correlate well with the structural trends observed along the seismic lines. We observed a good correlation between the high areas of crystalline basement seen on the time seismic sections and the high heat flow and gravity-anomaly values. For the Craiova–Bals–Optasi area, we computed a three-dimensional (3D) temperature model using calculated and measured temperature and geothermal gradient values in wells with an irregular distribution on the territory. The high temperatures from the Craiova–Bals–Optasi area correlate very well with the uplifted basement blocks seen on the time seismic sections and high gravity-anomaly values.

We have performed a deep seismic reflection study, DACIA-PLAN, based on the data recorded along a crooked line across the southeastern Romanian Carpathians. The signal-to-noise ratio (S/N) of these data varies along the seismic profile, and its variation is considered to be an effect of the rough topography, complex subsurface geology, and varying surface conditions encountered during seismic data acquisition. The migrated time section that covers the mountainous area is clear, without visible reflections, making the geologic interpretation very difficult. We used a seismic modeling technique to explain the poor S/N of the recorded data and to generate synthetic seismic sections that can be useful for the geologic interpretation of the field seismic section (migrated time section). We used ray-tracing modeling to obtain the expected seismic expression of horizons of interest. Subsurface illumination modeling indicates that the complex subsurface geology and irregularly deployed sources and receivers are responsible for the incomplete and/or uneven illumination of the subsurface and can lead to strong amplitude variations. We then used 2.5D acoustic finite-difference modeling to analyze the effect of a crooked line on seismic wave propagation. The synthetic shot gathers prove that crooked line arrival times for reflected and head waves contain static time shifts relative to a straight line regular sampling geometry. Some geologic interfaces of interest are not well-imaged on the synthetic seismic section, and this is considered to be an effect of poor positioning during seismic data acquisition. We used the velocity model from the tomographic inversion of first-arrival traveltimes and synthetic and field crooked line deep seismic reflection data to create a structural image for the southeastern Romanian Carpathians and the Focsani Basin, which tie well with the geologic model built for this area on the basis of geologic and well data only.

We present new images of lithospheric structure obtained from P-to-S conversions defined by receiver functions at the 85 broadband seismic stations of the EarthScope IDaho-ORegon experiment. We resolve the crustal thickness beneath the Blue Mountains province and the former western margin of cratonic North America, the geometry of the western Idaho shear zone (WISZ), and the boundary between the Grouse Creek and Farmington provinces. We calculated P-to-S receiver functions using the iterative time domain deconvolution method, and we used the H-k grid search method and common conversion point stacking to image the lithospheric structure. Moho depths beneath the Blue Mountains terranes range from 24 to 34 km, whereas the crust is 32–40 km thick beneath the Idaho batholith and the regions of extended crust of east-central Idaho. The Blue Mountains group Olds Ferry terrane is characterized by the thinnest crust in the study area, ~24 km thick. There is a clear break in the continuity of the Moho across the WISZ, with depths increasing from 28 km west of the shear zone to 36 km just east of its surface expression. The presence of a strong midcrustal converting interface at ~18 km depth beneath the Idaho batholith extending ~20 km east of the WISZ indicates tectonic wedging in this region. A north striking ~7 km offset in Moho depth, thinning to the east, is present beneath the Lost River Range and Pahsimeroi Valley; we identify this sharp offset as the boundary that juxtaposes the Archean Grouse Creek block with the Paleoproterozoic Farmington zone.

Starting with the middle of the ‘90s of the previous century, Republic of Moldova started to implement a series of important reforms, aimed at improving the access and the quality of the services for increasing the efficiency and the performances of the health system. The aim of the research is the analysis of the Regionalization Plan of the Hospital Services and the assessment of medical workers opinion from district and republican hospitals regarding the envisaged transformations, in order to elaborate conclusions and recommendations that will be considered at the stage of reform’s implementation. The object of the research is the physicians of different profile (therapeutic, surgical, diagnostic), which work in republican and district hospitals.

After a great subduction earthquake, viscoelastic stress relaxation causes prolonged seaward motion of inland areas of the upper plate, as was observed around the turn of the century in the area of the 1960 Mw 9.5 Chile earthquake with Global Navigation Satellite System (GNSS) measurements. However, recent GNSS observations during 2010–2019 indicate a systematic decrease in the velocity of the seaward motion over a region covering the latitudinal range of the southern half of the 1960 rupture. Data from the only long-lived continuous site in this region (COYQ since 1997), situated over 200 km away from the trench, suggest that the decrease in the seaward velocity (or increase in the landward velocity) occurred within a few years prior to 2010. This rapid and regional change cannot be explained by viscoelastic relaxation. We thus propose that the change was caused by a relatively sudden downdip widening of the zone of locking along the megathrust. Using three-dimensional finite element modelling, we find that the observed velocity change cannot be otherwise explained, although the amount of the increase in locking cannot be uniquely determined because of trade-offs between, and uncertainties in, the various parameters involved. For example, the degree of the increase in locking is affected by the value of coseismic slip in 1960 in the southernmost part of the rupture zone. A postseismic deformation model with greater coseismic slip in accordance with the most recent coseismic slip model in the literature better fits COYQ data prior to 2005 and requires greater locking increase afterwards. A model with less coseismic slip requires less locking increase but an additional long-term slow slip event prior to 2005. The rapid surface velocity change and the inferred increase in megathrust locking several decades after a great earthquake present new challenges to the understanding of fault mechanics and subduction zone dynamics.

The Petrosani basin is a large and important coal mining zone in the South Carpathians area of Romania. In recent times, most mines have been closed, but an extensive and dense network of galleries still exists. Most of the abandoned ones were not filled in with mine tailings. There is strong concern and evidence that the old galleries are collapsing and/or filling up with water, leading to significant surface deformation and potential hazards, especially for the local communities. We present an analysis of GPS data from nineteen (19) campaign sites spanning the period 2007–2012. Our results are quite consistent and show significant horizontal and vertical surface motions. The horizontal velocities range from 0 to 260 mm/year (mainly in WSW direction), while the vertical velocities range from +39 (uplift) to −263 (subsidence) mm/year. The largest motions appear to be associated with the central (oldest) sector of the mining area. The pattern of vertical motions suggests that the peripheral area is affected by slight uplift in response to the subsidence of the central sector.

Introduction Malaria is a major cause of morbidity and mortality among displaced populations in tropical zones. Bed nets are widely used to prevent malaria; however, few data are available on bed net distribution within displaced populations. Methods Mixed methods study in a single internally displaced persons (IDP) camp and neighboring community in Eastern Democratic Republic of the Congo (DRC). Qualitative data (focus group discussions, FGDs) and quantitative data (door-to-door survey and individual testing using malaria rapid diagnostic test, RDT) were collected. Results Ten FGDs were conducted with 55 individuals. Although malaria was widely recognized as a significant threat and bed nets were freely distributed in the camp, many households did not own or use them. IDPs converged on the following reasons for low bed net ownership and use: inconvenience of net installation and sale of nets to meet immediate needs such as food. One hundred households, comprised of 411 individuals, were surveyed in Birambizo. The burden of malaria was high (45/78 (58%) of children

We present new splitting measurements for SKS and SKKS phases recorded at four broadband seismic stations located within the Carpathian Arc, in the eastern part of the Transylvanian Basin. We made 75 measurements, of which 58 are nulls and 17 show clear splitting. We used two methods to estimate splitting parameters, ϕ (the fast polarization direction) and δt (the delay time between fast and slow split shear waves): minimization of energy on the horizontal component corresponding to the minimum eigenvalue of the polarization matrix, and simultaneous linearization of split waves from a suite of earthquakes recorded at a given station. We consistently observed no splitting at station IACB, in the northern part of the study area, for a range of well-recorded earthquakes at different backazimuths; we consider the station splitting to be null. Null splitting here is consistent with several possible tectonic scenarios, including downwelling of asthenospheric material as a result of the sinking Vrancea body, asthenospheric upwelling beneath Ciomadul volcano, or lack of anisotropic fabric development in the large Ciomadul magma chamber beneath the station. Fast polarized shear waves trend NW–SE at CHDM, in the Transylvanian Basin, and at PMAR, which lies at the boundary between the Transylvanian Basin and the E–W-striking Southern Carpathians; these fast directions are consistent with a regional trend in splitting ϕ azimuths over much of the Eastern Carpathians, the East European and Moesian Platforms, and the northwestern Transylvanian Basin away from the Vrancea Bend Zone. The regional NW–SE splitting trend parallels the NW-to-SE temporal migration of Neogene volcanism along the Eastern Carpathians, and is likely due to a combination of southeastward rollback of the Vrancea high velocity body and simultaneous southwestwards absolute plate motion of the thick leading edge of the East European Platform (Tornquist-Teisseyre Suture Zone), which together constrain regional mantle flow. Fast shear wave polarization, ϕ , at station COMD, at the juncture between the Vrancea Bend Zone and the Transylvanian Basin, trends NE–SW, consistent with splitting at stations VOIR and MLR in the Southern Carpathians. Splitting at these stations reflects perturbed mantle flow in the vicinity of the Vrancea body, which entails an abrupt change from NE–SW at VOIR to NNW–SSE at PMAR, consistent with redirection of mantle flow along the northwestern side of the Vrancea body. Delay times at the three stations with clear splitting vary from 0.96 to 2.73 s, indicating either the presence of an anisotropic layer ranging between ∼100 km thick beneath CHDM and 300 km beneath PMAR, or an unusually strong anisotropic fabric beneath the latter.

[1] We located continuous seismic tremor with coherent amplitude wave trains in the Chile ridge subduction region (~46.5°S) in two clusters north and south of the Chonos Archipelago, between the Chile trench and the North Patagonian fore arc. Tremor persisted from December 2004 to February 2007 (the entire period of the Chile Ridge Subduction Project temporary seismic deployment), and lasted >17 h on six occasions. Tremor in the more active southern cluster reached a maximum duration of 48 h, and we observed no more than 3 continuous days without tremor activity. The cluster locations coincide with the surface projections of subducted transform faults formed at the Chile ridge. We also detected simultaneous, colocated low-frequency microearthquakes with well-defined impulsive waves within the tremor signals distributed from the surface to 40 km depth, suggesting tremors and earthquakes are part of the same process. The periodicity of tremor duration is strongly correlated with semidiurnal, diurnal, and long-period tides, M2, N2, K1, O1, P1, and Mm (12.421 h, 12.000 h, 23.934 h, 25.819 h, 24.066 h, and 27.555 days, respectively). We found a significant correlation between tremor occurrence and Earth tides when tidal stress is calculated for the slip plane of a right-lateral strike-slip fault with strike N95°E, which is near parallel to subducted transform faults (N78°E) of the Chile ridge, indicating that the very small stresses resulting from the combination of ocean loading and solid Earth tides (~1 kPa) are sufficient to facilitate or suppress tremor production; tremors occur when shear stresses are maximum and wane or are low when shear stresses are minimum.

Surface waves, considered to be the most difficult type of coherent noise present on land seismic reflection data, carry useful information regarding S-wave velocities. The advantage of analyzing surface waves is that they are recorded using vertical component geophones but provide information that is usually obtained from seismic data recorded with three-component geophones. Nowadays, active and passive surface waves are analyzed to determine the distribution of the S-wave velocities in the near surface. One application of near-surface velocities is for determining microseismic event locations, especially for surface and shallow well geophone arrays.

In the southern Andes, the oblique convergence of the Nazca plate and the subduction of an active oceanic ridge represent two major tec- tonic features driving deformation of the forearc in the overriding continental plate, and the relative effects of these two mechanisms in the stress fi eld have been a subject of debate. North of the Chile triple junction, oblique subduction of the Nazca plate is associated with the Liquine-Ofqui fault zone, an ~1000-km-long strike-slip fault that is partitioning the stress and deformation in the forearc. South of the Chile triple junction, the Antarctic plate converges normal to the trench, and several ridge segments have been colliding with the overriding plate since 14 Ma. Proposed effects of the collision include episodes of uplift, extension, and formation of a forearc sliver. Using ambient seismic noise recorded by the Chile Ridge Subduction Project seismic network, we retrieved azimuthal anisotropy from inversion of Rayleigh wave group velocity in the 6-12 s period range, mostly sensitive to crustal depths. North of the Chile triple junction in the forearc region, our results show a fast velocity for azimuthal anisotropy oriented subparallel to the Liquine-Ofqui fault zone. South of the Chile triple junction, anisotropy is higher, and fast velocity measurements present clockwise rotation south of the subducted ridge and counterclockwise rota- tion north of the ridge. These results suggest the presence of two main domains of deformation: one with structures formed during oblique convergence of the Nazca plate north of the Chile triple junction and the other with structures formed during normal convergence of the Antarctic plate, coupled with collision of the Chile Ridge south of the Chile triple junction. Low velocities and high anisotropy over the sub- ducted Chile Ridge and slab window could be an indication of anomalously high thermal conditions, yielding a more plastic deformation compared with the north, where conditions are more cold and rigid.

We relocated the six large-magnitude (5.2 < M w < 6.2) earthquakes of the destructive, tsunamigenic Aysen seismic swarm, which occurred from 2007 January–October in Patagonian Chile. We used P and SH arrival times from near-source stations of a temporary seismic network fortuitously deployed in the area when the swarm began, and also traveltimes to stations of the permanent global networks, to locate the 2007 January 23, M w 5.2 earthquake, the first of the six large magnitude events. This earthquake's hypocentre lies at shallow depth (

SUMMARY We used cross-correlation of ambient seismic noise recorded in the Chile Triple Junction (CTJ) region to estimate interstation surface wave time-domain Green’s functions, and then inverted traveltimes to obtain crustal surface wave velocity models. Interstation distances within the Chile Ridge Subduction Project (CRSP) temporary seismic network ranged from 40 to ∼100 km. We selected 365 d, and cross-correlated and stacked 24 hr of vertical component data at 38 stations pairs, resulting in nominally 703 traveltimes along assumed-straight interstation paths. Velocities in 2-D cells of 30 km × 30 km were calculated using a linear least-squares inversion of the Rayleigh wave group velocity traveltimes. Furthermore we performed a Rayleigh wave group velocity dispersion analysis to estimate the sensitivity of different period waves at depth and to calculate a 3-D shear velocity model of the Patagonian crust. The process was applied to cross correlation pairs determined in two period bands, 5–10 s, corresponding to shallow crustal velocities down to approximately 10 km depth, and 10–20 s, for velocities down to around 20 km. Our results show that cell velocities correlate well with known geological features. We find high-crustal velocities where the Patagonian Batholith outcrops or is likely present at depth, and low velocities correlate with the active volcanic arc of the Southern Volcanic Zone and the subducted Chile ridge in Taitao peninsula, where thermal activity of hot springs is present. High velocities in the mountainous portions of the southeastern study area appear to correlate with outcropping older metamorphic units. Low velocity in the east correlate with sequences of volcaniclastic deposits.

A passive seismic survey in April 2009 had two main goals: the use of seismic interferometry to retrieve the seismic signal (reflected waves) from the background noise and to demonstrate that passive surveys can cover spatial gaps between active profiles. Seismic interferometry works well if the passive records are not affected by surface waves with high amplitudes; therefore, such records are neglected in the application of seismic interferometry.

A seismic swarm at the Aysen fjord started in January, 2007, reaching its highest activity between January and April, 2007. It was punctuated by the Mw5.3 23rd January event and the Mw6.2 21st April event which triggered a water-wave due to massive landslides; both with dextral strike slip focal mechanisms. More than 100 events were relocated with the Joint Hypocenter Determination method to study the depth distribution of the events of the swarm recorded by the Chile Ridge Subduction Project local network. The events are associated to a small area of approximately 7 × 7 km located in the Aysen fjord, on one of the main branches of the Liquine–Ofqui fault. Distribution in depth is located between 0 and 8 km and presents a west high dip with almost NS strike, consistent with the main trending of the Liquine–Ofqui fault and the published focal mechanisms. These characteristics, among others, suggest that the Liquine–Ofqui fault is active in this region and thus seismic risk has to be re-determined.

We deployed 39 broadband seismometers in southern Chile from Dec. 2004 to Feb. 2007 to determine lithosphere and upper mantle structure in the vicinity of the subducting Chile Ridge. Body-wave travel-time tomography clearly shows the existence of a long-hypothesized slab window, a gap between the subducted Nazca and Antarctic lithospheres. P-wave velocities in the slab gap are distinctly slow relative to surrounding asthenospheric mantle. Thus, the gap between slabs visible in the imaging appears to be filled by unusually warm asthenosphere, consistent with subduction of the Chile Ridge. Shear wave splitting in the Chile Ridge subduction region is very strong (mean delay time ~3 s) and highly variable. North of the slab windows, splitting fast directions are mostly trench parallel, but, in the region of the slab gap, splitting fast trends appear to fan from NW-SE trends in the north, through ENE-WSW trends toward the middle of the slab window, to NE-SW trends south of the slab window. We interpret these results as indicating flow of asthenospheric upper mantle into the slab window.

A velocity model of the upper crust (maximum depth 10-15 km) of the earthquake-prone Vrancea area (Romania) from 2D forward ray tracing of densely-spaced refraction data is presented. The model is derived from more than 11,000 travel times recorded at stations 100 m apart picked from 42 shot gathers along a 140 km line crossing the south-eastern Carpathian bending zone and the adjacent deep (foreland) Focsani Basin. The model refines basement structure beneath the south-eastern Carpathian nappe stack and Focsani Basin and documents reverse faults on which crystalline rocks or highly metamorphosed Mesozoic sedimentary cover of the crystalline basement have been elevated to depths as little as 3.5-4 km (with a vertical displacement of at least 2-2.5 km) beneath the external Carpathian nappes in the Vrancea Zone. Fault systems (flower structures) and normal faults associated with the overall tectonic subsidence of the foreland basin are also inferred. Some of the basement fault systems appear to be recently active, since they involve overlying young (Tertiary-Quaternary) sedimentary layers, and may be associated with intracrustal earthquakes recorded in the area. © 2009 Elsevier B.V. All rights reserved.

The Vrancea zone of Romania constitutes one of the most active seismic zones in Europe, where intermediate-depth (70–200 km) earthquakes of magnitude in excess of M w = 7.0 occur with relative frequency in a geographically restricted area within the 110° bend region of the southeastern Carpathian orogen. Geologically, the Vrancea zone is characterized by (a) a laterally restricted, steeply NW-dipping seismogenic volume (30 × 70 × 200 km), situated beneath (b) thickened continental crust within the highly arcuate bend region of the Carpathian orocline, and (c) miscorrelation of hypocenters with the position of known or inferred suture zones in the Carpathian orogenic system. Geologic data from petroleum exploration in the Eastern Carpathians, published palinspastic reconstructions, and reprocessing of industry seismic data from the Carpathian foreland indicate that (1) crust of continental affinity extends significantly westward beneath the external thrust nappes (Sub-Carpathian, Marginal Folds, and Tarcau) of the Eastern Carpathians, (2) Cretaceous to Miocene strata of continental affinity can be reconstructed westward to a position now occupied by the Transylvanian basin, and (3) geologic structure in the Carpathian foreland (including the Moho) is sub-horizontal directly to the east and above the Vrancea seismogenic zone. Taken together, these geologic relationships imply that the Vrancea zone occupies a region overlain by continental crust and upper mantle, and does not appear to originate from a subducted oceanic slab along the length of the Carpathian orogen. Accordingly, the Vrancea zone appears to potentially be an important place to establish evidence for active lithospheric delamination.

Results are presented from GPS measurements performed in the Southeastern Carpathians between 1997 and 2004. Data from 25 stations observed during 13 campaigns were analyzed by the Department of Earth Observation and Space Systems (DEOS) of Delft University of Technology. The repeatabilities of the solutions are on the order of 1–4 mm for the horizontal, and 4–8 mm for the vertical component. The resulting velocity estimates have an uncertainty of b1 mm/yr and b3 mm/yr, respectively. The region southeast of the Carpathian bend zone shows a horizontal movement towards SSE of ~2.5 mm/yr, while the Transylvanian Basin shows very small motions with respect to Eurasia. The vertical velocity field indicates the existence of uplift and subsidence domains in the SE Carpathians, in good agreement with Pliocene–Quaternary orogen and basin studies. Another 29 GPS stations installed in the last 3 yr will generate a denser velocity field in the coming years for this region. D 2005 Elsevier B.V. All rights reserved.

We use measurements of crustal and upper mantle seismic attenuation in the southeastern Carpathian Arc and surroundings to test mantle responses to Tethys closure in this region. Active seismicity at the Carpathians' Vrancea bend zone can delimit lithosphere and asthenosphere distributions through attenuation observations at overlying seismic stations. We measure frequency-independent attenuation via an iterative spectral ratio method which compares P and S spectra for evolving time windows of both arrivals, yielding 400 individual estimates of apparent differential QS and one composite measurement based on a normalized sum of the spectral ratios determined for the individual Q estimates. The procedure allows exclusion of subtle multipathed phases with attenuation different from that of the direct arrivals and yields a robust estimate of the measurement uncertainty. Measurements are retained for interpretation if the mean of the 400 individual Q estimates and the composite spectra Q estimate fall within the standard deviation of the 400 measurements. Results for 65 earthquakes recorded at the German–Romanian K2 accelerometer network during 1999 fall into clear groups: attenuation is low (high QS) at stations east and north of the Vrancea zone on the East European platform, the Scythian Platform, and in the eastern portion of the Moesian Platform. Inconsistent results at stations west of the Intramoesian fault, including those in and around Bucharest, probably reflect strong site effects at several locales. Attenuation at stations above and near the Vrancea zone, and at stations in the Transylvanian Basin, is high (low QS), most likely due to the presence of hot, shallow asthenosphere in these areas. The technique we developed may ultimately yield a strong test of slab detachment and continental lithosphere delamination hypotheses put forth to explain the unusual seismicity and volcanism of the Carpathian arc.

The Carpathians-Pannonian Basin system provides a natural laboratory for analysing lithospheric to surface controls on tectonic topography development in a coupled source-to-sink environment. To link processes taking place at depth and at the surface, recent research focused on the interplay between basin evolution, active tectonics, topography evolution and intraplate folding mechanisms. Neotectonic processes control landscape development and natural hazards, in particular the seismicity, during the late-stage (Late Neogene-Quaternary) evolution of both the Carpathians-Pannonian Basin system and its interaction with the adjacent Dinarides and Balkans. The deep structure of the SE Carpathians exerts a strong control on the post-collisional evolution of the system. New constraints are available from seismic tomography, deep seismic reflection and refraction profiling and detailed studies of the Vreancea seismicity. Inherited orogenic fabric and structure of the active Black Sea sink has a strong influence on the localisation of the Neogene sediment pathways. A close relationship has been established between the timing and mechanisms of stress changes in the Pannonian and Transylvania basins and structural episodes in the surrounding thrust belts, pointing to an intrinsic mechanical coupling with these basins, the orogen and its foredeep. Basin inversion taking place during the Pliocene-Quaternary times in the entire Carpathians-Pannonian system is related to changes in the regional stress field leading to differential vertical movements associated with a laterally variable folding mechanism active in the entire system. Short, crustal folding patterns alternate with lithospheric wavelengths in the SE Carpathians foreland, East and South Carpathians, Transylvania and Pannonian basins. The lateral variability is the result of a marked contrast in rheology between these areas, directly related to the crustal configuration, thermal properties and late-stage collision kinematics with the Carpathians foreland. Lateral variations in the properties of the downgoing plates largely control the collision mode in the Carpathias and the post-collisional evolution of the entire system. © 2005 Elsevier B.V. All rights reserved.

The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August-September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the experiment was to obtain new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea zone, including the Focsani Basin. The seismic reflection line had a WNW-ESE orientation, running from internal East Carpathians units, across the mountainous south-eastern Carpathians, and the foreland Focsani Basin towards the Danube Delta. There were 131 shot points along the profile, with about 1 km spacing, and data were recorded with stand-alone RefTek-125s (also known as "Texans"), supplied by the University Texas at El Paso and the PASSCAL Institute. The entire line was recorded in three deployments, using about 340 receivers in the first deployment and 640 receivers in each of the other two deployments. The resulting deep seismic reflection stacks, processed to 20 s along the entire profile and to 10 s in the eastern Focsani Basin, are presented here. The regional architecture of the latter, interpreted in the context of abundant independent constraint from exploration seismic and subsurface data, is well imaged. Image quality within and beneath the thrust belt is of much poorer quality. Nevertheless, there is good evidence to suggest that a thick (∼10 km) sedimentary basin having the structure of a graben and of indeterminate age underlies the westernmost part of the Focsani Basin, in the depth range 10-25 km. Most of the crustal depth seismicity observed in the Vrancea zone (as opposed to the more intense upper mantle seismicity) appears to be associated with this sedimentary basin. The sedimentary successions within this basin and other horizons visible further to the west, beneath the Carpathian nappes, suggest that the geometry of the Neogene and recent uplift observed in the Vrancea zone, likely coupled with contemporaneous rapid subsidence in the foreland, is detached from deeper levels of the crust at about 10 km depth. The Moho lies at a depth of about 40 km along the profile, its poor expression in the reflection stack being strengthened by independent estimates from the refraction data. Given the apparent thickness of the (meta)sedimentary supracrustal units, the crystalline crust beneath this area is quite thin (