南加州地壳的伴随层析成像

使用基于伴随方法的反演策略,研制出了南加州地壳的三维地震模型。该模型涉及到16次层析成像迭代,需要6800次波场模拟和总计80万个中心处理单位小时。与南加州地震中心给出的最初三维模型比较,该新的地壳模型揭示了更强的非均匀性,包括±30%的局部变化。模型说明了诸如沉积盆地和横跨断层的构造反差的浅部特征。也揭示了深部的地壳特征,从而帮助重建诸如俯冲捕获洋壳碎块的南加州构造。新模型有助于对地震危险性做出更实际而准确的评估。     

Removal of Lead,Copper, Zinc and Cadmium from Water Using Phosphate Rock

Removal of Pb^2＋, Cu^2＋, Zn^2＋ and Cd^2＋ from aqueous solutions by sorption on a natural phosphate rock （FAP） was investigated. The effects of the contact time and initial metal concentration were examined in the batch method. The percentage sorption of heavy metals from solution ranges generally between 50% and 99%. The amount of sorbed metal ions follows the order Cu〉Pb〉Cd〉Zn. Heavy metal immobilization was attributed to both surface complexation of metal ions on the surface of FAP grains and partial dissolution and precipitation of a heavy metal-containing phosphate. The very low desorption ratio of heavy metals further supports the effectiveness of FAP as an alternative and low-cost material to remove toxic Pb^2＋, Cu^2＋, Zn^2＋ and Cd^2＋ from polluted waters.     

In situ measurements of soil saturated hydraulic conductivity: Assessment of reliability through rainfall–runoff experiments

The saturated hydraulic conductivity, K_s, is a soil property that has a key role in the partitioning of rainfall into surface runoff and infiltration. The commonly used instruments and methods for in situ measurements of K_s have frequently provided conflicting results. Comparison of K_s estimates obtained by three classical devices—namely, the double ring infiltrometer (DRI), the Guelph version of the constant‐head well permeameter (GUELPH‐CHP) and the CSIRO version of the tension permeameter (CSIRO‐TP) is presented. A distinguishing feature in this study is the use of steady deep flow rates, obtained from controlled rainfall–runoff experiments, as benchmark values of K_s at local and field‐plot scales, thereby enabling an assessment of these methods in reliably reproducing repeatable values and in their capability of determining plot‐scale variation of K_s. We find that the DRI grossly overestimates K_s, the GUELPH‐CHP gives conflicting estimates of K_s with substantial overestimation in laboratory experiments and underestimation at the plot scale, whereas the CSIRO‐TP yields average K_s values with significant errors of 24% in the plot scale experiment and 66% in laboratory experiments. Although the DRI would likely yield a better estimate of the nature of variability than the GUELPH‐CHP and CSIRO‐TP, a separate calibration may be warranted to correct for the overestimation of K_s values. The reasons for such discrepancies within and between the measurement methods are not yet fully understood and serve as motivation for future work to better characterize the uncertainty associated with individual measurements of K_s using these methods and the characterization of field scale variability from multiple local measurements.     

Dynamics of particle flux and carbon export in the northwestern Mediterranean Sea: A two decade time-series study at the DYFAMED site

The DYFAMED time-series station, located in the open Ligurian Sea, is one of the few pluriannual flux programs in the world and the longest in the Mediterranean Sea. The trap data series is one of only three multi-decadal data sets in existence, and it provides flux information for an environment that is distinct from the other long-term data sets. At DYFAMED, downward fluxes of particles, carbon and other major elements have been regularly measured with sediment traps since 1986 at fixed depths of 200 and 1000 m. An overview is presented of the main trends of particle and carbon fluxes observed during the period 1988–2005, period when the mooring was located on the northern side of the Ligurian Sea. In spite of considerable interannual variability, fluxes displayed a marked seasonal pattern with the highest fluxes occurring during winter and spring and lowest fluxes throughout the stratified season (summer–autumn). Organic carbon fluxes measured at both depths were highly variable over time, ranging from 0.3 to 59.9 (mean 6.8) mg C m⁻² d⁻¹ at 200 m, and from 0.2 to 37.1 (mean 4.3) mg C m⁻² d⁻¹ at 1000 m. Mass fluxes were maximal in winter, whereas carbon fluxes were maximal in late spring. Reasonably good agreement existed between particle fluxes at both depths over the years, indicating a relatively efficient and rapid transport of particles from the upper ocean to the deep sea. However, during certain periods mass flux increased with depth suggesting lateral inputs of particles that by-pass the upper trap. Since 1999, the system has apparently shifted towards an increasing occurrence of extreme flux events in response to more vigorous mixing of the water column during the winter months. Although annual mass fluxes have increased in the last years, mean POC fluxes have not substantially changed over time, due mainly to lower carbon contents of the sinking particles during maxima of mass flux.     

Correction to: Characteristics of topographic submesoscale eddies off the Crimea coast from high-resolution satellite optical measurements

Ocean Dynamics - A Correction to this paper has been published: https: doi.org/10.1007/s10236-021-01463-y     

(137)Cs baseline levels in the Mediterranean and Black Sea: a cross-basin survey of the CIESM Mediterranean Mussel Watch programme

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.     

Strike-slip systems as the main tectonic features in the Plio-Quaternary kinematics of the Calabrian Arc

The oblique and diachronous collision of the Apennine-Maghrebian Chain with the Apulian (in the north-east) and Pelagian (in the south) continental forelands, has determined the characteristic arcuate structure of this orogen. The effects of Plio-Pleistocene deformation of the Calabrian Arc have been analysed on the basis of available reflection seismic profiles and using local time-structural maps reconstructed along the main structures. During this period, internal sectors of the Tertiary chain migrated forward on the oceanic Ionian foreland, and were cut by important strike-slip systems. These last have an orientation approximately coincident with that of the migration of the front, allowing differential movement of the different sectors of the arc, towards the weakly buoyant Ionian oceanic domain. The dataset suggests a clear connection between the development of the strike-slip systems cutting the chain and the direction of tectonic transport, towards the East during Late Messinian/Early Pliocene time, to the ESE during Late Pliocene/Early Pleistocene time, finally to the SSE during the Middle/Late Pleistocene to Present, showing a clockwise rotation in well defined stages during the kinematic evolution of the chain. The origin of the Strait of Messina during the different phases is also interpreted in the context of the analysed regional tectonic setting.