Segmentation and kinematics of the North America‐Caribbean plate boundary offshore Hispaniola

We explored the submarine portions of the Enriquillo–Plantain Garden Fault zone (EPGFZ) and the Septentrional–Oriente Fault zone (SOFZ) along the Northern Caribbean plate boundary using high‐resolution multibeam echo‐sounding and shallow seismic reflection. The bathymetric data shed light on poorly documented or previously unknown submarine fault zones running over 200 km between Haiti and Jamaica (EPGFZ) and 300 km between the Dominican Republic and Cuba (SOFZ). The primary plate‐boundary structures are a series of strike‐slip fault segments associated with pressure ridges, restraining bends, step overs and dogleg offsets indicating very active tectonics. Several distinct segments 50–100 km long cut across pre‐existing structures inherited from former tectonic regimes or bypass recent morphologies formed under the current strike‐slip regime. Along the most recent trace of the SOFZ, we measured a strike‐slip offset of 16.5 km, which indicates steady activity for the past ~1.8 Ma if its current GPS‐derived motion of 9.8 ± 2 mm a^?1 has remained stable during the entire Quaternary.     

Mauer – the type site of Homo heidelbergensis: palaeoenvironment and age

The mandible of Homo heidelbergensis was found 1907 in the sand pit Grafenrain at Mauer in coarse fluvial sands 24 m below the surface, deposited in a former course of the Neckar River. These ‘Mauer sands’ are overlain by a series of glacial-climate loess deposits with intercalated interglacial palaeosols, which can be correlated with Quaternary climate history, thus indicating an early Middle Pleistocene age for H. heidelbergensis. The ‘Mauer sands’ are famous for their rather rich mammal fauna, which clearly indicates interglacial climate conditions. The faunal evidence – in particular the micromammals – place the ‘Mauer sands’ into MIS 15 or MIS 13 although most stratigraphic arguments favour correlation to MIS 15 and therefore to an age of ca 600 ka.     

Tectonic significance of Triassic mafic rocks in the June Complex,Sanandaj–Sirjan zone,Iran

This study concentrates on the petrological and geochemical investigation of mafic rocks embedded within the voluminous Triassic June Complex of the central Sanandaj–Sirjan zone (Iran), which are crucial to reconstruct the geodynamics of the Neotethyan passive margin. The Triassic mafic rocks are alkaline to sub-alkaline basalts, containing 43.36–49.09 wt% SiO₂, 5.19–20.61 wt% MgO and 0.66–4.59 wt% total alkalis. Based on MgO concentrations, the mafic rocks fall into two groups: cumulates (Mg# = 51.61–58.94) and isotropic basaltic liquids (Mg# = 24.54–42.66). In all samples, the chondrite-normalized REE patterns show enrichment of light REEs with variable (La/Yb)_N ratios ranging from 2.48 to 9.00, which confirm their amalgamated OIB-like and E-MORB-like signatures. Enrichment in large-ion lithophile elements and depletion in high field strength elements (HFSE) relative to the primitive mantle further support this interpretation. No samples point to crustal contamination, all having undergone fractionation of olivine + clinopyroxene + plagioclase. Nevertheless, elemental data suggest that the substantial variations in (La/Sm)_PM and Zr/Nb ratios can be explained by variable degrees of partial melting rather than fractional crystallization from a common parental magma. The high (Nb/Yb)_PM ratio in the alkaline mafic rocks points to the mixing of magmas from enriched and depleted mantle sources. Abundant OIB alkaline basalts and rare E-MORB appear to be linked to the drifting stage on the northern passive margin of the Neotethys Ocean.     

Integration of stress testing with graph theory to assess the resilience of urban road networks under seismic hazards

Transportation networks daily provide accessibility and crucial services to societies. However, they must also maintain an acceptable level of service to critical infrastructures in the case of disruptions, especially during natural disasters. We have developed a method for assessing the resilience of transportation network topology when exposed to environmental hazards. This approach integrates graph theory with stress testing methodology and involves five basic steps: (1) establishment of a scenario set that covers a range of seismic damage potential in the network, (2) assessment of resilience using various graph-based metrics, (3) topology-based simulations, (4) evaluation of changes in graph-based metrics, and (5) examination of resilience in terms of spatial distribution of critical nodes and the entire network topology. Our case study was from the city of Kathmandu in Nepal, where the earthquake on April 25, 2015, followed by a major aftershock on May 12, 2015, led to numerous casualties and caused significant damage. Therefore, it is a good example for demonstrating and validating the developed methodology. The results presented here indicate that the proposed approach is quite efficient and accurate in assisting stakeholders when evaluating the resilience of transportation networks based on their topology.     

On the period changes of RR Lyrae variables in the globular cluster M3

O – C diagrams of 78 RR Lyrae variables of the years 1963 to 1978 were used to investigate their comparability with the diagrams of 1895 to 1963. Only 5% have been proved to show a fundamentally deviating trend of the period change.     

The Black Forest Observatory, Schiltach

The purpose of the geoscientific Observatory at Schiltach in the Black Forest in SW-Germany is to measure and monitor motions and deformations of the earth in a frequency band as broad as possible. The spectrum of geodynamic signal contains

• - the short period waves (up to 40 Hz) of near earthquakes,

• - the longer period body and surface waves from teleseismic events,

• - the free oscillations of the earth excited by giant earthquakes,

• - the earth tide deformations caused by the gravitational forces of the moon and the sun having periods of 12 h and longer,

• - deformations of the earth in a wide period range from other sources (e.g. atmosphere).

Besides providing high quality data with some continuity using ‘standard’ sensors, the observatory must be considered as an experimental station and research facility where new instruments and techniques can be tested.     

Polish forest ecosystems: The influence of changes in the economic system on the carbon balance

In order to study the effects of a change in the economic system on carbon balance at a national scale, a balance of the carbon influx and effluxes was prepared for forest ecosystems in Poland for 1988, and was repeated for 1990. The year 1988 was the first year of drastic economic changes (and severe crises) in Poland. Two entirely different approaches were used to estimate the carbon influx into a forest ecosystem. The forest inventory approach was based on data from conventional measurements of merchantable timber in forests, whereas the carbon flux and allocation approach was based on the estimate of net photosynthetic productivity of forest ecosystems to calculate the carbon influx. Results from both approaches were within the range 1.17 to 5.77t C/ha/yr which most likely defined lower and upper limits for the carbon influx into forest ecosystems in Poland. On the national scale, the carbon influx into Polish forest ecosystems was estimated by the forest inventory approach to be about 12.8 Mt C/yr. This result was similar for both years. Efflux of carbon from Polish forest ecosystems resulted almost entirely from the decay of logging residues. The efflux in 1990 (3.82 Mt C/yr) was about 26% lower than that in 1988. Storage of the carbon in Polish forest ecosystems (including an estimate of the carbon pool in forest soils) was 1.8% greater in 1990 (2518 Mt C) than in 1988, when it equalled 2473 Mt C.     

Possible influences of solar radiation variations on the atmospheric circulation in the northern hemisphere of the earth

The strength of the circumpolar zonal circulation of the atmosphere in the northern hemisphere, expressed by an index calculated from the air pressure gradient between 35° N and 65°N, shows a remarkable secular change in this century in the years 1935 to 1938, and probably again in the years after 1970. A contemporary change and parallel course with a high positive correlation can be found in a solar radiation index calculated by means of sunspot numbers and solar faculae areas. A good correlation was also found between this solar radiation index and a series of UV measurements on Mt. Wilson. The possible mechanism of action in the atmosphere will be discussed, and it is shown that this solar radiation index is also correlated with circulation parameters in the troposphere and stratosphere over Europe. There are indications of a decrease of the action from the upper to the lower atmosphere. The consequences of this secular change of circulation for the climatic history in the 20th century in Europe are presented and from that a hypothetical retrospective view of the European climatic history before the 20th century, based on the total series of sunspot numbers, is briefly discussed. In a general view with smoothed data it can be concluded that the sun seems to determine the basic structure of the north hemispheric circulation in middle latitudes, if a strong influence of sunspots and solar faculae on the solar radiation is assumed.