Combining satellite and seismic images to analyse the shallow structure of the Dead Sea Transform near the DESERT transect

The left-lateral Dead Sea Transform (DST) in the Middle East is one of the largest continental strike-slip faults of the world. The southern segment of the DST in the Arava/Araba Valley between the Dead Sea and the Red Sea, called Arava/Araba Fault (AF), has been studied in detail in the multidisciplinary DESERT (DEad SEa Rift Transect) project. Based on these results, here, the interpretations of multi-spectral (ASTER) satellite images and seismic reflection studies have been combined to analyse geologic structures. Whereas satellite images reveal neotectonic activity in shallow young sediments, reflection seismic image deep faults that are possibly inactive at present. The combination of the two methods allows putting some age constraint on the activity of individual fault strands. Although the AF is clearly the main active fault segment of the southern DST, we propose that it has accommodated only a limited (up to 60 km) part of the overall 105 km of sinistral plate motion since Miocene times. There is evidence for sinistral displacement along other faults, based on geological studies, including satellite image interpretation. Furthermore, a subsurface fault is revealed ≈4 km west of the AF on two ≈E–W running seismic reflection profiles. Whereas these seismic data show a flower structure typical for strike-slip faults, on the satellite image this fault is not expressed in the post-Miocene sediments, implying that it has been inactive for the last few million years. About 1 km to the east of the AF another, now buried fault, was detected in seismic, magnetotelluric and gravity studies of DESERT. Taking together various evidences, we suggest that at the beginning of transform motion deformation occurred in a rather wide belt, possibly with the reactivation of older ≈N–S striking structures. Later, deformation became concentrated in the region of today’s Arava Valley. Till ≈5 Ma ago there might have been other, now inactive fault traces in the vicinity of the present day AF that took up lateral motion. Together with a rearrangement of plates ≈5 Ma ago, the main fault trace shifted then to the position of today’s AF.     

Absolute Calibration of an Ashtech Z12-T GPS Receiver

Dual-frequency carrier phase and code measurements from geodetic type receivers are a promising tool for frequency and time transfer. In order to use them for clock comparisons, all instrumental delays should be calibrated. We have carried out the calibration of one such receiver, an Ashtech Z12-T type, by two different methods: first, by absolute calibration using a GPS simulator; second, by differential calibration with respect to a time transfer receiver that had previously been calibrated. We present the experimental set-ups and the results of the two experiments and estimate the uncertainty budget. An ultimate uncertainty of order 1 ns in the absolute calibration seems to be attainable. ? 2001 John Wiley & Sons, Inc.     

The International GLONASS Service – Pilot Project

The International GLONASS Service – Pilot Project (IGLOS-PP), a project of the International GPS Service, was launched in order to underscore the importance and benefits of integrating data from multiple systmes and techniques within IGS products. At first this article summarizes the contributing organizations and the available infrastructure. Later on the GLONASS related modeling techniques at the involved IGS Analysis Centers are described and we conclude with some remarks concerning the advantages for the expected user commmunity. ? 2001 John Wiley & Sons, Inc.     

Evaluation and comparison of spatial interpolators

This study evaluates 15 different estimators to determine their relative merits in estimating block concentrations at contaminant waste sites. The evaluation was based on 54 subsets of data drawn from an exhaustive set of 19,800 data. For each subset, 198 block estimates were made with each estimator. The measurements of estimation quality were a linear loss function and a more standard statistic, the mean square error. The linear loss function showed that seven of the estimators produced scores close enough to be within the same statistical population. Results based on the mean square error were similar. The surprising results of this study were that inverse distance and inverse distance squared both produced better scores than kriging.     

Hydrodynamic effects in a reservoir with semicircular cross-section and absorptive bottom

A three-dimensional dam-reservoir system under seismic load is analysed. The dam is assumed to be rigid. The reservoir is an infinite channel with semi-circular cross-section. The exact analytical solution, based on the assumption of potential fluid motion is presented, as well as numerical results for selected parameters.The most significant parameters are: the direction and frequency content of the seismic input; the radiation damping at the reservoir bottom; and the compressibility of the fluid. The response of the system depends strongly on the direction of the input ground motion. This is shown by the transfer functions as well as by the pressure time histories due to two earthquakes with different frequency content. The energy absorption at the reservoir bottom is important. A simple plane-wave model shows, that even for a rock foundation, the amount of transmitted energy can reach up to 80%. For comparison the case without bottom absorption is also shown. Compressbility has to be included to capture the resonance effects. The exact analytical solution is also used to verify numerical results obtained by a new method that combines a finite element model with a rigorous radiation boundary for the infinite channel in the time domain.     

GEOMETRICAL QUALITY CONTROL IN NUCLEAR POWER STATIONS: AN APPLICATION OF HIGH PRECISION UNDERWATER PHOTOGRAMMETRY†

This paper presents all the stages involved in the procedure for the determination of the shape of a fuel assembly, which is an essential part of a nuclear power plant and can only be handled underwater. Phototriangulation is used to obtain orientation elements, taking into account light refracting surfaces. Stereomodels are then set up for analytical restitution and the shape parameters for the object can be obtained. The project is a typical example of high precision underwater photogrammetry.     

Effect of weather conditions on the incidence of Lophodermium yellow needle blight in the dwarf mountain pine in the Karkonosze and Izerskie Mountains (Poland)

The study aimed to determine, by using a statistical model, the effect of weather conditions on the incidence of Lophodermium yellow needle blight causing by new species for science- Lophodermium corconticum, in the mountain dwarf pine growing in the subalpine Karkonosze Mountains and the Izerskie Mountains(Poland). Needles showed symptoms of yellow spots, gradual discolouration and premature fall in July. The assessment of healthiness of infected mountain dwarf pine needles spanned three years(2011- 2013) and was conducted in several test sites in the Karkonosze and Izerskie Mountains. The results were analyzed by taking into account the meteorological conditions. Field observations seem to indicate that the highest infestation of mountain dwarf pine occurs in June and July, while September and October see a significantly lower disease index in the Karkonosze Mountains. The lower indices of the infestation of mountain dwarf pine are characteristic for the vegetation in the Hala Izerska high mountain pasture; whereas the environmental conditions prevailing in the Kocio? Ma?ego Stawu cirque and above the Samotnia hostel are conducive to the development of Lophodermium yellow needle blight.