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Haldoupis et al. (1982), Uspensky et al. (1983) and Starkov et al. (1983) have recently found that the 140 MHz backscatter amplitude in the auroral ionosphere depends mainly on the mean electron density (height-integrated conductivity) in the E–layer. A similar relationship for the 46 MHz band was also found by Leinonen et al. (in press, 1983). In principle, this can be explained by only a slight dependence of the relative level of E-region drift turbulence < (∆N/ N)2 > in the auroral ionosphere on ionospheric parameters, viz. electric field and mean electron density. However, up to now, quantitative evidence for such a backscatter amplitude — electron density relationship is restricted to the few events which have so far been analyzed. Therefore, the aim of this short note is to add some more data to that data set. Furthermore, we will compare measurements made in the evening and morning sectors, where the conditions for irregularity excitation might be different.
ARK: https://n2t.net/ark:/88439/y063050
Permalink: https://geophysicsjournal.com/article/196
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The heat flow pattern of the Bohemian Massif is presented by the compilation of 47 heat flow values. The isolines of the geothermal activity were constructed using also data in the neighbouring countries. A clear relationship between heat flow and the tectonic structure can be observed, higher geothermal activity corresponds to the zones of the weakened Earth's crust coinciding with two major deep faulted zones bordering the most rigid central part of the whole massif.
ARK: https://n2t.net/ark:/88439/y053881
Permalink: https://geophysicsjournal.com/article/195
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The anhysteretic remanent magnetization (ARM) and hysteresis parameters of synthetic, small, multidomain particles (0.2–0.4 μ) of Fe3O4 , dispersed at various concentrations in a non magnetic matrix (packing factors p = 0.01–0.3), have been measured. The coercive force Hc is weakly dependent on p. At higher concentrations the shape of the sample has a strong influence on the magnetization. There appears to be an additional concentration dependence of the ARM. However, the independence of partial ARMs also holds for larger p.
ARK: https://n2t.net/ark:/88439/y043772
Permalink: https://geophysicsjournal.com/article/194
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A small part of the tidal forcing field whose contribution is omitted in the conventional spherical harmonic development of the tidal potential is caused by the flattening of the Earth. It is a homogeneous tidal field of magnitude of about 1 ngal superposed on the commonly known tidal forcing field. The conventional tidal forcing field can be completely described by the spatial variation of the gravity field of the tide-generating body within the space occupied by the Earth. The advantage of this description is that any reference to the Earth's motion with respect to the tide-generating body (called revolution without rotation) can be avoided.
ARK: https://n2t.net/ark:/88439/y033803
Permalink: https://geophysicsjournal.com/article/193
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In 1973, 1974 and 1975 three palaeomagnetic sampling trips were made in Central Iran including the Lut Block for a determination of the polar wander path of Central Iran. This area is believed to be a fragment of Gondwanaland according to paleogeographic evidence and evidence from reconstruction of the Indian Ocean compiled by Forster (1974, 1975) and also according to various geological aspects summarized by Stocklin (1974).
ARK: https://n2t.net/ark:/88439/y024314
Permalink: https://geophysicsjournal.com/article/192
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The presented crustal section under the Ionian Sea is the result of refractional seismic work on two cruises of the research ship "Meteor" in 1969 und 1971 under the coordination of Prof. Closs, and of three seismic stations on the Peloponnes near the coast in 1971. In that year 25 seismic land stations and four sono buoy sea stations have recorded explosions at sea on a profile line which crossed the Mediterranean Ridge, the Hellenic Trench, and the Peloponnes, and ended in the East near Agina.
ARK: https://n2t.net/ark:/88439/y014115
Permalink: https://geophysicsjournal.com/article/191
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A number of the largest earthquakes from the Swabian Alb recorded at the Grafenberg array have been examined (the geographic coordinates of the main station GRF are 49.69°N and 11.22°E; see Harjes and Seidl (1978) for a description of the array). It has been shown that the GRF records of some of the largest Swabian Alb earthquakes have a clear additional arrival between Pn and Pg.
ARK: https://n2t.net/ark:/88439/y003616
Permalink: https://geophysicsjournal.com/article/190
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Radar aurora amplitudes have been correlated with mean electron density measurements by means of ionosondes during two geophysically widely different events. A similar, roughly linear relationship was found between the two quantities in both cases. On the other hand, the amplitude seems to be almost independent of the ambient electric field, once it is well above the instability threshold.
ARK: https://n2t.net/ark:/88439/y093977
Permalink: https://geophysicsjournal.com/article/189
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The generation of short high frequency electromagnetic pulses in the VHF-band opens up the possibility of applying electromagnetic reflection methods in the geophysical prospecting of dry formations, with high resolution and also over small distances. A method has been developed using a spark transmitter for locating boundaries in salt deposits The transmitter, which is technically very simple in contrast to other pulse transmitters, produces short powerful pulses. The results to date show good quality reflections of salt clay and anhydrite.
ARK: https://n2t.net/ark:/88439/y082408
Permalink: https://geophysicsjournal.com/article/188
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Observations of teleseismic P wave residuals for 56 stations in the vicinity of the Rhenish Massif show that arrivals within the Massif may be up to 0.6 s later than those immediately outside. Stations within the Massif also tend to have delays which are strongly azimuthally dependent (up to 1 s variation) in marked contrast to those outside (maximum 0.3 s variation). The strongest variation and delays are associated with the area of the Massif west of the Rhine, and preliminary modelling suggests they are caused by a low velocity region in the uppermost mantle (ca. 50–150 km depth) centred beneath the West Eifel volcanic field. Delays of up to 0.8 s, but with little azimuthal variation, are also found within the Vogelsberg volcanics, and are attributed to a shallower (≲60 km) low velocity region.
ARK: https://n2t.net/ark:/88439/y073559
Permalink: https://geophysicsjournal.com/article/187
