Variation in style of magmatism and emplacement mechanism induced by changes in basin environments and stress fields (Pannonian Basin,Central Europe)

The development of high‐resolution 3D seismic cubes has permitted recognition of variable subvolcanic features mostly located in passive continental margins. Our study area is situated in a different tectonic setting, in the extensional Pannonian Basin system (central Europe) where the lithospheric extension was associated with a wide variety of magmatic suites during the Miocene. Our primary objective is to map the buried magmatic bodies, to better understand the temporal and spatial variation in the style of magmatism and emplacement mechanism within the first order Mid‐Hungarian Fault Zone (MHFZ) along which the substantial Miocene displacement took place. The combination of seismic, borehole and log data interpretation enabled us to delineate various previously unknown subvolcanic‐volcanic features. In addition, a new approach of neural network analysis on log data was applied to detect and quantitatively characterise hydrothermal mounds that are hard to interpret solely from seismic data. The volcanic activity started in the Middle Miocene and induced the development of extrusive volcanic mounds south of the NE‐SW trending, continuous strike‐slip fault zone (Hajdú Fault Zone). In the earliest Late Miocene (11.6–9.78 Ma), the style of magmatic activity changed resulting in emplacement of intrusions and development of hydrothermal mounds. Sill emplacement occurred from south‐east to north‐west based on primary flow‐emplacement structures. The time of sill emplacement and the development of hydrothermal mounds can be bracketed by onlapped forced folds and mounds. This time coincided with the acceleration of sedimentation producing poorly consolidated, water‐saturated sediments preventing magma from flowing to the paleosurface. The change in extensional direction resulted in change in fault pattern, thus the formerly continuous basin‐bounding strike‐slip fault became segmented which could facilitate the magma flow toward the basin centre.     

Migration and Extension of Solar Active Longitudinal Zones

Solar active longitudes show a characteristic migration pattern in the Carrington coordinate system if they can be identified at all. By following this migration, the longitudinal activity distribution around the center of the band can be determined. The half-width of the distribution is found to be varying in Cycles 21?–?23, and in some time intervals it was as narrow as 20?–?30 degrees. It was more extended around a maximum but it was also narrow when the activity jumped to the opposite longitude. Flux emergence exhibited a quasi-periodic variation within the active zone with a period of about 1.3 years. The path of the active-longitude migration does not support the view that it might be associated with the 11-year solar cycle. These results were obtained for a limited time interval of a few solar cycles and, bearing in mind uncertainties of the migration-path definition, are only indicative. For the major fraction of the dataset no systematic active longitudes were found. Sporadic migration of active longitudes was identified only for Cycles 21?–?22 in the northern hemisphere and Cycle 23 in the southern hemisphere.     

Role of the solar main magnetic dipole field in the solar-tropospheric relations. Part II. Dependence on the types of solar sources

Two criteria have previously been reported for efficient solar-tropospheric relations through corpuscular channels: the appropriate Sun-Earth attitude (equinoxes) and the mutual orientations of the terrestrial and solar main magnetic dipole fields. The effect also depends on the geographical position. The present paper reports a further criterion. The solar-meteorological correlations also depend on the solar origin of the given corpuscular impact: disturbances originating from the polar and equatorial regions release opposite behaviours. We conclude that the solar-meteorological relations can only be described by taking into account the specific spatial situations and polarity distributions.     

Study of possible subsurface influences on the emerging active regions

The large-scale distribution of the orientations of emerging sunspot groups has been studied for the year 1977. It is probable that the decimations from the azimuthal directions are not entirely randomly scattered, but they can be governed also by subsurface velocity fields. If this assumption is correct, the most probable internal velocity distribution is a non-axisymmetric (columnar) giant convection pattern with a longitudinal wave number l = 11 rotating slightly slower than the Carrington system, on the basis of the given material.     

Comparison of sunspot area data bases

Sunspot area measurements play an important role in the studies of sunspot groups and variations in solar irradiance. However, the measured areas may be burdened with systematic and random errors, which may affect the results in these fields. Mainly the total solar irradiance models can be improved by using more precise area data. In order to choose the most appropriate area data for a given study or create a homogeneous composite area data base, there is a need to compare the sunspot areas provided by different observatories. In this study we statistically investigated all the available corrected sunspot area data bases for the years 1986 and 1987. We find that the photographic data bases are in good agreement with each other but there are important systematic differences between the photographic and sunspot drawings data bases. We give the characteristic parameters for the systematic and random errors as well as the possible reasons for them.     

Some Polarity Conditions in Corpuscular Events

We present some refinements of the previously reported magnetic polarity conditions in solar-terrestrial relations. Appropriately selected subsets were used from the longest available data sets, the geomagnetic aa-index and the surface air temperature. The solar corpuscular impacts have conspicuous effects in the tropospheric behaviour. We reported previously a new kind of semi-annual fluctuation and opposite tropospheric responses to the effects coming from different regions of the Sun as well as their dependence on the orientation of the solar main magnetic dipole. It is shown in the present paper that the semi-annual fluctuation governed by shock and fluctuating disturbances (which originate from the lower-latitude solar regions) exhibits sign reversals in consecutive cycles. The effect can be detected only in the absence of recurrent disturbances (coming mainly from the polar regions). This complex phenomenon implies that the corpuscular events may preserve some of their polarity conditions of their specific solar origin even at the Earth's distance, and on the other hand the small-scale structure of the IMF plays an important role in the link between the solar particles and the tropospheric response.     

Role of the solar main magnetic dipole field in the solar-tropospheric relations. Part I. Semiannual fluctuations in Europe

The influence of the solar corpuscular radiation on weather is demonstrated by characterizing the corpuscular impact by means of the geomagnetic aa-index and the terrestrial response by European temperature data. Considering different spatial and vectorial circumstances the following conclusions can be drawn: 1. the efficiency of the corpuscular impact depends on the Sun-Earth attitude (semiannual fluctuation); 2. this regularity depends on the polarity of the solar main magnetic dipole field; and 3. the whole complex of phenomena also depends on the geographic position - it exists at European middle latitudes but it does not exist in northern and southern Europe. We conclude that the periods of differently or oppositely working mechanisms should be separated in order to recognize the regularities.     

Distinction between the climatic effects of the solar corpuscular and electromagnetic radiation

We study the possibilities of the separation of solar electromagnetic and corpuscular impacts on the terrestrial lower atmosphere by examining their characteristic differences. We focus on the behaviour of the solar-meteorological correlation with respect to characteristic magnetic properties. Examples are given that the solar meteorological correlation - the efficiency of the solar impact - depends on the Sun-Earth attitude, the polarity of the solar main dipole field (and IMF) and the type of the geomagnetic events. This can explain the virtual disappearance or reversal of certain solar-meteorological effects.