Effect of the zonal E × B plasma drift on the electron number density in the low-latitude ionospheric F region at high solar activity near the December solstice

The variations in the electron number density of the ionospheric F2 layer maximum (NmF2) under the action of the zonal plasma drift in the geomagnetic west-geomagnetic east direction perpendicularly to the electric (E) and geomagnetic (B) fields during a geomagnetically quiet period on December 7, 1989, at high solar activity have been studied based on a three-dimensional nonstationary theoretical model of electron number densities and temperatures in the ionospheric F region. Calculated and measured NmF2 values for 12 low-latitude ionospheric sounding stations have been compared. When the zonal E × B plasma drift is ignored, the NmF2 values become smaller by up to a factor of 3 under nighttime conditions in the low-latitude ionosphere. The average effect of the zonal E × B plasma drift on NmF2 in the low-latitude ionosphere is larger during winter nights than under summer nighttime conditions.     

Trace element characteristics of partial melts produced by melting of metabasalts at high pressures: Constraints on the formation condition of adakitic melts

Modern adakite, Archean tonalite-trondhjemite- granodiorite (TTG) and adakitic rocks derived from lower continental crust are high Na and Al felsic rocks and are characterized by strong heavy REE and Y de- pletion and high Sr/Y and La/Yb ratios, which sug…     

Reply to Comment by V. Vavryčuk on “Analysis of the State of Stress During the 1997 Swarm in the Western Bohemia” by A. Slancová and J. Horálek

Studia Geophysica et Geodaetica -     

Comment on Pisarenko et al., “Characterization of the Tail of the Distribution of Earthquake Magnitudes by Combining the GEV and GPD Descriptions of Extreme Value Theory”

In this short note, I comment on the research of Pisarenko et al. (Pure Appl. Geophys 171:1599–1624, 2014) regarding the extreme value theory and statistics in the case of earthquake magnitudes. The link between the generalized extreme value distribution (GEVD) as an asymptotic model for the block maxima of a random variable and the generalized Pareto distribution (GPD) as a model for the peaks over threshold (POT) of the same random variable is presented more clearly. Inappropriately, Pisarenkoet al. (Pure Appl. Geophys 171:1599–1624, 2014) have neglected to note that the approximations by GEVD and GPD work only asymptotically in most cases. This is particularly the case with truncated exponential distribution (TED), a popular distribution model for earthquake magnitudes. I explain why the classical models and methods of the extreme value theory and statistics do not work well for truncated exponential distributions. Consequently, these classical methods should be used for the estimation of the upper bound magnitude and corresponding parameters. Furthermore, I comment on various issues of statistical inference in Pisarenkoet al. and propose alternatives. I argue why GPD and GEVD would work for various types of stochastic earthquake processes in time, and not only for the homogeneous (stationary) Poisson process as assumed by Pisarenko et al. (Pure Appl. Geophys 171:1599–1624, 2014). The crucial point of earthquake magnitudes is the poor convergence of their tail distribution to the GPD, and not the earthquake process over time.     

Reply to the Discussion of “Effects of temporal resolution on hydrological model parameters and its impact on prediction of river discharge” by Littlewood et al.

Citation Wang, Y., He, B. & Takase, K. (2011) Reply to the Discussion of “Effects of temporal resolution on hydrological model parameters and its impacts on prediction of river discharge” by I. G. Littlewood, B. F. W. Croke & P. C. Young. Hydrol. Sci. J. 56(3), 525–528.     

Reply to “Comments on the paper “A crustal-upper mantle model for southeastern Sicily (Italy) from the integration of petrologic and geophysical data” by ”

We reply to the comments of Beccaluva et al. (2013) on the paper “A crustal-upper mantle model for southeastern Sicily (Italy) from the integration of petrologic and geophysical data” by Manuella et al. (2013). We entirely reject their speculative comments and strongly confirm our viewpoint on the aged oceanic nature of the lithospheric basement of southeastern Sicily and its offshore area.     

Comment on “Luminescence chronology of the Sankosh river terraces in the Assam–Buthan foothills of the Himalayas: Implications to climate and tectonics” by Quaternary Geochronology 72, 101364

In a study of which the main objective was to assess the impact of climate change and tectonics on the formation of river terraces along the Sankosh River, the eastern foreland of the Himalayas, the authors obtained geochrono-logical data using luminescence technique. Four strath river terraces (T4–T1) were distinguished within the valley bottom, and alluvial sediments from three terraces (T4, T2 and T1) were dated to the age range from 143 to 14 ka. The alluvial mantels of river terraces were then linked to the scheme of glacial-interglacial cycle. The paper, however, suffers from few inconsistent and missing information, and the assessment on the landscape evolution of the river valley is incomprehensive. The authors relied on feldspars and therefore the IRSL method was used, but “OSL ages” are discussed at the end. They state that (i) tectonics creates space for sediment accommodation and (ii) the luminescence ages flank deposition and incision phases. Despite the fact that the statements are questionable, the ways these happen are not elucidated within the paper. Due to the lack of geochronological data for T3 terrace, its formation is very enigmatic. It is even more mysterious in the light of the data for the other terraces, but the authors made no attempt to explain this riddle. However, that certain inability of reconstructing the history of T3 would shed a shadow on the robustness of the ages obtained.     

Comment on the “Analysis of the State of Stress During the 1997 Earthquake Swarm in Western Bohemia” by A. Slancová and J. Horálek (Studia geoph. et geod. 44(2000), 272–291)

Studia Geophysica et Geodaetica -