The relation between the heat flow field and the distribution ofP n -wave velocities for the European continent

Summary The dependence of P_n-wave velocities on the heat flow, temperature at the crustmantle boundary and the thickness of the Earth's crust in Europe was investigated in relation to the problem of lateral inhomogeneities in the upper mantle. A map was constructed of the distribution of P_n-wave velocities on the territory of Europe. The relations these investigations yielded, were compared with the results of laboratory experiments and all the results are discussed from the physical point of view. The conclusion drawn is that that temperature and pressure effect provide a sufficient explanation of the observed regional changes of P_n-wave velocities for the European continent.

---

auum ¶rt;auu mu n¶rt; ¶rt; nmu uua (P_n) u mn nm, mnam a nmu amuu u m a mumuu n a u¶rt;aa u numa ¶rt;¶rt;m amuu. mumuu n a maa a uu m P_n- a nmu uua. u¶rt;u umam ¶rt;a mama aam u¶rt;au uuu m n¶rt; amuu u u ¶rt;au u mnam mmmm mama n¶rt;aa am. ¶rt;a ¶rt;, m ua uu m P_n- a n mum ¶rt;mam um uuu mnam u ¶rt;au a nmu uua.

     

Die Ersatzkugel in geodätischen Berechnungen

Summary For precise geodetic computations over larger distances the reference surface of an ellipsoid of rotation should be used. However it is often replaced by a sphere of an adequate radius. The formulae are derived from figures which usually represent the conditions in a cross-section of the ellipsoid and the reference sphere through the normal plane. Equation (9) is given for the differences s of the length of the ellipse arc of the normal section and the corresponding arc of the circle with radius R. Also Eq. (19) is given for the distance d between the ellipse of the normal section and the circle (at the end point). Both equations are applied for various radii of the reference sphere. Table 1 shows the values s, Tab. 2 and Fig. 2 give the d-values for chosen lengths. It was found that especially the distance between the ellipsoid and the sphere need not always be negligible.     

On the problem of frequency calibration of induction variometers with large air-core loops

Zusammenfassung Es wird eine Methode für experimentelle Untersuchung der Frequenzkennlinien von Induktionsvariometern mit Aufnahmeschleifen nichttraditioneller Ausmasse beschrieben. Die Grundlage des beschriebenen Verfahrens bildet eine genaue Bestimmung jenes Teils des magnetischen Kraftflusses, der durch die Aufnahmeschleife durchgeht.     

Water Availability of Sub-Basins with Restrictions on Use under Climate Change Scenarios in Brazil

Water Resources - The Queima Pé Stream Basin (QPSB) and Ararão River Basin (ARB) in central Brazil have had recurrent problems with water scarcity. This may get worse under anthropogenic...     

The active layer in gravel-bed rivers: An empirical appraisal

The vertical position of the streambed–water boundary fluctuates during the course of sediment transport episodes, due to particle entrainment/deposition and bedform migration, amongst other hydraulic and bedload mechanisms. These vertical oscillations define a topmost stratum of the streambed (i.e. the ‘active layer or active depth’), which usually represents the main source of particles entrained during long and high-magnitude bedload transport episodes. The vertical extent of this layer is hence a capital parameter for the quantification of bedload volumes and a major driver of stream ecology in gravel-bed rivers. However, knowledge on how the active depth scales to flow strength and the nature of the different controls on the relation between the flow strength and the active depth is still scarce. In this paper we present a meta-analysis over active depth data coming from ~130 transport episodes extracted from a series of published field studies. We also incorporate our own field data for the rivers Ebro and Muga (unpublished), both in the Iberian Peninsula. We explore the database searching for the influence of flow strength, grain size, streambed mobility and channel morphology on the vertical extent of the active layer. A multivariate statistical analysis (stepwise multiple regression) confirms that the set of selected variables explains a significant amount of variance in the compiled variables. The analysis shows a positive scaling between active depth and flow strength. We have also identified some links between the active depth and particle travel distances. However, these relations are also largely modulated by other fluvial drivers, such as the grain size of the bed surface and the dominant channel macro-bedforms, with remarkable differences between plane-bed, step-pool and riffle-pool channels. © 2020 John Wiley & Sons, Ltd.     

Analysis of the weightiness of site effects on reinforced concrete (RC) building seismic behaviour: The Adra town example (SE Spain)

The damage distribution in Adra town (south‐eastern Spain) during the 1993 and 1994 Adra earthquakes (5.0 magnitude), that reached a maximum intensity degree of VII (European Macroseismic Scale (EMS scale)), was concentrated mainly in the south‐east zone of the town and the most relevant damage occurred in reinforced concrete (RC) buildings with four or five storeys. In order to evaluate the influence of ground condition on RC building behaviour, geological, geomorphological and geophysical surveys were carried out, and a detailed map of ground surface structure was obtained. Short‐period microtremor observations were performed in 160 sites on a 100m × 100m dimension grid and Nakamura's method was applied in order to determine a distribution map of soil predominant periods. Shorter predominant periods (0.1–0.3 s) were found in mountainous and neighbouring zones and larger periods (greater than 0.5 s) in thicker Holocene alluvial fans. A relationship T = (0.049 ± 0.001)N, where T is the natural period of swaying motion and N is the number of storeys, has been empirically obtained by using microtremor measurements at the top of 38 RC buildings (ranging from 2 to 9 storeys). 1‐D simulation of strong motion on different soil conditions and for several typical RC buildings were computed, using the acceleration record in Adra town of the 1993 earthquake. It is noteworthy that all the aforementioned results show the influence of site effects in the degree and distribution of observed building damage. Copyright © 2007 John Wiley & Sons, Ltd.