Ground-motion modelling at regional distances for earthquakes in a continental interior,I. Theory and observations

To understand the ground-motion contribution by multiple-mode surface-wave arrivals, the surface-wave theory required for predicting ground-motion time histories is discussed. The adequacy of the theory in accounting for observed earthquake ground motion is tested by comparing theoretically predicted long-period seismograms with real seismograms for two earthquakes in the central United States. The agreement between the predicted and observed maximum vertical component L_g ground velocities and accelerations in the 2- to 3-sec period range is excellent over a distance range of 100 to 2,000 km.     

Die Seismischen Grundlagen der Neuzeitlichen Erschütterungsmesstechnik bei Verkehr und in der Industrie

Резюме Для оценки опасности технических сотрясений до сих пор сушествующие шкалы неудобны. ПроизБеденые измерения (фиг. 1) находятся в соглашении с взглядом, что найболее удобной для характеристики опасности является скорость движения почвы.

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Vorgelegt bei der 1. seismologischen Konferenz der Tschechosl. Ak. d. Wiss. zu Liblice am 19. M?rz 1957.

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Anschrift: Freiberg, Nonnengasse 35, DDR.     

Do Cloud Properties in a Puerto Rican Tropical Montane Cloud Forest Depend on Occurrence of Long-Range Transported African Dust?

We investigated cloud properties of warm clouds in a tropical montane cloud forest at Pico del Este (1,051 m a.s.l.) in the northeastern part of Puerto Rico to address the question of whether cloud properties in the Caribbean could potentially be affected by African dust transported across the Atlantic Ocean. We analyzed data collected during 12 days in July 2011. Cloud droplet size spectra were measured using the FM-100 fog droplet spectrometer that measured droplet size distributions in the range from 2 to 49 µm, primarily during fog events. The droplet size spectra revealed a bimodal structure, with the first peak (D < 6 µm) being more pronounced in terms of droplet number concentrations, whereas the second peak (10 µm < D < 20 µm) was found to be the one relevant for total liquid water content (LWC) of the cloud. We identified three major clusters of characteristic droplet size spectra by means of hierarchical clustering. All clusters differed significantly from each other in droplet number concentration ( \(N_{\rm tot}\) ), effective diameter (ED), and median volume diameter (MVD). For the cluster comprising the largest droplets and the lowest droplet number concentrations, we found evidence of inhomogeneous mixing in the cloud. Contrastingly, the other two clusters revealed microphysical behavior, which could be expected under homogeneous mixing conditions. For those conditions, an increase in cloud condensation nuclei—e.g., from processed African dust transported to the site—is supposed to lead to an increased droplet concentration. In fact, one of these two clusters showed a clear shift of cloud droplet size spectra towards smaller droplet diameters. Since this cluster occurred during periods with strong evidence for the presence of long-range transported African dust, we hypothesize a link between the observed dust episodes and cloud characteristics in the Caribbean at our site, which is similar to the anthropogenic aerosol indirect effect.     

15. Morphologie und Tektonik aus den Lotungen der Deutschen Atlantischen Expedition 1925–27

Ohne Zusammenfassung     

Einige Tabeilen über die erdmagnetischen Registrierungen im Observatorium Wingst im Jahre 1942

Summary In the preceding report an extract of the observations at Wingst Observatory during the years 1942 is given, to continue the corresponding tables for 1939, 1940 and 1941, which have been published in the Annalen der Hydrographie und Maritimen Meteorologie. A copy of the registrations made during a rather heavy disturbance on March 1, 1942, is added.     

Diffusion of hydrogen through platinum membranes at high pressures and temperatures

The diffusion of hydrogen through platinum membranes has been measured at 450, 500, 550 and 600°C at 2000 bar pressure, using the hydrogen sensor technique. Ag + AgCl + 3 M HC1 was the starting solution inside the platinum tube. Hydrogen diffuses out of the platinum tube into a system containing Fe₂O₃ + Fe₃O₄ + H₂O; that is, a solution with a fixed hydrogen fugacity. After quench, the drop in f_H2 inside the platinum tube was calculated from measurements of pH and chloride molality. f_H2 is initially roughly proportional to $\text{t}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$. Diffusion constants were calculated from these data by numerical integration, and the results can be expressed by logD (cm²/sec) = ? 5489.6/T, K - 4.648.     

Vertical divergence of fogwater fluxes above a spruce forest

Two almost identical eddy covariance measurement setups were used to measure the fogwater fluxes to a forest ecosystem in the “Fichtelgebirge” mountains (Waldstein research site, 786 m a.s.l.) in Germany. During the first experiment, an intercomparison was carried out with both setups running simultaneously at the same measuring height on a meteorological tower, 12.5 m above the forest canopy. The results confirmed a close agreement of the turbulent fluxes between the two setups, and allowed to intercalibrate liquid water content (LWC) and gravitational fluxes. During the second experiment, the setups were mounted at a height of 12.5 and 3 m above the canopy, respectively. For the 22 fog events, a persistent negative flux divergence was observed with a greater downward flux at the upper level. To extrapolate the turbulent liquid water fluxes measured at height z to the canopy of height h_c, a conversion factor 1/[1+0.116(z−h_c)] was determined. For the fluxes of nonvolatile ions, no such correction is necessary since the net evaporation of the fog droplets appears to be the primary cause of the vertical flux divergence. Although the net evaporation reduces the liquid water flux reaching the canopy, it is not expected to change the absolute amount of ions dissolved in fogwater.