Vibration of a thin-walled prolate dome under external water pressure

The paper reports on a theoretical and an experimental investigation carried out on a thin-walled hemi-ellipsoidal prolate dome in air and also under external water pressure. The investigation found that there was good correlation between experiment and theory. The theoretical investigation was carried out using the finite element analysis to model both the structure and the fluid. The theoretical investigation used two different programs, one of which was the giant computer program ANSYS and the other was an in-house program developed by Ross. For the shell structure, the ANSYS program used 2 different doubly curved thin-walled shell elements, while the in-house program used a simpler axisymmetric thin-walled shell element. This axisymmetric element allowed a sinusoidal variation of the displacements in the circumferential direction, thus, decreasing preparation and computational time. Agreement between the 3 different finite elements was found to be good. This was found particularly encouraging for the in-house software, as it only took a few hours to set up the computer model, and a few seconds to analyse the vessel, whereas the ANSYS software took several weeks to set up the computer model, and several minutes to analyse the shell dome. The ANSYS software, however, did have the advantage in producing excellent graphical displays in both the pre-processing and post-processing modes.     

Deglacial pattern of circulation and marine productivity in the upwelling region off central-south Chile

A high-resolution sea surface temperature and paleoproductivity reconstruction on a sedimentary record collected at 36°S off central-south Chile (GeoB 7165-1, 36°33′S, 73°40′W, 797 m water depth, core length 750 cm) indicates that paleoceanographic conditions changed abruptly between 18 and 17 ka. Comparative analysis of several cores along the Chilean continental margin (30°–41°S) suggests that the onset and the pattern of deglacial warming was not uniform off central-south Chile due to the progressive southward migration of the Southern Westerlies and local variations in upwelling. Marine productivity augmented rather abruptly at 13–14 ka, well after the oceanographic changes. We suggest that the late deglacial increase in paleoproductivity off central-south Chile reflects the onset of an active upwelling system bringing nutrient-rich, oxygen-poor Equatorial Subsurface Water to the euphotic zone, and a relatively higher nutrient load of the Antarctic Circumpolar Current. During the Last Glacial Maximum, when the Southern Westerlies were located further north, productivity off central-south Chile, in contrast to off northern Chile, was reduced due to direct onshore-blowing winds that prevented coastal upwelling and export production.     

Transfrontier macroseismic observations of the Ml = 5.4 earthquake of February 22, 2003 at Rambervillers,France

The 2003 Ml = 5.4 Rambervillers earthquake, north-east of France, is the largest seismic event recorded north of the Alps since the 1992 Ms = 5.3, I₀ = VII, Roermond earthquake, Netherlands. With a maximum macroseismic intensity of VI-VII EMS-98, the 2003 event was broadly felt to a distance of 300 km from the epicentre. It provides a unique opportunity to test and compare the different procedures used in France, Germany and Switzerland when evaluating macroseismic intensities. The main purpose of this paper is to present a common transfrontier macroseismic map based on the EMS-98 intensity scale. Maximum horizontal accelerations recorded in the area are compared to the intensity values, and we propose to use a differential technique to re-estimate the magnitude of the 1682 Remiremont, I₀ = VIII, earthquake, which occurred 40 km south of Rambervillers.     

The Late Neoproterozoic granitoid magmatism of the Pelotas Batholith, southern Brazil

Geological mapping, petrography, geochemistry, and isotope studies enable the division of the Pelotas Batholith into six granitic suites: Pinheiro Machado (PMS), Erval (ES), Viamão (VS), Encruzilhada do Sul (ESS), Cordilheira (CS), and Dom Feliciano (DFS). The rocks of the PMS show a large compositional range (granite through granodiorite to tonalite), and the suite is considered pre- to syncollisional. Other suites show restricted compositional variations (granite to granodiorite) and are late to postcollisional. In general, the suites are metaluminous to slightly peraluminous (PMS, ES, and VS) or peraluminous (CS) or have alkaline tendencies (ESS and DFS). The magmatic evolution corresponds to high-K calc-alkaline to alkaline magmatism. The suites are enriched in K, Rb, and REE compared with rocks of typical calc-alkaline series. Initial ⁸⁷Sr/⁸⁶Sr ratios vary from 0.705 to 0.716, except in the CS, where they attain values of 0.732–0.740. Sm–Nd T_DM model ages vary between 0.98 and 2.0 Ga, with initial ε_Nd values ranging from −0.3 to −10. U–Pb zircon dates of samples from PMS, VS, and ESS suggest an age between 0.63 and 0.59 Ga for magmatism. Rb–Sr dates of samples of alkaline granites from DFS present ages between 0.57 and 0.55 Ga. The main tectonic controls of the magmatism of the Pelotas Batholith are high-dip sinistral shear zones.     

Earthquakes in Switzerland and surrounding regions during 2004

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2004. During this period, 677 earthquakes and 96 quarry blasts were detected and located in the region under consideration. With 22 events with M_L≥2.5, the seismic activity in the year 2004 was close to the average over the last 30 years. As in previous years, most of the activity was concentrated in the Valais and in Graubünden. In addition, several moderate earthquakes occurred in the lower crust below the northern Alpine foreland. Unusual was that five earthquakes were sufficiently strong to cause ground shaking of intensity IV over large portions of the territory. Two were located in Switzerland (Liestal, M_L 3.8, and Brugg, M_L 4.0). The epicenters of the other three strong events were located outside Switzerland (Besan?on in the French Jura, M_L 4.8, Waldkirch in southern Germany, M_L 5.1, and Lago di Garda in northern Italy, M_L 5.3).     

Earthquakes in Switzerland and surrounding regions during 2009

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2009. During this period, 450 earthquakes and 68 quarry blasts were detected and located in the region under consideration. The three strongest events occurred about 15 km NW of Basel in southern Germany (M_L 4.2), near Wildhaus in the Toggenburg (M_L 4.0) and near Bivio in Graubünden (M_L 3.5). Although felt by the population, they were not reported to have caused any damage. With a total of 24 events with M_L ≥ 2.5, the seismic activity in the year 2009 was close to the average over the previous 34 years.     

Hierarchy of tectonic control on stratigraphic signatures: Base-level changes during the Early Permian in the Paraná Basin, southernmost Brazil

The Lower Permian sedimentary succession of the Paraná Basin in southernmost Brazil has an overall transgressive sedimentation regime, recorded by a clear retrogradation of the facies belt. However, important depositional strike-orientated variations and regional inversions occur in the sedimentation regime along the paleo-shoreline (i.e., along-strike) of the basin. At the regional scale, a huge source area was uplifted by the end of the Artinskian in the north and caused regression; the southern part of the study area increasingly was transgressed by the epicontinental sea (= regional inversion). This important tectonic overprint on the stratigraphic signature of the basin’s infill has a tectonic origin. The variable sedimentation regime along the paleo-shoreline is controlled by the structural framework of the basement, which is formed by several crustal blocks with different responses to tectonic strain induced by terrain accretion on the occidental margin of Gondwana during the Permian. Stratigraphic data indicate that during the Early Permian, there were at least two differential subsidence and uplift events, one by the end of the Sakmarian–Artinskian and another during the Late Artinskian–Kungurian.     

Holocene landscape reconstruction in the surroundings of the Temple of Pepi I at ancient Bubastis,southeastern Nile Delta (Egypt)

In ancient Egypt, lakes, canals, and other water bodies were an essential part of the sacred landscape in which temples were embedded. In recent years, geoarchaeological research at the site of the Temple of Bastet at Bubastis in the southeastern Nile Delta has proven the existence of two water canals surrounding the temple. It has now been investigated whether these canals were connected to the Temple of Pepi I (2300–2250 B.C.E.), located approximately 100 m to the west of the Temple of Bastet. To explore the Holocene landscape genesis of the Temple of Pepi I, 15 drillings and six geoelectrical profile lines were performed in the surroundings of the temple in spring 2022. The results show loamy to clayey sediments in deeper sections of all drillings with a maximum thickness of 1.70 m, indicating a marshy or swampy depositional environment. Based on the recovered sediment sequences and archaeological remains in the vicinity of the Temple of Pepi I, the marshy or swampy area existed before the Fourth Dynasty. During the Old Kingdom (ca. 2850–2180 B.C.E.), the former marshland either dried up through natural processes or was intentionally drained and filled with sediments for subsequent use for occupation. Regarding the original research question, there is as yet no evidence for a direct connection to the canals of the Temple of Bastet.