The AA. report how a pioneer liverwort, Nardia succulenta, stimulates accretion of volcanic ash, creating layers adhering to vertical bare cliffs and bridging fresh volcanic boulders, as well as creating habits that probably favour the liverworts
The relationship of large volcanic eruption in the world and the summer drought/flood in China
China ; Drought ; Flood ; Precipitation ; Sichuan ; Statistics ; Summer ; Temperature ; Volcanic eruption ; Weather type
Based on data in the last 500 years for strong volcanic activity and the summer drought/flood types available in China, the statistical relations of the volcanic eruptions in seasons and several regions and the drought/flood types and grade index
of main regions in China have been investigated. The possible teleconnection between flood in the Yangtze River and the Haihe River valleys in 1991 and the volcanic eruption of Mt Pinatubo in June of 1991 has been also examined.
The aim of this paper is to evaluate the effect of volcanic events on glaciations on the Tateyama Volcano during the last glacial period. For this purpose, this paper describes the distribution and stratigraphic relationships of the volcanic ejecta
The present paper focuses on the relationships between Pliocene volcanic activity and geomorphological evolution of Sinis region (western Sardinia, Italy). Plio-Pleistocene volcanic activity plays a key role in the recent landscape evolution
. Morphological evolution has been reconstructed on the basis of chronological data obtained on different volcanic episodes. - (NF)
Volcanic ejecta largely contributed to landscape building also very far from volcanic areas, providing substratum for soil genesis. The AA. studied the role of pyroclastics as soil forming factor on the carbonate relieves in the Partenio Mountain
Holocene yardangs in volcanic terrains in the southern Andes, Argentina
Aeolian features ; Andes ; Argentina ; Arid area ; Basalt ; Holocene ; Mountain ; Semi-arid area ; Volcanic ash ; Wind erosion
The aim of this paper is to report on yardangs in the Payun Matru Volcanic Field, a semiarid area east of the southern Andes mountains, and to analyse the geomorphic fators for their formation, and their relationship to the upper Pleistocene
and Holocene lava flow events in the area. The yardang development is explained by the strong unidirectional winds, the poor vegetational cover due to the aridity of the region, the available quartz sand and volcanic ash particles as abrasive agents
, and the volcanic lithology texture and flow structure.
Cet ouvrage présente la beauté diabolique des volcans avec 200 magnifiques photos en couleurs, qui révèlent la force destructrice des volcans, mais aussi la fascination qu'ils exercent sur les hommes. Le texte est clair, vivant et bien documenté. Il
The AA. present the geological and volcanic setting of the Misti volcano which encompasses 2 edifices : the old Misti stratovolcano and the young Misti stratocone. They analyze the stratigraphy and the chronology of its eruptive activity
, in particular over the past 100,000 years : 7 compound groups of deposits record the late Pleistocene eruptive of the modern Misti stratocone. Then, they aim to assess the volcanic hazards of future eruptions at Misti, based on mapping, recent eruptive deposits
, and models used on similar stratovolcanoes : 700,000 people in the Arequipa-Chiguata region are threatened by at least 4 types of volcanic hazards.
Douze édifices volcaniques ont été inventoriés dans la région du dôme des Tharsis. Alba Patera (1 400 km de diamètre) n'a pas d'équivalent sur terre. Olympus Mons et les trois Tharsis sont des volcans géants qui culminent tous les quatre à 27 km
. L'existence de ces volcans géants s'explique par l'absence sur Mars d'une tectonique des plaques et la fixité des points chauds. Ils possèdent des caractères propres, que l'on peut attribuer au gigantisme des chambres à magma. 7 volcans de plus petite taille
Le Vésuve est le premier volcan qui ait fait l'objet d'une reconnaissance topographique et altimétrique précise. Suite à cette considération, l'A. présente de façon minutieuse les premiers travaux sur la représentation scientifique du volcan. - (MR)
Detailed heavy-minerals analysis allowed to discover the influence of two volcanic Eifel eruptions. Green acicular augite grains are typical for the early Rissian Caberg-Pietersem and end Rissian Eisden-Lanklaar Meuse terraces. - (L'A.).
Soil variation with altitude on Volcan Barva, Costa Rica
Altitude ; Barva volcan ; Costa Rica ; Géographie physique ; Montagne ; Propriété du sol ; Pédologie ; Sol ; Zonation altitudinale ; Zone intertropicale
The AA. examine the hypothesis that soil chemical properties other than nitrogen supply partly explain the altitudinal changes in the rain forest. They also compare the soils on Volcan Barva with those on several other tropical mountains to see
Based on observations, the A. concluded that the possible continuation of the volcanic activity in the Carpathian-Pannonian region is not just a pure speculation, but is supported by scientific data. Thus, detailed, integrated researches
on the possible future volcanism are crucial. - (AM)
Several occurrences of metamorphosed pre-Hercynian volcanic rocks crop out in the Paleozoic basement of Southern Sulcis (SW Sardinia), hosted in Cambrian-Early carboniferous sedimentary sequences belonging to two different structural units. - (NF)
Geomorphology of South Atlantic Volcanic Islands. Part I: the Tristan da Cunha group
Atlantique ; Atlantique, sud ; Côte volcanique ; Géographie physique ; Géomorphologie ; Géomorphologie littorale ; Ile ; Ile volcanique ; Littoral ; Tristan da Cunha ; Volcan ; Volcanisme
Volcanoes of the Tristan Group have varied physiography resulting from the interplay of repeated volcanic eruptions, coastal erosion and fluvial erosion. The geomorphic histories of the islands are more complicated than was described in earlier
Submarine slides on volcanic islands - a source for mega-tsunamis in the Quaternary
Coastal geomorphology ; Island ; Mass movement ; Natural hazards ; Quaternary ; Sea floor ; Tsunami ; Volcanism
This paper overviews the distribution, magnitude, recurrence interval, and age of large submarine slides on volcanic islands and their potential for the generation of mega-tsunamis during the Quaternary. This paper also discusses the geomorphic
Comparative geochemistry of volcanics from rift valleys, transform faults and aseismic ridges
It is suggested that transform faults have, by faulting, exposed more fractioned types of basaltic rocks (may be as intrusives) than the rift valley volcanics. While aseismic ridges have undergone a greater degree of differentiation than both