 |
| Titel |
Landslides density map of S. Miguel Island, Azores archipelago |
| VerfasserIn |
P. Valadão, J. L. Gaspar, G. Queiroz, T. Ferreira |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1561-8633
|
| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 2, no. 1/2 ; Nr. 2, no. 1/2, S.51-56 |
| Datensatznummer |
250000265
|
| Publikation (Nr.) |
 copernicus.org/nhess-2-51-2002.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Azores
archipelago is located in the Atlantic Ocean and is composed of nine
volcanic islands. S. Miguel, the largest one, is formed by three active,
E-W trending, trachytic central volcanoes with caldera (Sete Cidades, Fogo
and Furnas). Chains of basaltic cinder cones link those major volcanic
structures. An inactive trachytic central volcano (Povoação) and an old
basaltic volcanic complex (Nordeste) comprise the easternmost part of the
island. Since the settlement of the island early in the 15th century,
several destructive landslides triggered by catastrophic rainfall
episodes, earthquakes and volcanic eruptions occurred in different areas
of S. Miguel. One unique event killed thousands of people in 1522. Houses
and bridges were destroyed, roads were cut, communications, water and
energy supply systems became frequently disrupted and areas of fertile
land were often buried by mud. Based on (1) historical documents, (2)
aerial photographs and (3) field observations, landslide sites were
plotted on a topographic map, in order to establish a landslide density
map for the island. Data obtained showed that landslide hazard is higher
on (1) the main central volcanoes where the thickness of unconsolidated
pyroclastic deposits is considerable high and (2) the old basaltic
volcanic complex, marked by deep gullies developed on thick sequences of
lava flows. In these areas, caldera walls, fault scarps, steep valley
margins and sea cliffs are potentially hazardous. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|