620 likes | 805 Views
Volcanic processes. Volcanic processes and types. « grey » volcanoes More explosive Andesitic Subductions. « red » volcanoes Less explosive Basaltic Intra-plate. Dynamic types related to magma/water interactions Dynamic types related to dissolved bubbles
E N D
Volcanic processes and types « grey » volcanoes More explosive Andesitic Subductions « red » volcanoes Less explosive Basaltic Intra-plate
Dynamic types related to magma/water interactions • Dynamic types related to dissolved bubbles • Dynamic types related to domes growth and collapse • Dynamic types related to lava flows etc. • Destruction of volcanic edifices • Complex edifices
Magma viscosity Figure 4-1. a. Calculated viscosities of anhydrous silicate liquids at one atmosphere pressure, calculated by the method of Bottinga and Weill (1972) by Hess (1989), Origin of Igneous Rocks. Harvard University Press. b.Variation in the viscosity of basalt as it crystallizes (after Murase and McBirney, 1973), Geol. Soc. Amer. Bull., 84, 3563-3592.c. Variation in the viscosity of rhyolite at 1000oC with increasing H2O content (after Shaw, 1965, Amer. J. Sci., 263, 120-153).
Dome growth and collapse • Cortex of the dome « chills », interior still hot • Steep slopes, local collapse • Breccias • Pyroclastic flows: « block and ash flow » • Dense flow, rich in blocks • Smaller scale than plinian!!
Volcanic processes and types « grey » volcanoes More explosive Andesitic Subductions « red » volcanoes Less explosive Basaltic Intra-plate
Dynamic types related to magma/water interactions • Dynamic types related to dissolved bubbles • Dynamic types related to domes growth and collapse • Dynamic types related to lava flows etc. • Destruction of volcanic edifices • Complex edifices
Scenic volcanoes! Stromboli (Italy)
Puy de Pariou (France) (note also the pelean dome of Puy de Dome at the back)