A càrrec de August Gudmundsson (Department of Earth Sciences, Royal Holloway University of London, Regne Unit)
SEMINARIS DE LA FACULTAT DE GEOLOGIA I L'INSTITUT DE CIÈNCIES DE LA TERRA JAUME ALMERA

Universitat de Barcelona (UB)
Consell Superior d'Investigacions Científiques (CSIC)

Dia: dimecres, 9 de desembre
Hora: 12.00 h
Lloc: sala de juntes de la Facultat de Geologia

Resum: Many composite edifices have slopes of up to 35-42° and stand 2-4 km above their surroundings; some maintain their ideal upward-concave form for 103-4 years. Many composite edifices erupt only once every 103-4 years. By contrast, many basaltic edifices (large shield volcanoes) have slopes of 2-12°, erupt once every few years, and are frequently subject to lateral and vertical collapses. In comparison with a typical basaltic edifice, a typical composite edifice is infrequently subject to large-scale fracture-failure, as exemplified by dyke-fed eruptions, large landslides, and caldera collapses. So, why is it easier to propagate a large-scale fracture in a basaltic edifice than in a composite edifice? To answer this question, I focus on three related topics: (1) fracture initiation and propagation, (2) internal structure, and (3) elastic mismatch between the layers that constitute the volcanic edifices.