ERTH 2415 Lecture : Lecture Notes 16 Volcanoes .doc
11 Apr 2012
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Document Summary
Helens, washington - composite cone or stratovolcano , material blown in the air eruptions: calderas: example: aniakchak caldera alaska: collapsed of an existing volcanoes due to eruption and evacuation of magma reservoir. Shield volcanoes: 3 hazards: lava flows, gas emissions, faults, earthquakes, tsunamis. The big island: 3 active volcanoes, 1 dormant volcano, 1 extinct volcano, kilauea volcano, typical eruption, halemaumau, an atypical explosive eruption, halemaumau, 1924; lava lake level dropped, al- lowed groundwater into lake, now: first explosive eruption since 1924. La palma, canary islands: 1949 eruption opened 2 km-long fracture along cumbre vieja, west side slumped few metres towards sea, cinder cones, craters of the moon, idaho, lava flows cinder bombs blocks. Pyroclastic flow: fast moving cloud of hot gas, ash, magma (pumice) and rock frag- ments. Pelee destroys village of st. pierre, martinique; 29, Eruption clouds: ash pumice blown into air, eventually falls to ground: 1991: mt.
