Hazards:Volcanoes Flashcards
volcanoes at constructive plate boundaries
-shield volcanoes
-basaltic lava(runny)
-
volcanoes at destructive plate boundaries
-composite volcanoes
-andesitic lava(sticky)
-explosive eruptions
how do volcanoes form at the side of rift valleys
continental plates move apart from each other and becomes thinner due to stretching.Magma rises through the crust more easily and forms volacano
what is the hotspot theory
explains how not all volcanoes form at plate boundaries
explain hotspot theory
radioactive processes in the core causes mantle to melt and magma rises via plumes >forms shield volcanoes
example of hotspots on earth
Hawaii
example of a volcano next to rift valley
Nyiragongo
how magnitude of volcanoes is measured
the volcanic explosivity index (VEI)
scale of the VEI
0-7
0 is non explosive (most frequent)
7 is explosive (least frequent)
goes up to 8 but is really rare and for supervolcanoes only
primary impacts of volcanic eruption
Lava flows
Pyroclastic flow (nuees ardentes)
volcanic gases
gases emitted
they are poisonous:
sulphur dioxide
carbon dioxide
secondary impacts of volcanic eruptions
-Lahars
-climate change
-tsunamis
-acid rain
-flooding
lahars
mudflows that are melted ice mixed with ash and can go up to high speeds of 200km/h
climate change
ash goes into atmosphere and can cause global cooling
tsunamis
eruption tends to cause earthquakes and if underground can cause tsunamis
