volcanoes Flashcards
what plate boundaries to volcanoes mainly occur at
destructive and constructive
primary impacts of volcanoes
pyroclastic flow
tephra and ash
lava flows
gases
secondary impacts of volcanoes
lahars
jokulhlaups
info about pyroclastic flow
very hot (1000d C) and travels very quickly, most hazardous when coming out sideways
info about tephra and ash
ejected material from large to fine dust objects as well as rock fragment
can lead to building roofs collapsing
info about lava flows
slow movement usually, is very viscous so causes damage to buildings
examples of gases released by volcanoes
water vapour, sulfur dioxide, hydrogen, carbon monoxide
info about lahars
volcanic mudflow which causes damage to buildings
often affected by heact rainfall and water from snow caps
factors affecting lahars
steepness, volume of material particle size
info about jokulhlaups
a glacial outburst flood which deposits water, ice and debri when a volcano lies under a glacier, causing potential deposition and erosion
what 2 factors affect strength of volcanoes
viscosity of lava (more viscous + more explosive)
how easily gases are able to escape from the lava
how are volcanoes measured
VEI combining magnitude and intensity
score from 0-8
how can volcanoes be predicted
tectonic activity
changes in air gas composition
temperature changes/ steaming at volcano
difference between basaltic lava and andesilic/rhyoltic lavs
basaltic is hotter, contains less silica so is less viscous and has more frequent eruptions SO may be less explosive
