Volcanic hazards Note helper
•Eruptions of magma are driven by _____ and w_____ v_________
–At depth, they are d______________ in the magma due to high p____________
–As magma rises, pressure is r____________ and g_________ are r__________
suddenly
–Gases e__________ to ________x their initial v___________
–Fluid m________ lava allow gas bubbles to e__________
–Viscous f____________ magma traps bubbles that i__________ in size and until
e________________ejected
Silica Content Viscosity Gas Content Tendency to form Volcanic landform
Composition
pyoclastics
Basaltic
low
Shield
MOR
Cinder Cones
Andesitic
(Intermediate)
Med
Composite
Rhyolite
(Felsic)
High
Pyroclastic flows
Domes
P__________________
•Volcanic rock ejected during an eruption, including
–A____
–B________
–B___________
Associated with c__________ volcanoes, c_____________s, d___________ volcanoes
Lahar: M____________s of a________ and debris on volcanic slopes.
Where: c_________________ volcanoes (active & inactive)
Due to s______________ of debris from m__________ snow due to the heat of an
erupting volcano, or heavy r________________
Flow: ____________
Nuee Ardente
•H______ molten volcanic material brought up by g________, includes a______, blocks
& p________, flows down the sides of volcano
•Where: active c___________ volcanoes
•Flow: _________, avalanche like for 100’s km
Volcanic Gases
Carbon dioxide in soil kills trees on volcano in California
Volcanic Ash
•Fine grained, travel __________’s km carried by wind
•Flows down hill in Nuee Ardentes
Phreatic eruptions
are s_______-driven explosions that occur when w________ beneath the ground or on
the surface is h_________ by magma, lava, hot rocks, or new volcanic deposits
causing an e__________ of s_________, water, a______, blocks, and b________.
P___________ Eruptions
•Increased local s___________
•B__________________ of the mountain
•I____________ in g________s being emitted (carbon dioxide, sulfur, water)