composite/strato volcanoes Flashcards
1
Q
what percentage of all earths volcanoes are strato
A
over 60
2
Q
alternating layers of
A
lava and pyroclasts
3
Q
where do they form
A
convergent plate boundaries
4
Q
shape?
A
conical but sometimes irregular
5
Q
what will causes irregular shape
A
slope failure, caldera collapse or explosive damage
6
Q
how are complex volcanoes formed
A
new cones building up
7
Q
where do viscous lavas flow
A
not past the base oft the volcano
8
Q
where will the ash flow
A
vast areas
9
Q
what is the range of silica composition
A
50-71
10
Q
what do silicic lavas form and why
A
lava domes because they are so viscous
11
Q
describe lava domes
A
steep sided and bulbous
12
Q
what leads to pyroclastic flows
A
the high gas content of silicic magmas
13
Q
what type of eruptions
A
violent
