How Volcanoes Work

 Philipp Hackert's Vesuvio


No. of Questions= 10
Pass mark is - 70 %.

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1. Basalt lava with a smooth, billowy, or ropey surface is called ________.
a) cheesy lava  
b) a'a lava  
c) mokeoweoweo lava  
d) pahoehoe lava  
e) rheomorphic lava  
2.  Pahoehoe lava can be converted to a'a lava by ________.
a) increasing the viscosity  
b) increasing the rate of shear  
c) decreasing the rate of shear  
d) (a) and (b)  
e) none of the above  
3.  A short, thick lobe of dacitic to rhyolitic lava extruding asymmetrically from a vent (photo) is called a(n) _________.
a) lava dome  
b) coulee  
c) blocky lava  
d) kipuka  
e) hornito  
4.  Andesite lava flows are generally ______ viscous and ______ than basaltic lava flows.
a) more / thicker  
b) less / thinner  
c) more / thinner  
d) less / thicker  
e) these lava types vary little in viscosity and thickness  
5.  Many basaltic lava flows display a three-tiered character based on variations in the joint (crack) pattern generated during cooling. The photo below displays the two lowermost tiers in a lava flow from Scotland. The hackly jointed tier above the "lower colonnade" is called the ___________.
a) upper colonnade  
b) pillow lava zone  
c) entablature  
d) mesozone  
e) shelly pahoehoe layer  
6.  A collapse depression above a lava tube is called a(n) __________.
a) Hawaiian hot pot  
b) spatter hole  
c) fumarole  
d) caldera  
e) skylight  
7.  Volumetrically, most lava on earth is of a(n) ________ composition.
a) basaltic  
b) andesitic  
c) rhyolitic  
d) granitic  
e) none of the above  
8.  The bulbous bodies with quenched glassy rinds in the photo below are known as ________.
a) peperites  
b) accretionary lava balls  
c) pillow basalts  
d) pahoehoe toes  
e) lava stalagmites  
9.  The abrupt quenching of basalt lava as it enters water can result in its fragmentation, which generates an accumulation of angular, glassy fragments called _________.
a) A'a lava  
b) hydromelange  
c) hyaloclastite  
d) peperite  
e) patagonian tuff  
10.  In some cases, moving lava may mix with wet sediment to produce ________, a heterogeneous deposit composed of dark basalt fragments and light-colored sediment.
a) hyaloclastite  
b) palagonite  
c) pillow basalt  
d) peperite  
e) ignimbrite  

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