Section 13-2 Review Page #330:1-9

#1 Summarize the difference between mafic and felsic magma. Mafic Magma magnesium & iron dark less viscous Felsic Magma silica & feldspars light more viscous

#2 Explain how the composition of magma affects the force of volcanic eruptions. More viscous magma traps gases more easily than less viscous magma, which may lead to more explosive eruptions.

#3 Compare three major types of lava flows. Pahoehoe – ropy Aa – jagged Blocky Lava – large chunks

Pahoehoe

Aa

#4 Define pyroclastic material, and list three examples. Pyroclastic material consists of fragments of rock that form during an explosive eruption.

Pyroclastic Material volcanic ash/dust volcanic bombs lapilli

Volcanic Ash

Bomb

#5 Identify the three main types of volcanic cones. shield volcano cinder cones composite volcano

Types of Volcanoes

Shield Volcano Mauna Loa - Hawaii

Cinder Cone http://video.google.com/videoplay?docid=5804326697533034741&q=cinder+cone+eruption&hl=en

Composite Volcano http://video.google.com/videoplay?docid=3977416382972126736&q=mt+st+helens+eruption&hl=en

#6 Describe how calderas form. A caldera forms when the magma chamber of a volcano empties, causing the volcanic cone to collapse in upon it, or when magma is ejected violently and the cone is destroyed.

Caldera

Crater Lake

#7 List three events that may precede a volcanic eruption. earthquake activity rock temperatures increase volcano area bulges

#8 Would quiet eruptions or explosive eruptions be more likely to increase the steepness of a volcanic cone? Explain your answer. Explosive eruption are more likely to increase volcano height, because the pyroclastic materials rise upward and fall close to the volcanic vent.

#9 Why would a sudden increase of earthquake activity around a volcano indicate a possible eruption. Sudden earthquake activity could be caused by magma moving upward through the rock around the volcano.

The End On “Io” a moon of Jupiter