chapter 7 volcanoes 1 reading quiz

Which of the following steps taken by residents of Vestmannaeyjar, Iceland, were helpful in stopping and redirecting the lava flow during the 1973 eruption? 1. helpful 2. not helpful ___ movement of harb or to the other side of the island to avoid future disasters ___ trenches dug to redirect lava out of town ___ seawater sprayed on lava flows to cool approaching lava ___ pyroclastic material bulldozed to create barriers and redirect flow

1 2 1 1

Seafloor spreading generates __________ magma. basaltic granitic andesitic rhyolitic felsic

basaltic

True or false? Airline traffic was disrupted for 6 months during the 2010 eruption of Eyajafajallajokull in southern Iceland.

false

True or false? Magma at spreading centers is low-temperature, high-viscosity, and granitic, with easy escape of gases, providing all the factors that promote the peaceful eruption of magma.

false

The vulcanian eruption of Eyajafjallajokull in southern Iceland in 2010 resulted from __________. an increase in subduction glacial meltwater pouring into the magma chamber temperature of the magma increasing an earthquake

glacial meltwater pouring into the magma chamber

Most Icelandic eruptions are __________. peaceful fissure eruptions super-eruptions explosive rhyolitic eruptions plinian eruptions

peaceful fissure eruptions

True or false? In Icelandic-type eruptions, low-viscosity, low-volatile content lava erupts peacefully.

true