Exam 7: Volcano Processes and Deadly Events

The Pacific Northwest of the United States (Washington and Oregon)has long-term risk for both explosive volcanic eruptions and a moment-magnitude earthquake of around 9.

In Icelandic-type eruptions,low viscosity,low-volatile content lava erupts peacefully.

The energy behind the 1902 pyroclastic flow that destroyed St.Pierre came from _________________.

In 1973 the town of Vestmannaeyjar on the island of Heimaey (off the coast of Iceland),was devastated by pyroclastic flows which completely filled and closed the town's harbor.

Ways of generating pyroclastic flows include ______________.

The two most active Cascade Range volcanoes over the past 4000 years are _______________.

At Lake Nyos in 1986,a gas cloud wiped out all plant and animal life,as well as killed 1700 people.

In the United States,there was great concern in the early 1980s when earthquakes were frequent,including harmonic tremor,and four magnitude 6 earthquakes caused damage near this volcanic center.

Active volcanoes today in Oregon and Washington,including Mt.St.Helens,result from _________________.

During the 1990's,hundreds of trees were killed at Mammoth Mountain,California,by the diffuse emission of _________ gas.

Pyroclastic flows cannot travel down all sides of a volcano simultaneously.

In 1883,Edvard Munch created his famous painting The Scream after witnessing a blood red sky over Oslo,Norway,caused by the eruption of _________.

The plate-tectonic process responsible for volcanoes in the Pacific Northwest region of North America is identical to the cause of the region's great earthquakes-subduction of the Juan de Fuca plate.

At Mt.St.Helens,about 60 people were killed in 1980,primarily by pyroclastic flows and effects related to lateral blast.

Many of the deaths at Mt.St.Helens on May 18,1980 were related to ________________.

On 8 May 1902,a massive eruption of this volcano killed 30,000 people in the town of St.Pierre.The volcano was _______________________.

Several geologic phenomena are being studied as signs of an impending volcanic eruption.These include seismic waves,______________,and the release of gases.

The largest lava dome known is Mt.Lassen,California.

In August 1986,a gigantic volume of gas belched forth from Lake Nyos in Cameroon and swept down the adjacent valleys asphyxiating 1700 people.The gas was _____________.

The eruption of Mt.Pinatubo in 1991 endangered people,animals,and property because of __________________.