Geol Hmw Ch. 5

In order to cover such large expanses of seafloor, shield volcanoes erupt ________ lava

Basaltic

In which of the following lava types would you expect to see the development of pahoehoe?

Basaltic

Which of the following lavas make up 90% of the total volume of lava on Earth?

Basaltic

Which of the following types of lava will most likely lead to a volcanic eruption of an effusive nature?

Basaltic

What do we call pyroclastic material, ejected during a volcanic eruption, composed of incandescent lava that is greater than 64 millimeters (2.5 inches) in diameter?

Bombs

Which of the following volcanic types typically produces small, steep-sided structures composed of pyroclastic material?

Cinder Cones

Which of the following volcanic forms best describes large, nearly symmetrical structures composed of interbedded lavas and pyroclastic material primarily deposited from a central vent?

Composite Volcanoes

Which of the following is the volcanic feature in which magma rises through before it is released at the surface?

Conduit

Which of the following geologic regions creates volcanic arcs?

Convergent plate boundaries

Most cinder cones have eruptive phases that last for centuries

False

The more silica in magma, the lower the viscosity

False

Lava domes are ______

Felsic

What is the driving force behind pyroclastic flows?

Gravity

what do we call mudflows produced by the melting of snow and glaciers on composite volcanoes?

Lahars

Which of the following volcanic materials flows out of a volcanic vent?

Lava

Basaltic magmas have a _____ viscosity, whereas rhyolitic magmas have a _____ viscosity.

Low; High

At which type of tectonic setting would you expect the development of shield volcanoes?

Mantle PLumes

At which of the following tectonic settings would you expect to find volcanoes producing significant amounts of very fluid, high-temperature lavas?

Mantle plumes

Which of the following objects has a size similar to that of lapilli?

Marble (15mm)

Volcanic ash is best described as which of the following?

Microscopic pieces of rock ejected by a volcano

The Ring of Fire is a narrow zone of composite cone volcanoes rimming the ________ Ocean.

Pacific

________ is pulverized rock, lava fragments, and ash erupted from a volcano

Pyroclastic

In which of the following lava types would you expect to find the greatest percentage of gases?

Rhyolitic

In which of the following types of lavas would you expect to find the greatest production of pyroclastic material?

Rhyolitic

which of the following types of madam has the highest viscosity?

Rhyolitic

Lavas erupting from composite cones are generally ________-rich, making them very viscous.

Silica

Which type of volcanic hazard can decrease global temperatures?

Volcanic Ash

Which of the following gases is most abundant in basaltic lavas?

Water Vapor

Which of the following indicates that a volcanic eruption could be imminent?

a change in the composition of gasses being released

Which of the following is a feature of an aa flow?

aa flows have sharp, jagged edges

In addition to viscosity, which of the following parameters has an influence on whether a volcanic eruption will be effusive or violent?

amount of gas in the magma

Which of the following would decrease the viscosity of magma?

an increase in temperature

At which type of tectonic setting would you expect the development of composite volcanoes?

an oceanic plate subducted beneath a continental plate

What drives melting at divergent boundaries?

decompression melting

What type of boundary is present along the eastern boundary of the North American plate?

divergent oceanic-oceanic

At what tectonic setting is Hawaii located?

oceanic hot spot

A hot spot that occurs in oceanic crust is likely to produce which of the following types of eruptions?

quiet and effusive

At which of the following tectonic settings would you expect to find volcanoes producing the highest volumes of pyroclastic material?

subduction of an oceanic plate under a continental plate

Which of the following tectonic settings does NOT produce volcanism?

transform boundary

The subduction of oceanic crust under continental crust predominantly produces which of the following types of volcanic eruption?

violent and explosive

What type of volcanism characterizes the ring of fire?

volcanism caused by convergent oceanic-oceanic boundaries, volcanism caused by convergent oceanic-continental boundaries