geology ch.5 hw

Which of the following statements correctly describes a parasitic cone? -A parasitic cone is a small cone on the side or base of a volcano that has formed as a result of the ejection of pyroclastic materials. -A parasitic cone is a small cone within the crater of a volcano that has formed during repeated conduit eruptions. -A parasitic cone is a small cone on the side or base of a volcano; this cone's fissure only emits gases. -A parasitic cone is a small cone on the side or base of a volcano that has formed during repeated flank eruptions. -A parasitic cone is a small cone within the caldera of a volcano that has formed during repeated conduit eruptions.

A parasitic cone is a small cone on the side or base of a volcano that has formed during repeated flank eruptions.

How are island arc and continental arc magmas similar? Both are formed near transform boundaries. Both are formed near subduction zones. Both are formed near spreading centers. Both are formed near hot spots.

Both are formed near subduction zones.

How are continental rift magmas and continental arc magmas different? -Continental arc magmas are less dangerous than continental rift magmas. -Continental arc magmas are less viscous than continental rift magmas. -Continental arc magmas are more viscous than continental rift magmas. -Continental arc magmas are more dangerous than continental rift magmas.

Continental arc magmas are more viscous than continental rift magmas.

Which of the following is an example of modern-day mantle plume volcanism? East African rift Hawaiian Islands Aleutian Islands Mariana Islands

Hawaiian Islands

Which statement describes the composition and viscosity of the lava associated with shield volcanoes? Lava from shield volcanoes is mafic and has a high viscosity. Lava from shield volcanoes is mafic and has a low viscosity. Lava from shield volcanoes is felsic and has a low viscosity. Lava from shield volcanoes is intermediate and has a very low viscosity. Lava from shield volcanoes is felsic and has a high viscosity.

Lava from shield volcanoes is mafic and has a low viscosity.

Contrast pahoehoe and aa lava flows. -Aa flows exhibit smooth surfaces, are hotter, and are more fluid than pahoehoe flows, which exhibit jagged surfaces with sharp edges. -Pahoehoe flows exhibit smooth surfaces, are hotter, and are less fluid than aa flows, which exhibit jagged surfaces with sharp edges. -Pahoehoe flows exhibit smooth surfaces, are hotter, and are more fluid than aa flows, which exhibit jagged surfaces with sharp edges. -Pahoehoe flows exhibit jagged surfaces with sharp edges, are hotter, and are more fluid than aa flows, which smooth surfaces. -Pahoehoe flows exhibit smooth surfaces, are cooler, and are less fluid than aa flows, which exhibit jagged surfaces with sharp edges.

Pahoehoe flows exhibit smooth surfaces, are hotter, and are more fluid than aa flows, which exhibit jagged surfaces with sharp edges.

How is magma generated along convergent plate boundaries? -Friction from the subducting slab raises the temperature of the rock under which it subducts, melting this rock into magma. -The subducting slab pushes mantle rock upwards, which decompresses as it rises. This decompression allows the mantle rock to melt. -The subducting slab drives water and carbon dioxide into the mantle, which reduces the temperature at which it melts, allowing mantle rock to melt and rise. -The collision of two continental slabs create enough heat to melt rock, thus producing magma. -The subducting slab pushes mantle rock upwards, where it reaches the surface through the trench.

The subducting slab drives water and carbon dioxide into the mantle, which reduces the temperature at which it melts, allowing mantle rock to melt and rise.

Why are volcanic rocks often exposed at Earth's surface as hills, ridges, and mountains surrounded by areas of lower elevation? Volcanic rocks are often older than surrounding rock. Volcanic rocks are often more susceptible to erosion than surrounding rock. Volcanic rocks are often more resistant to erosion than surrounding rock. Volcanic rocks are often younger than surrounding rock.

Volcanic rocks are often more resistant to erosion than surrounding rock.

What is a mantle plume? an island arc volcano that sits below the surface of the ocean a circular column of rock that rises from close to Earth's surface a circular column of magma that rises from deep within Earth an island arc volcano that stands high above Earth's surface

a circular column of magma that rises from deep within Earth

What is a lahar? lavas of an intermediate composition a mudflow resulting from volcanic debris saturated with lava a mudflow of volcanic debris saturated with water a settling of ash and cinders after they have been ejected into the atmosphere

a mudflow of volcanic debris saturated with water

Which of the following often forms after continental rifting? a new ocean basin a subduction zone a new continent a new mountain a transform boundary

a new ocean basin

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 -temperature of the magma -how fast the lava cools -the slope of the volcanic cone -the depth of the magma chamber

amount of gas in the magma

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

basaltic

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

basaltic

What is a magma chamber called after the conduit has solidified and been exposed by erosion? batholith dike sill volcanic neck volcanic conduit

batholith

When contrasting lava from composite volcanoes to lava from shield volcanoes, -composite volcanoes most often produce silica-rich lavas with high viscosities, whereas shield volcanoes produce basaltic lavas with low viscosities. -composite volcanoes most often produce basaltic lavas with low viscosities, whereas shield volcanoes produce silica-rich lavas with high viscosities. -composite volcanoes most often produce basaltic lavas with high viscosities, whereas shield volcanoes produce silica-rich lavas with low viscosities. -both types of volcano produce silica-rich lavas, but the lavas of composite cones have low viscosities, whereas the lavas of shield volcanoes have high viscosities. -composite volcanoes most often produce silica-rich lavas with low viscosities, whereas shield volcanoes produce basaltic lavas with high viscosities.

composite volcanoes most often produce silica-rich lavas with high viscosities, whereas shield volcanoes produce basaltic lavas with low viscosities.

Which of the following are common tectonic settings associated with volcanic activity? continental rifts mantle plumes transform plumes continental arcs island arcs

continental rifts mantle plumes continental arcs island arcs

Most magma on Earth is produced at ___ plate boundaries. oceanic-oceanic convergent transform continental-oceanic convergent divergent continental-continental convergent

divergent

The volcanoes in the Ring of Fire are generally described as -having violent eruptions, as most of these volcanoes are shield volcanoes which eject basaltic lava. -having violent eruptions, as most of these volcanoes are composite cones which eject basaltic lava. -having quiescent eruptions, as most of these volcanoes are shield volcanoes which eject basaltic lava. -having quiescent eruptions, as most of these volcanoes are composite cones which eject andesitic lava. -having violent eruptions, as most of these volcanoes are composite cones which eject andesitic lava.

having violent eruptions, as most of these volcanoes are composite cones which eject andesitic lava.

What lies underneath volcanic features at Earth's surface? volcanic conduits and mantle chambers magma conduits and volcanic chambers magma chambers and volcanic conduits mantle conduits and volcanic chambers

magma chambers and volcanic conduits

Where are continental volcanic arcs found? on the downgoing plate near a mid-ocean ridge on the overriding plate near a mid-ocean ridge on the overriding plate near a subduction zone on the downgoing plate near a subduction zone

on the overriding plate near a subduction zone

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

rhyolitic

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

rhyolitic

Which of the following types of magma has the highest viscosity? basaltic rhyolitic andesitic

rhyolitic

What region of the world has the greatest concentration of composite volcanoes? the volcanic field near Flagstaff, Arizona Ring of Fire Italy the Hawaiian Islands Japan

ring of fire

What is a volcanic conduit called after the conduit has solidified and been exposed by erosion? hot spot volcano volcanic conduit volcanic neck

volcanic neck

Which of the following gases is most abundant in basaltic lavas? nitrogen water vapor argon sulfur dioxide carbon dioxide

water vapor