Geology: Volcanoes, Earth's Interior, and Plate Tectonics

Comprehensive practice flashcards covering the structure of the Earth, plate tectonics, magma and lava properties, mantle plumes, and the four volcano types.

The word "volcano" is derived from __________, the name of a volcanic Italian island north of Sicily.

Vulcano

The island Vulcano is named after Vulcan, the ancient Roman god of __________.

fire

Shown in the figure is a statue of Vulcan created by the Danish and Icelandic sculptor __________.

Albert B. Thorvaldsen

The Yakama Nation of Washington State referred to Mount Saint Helens as __________, meaning "woman".

Si Yett

In Yakama legend, Mount Saint Helens was placed to protect the bridge of the gods on the Columbia River from the two battling brothers __________ and Mount Hood.

Mount Adams

In terms of volcanic status, Mount Adams is considered potentially active, whereas Mount Hood is considered __________.

dormant

Mount Saint Helens continuously erupted from $2004$ to __________, after having caused the most disastrous eruption in US history in $1980$.

$$2008$$

Earth consists of three fundamental layers: the core, the mantle, and the __________.

crust

While the outer core consists of molten rock, the inner core contains solid rock due to __________.

high pressures

The outer core of the Earth primarily consists of molten __________.

$\text{Fe}$ (iron)

Magma consists of liquefied rocks known as the melt, crystallized minerals, solid rocks pulled into the melt, and dissolved __________.

gases

The oldest known depiction of a volcanic eruption is cave art found in the __________ cave in France.

Chauvet-Pont D’Arc

Magma is molten or semi-molten rock located __________ Earth's surface.

beneath

Lava is molten or semi-molten rock located __________ Earth's surface.

on

The temperature of magma typically ranges between $600^\circ\text{C}$ and __________.

$$1300^\circ\text{C}$$

The temperature of lava typically ranges between $700^\circ\text{C}$ and __________.

$$1200^\circ\text{C}$$

The radius of the Earth is approximately __________.

$$6370\text{ km}$$

The diameter of the Earth ($2 \times 6370\text{ km}$) is approximately __________.

$$12740\text{ km}$$

Continental crust typically has a thickness ranging from $10\text{ km}$ to __________.

$$75\text{ km}$$

Oceanic crust typically has a thickness of __________.

$$5 - 7\text{ km}$$

Compared to continental crust, oceanic crust is thinner but __________.

denser

The lithosphere refers to the outermost solid layer of Earth, comprising the crust and the upper portion of the __________.

mantle

The four recognized spheres of Earth are the lithosphere (geosphere), the biosphere, the atmosphere, and the __________.

hydrosphere

Most atmospheric gases are held close to Earth's surface in the lowest region called the __________.

troposphere

The hydrosphere encompasses all __________ on or near Earth's surface.

water

The biosphere includes all __________ on Earth, such as mammals, birds, plants, fungi, and bacteria.

living organisms

Earth's lithosphere is divided into $7$ major tectonic plates and __________ minor tectonic plates.

$$8$$

Tectonic plates float and slide upon the __________, which is a partially molten layer of the mantle.

asthenosphere

Tectonic plates that pull away from one another form a __________ plate boundary.

divergent

Tectonic plates that collide into one another form a __________ plate boundary.

convergent

Tectonic plates that slide horizontally past one another form a __________ plate boundary.

transform

This diagram illustrates a __________ plate boundary where continental plates slide past each other.

Continent-Continent Transform

A long, narrow, raised part of Earth's surface where the sides slope away from a crest is called a __________.

ridge

The interconnected mid-oceanic ridges measure approximately __________ in total length.

$$60,000\text{ km}$$

Approximately __________ of Earth's volcanic activity occurs underwater along mid-oceanic ridges.

$$70\%$$

A __________ zone is created when a denser oceanic tectonic plate sinks beneath a less dense continental plate.

subduction

At subduction zones, the sinking oceanic plate drags tonnes of sediment down, creating magma rich in __________.

silica (silicon dioxide)

Ordinary quartz and sand are composed chemically of silicon dioxide, which has the formula __________.

$$\text{SiO}_2$$

Subduction zone stratovolcano eruptions release large volumes of trapped gases, mainly $\text{H}_2\text{O}$, $\text{CO}_2$, and __________.

$$\text{SO}_2$$

Because sticky, silica-rich lava does not flow away easily, it forms a tall, steep cone-shaped volcano known as a __________.

stratovolcano

Mount Saint Helens, Mount Vesuvius, and __________ in the Philippines are classic examples of stratovolcanoes.

Mayon

Mount Fuji in Japan is categorized as an active __________.

stratovolcano

The famous fault in Western California that represents a transform plate boundary is the __________.

San Andreas Fault

The Hawaiian Islands are volcanic islands located far from any plate boundaries, in the middle of the __________ Plate.

Pacific

A plume is defined as a geological structure spreading out in the shape of a __________.

feather

Mantle plumes consist of extremely hot magma originating deep at the __________ boundary.

core-mantle

The head of a rising mantle plume spreads out like a __________ just below the lithosphere.

mushroom

When magma gradually cools and solidifies beneath the surface without erupting, it forms __________ rock.

igneous

The Hawaiian Islands form a linear trail of volcanoes because the mantle plume remains stationary while the overlying __________ moves.

tectonic plate (lithosphere)

Along the Hawaiian island chain, Kauai is the oldest island, whereas the island of __________ is the youngest.

Hawaii

The future Hawaiian island currently forming underwater southeast of Hawaii is Loihi, now referred to as __________.

Kama’ehuakanaloa

The volcano __________ on the island of Hawaii has been erupting for approximately $30$ years, including an eruption in September $2023$.

Kilauea

Volcanoes like Kilauea erupt less violently because their magma contains far less __________ than subduction zone magma.

silica

From above, shield volcanoes get their name because their broad shape resembles an ancient __________ shield.

Greek

The massive Martian volcano shown in the image is a giant shield volcano known as __________.

Olympus Mons

The property defining a fluid's internal resistance to flow or deformation is called __________.

viscosity

Magma originating from shield volcanoes is __________ viscous than magma originating from stratovolcanoes.

less

Lava from shield volcanoes is rich in magnesium and __________.

iron

The fluid, low-silica lava of shield volcanoes solidifies to form the dense rock shown here, known as __________.

basalt (basaltic rock)

Basaltic rock makes up the majority of the __________ floor.

ocean

A volcanic depression called a __________ forms when the rock collapses into an emptied magma chamber after an eruption.

caldera

The viscous lava of stratovolcanoes commonly solidifies into __________, an igneous rock composed of $52 - 63\%$ silica by weight.

andesite

Small, steep volcanoes typically less than $400\text{ m}$ high made of pyroclastic rock fragments are known as cinder cones or __________ cones.

scoria

The porous, vesicular pyroclastic rock shown in the image that forms during violent cinder cone eruptions is __________.

scoria

In geology, the word "pyroclastic" is derived from Greek roots where "pyro" means fire and "clastic" means __________.

broken

Pyroclastic material fragments measuring less than __________ in diameter are classified as volcanic ash.

$$2\text{ mm}$$

Volcanoes formed by extremely viscous lava that cannot travel far and piles directly around the vent are called volcanic domes or __________.

lava domes

Piton de la Fournaise, Mount Karthala, and Mount Terror are all classified as __________ volcanoes.

shield

Measured from the ocean floor, Hawaii's Mauna Kea reaches over __________ in total height, making it taller than Mount Everest.

$10,203\text{ m}$ ($19,700\text{ ft}$)

The hill shown in the photograph, located in Montreal, is __________, which was formed as the product of a magma hot spot.

Mount Royal