Plate Tectonics, Volcanoes, Fold Mountains, and Earthquakes

Fill-in-the-blank review flashcards covering Earth's internal structure, plate tectonics, volcano classification and formation, fold mountains, and earthquake mechanics and case studies.

The __________ crust contains land and is approximately 30 to 70 km thick.

continental

The __________ crust contains ocean and is approximately 5 to 7 km thick.

oceanic

The Earth's outer core is approximately 2,200 km thick and is made of molten __________.

nickel

The Earth's inner core is solid and composed of nickel and __________.

iron

Circular movements of magma in the mantle that cause tectonic plates to move are known as __________.

convection currents

At a __________ plate boundary, two plates are pulled away from each other and move apart.

separating

In a process known as __________, the heavier oceanic plate sinks under the lighter continental plate.

subduction

An example of a sliding or transform plate boundary is the San Andreas Faultline in California, __________.

USA

Millions of years ago, all continents were part of a single supercontinent called __________.

Pangaea

Volcanoes that erupt regularly, such as Mount Etna in Sicily, are categorized as __________.

active

Volcanoes that have not erupted for a long time but might erupt again are called __________.

dormant

Croghan Hill in Co Offaly is an example of an __________ volcano that will not erupt again.

extinct

An underwater mountain range formed by plate tectonics at a divergent boundary is called a __________.

mid-ocean ridge

When two plates collide, rock layers that fold upwards form an __________.

anticline

When rock strata fold downwards during plate collision, they form a __________.

syncline

The __________ folding period occurred over 400 million years ago and formed the Twelve Bens Mountains in Connemara.

Caledonian

The Armorican folding period took place around __________ million years ago and created mountains in Ireland such as the Galtee Mountains.

$$250$$

The Alpine folding period took place 65 to 2.5 million years ago when the Eurasian and __________ plates collided.

African/Indian

A river of mud created when volcanic material mixes with water, snow, or ice is called a __________.

lahar

Iceland is a volcanic island located on the boundary between the North American plate and the __________ plate.

Eurasian

On the labelled volcano diagram, feature number (1) located deep beneath the volcano is the __________.

magma chamber

__________ lava is thick, slow, and cools quickly, forming tall, steep, cone-shaped volcanoes.

Acidic

__________ lava is thin, quick, and cools slowly, forming short, wide, gentle-sloped volcanoes.

Basic

Scientists who study volcanoes using geography, fieldwork, science, and geology are called __________.

vulcanologists

The point beneath the Earth's surface where an earthquake originates is called the __________.

focus

The point on the Earth's surface directly above the focus where shaking is strongest is the __________.

epicentre

A smaller earthquake that follows the main shock of a larger earthquake is called an __________.

aftershock

The term __________ comes from the Japanese word for an ocean wave caused by an underwater earthquake.

tsunami

A sensitive piece of equipment used by seismologists to record earthquake shockwaves is a __________.

seismograph

The __________ scale measures earthquake damage and observed human effects on a scale from 1 to 12.

Mercalli

Developed in 1979, the __________ Magnitude scale measures the amount of movement caused and serves as a global standard.

Moment

In earthquake-proof skyscraper design, __________ shock absorbers are placed at the base to reduce building shaking.

rubber

On 11 March 2011, a magnitude 9.0 earthquake off Japan was caused by the subduction of the Pacific plate under the __________ plate.

North American

The earthquake in Pakistan on 6 October 2021 recorded a magnitude of __________ on the Moment Magnitude scale.

$$5.9$$