Geography Review: Endogenic and Exogenic Forces, Continental Drift, and Earthquakes

Ten practice flashcards covering endogenic/exogenic forces, continental drift, earthquakes, seismic measurement, and related terminology.

What are endogenic forces and what effects do they have on the Earth's crust?

Endogenic forces originate within the Earth and cause horizontal or vertical movements of the crust, leading to land uplift or sinking, formation of mountains and valleys, and sometimes abrupt events like earthquakes and volcanic eruptions, with occasional gradual uplift of mountains by a few centimeters per year.

What are exogenic forces and what role do they play in shaping landforms?

Exogenic forces are external forces acting on the Earth's surface (natural agents of erosion such as running water, wind, glaciers, and tidal waves) that erode or deposit to modify landforms formed by endogenic forces.

What did Alfred Wegener propose in 1912 about Earth's continents?

Continental drift: about 200 million years ago a supercontinent named Pangaea began to break apart, and its pieces moved to form today's continents.

What evidence did Wegener use to support continental drift?

Matching rock formations and similar fossils in Brazil and West Africa, and the way South America and Africa fit together like puzzle pieces.

What causes earthquakes and what are the waves that travel during an earthquake called?

Movements and collisions of tectonic plates cause earthquakes; seismic waves travel through the Earth from the focus to the surface.

Where is the focus (hypocentre) located, and what is the epicenter?

The focus is the point inside the Earth where the earthquake originates; the epicenter is the point on the Earth's surface vertically above the focus.

Where are earthquakes recorded and how is magnitude estimated?

A seismograph records the movement of seismic waves; magnitude is estimated using the Richter scale (present-day instruments calibrate to compute Richter magnitudes).

What magnitude ranges on the Richter scale are described in the notes, and what do they signify?

1.0–1.9 micro; 2.0–2.9 minor; 3.0–3.9; 4.0–4.9; 5.0–5.9; 6.0–6.9 strong; 7.0–7.9 major; 8.0–8.9 devastation; 9.0 and greater great.

Give an example of a gradual endogenic movement mentioned in the notes.

Gradual elevation of a mountain by a few centimeters each year.

How do endogenic and exogenic forces interact to shape the Earth's surface?

Endogenic forces create initial landforms such as mountains and uplift, while exogenic forces erode and deposit materials to modify and refine those landforms.