Earthquakes Practice Flashcards

A set of flashcards covering the definition, mechanics, measurement, and statistics of earthquakes based on Geography lecture notes.

What is the definition of an earthquake?

Sudden shake or vibrations from within the earth crust that is felt on the surface of the earth.

Where do shock waves radiate from and to during an earthquake?

They radiate in circles upwards and outwards from the FOCUS to the EPICENTER where the damage is felt.

According to the notes, how far in radius can earthquake damage be felt?

Over $100\,\text{km}$ away.

What causes the shock waves known as earthquakes when tectonic plates move?

Tectonic plates get jammed and the resulting pressure creates shock waves.

What is the alternative term for the FOCUS of an earthquake?

Hypocenter

What does a Richter Scale indicate?

How much energy an earthquake has and how big it is.

According to the Richter Scale readings, what is the interpretation of a reading of $8$?

Destructive

According to the Richter Scale readings, what is the interpretation of a reading of $9$?

Ruinous

According to the Richter Scale readings, what is the interpretation of a reading of $10$?

Disastrous

According to the Richter Scale readings, what is the interpretation of a reading of $11$?

Very Disastrous

According to the Richter Scale readings, what is the interpretation of a reading of $12$?

Catastrophic

What instrument is used to measure the strength of shock waves, and who uses it?

A SEISMOMETER is used by SEISMOLOGISTS.

Besides the Richter Scale, what other scale do experts use to rate earthquakes?

MERCALLI SCALE

What are TSUNAMIS?

Huge waves that occur as a result of undersea earthquakes.

How many earthquakes are detected worldwide each year, and how many cause actual damage?

About $800,000$ are detected, but less than $1,000$ actually cause damage.

Why would a village $150\,\text{km}$ away from an epicenter experience less damage than a town $20\,\text{km}$ away?

Shock waves lose energy as they radiate upwards and outwards.