Epicentral distance

High school (ages 12+)
Environment & Earth

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/epicentral-distance

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the symbol for epicentral distance?Δ (delta)
2. What is the primary measurement units?Kilometers (km) for near earthquakes and degrees (°) for distant earthquakes
3. Why does the shaking feel stronger when the epicentral distance is smaller?When the epicentral distance is small, the seismic waves have less distance to travel, so they keep more energy and make the ground shake harder. At larger distances the waves lose energy and the shaking is gentler.
4. How do scientists measure epicentral distance?Scientists use seismometers that record the waves and calculate how far the waves have traveled. By comparing the arrival times of different waves, they can find the epicentral distance.

Hypocenter: The three-dimensional point within the Earth where an earthquake rupture originates.
Seismic Attenuation: The gradual loss of seismic wave energy as they travel through the Earth's interior.
Teleseismic Event: An earthquake recorded by seismometers located at large distances, typically greater than 1000 kilometers.
Moment Magnitude Scale (Mw): A modern scale that measures the total energy released by an earthquake based on seismic moment.