Exploring USGS Earthquake Resources
Type your answers in the boxes.
Open the USGS Earthquake map
This site shows all of the earthquakes greater than a magnitude 2.5 that have occurred in
the past 24 hours.
1. Use the Key and the Layers menu in the upper right to explore what the map shows
● What do the different colors mean?
The different colors show the age of the earthquake
● How are different size earthquakes symbolized?
The size of the circle
● What are the red lines on the map?
Fault lines
2. How many earthquakes of magnitude >2.5 occurred globally in the past 24 hours?
28
3. Find the closest earthquake to you that occurred within the past day.
M 2.6 - 16 km S of Tres Pinos, CA
What was the magnitude of this quake?
2.6
What was the intensity of this quake?
4
Zoom out to view the entire globe
4. Where did the largest earthquake occur worldwide in the past 24 hours?
M 5.8 - 61 km S of Labuha, Indonesia
What was the magnitude of this quake?
5.8
What was the intensity of this quake?
3
Visit: How Close to a Fault do you Live?
5. Click on the layers to turn-off M2.5 Earthquakes so that you are able to see the red
lines that represent fault lines. Find the fault zone nearest your home location and scroll
the mouse over the faults to get its name. What is the fault zone called:
Monterey Bay- Tularcitos fault zone
6. Turn the earthquake layer back on. Find the LARGEST earthquake to have occurred
on or near that fault zone. How big was this quake and when did it occur?
M2.6, August 13th 1987
7. Often the closest fault lines are not the ones that pose the most risk. Here in
California, the San Andreas fault line poses one of the biggest hazards. Find the San
Andreas fault on the map.
What is the largest quake to have occurred on the section of the San Andreas fault
closest to where you live? How big was this quake and when did it occur?
M5.4 September 14th 1963
Visit: What’s your earthquake risk? (Original map with extra background
information posted here: USGS National Seismic Hazards Map)
8. Search for your hometown. What is the earthquake Hazard Level where you live?
Highest
9. Are there any high earthquake hazard zones that do not fall along a tectonic plate
boundary? Where are they located?
Border of Missouri, Arkansa, Kentucky, and Tennessee
Visit “Did You Feel It?” Scientific Background
10. What is DYFI?
Did You Feel It
11. Describe the difference between earthquake magnitude and intensity.
Earthquake magnitude measures the energy released at the earthquake's source.
While intensity describes the effects and shaking experienced in different locations.
Magnitude is a fixed measure of strength, while intensity varies by location and
damage.
12. What are some factors other than earthquake magnitude that could impact the
intensity of the shaking from an earthquake at a given location?
The distance from the epicenter, local geological conditions, and the type of soil or
rock in the area. Building structures and their designs can affect how much shaking is
felt, with poorly constructed buildings experiencing more damage than better built
ones.
Visit Did You Feel It? Annual Data View This map shows the highest intensity
shaking that occurred within each 10x10 km square block over the past 20 years.
The colors refer to the amount of shaking measured by the Modified Mercalli
Intensity scale.
13. Zoom into your area. What was the maximum amount of shaking your region
experienced from an earthquake over the last 20 years?
4.5
Visit the Felt Report - This links to a survey that you can fill out after you
experience an earthquake. These data are then incorporated into the intensity
ratings and plotted on “Did you feel it?” intensity maps.
14. Scroll through the survey questions. Are there any questions you find surprising or
interesting? Copy and paste one question from the survey here that you find
particularly intriguing:
“How did you respond?”
Be sure to visit the DYFI site and fill out the survey if you ever experience an
earthquake!
Visit the USGS Site: What can I do to be prepared for an earthquake?
15. List one thing you have personally done to prepare for a future earthquake.
School drills
List one thing you now plan to do to prepare for a future earthquake.
Not be in a building
