Google Earth Exploration of Earthquakes
Part 1: Tectonic Plate Boundaries
Go to http://earthquake.usgs.gov/regional/nca/virtualtour/global.php and click on Tectonic Plate
Boundaries file (a Google Earth KMZ file).
Fill in the table:
Google Earth Plate Boundaries
Plate boundary
Color coding
Plate Movements
1. California is part of which two plates?
2. Which type of plate boundary occurs where these two plates meet?
3. Which type of fault occurs at this type of plate boundary?
4. Which direction does each plate move?
5. Describe what you see off the coast of Washington and Oregon.
Part 2: Bay Area Faults
Go to http://earthquake.usgs.gov/regional/nca/1868virtualtour/bayarea.php and click on Bay Area
Faults (a Google Earth KMZ file).
1. How many faults run through the Bay Area?
2. Which faults are closest to Dublin?
Background: The following is taken from “A Virtual Tour of the 1868 Hayward Earthquake in Google
Earth” http://earthquake.usgs.gov/regional/nca/1868virtualtour/
Why are there earthquakes in the Bay Area? The Bay Area lies on an active plate boundary, one that
separates the North American and Pacific plates. As the two plates grind past each other at a rate of
about 2 in/yr (5 cm/yr), numerous earthquakes of all sizes occur along the boundary. As the Pacific
plate moves north relative to the North American plate, strain is placed on the Bay Area faults.
One of the most damaging earthquakes in California history occurred on October 21, 1868 as a result of
build up of strain on the Hayward Fault. It was a magnitude 6.8 on the Hayward Fault. The plates keep
moving, as they have for 30 million years, which means strain continues to build and future earthquakes
like the 1868 are a certainty. Recent geological studies indicate that the average interval between the
past five large earthquakes on the Hayward Fault is 140 years, meaning that another large quake can
occur at any time.
Part 3: Earthquake Probabilities
Go to http://earthquake.usgs.gov/regional/nca/1868virtualtour/modern.php and click on the Google
Earth KMZ file: Earthquake Probabilities under How Likely is a Damaging Earthquake in the Bay Area?
1. Which faults have a greater than 10% chance of having a 6.7 or larger earthquake in the next 30
years?
Part 4: Earthquake Preparedness
We know:
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the Bay Area straddles two of the largest tectonic plates (North American and Pacific) and those
plates are slowly moving past each other
when faults break, the plates lurch and cause earthquakes
we are at risk for large and damaging earthquakes
there are ways to reduce losses
Go to the USGS Preparedness web page “Putting Down Roots in Earthquake Country” at
http://earthquake.usgs.gov/regional/nca/prepare/ and click “read online” or use the class set of
booklets. Identify the seven steps to earthquake safety.
1.
2.
3.
4.
5.
6.
7.
Homework:
Assign “Home Hazard Survey” or complete a safety inspection for school.