Overview
ArcData Online allows you to browse a wide variety of geographic data to create maps of your areas of interest. Here you can access near-real-time seismic data to see maps of the latest earthquake locations. Earthquake maps are provided for both the world and the United States. The data is time sensitive and only dates back to the previous month. This means that if major earthquakes have not occurred recently then the students will only be looking at low magnitude quakes.

Goals:
Students should be able to look at the World map and find earthquakes near plate boundaries. Then students should be able to locate and describe earthquakes in the United States and California.

Central Question:
What does the location, depth and strength tell us about the Plate Boundary where you find earthquakes?

Materials for each team:
Access to a Macintosh computer
Web Browser program, such as Netscape Navigator
http://www.esri.com/data/online/earthquake/index.html
Other resources:
Activity sheets
World tectonic map

Setting the stage:
You may want to go through the instructions as a class before splitting into groups of three or four students per computer. Introduce the students to the ESRI earthquake web page, show them how to access the maps of the world and the United States. They also need to know how to zoom in and out, and to scroll to the bottom of the page for detailed information on the earthquakes. Have students look at the depth of earthquake and the magnitude. Explain to students that earthquakes near mid-ocean ridges occur with great frequency, but are low magnitude. These type of earthquakes are associtated with spreading zones. Converging boundaries produce earthquakes of large magnitude that are usually deep beneath the Earth's crust. These earthquakes occur less frequently. Earthquakes along transform boundaries, such as the San Andreas fault, are very shallow, but their magnitudes can vary from small (more common) to large (infrequent).

Exploration/Investigation
Discover the relationships between depth of earthquakes and magnitude. Investigate seismic activity at Plate Boundaries.

Bringing it together:
Class discussion
Have students describe where the most earthquake activity is occurring in the World, and the type of plate boundary.

Where in the United States is the most earthquake activity occurring? On what type of plate boundary is the activity occurring?

Where are earthquakes occurring in California? Are they near large population centers? Should residents of California spend time and money preparing for earthquakes?

The maps you looked at only show earthquakes that have occurred during the last month. If you looked at the maps in another month, will the patterns of earthquakes have changed much?

Which regions of the world can expect large magnitude earthquakes in the next 100 years?

Assessment:
Study Questions:
Find regions on your National Geographic World Map of converging boundaries and diverging boundaries. Look at the ESRI web page and find the following information.
1) What was the depth of the last earthquake to occur? What was the magnitude?

2) Was the earthquake near a population center?

Background:
ESRI Live Earthquake Site
The earthquake data are drawn from several online data sources, including the U.S. Geological Survey National Earthquake Information Service (NEIS) and other Council of the National Seismic System (CNSS) members. If you would like detailed information on earthquake activity and seismology, you can visit the USGS National Earthquake Information Center.
You can zoom in on an area of interest. Look at the different types of margins. Remember that the data is only a month old. If no major earthquakes have occurred recently, then converging boundaries will not appear as active. Converging boundaries produce large magnitude earthquakes deep beneath the Earth's crust. Diverging boundaries, where new crust is being made, produce frequent, low magnitude, shallow earthquakes.

Activity Sheets:
Student Activity sheet can be downloaded and printed from HERE..