Significant Earthquake Instructions:
Under "Significant Events by Name " and "Significant Events by Magnitude " you can toggle sets of placem\ arks which mark the location of significant earthquakes that have occurred roughly within the last 100 years. Click on these placemarks for an info balloon with more detail on the event and links to relevant web pages. Notice that for each set of earthquake markers selected for display, a corresponding list will appear just below the control panel allowing alphabetical traversal of the events within their magnitude range.

Fault Map Instructions:
This map, illustrating the faults of Southern California, is interactive. Clicking on a fault trace (represented by the red lines on the map) will open an information balloon with the fault name, a brief description of the fault's attributes, and links to pages providing in-depth information relevant to that selection.

Grab and drag the map to reposition (pan) the view. By clicking on the map to make it active, you can also pan using the "up", "down", "left" and "right" arrow keys on your keyboard. To reposition the map by 3/4 of its size, try pressing the "Page Up", "Page Down", "Home" and "End" keyboard keys.

To change the zoom level you can either use the "+/-" buttons in the upper-left corner of the map, use your mouse to double-click on the map to zoom to that point or, alternately, use the "+" or "-" buttons on your keyboard while the map is active. The "RESET" button re-initializes the map to its default position and zoom level. This will not close info windows or delete any custom markers you may have placed there (see the "Control Panel" instructions using the link below).

To change the type of map you wish to view, click the overlay icon to choose between "Terrain", "Gray", "Street" or "Satellite".

For reference to seismological/ geological terminology, see the Glossary