Mapping Earthquakes in Northern California

Table of Contents

  1. Mapping Earthquakes in Northern California
  2. Setting Up Your Workspace
  3. Downloading Data from Natural Earth
  4. Download Data from the Northern California Earthquake Data Center (NCEDC)
  5. Skill Drill: Download Data from the United States Census Bureau
  6. Adding California as a Basemap Layer
  7. Skill Drill: Adding the Humboldt County Boundary as a Basemap Layer
  8. Adding XY Data
  9. Changing the Map Projection of the Data Frame
  10. Representing Earthquake Magnitude Using Graduated Symbols
  11. Changing the Map Size and Position
  12. Creating an Inset Map
  13. Inserting A Map Title
  14. Inserting a Map Legend
  15. Inserting a North Arrow, Scale Bar, and Acknowledgments
  16. Exporting your map as a PDF file

Creating an Inset Map

An inset map shows more detail for a specific region within the main map. In this step, you will generate an inset map that shows more detail for the area around Humboldt County. In a previous activity, you learned how to create multiple data frames. Create a second data frame for the inset map. If you recall, you select Insert from the main menu, then Data Frame. A new blank data frame appears in the Table of Contents. On the map, the new data frame appears near the center.

An image of the new data frame for earthquake map
When you have multiple data frames, you will need to arrange their position on the page. Click to view a larger sized image.

Hold down the shift key and select each layer in the California Earthquakes data frame. Then, right-click and choose Copy. Then, right-click on the new data frame and select Paste Layer(s). A copy of the layers appears in the new data frame.

An image of the paste layers option
You can access contextual menus by right-clicking.

Using what you learned in previous steps, change the name of the new data frame to “Humboldt County Inset.” Change the coordinate system to North America Lambert Conformal Conic.

Note: Though we are using Lambert Conformal Conic for the inset map, there are other map projections that work better for Humboldt County. You will learn about these in a later chapter.

Change size and position properties so that the width to 10 inches and the height to 7 inches. Anchor the new data frame to the lower left corner by setting the X and Y values to zero. Set the background color to blue and give it the same border as the main map.

Zoom in close to Humboldt County. Be sure you can see all of the earthquakes off the coast. On the main map, move California to the right so that there is more space between the main map and the inset. It will give you room later when you want to place a scale bar.

An image of the earthquake map with new inset
Resize your inset map so that it fits over the ocean in the lower left corner. Click to view a larger sized image.

Take a moment to save your map document before moving on to the next step.