Sunday 27 March 2011

World Map of Fault Lines

Fault lines are the lines that mark a boundary between two tectonic plates of the Earth's crust. Earthquakes usually take places along these fault lines, as two plates move in different directions and built up pressure is released as the plates slip suddenly.

Why do tectonic plates move like that? Well, the plates are part of the Earth's crust, which sits on top of the Earth's mantle which is semi-molten. Since the mantle is not as hard as the crust, the crust "floats" so to speak, or slips/slides.

One fault line well known to North Americans is the San Andreas fault, which runs up the westcoast of the USA and was the location of the San Francisco earthquake.

Below you can find a world map of fault lines that may help you with your reference.

Faults of Southern California

Faults of Southern California

Below is a map of southern California, with five regions highlighted:
1. Southern Coast Ranges and Central Valley area is orange.
2. Sierra Nevada and Basin and Range area is green.
3. Mojave region is yellow.
4. Extreme southern end of California is red.
5. Los Angeles area is blue-violet.

This map is clickable. Clicking on a region will take you to an enlarged relief map of the area, with local faults highlighted in a variety of colors, and linked to pages detailing information about these faults. In all of the maps, that segment of the San Andreas fault which is visible will be red, and scales for distances and elevations will be given. A few city and highway labels will also appear on the smaller maps.

Select a region
These maps were created using public-domain fault data which was modified by hand to more accurately reflect our current understanding of California's fault system. The 1994 Fault Activity Map of California and Adjacent Areas by Charles W. Jennings (available from the California Geological Survey ) was used as a guide. These maps should not be considered as zoning guides, nor be used for risk assessment. Because of the sheer number of faults in southern California, this is not an exhaustive collection. The faults featured within this section were chosen typically because they are larger and/or exhibit more recent offset than others. Most, if not all, of this material has a certain level of uncertainty to it. Our understanding of faults is constantly expanding, and new faults and better data may be added to these maps as our knowledge about these structures advances.
Note: Some browsers may distort the color palette of these images. If the elevation scale seems "odd" or "wrong", you may be experiencing this problem. Also, to use these imagemaps your browser must be compatible with client-side imagemaps. Comments are welcome.




RELATED INFORMATION

Alphabetical Fault Index
Historic Earthquakes in Southern California
Research Tools

U.S. Fault Lines GRAPHIC: Earthquake Hazard MAP

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Some may be curious of the U.S. fault lines with earthquakes in the news lately.
The fact is most states are at risk of major earthquakes, with 39 of the 50 states in moderate to high risk areas for seismic activity, ABC News reports.
This map courtesy of the U.S. Geological Survey (USGS) shows the major earthquake hazard areas within the United States based on fault lines:

Latest Earthquakes

USA (Magnitude 1+)

March 28, 2011 02:28:33 UTC
California Nevada Map U.S. Map Alaska Map Hawaii Map Puerto Rico Map

World (Magnitude 4.5+)

March 28, 2011 02:13:55 UTC
World Map

Regional Offices

Our scientists study earthquakes around the world. Learn about research conducted in our regional offices, regional seismic network monitoring, and local activities of interest.

Additional Resources

California-Nevada Fault Map centered

Earthquake map centered at 36°N,121°W Advanced National Seismic System Homepage M=1.8 2011/03/27 18:51:23 M=2.2 2011/03/27 14:45:33 M=1.3 2011/03/27 04:34:48 M=1.1 2011/03/26 23:51:36 M=2.5 2011/03/26 18:46:20 M=1.7 2011/03/26 08:24:17 M=1.4 2011/03/26 05:29:55 M=2.4 2011/03/26 04:25:39 M=1.7 2011/03/25 18:21:25 M=3.0 2011/03/25 18:08:17 M=2.7 2011/03/25 16:55:10 M=1.4 2011/03/24 18:11:35 M=2.5 2011/03/24 15:51:38 M=1.4 2011/03/24 06:44:25 M=2.2 2011/03/24 06:35:47 M=1.2 2011/03/24 01:07:29 M=2.8 2011/03/23 22:44:32 M=1.1 2011/03/23 07:40:25 M=1.4 2011/03/23 02:15:27 M=1.7 2011/03/23 02:13:54 M=1.1 2011/03/22 21:41:55 M=1.5 2011/03/22 21:04:31 M=1.8 2011/03/22 21:03:44 M=1.2 2011/03/22 19:02:55 M=2.1 2011/03/22 17:00:26 M=1.2 2011/03/22 15:29:55 M=1.3 2011/03/22 11:14:13 M=1.2 2011/03/22 07:45:31 M=1.2 2011/03/22 06:15:26 M=1.0 2011/03/21 21:22:38 M=2.0 2011/03/21 16:22:57 M=1.0 2011/03/21 12:06:33 M=1.3 2011/03/21 12:02:53 M=1.2 2011/03/21 06:46:07 M=1.4 2011/03/21 06:40:40 M=1.8 2011/03/20 22:46:48 Calaveras fault Cambria fault Hosgri fault zone Los Osos fault zone Monterey Bay fault zone O\'Neil fault system Oceanic-west Huasna fault zone Ortigalita fault Paicines fault Quien Sabe fault Reliz fault Rinconada fault San Andreas fault zone San Gregorio fault San Joaquin fault San Simeon fault Santa Maria River fault system Sargent fault Vergeles fault map centered at 37° N, 122° W map centered at 37° N, 121° W map centered at 37° N, 120° W map centered at 36° N, 122° W map centered at 36° N, 120° W map centered at 35° N, 122° W map centered at 35° N, 121° W map centered at 35° N, 120° W

Instructions

Tips

  • Red lines are known faults (orange lines are unnamed faults).
  • Thin grey lines are roads.
  • Magnitude = ? for new earthquakes until a magnitude is determined (takes 4-5 minutes).
  • Earthquakes can appear near a fault without having occurred on that fault. To associate an earthquake with a fault requires viewing both of them in three-dimensions.
  • Maps show events recorded in the past 7 days.
  • Maps are updated whenever a new earthquake has been located. Try to reload this page if you do not have the most current map.