Remembering 9/11
Sunday marks the 10th anniversary of the terrorist attacks in New York City, Washington, DC, and Shanksville, PA. This is a time to reflect, to honor those who lost their lives, and to stand with their families and loved ones.Please observe a moment of silence on September 11 at 8:46 a.m.…
What is the Earth's "water cycle?"
The water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. For a summary go to water cycle . Learn more at http://ga.water.usgs.gov/edu/watercycle.html .
What do I need to know to get my GPS into correct operation?
We generally emphasize the following four points: a) Select a coordinate system (also called a "position format") you feel comforatble using. We suggest using Universal Transverse Mercator (UTM) or latitude/longitude. Most users find UTM coordinates easier to locate on USGS…
What is the relationship between faults and earthquakes? What happens to a fault when an earthquake occurs?
Earthquakes occur on faults - strike-slip earthquakes occur on strike-slip faults , normal earthquakes occur on normal faults , and thrust earthquakes occur on thrust or reverse faults. When an earthquake occurs on one of these faults, the rock on one side of the fault slips with respect to the…
What is an earthquake and what causes them to happen?
An earthquake is caused by a sudden slip on a fault . The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust…
What are the file formats for the National Atlas map layers and data tables?
Most map layers are available in the Shapefile format introduced by Environmental Systems Research Institute (ESRI). Here is a link to technical whitepaper for the Shapefile format . This information is in portable document format (PDF). Reading it requires an Acrobat Reader plug-in for your web…
What was the extent of ash deposition from the largest Yellowstone eruptions?
During the three giant caldera-forming eruptions that occurred between 2.1 million and 640,000 years ago, tiny particles of volcanic debris ( volcanic ash ) covered much of the western half of North America, likely a third of a meter deep several hundred kilometers from Yellowstone and several…
How Hot Is A Volcano?
Lava and Lava Flows The temperature of basalt lava at Kilauea reaches 1,160 degrees Celsius (2,120 degrees Fahrenheit). -- USGS/VHP Website, 1998 The tube system (lava tubes) of episode 53 (Pu'u O'o eruption, Hawaii) carried lava for 10 kilometers (6 miles) from the vent to the sea. So…
What is a P wave? An S wave?
When an earthquake occurs, it releases energy in the form of seismic waves that radiate from the earthquake source in all directions. The different types of energy waves shake the ground in different ways and also travel through the earth at different velocities. The fastest wave, and therefore the…
What is the National Biological Information Infrastructure (NBII)?
The National Biological Information Infrastructure (NBII) is a broad, collaborative program to provide increased access to data and information on the nation's biological resources. The NBII links diverse, high-quality biological databases, information products, and analytical tools maintained…
What categories of water data does the USGS make available to the public?
The USGS provides access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, and Puerto Rico. Online access to this data is organized around the categories listed to the left. The USGS investigates the occurrence, quantity, quality,…
Where have amphibian declines been noted?
Scientists have documented four major 'hot spots' for amphibian declines: western North America, Central America, northeast Australia, and Puerto Rico. Researchers believe that all of these declines--most in seemingly pristine areas--have occurred since around 1980. Other areas of the world…