USGS Frequently Asked Questions - Frequently Asked Questions

Why does my drinking water look cloudy sometimes?

Sunday, July 25, 2010

Once in a while you get a glass of water, and it looks cloudy; maybe milky is a better term. After a few seconds it miraculously clears up! The cloudiness is due to tiny air bubbles in the water. Like any bubbles, the air rises to the top of the water and goes into the air, clearing up the water. The water in the pipes coming into your house might be under a bit of pressure, and gases (the air), which are dissolved in the pressurized water, will come out as the water flows into your glass, where is under normal atmospheric pressure.

What is the difference between consolidated and unconsolidated sediments?

Monday, February 11, 2013

"Consolidated sediments" is essentially solid rock made from materials that have been metamorphosed or cemented together. For example, limestone is made of oceanic deposits of billions of shells; likewise, sandstone is made of tiny grains of sand. Ground water flows through fracture networks and/or pore space in these consolidated sediments. Consolidated sediments are sedimentary rocks, including conglomerate, sandstone, siltstone, shale, limestone, and coal. Geologic processes over time can fold, break, erode, and change (metamorphose) sedimentary rocks.
Unconsolidated sediments are loose materials, ranging from clay to sand to gravel. Ground water flows through spaces between the grains. Geologic processes can likewise erode and metamorphose unconsolidated sediments. Earthquakes, for example, can liquefy unconsolidated sediments (but not consolidated sediments).

How often do giant debris flows occur at Mount Rainier?

Thursday, April 11, 2013

During the past 10,000 years, about 60 giant debris flows from Mount Rainier have filled river valleys to a depth of hundreds of feet near the volcano, and have buried the land surface under many feet of mud and rock sixty miles downstream. Seven debris flows large enough to reach Puget Sound have occurred in the past 6,000 years.
Driedger, C.L., and Scott, W.E., 2008, Living with a volcano in your back yard -- volcanic hazards at Mount Rainier: U.S. Geological Survey Fact Sheet 2008-3062, 4 p.

Why do salmon come back to the same stream?

Friday, July 20, 2012

Salmon come back to the same stream they were 'born' in because they 'know' it is a good place to spawn and they won't waste time looking for another stream with good habitat and other fish to spawn with.

Can I eat Asian carp?

Wednesday, June 06, 2012

Asian carp of all types have white, firm, mild flesh, which is excellent table fare, but all Asian carp also have intramuscular bones in the filets that many people find undesirable. Asian carp feed low on the food web, are fast growing, are low in fat in the filets, and are not usually bottom feeders — all properties of fish that are lower in contaminants. Like any fish taken from inland waters, however, be aware of restrictions on consuming fish from any particular water way. For instructions on how to deal with the bones in Asian carp filets, see Flying Fish, Great Dish.

What are we doing about acid rain?

Wednesday, August 04, 2010

Scientists from many disciplines are studying acid precipitation and its impact. The National Acid Precipitation Assessment Program, a Federal program involving representatives from more than a dozen Federal agencies, has sponsored studies on how acid rain forms and how it affects lakes, crops, forests, and materials.

Because buildings and monuments cannot adapt to changes in the environment, as plants and animals can, historic structures may be particularly affected by acid precipitation. Scientists are studying effective control technologies to limit the emissions from power plants and automobiles that cause acid rain. The impact and usefulness of regulations that would require limits on air pollution are also being studied. Finally, scientists are examining the processes of deterioration to find effective ways to protect and repair our historic buildings and monuments.

Agencies like the National Park Service, which are charged with protecting and preserving our national heritage, are particularly concerned not only about the impact of acid rain but also about making the best choices for maintaining and preserving our historic buildings and monuments.

Why don't you have the earthquake I felt?

Friday, October 05, 2012

If the earthquake just happened a few minutes ago, you may have arrived at the Web page before our system has finished locating the earthquake and updating the Web pages. If this is so, please fill out an unknown event questionnaire and check back in a few minutes to see if your event is now in place.If the earthquake you felt occurred several years ago, chances are that it will not be in the database. DYFI was put online mainly as an information tool for current earthquakes and future damaging earthquakes. Some larger, historic events were added to the database as a calibration of the system, but some historic and past earthquakes are not on the list. Be sure to thoroughly check the archives.It may also be that you felt an earthquake just below the magnitude cutoff for an automatic triggering. Generally, new maps are automatically made for earthquakes for magnitude 3.8 and greater (2.8 in certain urban areas). However, if you felt a smaller earthquake that is not on our site, please send in an "unknown report." We review and associate the unknown reports regularly and will post maps if we receive reports on smaller earthquakes.There is also the possibility that what you felt was not an earthquake. It is not uncommon for users to fill in unknown reports for sonic booms, trucks, explosions, mine blasts, and other events, thinking they were earthquakes.

How will printed copies of the maps be made available to the public?

Friday, February 22, 2013

Printed copies can be ordered at the store.usgs.gov or by calling 1-888-275-8747 (1-888-ASK-USGS) option 1. Maps are $15.00. Major credit cards are accepted and a $5 handling fee is applied to all orders.

Why was the PDF file format selected for US Topo maps?

Thursday, July 26, 2012

US Topo is intended to serve map users who are not GIS specialists. The priority design objectives were to create a traditional topographic map, in a digital format that can be displayed on any normal office computer without specialized software, and printed at map scale without specialized software or expertise. We believe PDF is the only format in common use that satisfies these requirements. The geospatial extensions add limited GIS functionality "for free" – users who are not interested in georeferencing can still use the product as a plain PDF. Further information about GeoPDF is available at http://en.wikipedia.org/wiki/Geopdf GeoPDF and at http://www.terragotech.com/.

Are aerial photography products available to the public?

Friday, July 27, 2012

The public may download digital aerial photography products at no cost from the Earth Resources Observation and Science Center (EROS). For those who specifically need paper or film products, there is a list of USGS Business Partners who provide aerial photographic research and image printing services. Photographic reproduction of images from the USGS film archives ceased on September 3, 2004, but for online help to search and order USGS printed film products, please visit Search Assistance-Products. Available coverage areas and photographic acquisition types (e.g., black and white, natural color, color infrared) vary by project depending upon the collection criteria.
Other digital aerial photography products can be searched and downloaded at no cost through EarthExplorer or GloVis.
Learn more:
Maps, Imagery, and Publications
National Aerial Photography Program
National High Altitude Photography Program
EROS (Find Data)
LandsatLook Viewer
Earth Observing-1 (EO-1)