Landsat 8 Satellite Sees Rim Fire from Space plus 2 more

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Title: USGS Newsroom

Landsat 8 Satellite Sees Rim Fire from Space plus 2 more

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• Landsat 8 Satellite Sees Rim Fire from Space
• Tsunami on the Delaware River? Study of Historical Quake and Early East Coast Seismicity
• Mapping the Final Frontier

Landsat 8 Satellite Sees Rim Fire from Space

Posted: 03 Sep 2013 12:50 PM PDT

Image Feature

Two recent images from the Landsat 8 satellite compare land conditions in the vicinity of Yosemite National Park before and during the Rim Fire. The images, from August 15 before the fire began and from August 31, can be contrasted and downloaded from the USGS Earth Resources Observation and Science (EROS) Center. 

As of September 3, the Rim Fire, currently the fourth-largest wildfire in California history, has burned over 235,841 acres (about 16 times the land area of Manhattan Island) and is 70-percent contained. The Rim Fire started August 17 on lands to the west of Yosemite National Park, but spread quickly into western regions of the park. 

Landsat imagery provides critical vegetation and fuels information that is used to model fire behavior and make tactical decisions. After a fire, scientist and land managers use Landsat imagery to determine the severity of the fire's effect and to monitor the recovery of the land. 

Both images are false-colored to allow identification of critical vegetation and fuels information. In the images fire appears bright red, vegetation is green, smoke is blue, clouds are white, and bare ground is tan-colored.

The USGS supports both the Department of the Interior and U.S. Forest Service wildfire response. Throughout the fire season, USGS regularly uploads images for wildfires from several satellites to the Hazard Data Distribution System. These remotely sensed data are used by wildfire responders to map potential risks to communities and determine immediate post-fire effects. So far in 2013, 2,156 images have been distributed for wildfires. 

The USGS helps staff the Geospatial Multi-Agency Coordination Group (GeoMAC). The GeoMAC viewer is a mapping application that allows fire managers and the public to access online maps of current fire locations and fire perimeters. Currently, for 2013, GeoMAC is maintaining up-to-date perimeter information for 620 wildfires across the United States. 

Landsat is a joint effort of both USGS and NASA. Landsat images are unique in that they provide complete global coverage, they are available for free, and they span more than 41 years of continuous earth observation. 

Learn more

• USGS Southern California Wildfire Risk Scenario Project
• NASA 'Fire Towers' in Space
• USGS Landsat 
• NASA Landsat

Tsunami on the Delaware River? Study of Historical Quake and Early East Coast Seismicity

Posted: 03 Sep 2013 12:00 PM PDT

PASADENA, Calif. — Imagine the Delaware River abruptly rising toward Philadelphia in a tsunami-like wave of water. Scientists now propose that this might not be a hypothetical scenario. A newly published paper concludes that a modest (one-foot) tsunami-like event on the East Coast was generated in the past by a large offshore earthquake. This result may have potential ramifications for emergency management professionals, government officials, businesses and the general public.

Early in the morning of Jan. 8, 1817, earthquake shaking was felt along the Atlantic seaboard as far north as Baltimore, Md., and at least as far south as Charleston, S.C. Later that morning, a keen observer documented an abrupt rise in the tide on the Delaware River near Philadelphia, commenting on the earthquake felt earlier to the south, and remarking that the tidal swell was most likely "the reverberation or concussion of the earth operating on the watery element."

Scientists have previously interpreted this earthquake to have a magnitude around 6 and a location somewhere in the Carolinas or slightly offshore. In a new study, USGS research geophysicist Susan Hough and colleagues reconsider the accounts of shaking and, for the first time, consider in detail the Delaware River account. They show that the combined observations point to a larger magnitude and a location farther offshore than previously believed. In particular, they show that a magnitude-7.4 earthquake located 400-500 miles off South Carolina or Georgia could have generated a tsunami wave large enough to account for the tidal swell on the Delaware. Using new computer-assisted research techniques, they uncover first-hand accounts from newspapers and ships' logs that give a wider perspective on the 1817 event. Notably, the predicted timing of such a tsunami wave from this location matches the documented timing in the eyewitness account.

The USGS monitors earthquakes offshore, and in recent years has undertaken research to better understand shaking and tsunami hazard from offshore earthquakes and landslides. Scientific understanding of faults and geological processes in this part of the Atlantic is limited. Still, it has long been understood that large, infrequent offshore earthquakes may pose a tsunami hazard to the Atlantic coast. In 1978, a magnitude-6 earthquake occurred roughly 240 miles southwest of Bermuda, even farther offshore than the inferred location of the 1817 earthquake. In 1929, the magnitude-7.2 Grand Banks, Newfoundland, earthquake triggered a submarine landslide that generated a large tsunami. Waves 10-13 feet high struck the Newfoundland coast, killing 29 people and leaving 10,000 temporarily homeless. 

The inferred 1817 tsunami was significantly smaller than the Newfoundland disaster. However, the new interpretation by Hough and colleagues highlights the potential earthquake and tsunami hazard along the Atlantic seaboard from the still poorly understood offshore earthquake faults. The new study highlights that there is still work to be done to characterize this hazard in the southeastern United States. 

The study, "Reverberations on the Watery Element: A Significant, Tsunamigenic Historical Earthquake Offshore the Carolina Coast," by Susan E. Hough, Jeffrey Munsey, and Steven N. Ward, is published in the September/October issue of Seismological Research Letters. 

Mapping the Final Frontier

Posted: 03 Sep 2013 11:30 AM PDT

USGS releases more than 400 updated US Topo maps of Alaska

More than 400 new topographic maps are now available for the state of Alaska. The new maps are part of the U.S. Geological Survey Alaska Mapping Initiative, to update foundational data for the state and to replace the existing maps that are about 50 years old.

"These new digital maps of Alaska are elevating our visual record of the surface of the state to 21^st century levels," said Anne Castle, Assistant Secretary of the Interior for Water and Science.  "The associated advances in human safety, navigation, and natural resource management cannot be overestimated. The productive partnership between the State government and the USGS is facilitating acquisition of the necessary data to complete digital mapping of Alaska, which is a critical chapter in the history of our geographical knowledge of the North American continent."

The first 400-plus new US Topo maps for Alaska are now accessible and are the beginning of a multi-year project, ultimately leading to more than 11,000 new maps for the entire state. The goal of the AMI is the production of a complete series of digital topographical maps at a scale of 1:25,000 to replace the 1:63,360-scale maps produced about 50 years ago. The maps will be published in digital PDF format (GeoPDF^©) and are available for free download and manipulation on a computer.

These new maps include several layers, with an option for the user to turn them on or off. Major updated features include:

• Satellite image layers which allows a recent view of the earth's surface.
• Contours and shaded relief layers showing the lay of the land derived from newly acquired 5-meter radar elevation data.
• Surface water features from the USGS National Hydrography Dataset, which are updated by local stewards and USGS.
• Glaciers updated using Randolph Glacier Inventory data.
• Boundaries integrated from multiple sources, including Census and major Federal landholders.
• The Public Land Survey System layer from the Bureau of Land Management.
• Roads from a commercial vendor under a USGS contract.
• Railroads and the Trans-Alaska oil pipeline data from local sources.
• Important buildings including police stations, schools, and hospitals.
• Airports, heliports and seaplane landing strips compiled by USGS from multiple sources.
• Feature names from the USGS-maintained Geographic Names Information System.

To ensure that the maps meet current accuracy specifications and standards, the maps will be made using newly acquired elevation and imagery data from multiple state, federal and commercial sources. The map-making process will be largely automated using software specially adapted by the USGS to create approximately 11,275 digital map quadrangles, covering the entire area of the state.

Mapping in Alaska did not keep pace with records for the rest of the nation as a result of difficult terrain, remote locations, and vast distances. Modern mapping information does not exist over the majority of land in the state. Prior to this effort, topographical maps for much of Alaska were about 50 years out of date and not produced to current standards, which rely largely on high resolution digital imagery and elevation data. As a consequence, essential public services have suffered, among them transportation planning and safety, urban and regional planning, economic development, natural resource management, conservation and scientific research.

This new generation of digital topographic maps will continue the rich and valuable USGS cartographic history, and serve the Nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect quality of life.

For more information and download, go to: http://nationalmap.gov/alaska/

Historically, Alaska has been a proving ground for many developments in modern surveying and mapping. Field surveying and topographical mapping of the Alaskan interior by the USGS began in the 1890s following the discovery of gold in the Yukon. Travel was often by dog sled and pack train, canoe and walrus-skin kayak as shown in this undated photo. (Larger image)	Part of a new US Topo quadrangle map of Fairbanks, Alaska – southwest borough with enhanced elevation contours, surface water, names, transportation, and structures data. (Larger image, 25 MB)