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Last Frontier Historical Topographic Maps


Last Frontier Historical Topographic Maps

More than 8,000 historical topographic quadrangles, some over a century-old, covering all of Alaska are released for free download.

The U.S. Geological Survey announces it is now possible to see the topography and geography of Alaska in an extensive set of topographic maps dating back to 1899. This recent addition to the Historical Topographic Map Collection provides a comprehensive landscape repository of our northernmost State and shows changes through time, providing essential clues critical in the understanding our Nation’s development.

“No other State so captures the American spirit of adventure and love for the wild than Alaska, and thus it is important to preserve its history in this important map collection,” said USGS Director Marcia McNutt. “And as climate change continues to alter the Alaska landscape, these historic records will only grow in value to science.”

Approximately 500 maps were published in various portions of Alaska prior to 1950. In preparation for statehood in January, 1959, an intensive mapping program compiled and published more than 7,500 topographic maps. These recent era maps are mostly at 1:63,360 scale (one inch equals a mile) and provide a detailed view of Alaska topography, physiography and culture. The collection of historical topographic maps will provide valuable support to the developing Alaska Mapping Initiative, a multi-agency effort to remap the State of Alaska at 1:25,000 scale.

Historical maps are an important national resource as they provide the long-term record and documentation of the natural, physical and cultural landscape. The history documented by this collection and the analysis of distribution and spatial patterns is invaluable throughout the sciences and non-science disciplines. Genealogists, historians, anthropologists, archeologists and others use this collection for research as well as for a framework on which a myriad of information can be presented in relation to the landscape.

For more than 130 years, the USGS topographic mapping program has accurately portrayed the complex geography of our nation through maps using the lithographic printing process. The Collection contains high resolution scanned images from the USGS legacy series and other sources.

Historical maps are available to the public at no cost in GeoPDF format or as a printed copy for plus a handling charge from the USGS Store . The electronic maps are georeferenced and can be used in conjunction with the new USGS digital topographic map, the US Topo.

For more information visit the USGS HTMC.

USGS Newsroom


More information

Parameter Value Description
Magnitude mb The magnitude for the event.
Longitude ° East Decimal degrees longitude. Negative values for western longitudes.
Latitude ° North Decimal degrees latitude. Negative values for southern latitudes.
Depth km Depth of the event in kilometers.
Place Textual description of named geographic region near to the event. This may be a city name, or a Flinn-Engdahl Region name.
Time 1970-01-01 00:00:00 Time when the event occurred. UTC/GMT
Updated 1970-01-01 00:00:00 Time when the event was most recently updated. UTC/GMT
Timezone offset Timezone offset from UTC in minutes at the event epicenter.
Felt The total number of felt reports
CDI The maximum reported intensity for the event.
MMI The maximum estimated instrumental intensity for the event.
Alert Level The alert level from the PAGER earthquake impact scale. Green, Yellow, Orange or Red.
Review Status Indicates whether the event has been reviewed by a human.
Tsunami This flag is set to "1" for large events in oceanic regions and "0" otherwise. The existence or value of this flag does not indicate if a tsunami actually did or will exist.
SIG A number describing how significant the event is. Larger numbers indicate a more significant event.
Network The ID of a data contributor. Identifies the network considered to be the preferred source of information for this event.
Sources A comma-separated list of network contributors.
Number of Stations Used The total number of Number of seismic stations which reported P- and S-arrival times for this earthquake.
Horizontal Distance Horizontal distance from the epicenter to the nearest station (in degrees).
Root Mean Square sec The root-mean-square (RMS) travel time residual, in sec, using all weights.
Azimuthal Gap The largest azimuthal gap between azimuthally adjacent stations (in degrees).
Magnitude Type The method or algorithm used to calculate the preferred magnitude for the event.
Event Type Type of seismic event.
Event ID Id of event.
Event Code An identifying code assigned by, and unique from, the corresponding source for the event.
Event IDS A comma-separated list of event ids that are associated to an event.

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