Volcanoes

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How should this data set be cited?

   National Atlas of the United States, 200404, Volcanoes: National Atlas of the United States, Reston, VA.

   Online Links:

   • <http://nationalatlas.gov/atlasftp.html?openChapters=chpgeol#chpgeol>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: 120

   East_Bounding_Coordinate: 7

   North_Bounding_Coordinate: 90

   South_Bounding_Coordinate: 10

3. What does it look like?

4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 2004

   Currentness_Reference: Publication date

5. What is the general form of this data set?

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Point (722)

   2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.01. Longitudes are given to the nearest 0.01. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS1980.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222.
      

7. How does the data set describe geographic features?

   Volcano (described by volcanx020.dbf)

   A vent or opening in the surface of the Earth through which magma erupts; it is also the landform that is constructed by the erupted material. This map layer includes volcanoes thought to be active in the last 10,000 years (Holocene). (Source: National Atlas of the United States)

   Shape

   The representation of the entity in the data. (Source: National Atlas of the United States)

   Value	Definition
   Point	0-dimensional element

   Volcanx020

   Internal feature number. (Source: National Atlas of the United States)

   Range of values
   Minimum:	1
   Maximum:	722

   Number

   The volcano number, based on a system developed by the Catalog of Active Volcanoes of the World (CAVW), in the format ####-##-. The first two numerals identify the region, the next two identify the subregion, and the last two or three (after the hyphen) identify individual volcanoes in that subregion. When there are three final characters and the last character is "=", the number is the same as that found in the CAVW; where the last character is "-", the number is not found in the CAVW because the region was not numbered in the CAVW or has been renumbered for this map layer; where the last character is a number, the volcano is in an area included in the CAVW but the number is a new one that does not appear in the CAVW. See <http://www.volcano.si.edu/world/globallists.cfm?listpage=summdesc#VolcanoNumber> for more information. (Source: Global Volcanism Program, Smithsonian Institution)

   Formal codeset
   Codeset Name:	Catalog of Active Volcanoes of the World (CAVW)
   Codeset Source:	Global Volcanism Program, Smithsonian Institution

   Name

   The name of the volcano. See <http://www.volcano.si.edu/world/globallists.cfm?listpage=summdesc#VolcanoName> for more information. (Source: Global Volcanism Program, Smithsonian Institution)

   There is no predefined set of valid names.

   Location

   The location of the volcano by geographical and (or) political area. (Source: Global Volcanism Program, Smithsonian Institution)

   There is no predefined set of valid locations.

   Status

   The type of evidence used to determine volcanic activity. (Source: Global Volcanism Program, Smithsonian Institution)

   Value	Definition
   Anthropology	Volcanoes with undated but recent activity described in native legends as well as activity dated by buried artifacts.
   Dendrochronology	Volcanoes for which dating of eruptions is based on the study of tree ring growth.
   Fumarolic	Volcanoes for which evidence of activity is based on steam and volcanic gas, or fume, reaching the surface.
   Historical	Volcanoes with eruptions documented during or shortly after observation.
   Holocene	Volcanoes without dated products but that are virtually certain to have been active in postglacial time.
   Holocene?	Volcanoes without dated products but where there is some certainty that they have been active in postglacial time.
   Hot springs	Volcanoes for which evidence of activity is based on a large amount of hot water at the surface.
   Hydrophonic	Volcanoes for which evidence of activity and dating is based on hydrophonic methods that use information recorded under water.
   Pleistocene-Fumarolic	Volcanoes for which evidence of activity is based on postglacial steam and volcanic gas, or fume, reaching the surface.
   Potassium-Argon	Volcanoes for which evidence of activity and dating is based on potassium-argon dating methods.
   Radiocarbon	Volcanoes for which evidence of activity and dating is based on radiocarbon methods.
   Seismicity	Volcanoes for which evidence of activity and dating is based on seismic activity.
   Tephrochronology	Volcanoes for which evidence of activity and dating is based on volcanic ash beds and tuffs.
   Uncertain	Volcanoes with possible Holocene activity, but with questionable documentation.
   Varve Count	Volcanoes for which evidence of activity and dating is based on annual layers of sediment.

   Elev

   The summit elevation in meters above or below sea level. (Source: Global Volcanism Program, Smithsonian Institution)

   Value	Definition
   -9999	The elevation is unknown.

   Range of values
   Minimum:	-6000
   Maximum:	5675

   Type

   The shape and size of the volcano (morphology). (Source: National Atlas of the United States)

   Value	Definition
   Caldera(s)	A large volcanic collapse depression, commonly circular or elliptical when seen from above.
   Cinder cone(s)	A steep-sided volcano formed by the explosive eruption of cinders that form around a vent.
   Complex volcano(es)	A volcano composed of a mixture of landforms. In most cases, they occur because of changes either in eruptive habit or in location of the principal vent area.
   Compound volcano	A volcano composed of a mixture of landforms. In most cases, they occur because of changes either in eruptive habit or in location of the principal vent area.
   Cones	Volcanic cones composed of fragmented material ejected from a volcano.
   Crater rows	An area of congealed lava produced by isolated lava fountains along a fissure (volcanic vent).
   Fissure vent(s)	Linear volcanic vents through which lava erupts, usually without any explosive activity. The vents are usually a few meters wide and may be many kilometers long.
   Fumarole field	Areas where there are cracks in the ground that allow gases to reach the surface.
   Hydrothermal field	An area where water heated by magma or in association with magma reaches the surface.
   Lava dome(s)	A rounded, steep-sided mount that forms when very viscous lava is extruded from a volcanic vent.
   Maar(s)	Shallow, flat-floored craters formed above diatremes (volcanic vents or pipes drilled through rocks by the explosive energy of gas- charged magmas) as a result of a violent expansion of magmatic gas or steam. Maars often fill with water to form a lake.
   Pyroclastic cone(s)	A volcanic cone composed of fragmented material ejected from a volcano.
   Pyroclastic shield	A volcano with long, gentle slopes composed of ejected fragmental material.
   Scoria cones	A steep-sided volcano formed by the explosive eruption of scoria. Scoria is formed when blobs of gas-charged lava are thrown into the air during an eruption and cool in flight, falling as dark volcanic rock containing cavities created by trapped gas bubbles.
   Shield volcano(es)	A volcano that resembles an inverted warrior's shield, with broad, gentle slopes, built by multiple eruptions of fluid basalt lava. Basalt lava tends to build enormous, low-angle cones because it flows across the ground easily and can form lava tubes that enable lava to flow tens of kilometers from an erupting vent with very little cooling.
   Somma volcano(es)	A large volcanic collapse depression that is partially filled by a new central cone.
   Stratovolcano(es)	A steep-sided volcano built by lava flows and tephra deposits. Tephra is solid material of all sizes explosively ejected from a volcano into the atmosphere.
   Stratovolcano ?	A steep-sided volcano possibly built by lava flows and tephra deposits. Tephra is solid material of all sizes explosively ejected from a volcano into the atmosphere.
   Subglacial volcano	A volcanic form produced by eruptions beneath a glacier or beneath the surface of a lake within a glacier.
   Submarine volcano(es)	A volcanic form produced by eruptions in the ocean.
   Submarine volcano ?	A possible volcanic form produced by eruptions in the ocean.
   Tuff cone(s)	A volcanic cone formed by the interaction of basaltic magma and water.
   Tuff rings	Shallow, flat-floored craters formed by the interaction of magma and water.
   Unknown	The volcano morphology is not known.
   Volcanic field	A collection of cinder cones and (or) lava flows.

   Timeframe

   Age of the volcanic eruption (Source: Global Volcanism Program, Smithsonian Institution)

   Value	Definition
   D	Last known eruption B.C. (Holocene)
   D1	Last known eruption in 1964 or later.
   D2	Last known eruption from 1900-1963, inclusive.
   D3	Last known eruption from 1800-1899, inclusive.
   D4	Last known eruption from 1700-1799, inclusive.
   D5	Last known eruption from 1500-1699, inclusive.
   D6	Last known eruption from A.D. 1-1499, inclusive.
   D7	Last known eruption B.C. (Holocene)
   Q	Quaternary eruption(s) with the only known Holocene activity being hydrothermal.
   U	Undated, but probable Holocene eruption.
   ?	Uncertain Holocene eruption.

   Long

   The volcano longitude as a single value, in decimal degrees (NAD83). (Source: National Atlas of the United States)

   Range of values
   Minimum:	-178.794
   Maximum:	179.580

   Lat

   The volcano latitude as a single value, in decimal degrees (NAD83). (Source: National Atlas of the United States)

   Range of values
   Minimum:	10.030
   Maximum:	88.270

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • National Atlas of the United States

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Gita Urban-Mathieux
   National Atlas of the United States
   12201 Sunrise Valley Drive
   Reston, VA 20192
   

   703-648-5175 (voice)
   [email protected]
   

Why was the data set created?

These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:2,000,000-scale data. No responsibility is assumed by the National Atlas of the United States in the use of these data.

How was the data set created?

1. From what previous works were the data drawn?

   VOL (source 1 of 2)

   Global Volcanism Program, Smithsonian Institution, 2002, Volcanoes of the World: Smithsonian Institution, Washington, DC.

   Online Links:

   • <http://www.volcano.si.edu/world/globallists.cfm>

   Type_of_Source_Media: Online

   Source_Contribution: Spatial and attribute information

   SHORE (source 2 of 2)

   National Atlas of the United States, 2002, Shorelines for the National Atlas: National Atlas of the United States, Reston, VA.

   Type_of_Source_Media: Internal file

   Source_Contribution: Geographic extent information

2. How were the data generated, processed, and modified?

   Date: Apr-2004 (process 1 of 1)

   The Excel spreadsheet of Volcanoes of the World (VOL) was downloaded from the Global Volcanism Program Web site and converted to a dBASE IV file. West longitude and south latitude values were converted to negative values. The points that are within the geographic extent of the National Atlas SHORE file were extracted. The file was loaded into ArcView and a shapefile was created.

   Data sources used in this process:

   • VOL
   • SHORE

3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?

2. How accurate are the geographic locations?

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

   This map layer includes all volcanoes thought to be active in the last 10,000 years in the United States, Canada, Iceland, the West Indies, Mexico, Central America, Europe, and eastern Asia.

5. How consistent are the relationships among the observations, including topology?

   No tests for logical consistency were performed on this map layer.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None

Use_Constraints:

None. Acknowledgment of the National Atlas of the United States of America and the Global Volcanism Program, Smithsonian Institution would be appreciated in products derived from these data.

1. Who distributes the data set? (Distributor 1 of 1)
   Earth Science Information Center, U.S. Geological Survey
   507 National Center
   Reston, VA 20192
   

   1-888-ASK-USGS (1-888-275-8747) (voice)
   

   Contact_Instructions:

   In addition to the address above, there are other ESIC offices throughout the country. A full list of these offices is at <http://ask.usgs.gov/esic_index.html>.

2. What's the catalog number I need to order this data set?

3. What legal disclaimers am I supposed to read?

   Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. No responsibility is assumed by the U.S. Geological Survey in the use of these data.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	ESRI Shapefile
     Network links:	<http://nationalatlas.gov/atlasftp.html?openChapters=chpgeol#chpgeol>

     Data format:	SDTS
     Network links:	<http://nationalatlas.gov/atlasftp.html?openChapters=chpgeol#chpgeol>

   • Cost to order the data: There is no charge for the map layer.

Who wrote the metadata?

Dates:

Last modified: 12-Sep-2006

Metadata author:

Gita Urban-Mathieux
National Atlas of the United States
12201 Sunrise Valley Drive
Reston, VA 20192

703-648-5175 (voice)
[email protected]

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)