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A compilation of sulphur dioxide and carbon dioxide emission-rate data from Cook Inlet volcanoes (Redoubt, Spurr, Illiamna, and Augustine), Alaska during the period from 1990 to 1994

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?

   Doukas, Michael P. , 1995, A compilation of sulphur dioxide and carbon dioxide emission-rate data from Cook Inlet volcanoes (Redoubt, Spurr, Illiamna, and Augustine), Alaska during the period from 1990 to 1994: U.S. Geological Survey Open-File Report 95-55, U.S. Geological Survey, Anchorage, Alaska.

   Online Links:

   • <http://pubs.usgs.gov/of/1995/of95-055/>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -153.42

   East_Bounding_Coordinate: -152.25

   North_Bounding_Coordinate: 61.30

   South_Bounding_Coordinate: 57.37

3. What does it look like?

   <http://pubs.usgs.gov/of/1995/of95-055/core/meta/gifs/cook_inlet.gif> (GIF)

   Map of the Cook Inlet area, Alaska showing the location of the Cook inlet volcanoes included in this report. Filled triangles = volcanoes of this report; open triangles = location of other nearby volcanoes.

   <http://pubs.usgs.gov/of/1995/of95-055/core/meta/gifs/redoubt.gif> (GIF)

   Graph of average SO2 and CO2 emission rates (metric tonnes per day) from Redoubt Volcano, March 1990 to April 1993. Open boxes = average sulfur dioxide emission rate for a single flight; closed triangles = carbon dioxide emission rate; vertical solid line = onset of 1989 - 1990 eruptions of Redoubt Volcano.

   <http://pubs.usgs.gov/of/1995/of95-055/core/meta/gifs/spurr.gif> (GIF)

   Graph of average SO2 and CO2 emission rates (metric tonnes per day) from Spurr volcano, July 1991 to July 1994. Open boxes = average sulfur dioxide emission rate; closed triangles = carbon dioxide emission rate; vertical solid lines = 1992 eruptions of Spurr Volcano.

   <http://pubs.usgs.gov/of/1995/of95-055/core/meta/gifs/ilithm.gif> (GIF)

   Graph of average SO2 and CO2 emission rates (metric tonnes per day MT/D) from Iliamna volcano, from Ilianma Volcano, March 1990 to April 1993. Open boxes = average sulfur dioxide emission rate; closed triangle = CO2 emission rate.

   <http://pubs.usgs.gov/of/1995/of95-055/core/meta/gifs/augthm.gif> (GIF)

   Graph of average SO2 and CO2 emission rates (metric tonnes per day) from Augustine volcano, March 1990 to July 1994. Open boxes = average sulfur dioxide emission rate; closed triangle = CO2 emission rate.

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

   Beginning_Date: 20-Mar-1990

   Ending_Date: 07-Jul-1994

   Currentness_Reference:

   The time period is defined by the collection dates of the data included in the report.

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

   Geospatial_Data_Presentation_Form: map

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

   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.

7. How does the data set describe geographic features?

   Sulfur dioxide and carbon dioxide emission rates

   Rate of sulfur dioxide and carbon dioxide emitted by a volcano, calculated from the SO2 burden, width of plume, velocity of plume, and compared to background levels of SO2 and CO2. Units are metric tons/day (t/d). (Source: U.S. Geological Survey Open-File Report 95-55.)

   Sulfur dioxide gas

   Airborne sulfur dioxide associated with volcanic activity. (Source: U.S. Geological Survey Open-File Report 95-55.)

   Frequency of measurement: Intermittent measurementsof SO2 began at Augustine, Spurr, Redoubt and Iliamna in 1986 and are ongoing at the time of the report. Intermittent measurements of SO2 began at Mt. Spurr in 1991 and are ongoing at the time of the report. Measurements reported here end July 7, 1994.

   Range of values
   Minimum:	0
   Maximum:	6120
   Units:	metric tons per day
   Resolution:	1

   Carbon dioxide gas

   Airborne carbon dioxide associated with volcanic activity. (Source: U.S. Geological Survey Open-File Report 95-55.)

   Frequency of measurement: Intermittent measurements of CO2 began at Mt. Spurr, Augustine, and Iliamna in March, 1990 and are ongoing at the time of the report. Intermittent measurements of CO2 began at Redoubt in June 1990 and are ongoing at the time of the report. Measurements reported here end July 7, 1994.

   Range of values
   Minimum:	0
   Maximum:	12000
   Units:	metric tons per day
   Resolution:	10

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Michael P. Doukas

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Michael P. Doukas
   Cascades Volcano Observatory
   5400 MacArthur Blvd
   Vancouver, WA 98661
   United States of America
   

   (360) 696-7804 (voice)
   mdoukas@usgs.gov
   

Why was the data set created?

Airborne sulfur dioxide gas sampling of the Cook Inlet volcanoes (Redoubt, Spurr, Iliamna, and Augustine) began in 1986 when several measurements were carried out at Augustine volcano during the eruption of 1986. From March 1990 to October 1994, more than one hundred fixed-wing aircraft flights were made by the USGS in order to measure and characterize gas emissions from the Cook Inlet volcanoes.

How was the data set created?

1. From what previous works were the data drawn?

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

   Date: Ongoing (process 1 of 2)

   Measurement of airborne SO2. A correlation spectrometer (COSPEC) is used to measure SO2 in volcanic plumes. The upward-looking COSPEC is mounted in a fixed- wing aircraft and flown below and at right angles to the plume. The first traverse (or orbit) during a measurement is used to determine the size, location and direction of the volcanic plume. In some cases no SO2 plume is detected by the instrument and a value of zero was reported as the SO2 rate. Typically, three to six traverses are made underneath the plume to determine an average SO2 burden (concentration multiplied by the pathlength) within a cross-section of the plume. Knowing the burden, the plume width and plume velocity (assumed to be the same as ambient wind speed), the emission rate of SO2 is calculated. The resultant value of SO2 is reported after values of more than one standard deviation from the average are removed. All emission rates are reported in metric tons/day (t/d) above the background level upwind of the volcano.

   Date: Not complete (process 2 of 2)

   Measurement of airborne carbon dioxide. Carbon dioxide is measured by an infrared spectrometer (MIRAN) tuned to the 4.26 micrometers CO2 absorption band. Volcanic CO2 is defined as that gas detected within a volcano's plume that is in excess of the concentration of ambient CO2 in the atmosphere. An external sample tube is attached to the fuselage of a twin-engine aircraft to deliver outside air to the gas cell of the MIRAN. The aircraft is then flown at several different but increasing elevations through the plume. These traverses were at right angles to the plume trajectory and define plume area and CO2 concentration in a vertical cross-section of the plume. Plume area, CO2 density at the mean altitude of the plume, and the plume velocity (assumed to be equal to the ambient wind speed), are then used to calculate the CO2 emission rate. During times of low emission rates and low wind speeds, orbits within a kilometer of the vent are required, which gave low results because of slow instrumental response times. Thus, some CO2 measurements reported here are indicated to be minimum values. All emission rates are reported in metric tons/day (t/d) above the background level upwind of the volcano.

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?

   A correlation spectrometer (COSPEC) was used to measure SO2. In some cases no SO2 plume was detected by the instrument and a value of zero was reported as the SO2 rate. Even though SO2 may have been sensed by the operator's nose (more sensitive than the instrument), a rate of zero was still reported. Typically, three to six traverses were made underneath the plume to determine an average SO2 burden (concentration multiplied by the pathlength) within a cross-section of the plume. Knowing the burden, the plume width and plume velocity (assumed to be the same as ambient wind speed), the emission rate of SO2 was calculated. The resultant value of SO2 is reported after values of more than one standard deviation from the average have been removed. All emission rates are reported in metric tons/day (t/d) above the background level upwind of the volcano.
   Carbon dioxide in the Cook Inlet volcanic plumes was measured by an infrared spectrometer (MIRAN) tuned to the 4.26 micrometers CO2 absorption band. Volcanic CO2 is defined as that gas detected within a volcano's plume that is in excess of the concentration of ambient CO2 in the atmosphere. Plume area, CO2 density at the mean altitude of the plume, and the plume velocity (assumed to be equal to the ambient wind speed), were then used to calculate the CO2 emission rate. The resulting calculated CO2 emission rate represents one measurement, not an average of several. During times of low emission rates and low wind speeds, orbits within a kilometer of the vent were required, which gave low results because of slow instrumental response times. Thus, some CO2 measurements reported here are indicated to be minimum values. All emission rates are reported in metric tons/day (t/d) above the background level upwind of the volcano.

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?

   SO2 measurement. In some cases, no SO2 plume was detected by the instrument and a value of zero was reported as the SO2 rate, eventhough SO2 may have been sensed by the operator's nose.

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

   Three to six traverses were made underneath the plume to determine an average SO2 burden. The calculated CO2 emission rate represents one measurement, not an average of several measurements.
   During times of low emission rates and low wind speeds, orbits within a kilometer of the vent were required, which gave low results because of slow instrumental response times. Thus, some CO2 measurements reported here are indicated to be minimum values.

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

1. Who distributes the data set? (Distributor 1 of 2)
   USGS Information Services
   Mail Stop 517
   U.S. Geological Survey
   Box 25286
   Denver Federal Center
   Building 810
   Denver, Colorado 80225-0286
   

   (303) 202-4210 (voice)
   (303) 236-4693 (FAX)
   

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

   U.S. Geological Survey Open-File Report 95-55

3. What legal disclaimers am I supposed to read?

   This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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

     The full data set is published in paper form.

   • Cost to order the data: See <http://mapping.usgs.gov/esic/prices/index.html>

---

1. Who distributes the data set? (Distributor 2 of 2)
   Kevin M. Foley
   Global Climate History Program, U.S. Geological Survey
   Mail Stop 918
   U.S. Geological Survey
   12201 Sunrise Valley Drive
   Reston, Virginia 20192
   

   (703) 648-5285 (voice)
   (703) 648-6560 (FAX)
   kfoley@usgs.gov
   

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

   U.S. Geological Survey Open-File Report 95-55

3. What legal disclaimers am I supposed to read?

   This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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

     Data format:	The information is structured and formatted for retrieval using web browsers. in format TEXT tab-delimited
     Network links:	<http://pubs.usgs.gov/of/1995/of95-055/core/meta/tables/table1.tab> <http://pubs.usgs.gov/of/1995/of95-055/core/meta/tables/table2.tab>

   • Cost to order the data: none

Who wrote the metadata?

Dates:

Last modified: 31-May-1996

Metadata author:

Kevin M. Foley
Mail Stop 918
U.S. Geological Survey
12201 Sunrise Valley Drive
Reston, VA 20192

(703) 648-5285 (voice)
(703) 648-6560 (FAX)
kfoley@usgs.gov

Metadata standard:

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